A101f. Camera User s Manual. Document ID Number: DA Revision Date: May 20, 2002 Subject to Change Without Notice Basler Vision Technologies

Transcription

1 Draft A101f Camera User s Manual Document ID Number: DA Revision Date: May 20, 2002 Subject to Change Without Notice Basler Vision Technologies Basler Support Worldwide: Americas: Europe: Asia: vc.support.usa@baslerweb.com vc.support.europe@baslerweb.com vc.support.asia@baslerweb.com

2 For customers in the U.S.A. This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense. You are cautioned that any changes or modifications not expressly approved in this manual could void your authority to operate this equipment. The shielded interface cable recommended in this manual must be used with this equipment in order to comply with the limits for a computing device pursuant to Subpart J of Part 15 of FCC Rules. For customers in Canada This apparatus complies with the Class A limits for radio noise emissions set out in Radio Interference Regulations. Pour utilisateurs au Canada Cet appareil est conforme aux normes Classe A pour bruits radioélectriques, spécifiées dans le Règlement sur le brouillage radioélectrique. Life Support Applications These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Basler customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Basler for any damages resulting from such improper use or sale. Warranty Note Do not open the housing of the camera. The warranty becomes void if the housing is opened.

3 Table of Contents 1 Introduction 1.1 Camera Models Performance Specifications Environmental Requirements Temperature and Humidity Ventilation Precautions Camera Interface 2.1 Connections eneral Description Pin Assignments Connector Types Video Data and Control Signals Input Signals ExTrig: Controls Exposure Start Output Signals IntEn: Indicates that Exposure is Taking Place TrigRdy: Indicates that Exposure Can Begin Pixel Data IEEE 1394 Device Information Camera Power Status LEDs Operation and Features 3.1 Functional Description Exposure Control Setting the Exposure Time Controlling Exposure Start via the 1394 Interface Controlling Exposure Start with an ExTrig Signal Recommended Methods for Controlling Exposure Start Trigger Ready Signal What Happens if you Toggle ExTrig while TrigRdy is Low Integrate Enabled Signal Version Information ain and Brightness ain settings in more detail Binning Area of Interest (AOI) Changes to the Frame Rate With AOI Test Images BASLER A101f I

4 3.10 Low Smear Color Creation in the A101fc White Balance Using the A101fc in a Monochrome Mode Integrated IR Cut Filter on C-Mount Equipped Cameras Available Video Formats, Modes, & Frame Rates Standard Formats, Modes, and Frame Rates on the A101f Monochrome Camera Customizable Formats and Modes on the A101f Monochrome Camera Standard Formats, Modes, and Frame Rates on the A101fc Color Camera Customizable Formats and Modes on the A101fc Color Camera Configuring the Camera 4.1 Block Read and Write Capabilities Register Write Order Changing the Video Format setting Implemented Registers Advanced Features Advanced Features Access Register Advanced Features Registers Mechanical Considerations 5.1 Camera Dimensions C-Mount Adapter Dimensions F-Mount Adapter Dimensions Positioning Accuracy of the Sensor Chip Maximum Lens Thread Length on A101fc Troubleshooting 6.1 Fault Finding Using Camera LEDs Yellow LED reen LED Revision History i Index iii II BASLER A101f

5 Introduction 1 Introduction The BASLER A101f progressive scan camera is a versatile camera designed for industrial use. Superb image sensing features are combined with a robust, high precision housing. Important features are: Compliant with the 1394 TA Digital Camera Specification (V 1.20) High spatial resolution High sensitivity Anti-blooming Asynchronous full frame shutter via electronic control Square sensor cells High Signal-to-Noise Ratio Area of interest (AOI) scanning Binning mode Correlated double-sampling Industrial housing manufactured with high planar, parallel and angular precision Compact size 1.1 Camera Models The camera is available in a monochrome model (the A101f) and a color model (thea101fc). Throughout the manual, the camera will be called the A101f. Passages that are only valid for a specific model will be so indicated. BASLER A101f 1-1

6 Introduction 1.2 Performance Specifications Specification Sensor Type Pixels Pixel Size A101f Sony ICX085AL/AK - 2/3 inch, HAD, interline transfer, progressive scan CCD 1300 (H) x 1030 (V) 6.7 µm (H) x 6.7 µm (V) Anti-Blooming 1:100 Dark Signal Non-uniformity ± 1 DN Photo Response Non-uniformity ± 5% Max. Frame Rate (at full resolution) Video Output Signal ain and Brightness Exposure Time Control Synchronization Power Requirements 12 frames/sec. Mono: 8 bits per pixel, IEEE 1394 Compliant Color: YUV 4:2:2, 16 bits/pixel average, IEEE 1394 Compliant Programmable via IEEE 1394 bus Programmable via IEEE 1394 bus External via External Trigger signal ExTrig input is opto-isolated, max. 1.4 V, max 50 ma 12 VDC (± 10%), 5.0 W, < 1% ripple supplied via 1394 cable Max. Cable Lengths 1394: 4.5 m I/O: 10 m Shock Vibration Lens Adapter 20 with 50 repetitions in each axis 10 (58-500Hz) for 1 hour in each axis C-mount or F-mount Housing Size (L x W x H) without lens adapter: with C-mount adapter: with F-mount adapter: 48.7 mm x 62 mm x 62 mm 51.2 mm x 62 mm x 62 mm 80.2 mm x 62 mm x 62 mm Weight without lens adapter: ~ 202 g with C-mount adapter: ~ 242 g with F-mount adapter: ~ 310 g Conformity CE, FCC Table 1-1: Performance Specifications 1-2 BASLER A101f

7 Introduction The spectral responsivity for monochrome cameras is shown in Figure 1-1. The graph includes lens characteristics and excludes light source characteristics Wave Length [nm] Figure 1-1: Spectral Responsivity - Monochrome Cameras BASLER A101f 1-3

8 Introduction The spectral responsivity for color cameras is shown in Figure 1-2. The graph includes lens characteristics and excludes light source characteristics B R Wave Length [nm] Figure 1-2: Spectral Responsivity - Color Cameras Cameras equipped with a C-mount lens adapter contain an integrated IR cut filter. On cameras equipped with an F-mount adapter, use of a suitable IR cut filter is recommended to maintain spectral balance and optimum MTF. 1-4 BASLER A101f

9 Introduction 1.3 Environmental Requirements Temperature and Humidity Housing temperature during operation: 0 C + 50 C (+ 32 F +122 F) Humidity during operation: 20% 80%, relative, non-condensing Ventilation Allow sufficient air circulation around the camera to prevent internal heat build-up in your system and to keep the camera housing temperature below 50 C. Provide additional cooling such as fans or heat sinks if necessary.! Warning! Without sufficient cooling, the camera can get hot enough during operation to cause burning when touched. 1.4 Precautions Read the manual Read the manual carefully before using the camera. Keep foreign matter outside of the camera Do not open the casing. Touching internal components may damage them. Be careful not to allow liquid, flammable, or metallic material inside the camera housing. If operated with any foreign matter inside, the camera may fail or cause a fire. Electromagnetic Fields Do not operate the camera in the vicinity of strong electromagnetic fields. Avoid electrostatic charging. Transporting Only transport the camera in its original packaging. Do not discard the packaging. Cleaning Avoid cleaning the surface of the CCD sensor if possible. If you must clean it, use a soft, lint free cloth dampened with a small quantity of pure alcohol. Do not use methylated alcohol. Because electrostatic discharge can damage the CCD sensor, you must use a cloth that will not generate static during cleaning (cotton is a good choice). To clean the surface of the camera housing, use a soft, dry cloth. To remove severe stains, use a soft cloth dampened with a small quantity of neutral detergent, then wipe dry. Do not use volatile solvents such as benzine and thinners; they can damage the surface finish. BASLER A101f 1-5

10 Introduction 1-6 BASLER A101f

11 Camera Interface 2 Camera Interface 2.1 Connections eneral Description The A101f is interfaced to external circuitry via an IEEE 1394 socket and a 9-pin micro-d plug located on the side of the housing. Figure 2-1 shows the location of the two connectors. There are also two status LEDs on the back of the camera. The LEDs indicate signal integrity and power OK (see Section 6.1). reen LED (Power OK) 9 Pin Micro D Plug Yellow LED (Signal Integrity) IEEE 1394 Socket Figure 2-1: Camera Connectors and Indicators BASLER A101f 2-1

12 Camera Interface Pin Assignments The IEEE 1394 socket is used to supply power to the camera and to interface video data and control signals. The pin assignments for the socket are shown in Table 2-1. Pin Signal Pin Signal VDC 4 TPB+ 2 DC nd 5 TPA- 3 TPB- 6 TPA+ Table 2-1: Pin Assignments for the IEEE 1394 Socket The 9-pin micro-d plug is used to interface the external trigger, integrate enabled, and trigger ready signals. The pin assignments for the plug are shown in Table 2-2 Pin Signal Pin Signal 1 External Trigger + 6 External Trigger - 2 Integrate Enabled + 7 Integrate Enabled - 3 Trigger Ready + 8 Trigger Ready - 4 Not Connected 9 Not Connected 5 Not Connected Table 2-2: Pin Assignments for the 9-Pin Micro-D Plug The camera housing is not grounded and is isolated from the circuit boards inside of the camera Figure 2-2: A101f Pin Numbering 2-2 BASLER A101f

13 Camera Interface Connector Types The 6-pin connector on the camera is a standard IEEE-1394 socket. The 9-pin Micro-D plug is Molex Part Number or the equivalent. 2.2 Video Data and Control Signals Input Signals ExTrig: Controls Exposure Start An external trigger (ExTrig) signal can be used to control the start of exposure. ExTrig can be a periodic or a non-periodic function. When the camera is operating under the control of an ExTrig signal, the frequency of the ExTrig signal determines the camera s frame rate. For more detailed information on using the ExTrig signal, see Sections 3.2 and 3.3. As shown in Figure 2-3, the input for the ExSync signal is opto-isolated. The voltage of the LED in the opto-coupler is 1.4 V. The absolute maximum input current for the LED is 50 ma. 1 For the ExSync input, a current of more than 5 ma means a logical one. A current of less than 0.1 ma means a logical zero Output Signals IntEn: Indicates that Exposure is Taking Place The integration enabled (IntEn) signal indicates that exposure is taking place. The IntEn signal will be high during exposure and low when exposure is not taking place. As shown in Figure 2-3. the output for the IntEn signal is opto-isolated. The maximum forward voltage is 35 V, the maximum reverse voltage is 6 V, and the maximum collector current is 100 ma. 1 A conducting transistor means a logical one and a non-conducting transistor means a logical zero TrigRdy: Indicates that Exposure Can Begin When the trigger ready (TrigRdy) signal goes high, it indicates that exposure of the next frame can be triggered. Section 3.3 explains the operation of the trigger ready signal in more detail. As shown in Figure 2-3. the output for the TrigRdy signal is opto-isolated. The maximum forward voltage is 35 V, the maximum reverse voltage is 6 V, and the maximum collector current is 100 ma. 1 A conducting transistor means a logical one and a non-conducting transistor means a logical zero. 1 The opto-isolator used in the camera is a Sharp PC3Q64Q or the equivalent. A detailed spec sheet for this device is available at the Sharp Microelectronics roup ( BASLER A101f 2-3

14 Camera Interface Pixel Data Pixel data are transmitted as isochronous data packets according to version 1.20 of the based Digital Camera Specification issued by the 1394 Trade Association. The first packet of each frame is identified by a 1 in the sync bit of the packet header. The video data for each pixel is output in an 8 bit format. Thus the range of intensity for each pixel includes 256 gray levels. The digital gray value of 0 corresponds to black and the digital gray value of 255 to white IEEE 1394 Device Information The A101f uses an IEEE 1394a compliant physical layer device to transmit pixel data. Detailed spec sheets for devices of this type are available at the Texas Instruments web site ( Camera Housing Shield Shield To 1394a Compliant Physical Layer Controller +12 VDC Input nd TPA+ TPA- TPB+ TPB- V VP IEEE 1394 Socket PC3Q64Q 1 2 PC3Q64Q K 390 Ω 3 BC847 2 ExTrig ExTrig IntEn+ IntEn- TrigRdy+ TrigRdy Pin Plug BC847 PC3Q64Q 2.7 K 2 Figure 2-3: I/O Schematic 2-4 BASLER A101f

15 Camera Interface 2.3 Camera Power Power must be supplied to the camera via the IEEE 1394 cable. The camera requires +12 VDC ± 10%. Maximum power consumption is 5.0 W for the A101f. Ripple must be less than 1%. 2.4 Status LEDs reen LED The green LED on the back of the camera is used to indicate whether power is being supplied to the camera. When the green LED is out, it means that no power is present. When the green LED is lit, it means that power is present. Keep in mind that the circuit used to light the green LED does not perform a range check. If power to the camera is present but it is out of range, the LED may be lit but the camera will not operate properly. Yellow LED The yellow LED indicates signal integrity. In case of an error, blinking signals from the yellow LED indicate that an error condition is present. See Section 6.1 for more information. BASLER A101f 2-5

16 Camera Interface 2-6 BASLER A101f

17 Operation and Features 3 Operation and Features 3.1 Functional Description The A101f area scan camera employs a CCD-sensor chip which provides features such as electronic exposure time control and anti-blooming. Normally, exposure time and charge readout are controlled by values transmitted to the camera s control registers via the IEEE 1394 interface. Command registers are available to set exposure time and frame rate. There are also command registers available to set the camera for single frame capture, multiple frame capture, and continuous frame capture. Exposure start can also be controlled via an externally generated trigger (ExTrig) signal. The ExTrig signal facilitates periodic or non-periodic start of exposure. When exposure start is controlled by an ExTrig signal, exposure begins when the trigger signal goes low and continues for a pre-programmed period of time. Accumulated charges are read out when the programmed exposure time ends. At readout, accumulated charges are transported from the sensor s light-sensitive elements (pixels) to the vertical shift registers (see Figure 3-1). The charges from the bottom line of pixels in the array are then moved into a horizontal shift register. As charges move out of the horizontal shift register, they are converted to voltages which are proportional to the size of each charge. Shifting is clocked according to the camera s internal data rate. The voltages moving out of the horizontal shift register are amplified by an internal Variable ain Control (VC) and then digitized by a 10 bit Analog-to-Digital converter (ADC). For optimal digitization, gain and brightness can be programmed by setting command registers in the camera. Since the IEEE 1394 bus can only handle 8 bit data, the two least significant bits from the ADC are dropped. The 8 bit pixel data leaving the ADC is transferred to an image buffer. From the buffer, the image data is moved to a 1394 link layer controller where it is assembled into data packets that comply with version 1.20 of the based Digital Camera Specification issued by the 1394 Trade Association. The packets are passed to a 1394 physical layer controller which transmits them isochronously to a 1394 interface board in the host PC. The physical and link layer controllers also handle transmission and receipt of asynchronous data such as programming commands. The image buffer between the sensor and the link layer controller allows data to be transferred out of the sensor at a rate that is independent of the of the data transmission rate between the camera and the host computer. This ensures that the data transmission rate has no influence on image quality. BASLER A101f 3-1

18 Operation and Features CCD Sensor Vert. Shift Reg. Pixels Vert. Shift Reg. Pixels Vert. Shift Reg. Pixels Vert. Shift Reg. Pixels ADC VC Horizontal Shift Register Figure 3-1: Sensor Architecture Microcontroller 1 Control Microcontroller 2 Image Data 2 MB SDRAM Image Buffer CCD Sensor - A/D Converter Image Data ain & Brightness IntEn FPA Control: Shutter Binning AOI ain Brtness. ExTrig Image Data Control Link Layer Controller Asynchronous Data Isochronous and Asynchronous Data Physical Layer Controller Isochronous and Asynchronous Data IEEE 1394 Bus Figure 3-2: Block Diagram 3-2 BASLER A101f

19 Operation and Features 3.2 Exposure Control Setting the Exposure Time Exposure time is determined by the value stored in the SHUTTER control register. The value in the register can range from 0 to 4095 (0x000 to 0xFFF). The value in the register represents n in the equation: Exposure Time = (n + 1) x 20 µs. So, for example, if the value stored in the SHUTTER register is 100 (0x064), the exposure time will be ( ) x 20 µs or 2020 µs Controlling Exposure Start via the 1394 Interface One-Shot Operation In one-shot operation, the camera exposes and transmits a single frame. Exposure begins when the ONE_SHOT control register is set to 1. Exposure time is determined by the value stored in the SHUTTER control register (see Section 3.2.1). The ONE_SHOT control register is self cleared when transmission of frame data begins. See Section 4.2, Register Write Order, for a complete description of the order in which the camera registers must be written. This applies for one-shot, multi-shot, and continuous-shot operation. Multi-Shot Operation In multi-shot operation, the camera exposes and transmits multiple frames. The exposure for the first frame begins when the MULTI_SHOT control register is set to 1. The number of frames that will be transmitted is determined by the value stored in the COUNT_NUMBER field of the control register. The exposure time for each frame is determined by the value stored in the SHUTTER control register (see Section 3.2.1). The start of exposure on the second and subsequent frames is automatically controlled by the camera. If the camera is operating in video Format 0, Format 1, or Format 2, the rate at which frames will be captured and transmitted is determined by the value stored in the CUR_V_FRM_RATE / REVISION control register. If the camera is operating in video Format 7, the rate at which frames will be captured and transmitted is determined by the value stored in the BYTE_PER_PACKET control register (see Section ). The MULTI_Shot control register is self cleared when transmission of the last frame begins. Continuous-Shot Operation In continuous-shot operation, the camera continuously exposes and transmits frames. The exposure of the first frame begins when the ISO_EN/CONTINUOUS_SHOT control register is set to 1. The exposure time for each frame is determined by the value stored in the SHUTTER control register (see Section 3.2.1). The start of exposure on the second and subsequent frames is automatically controlled by the camera. If the camera is operating in video Format 0, Format 1, or Format 2, the rate at which frames will be captured and transmitted is determined by the value stored in the CUR_V_FRM_RATE / REVISION control register. BASLER A101f 3-3

20 Operation and Features If the camera is operating in video Format 7, the rate at which frames will be captured and transmitted is determined by the value stored in the BYTE_PER_PACKET control register (see Section ). Frame exposure and transmission stop when the ISO_EN/CONTINUOUS_SHOT control register is set to Controlling Exposure Start with an ExTrig Signal The external trigger (ExTrig) input signal can be used to control the start of exposure. A rising edge on the ExTrig signal begins exposure. The ExTrig signal can be periodic or non-periodic. The ExTrig signal must be used in combination with a one-shot, multi-shot, or continuous-shot command. If precise control of exposure start time is desired, you must also monitor the Trigger Ready signal and you must base the timing of the ExTrig signal on the state of Trigger Ready. (See section 3.3 for a detailed explanation of the Trigger Ready signal.) To enable the external trigger feature and set the camera for rising edge triggering, set the ON_OFF field of the TRIER_MODE control register to 1, the Trigger_Polarity field to 1, and the Trigger_Mode field to 0. ExTrig/One-Shot Operation In ExTrig/One shot operation, the camera exposes and transmits a single frame. To use this method of operation, follow this sequence: 1. Set the SHUTTER control register for your desired exposure time (see Section 3.2.1). 2. Set the ONE_SHOT control register to Check the state of the TrigRdy signal: a) If TrigRdy is high, you can toggle ExTrig when desired. b) If TrigRdy is low, wait until TrigRdy goes high and then toggle ExTrig when desired. 4. When ExTrig goes high, exposure will begin. Exposure will continue for the length of time specified in the SHUTTER control register. 5. At the end of the specified exposure time, frame readout and transmission will take place. The ONE_SHOT control register is self cleared after frame transmission. See Section 4.2, Register Write Order, for a complete description of the order in which the camera registers must be written. This applies for one-shot, multi-shot and continuous-shot operation. ExTrig/Multi-Shot Operation In ExTrig/Multi shot operation, the camera exposes and transmits multiple frames. The number of frames that will be transmitted is determined by the value stored in the COUNT_NUMBER control register. To use this method of operation, follow this sequence: 1. Set the SHUTTER control register for your desired exposure time (See Section 3.2.1). 2. Set the MULTI_SHOT control register to 1 and set the COUNT_NUMBER control register to the desired number of frames. 3-4 BASLER A101f

21 Operation and Features 3. Check the state of the TrigRdy signal: a) If TrigRdy is high, you can toggle ExTrig when desired. b) If TrigRdy is low, wait until TrigRdy goes high and then toggle ExTrig when desired. 4. When ExTrig goes high, exposure will begin. Exposure will continue for the length of time specified in the SHUTTER control register. 5. At the end of the specified exposure time, frame readout and transmission will take place. 6. Repeat steps 3, 4, and 5 until you have captured the number of frames specified in the count number register. The MULTI_SHOT control register is self cleared after transmission of the last frame. ExTrig/Continuous-Shot Operation In ExTrig/Continuous-shot operation, the camera continuously exposes and transmits frames. To use this method of operation, follow this sequence: 1. Set the SHUTTER control register for your desired exposure time (see Section 3.2.1). 2. Set the ISO_EN/CONTINUOUS_SHOT control register to Check the state of the TrigRdy signal: a) If TrigRdy is high, you can toggle ExTrig when desired. b) If TrigRdy is low, wait until TrigRdy goes high and then toggle ExTrig when desired. 4. When ExTrig goes high, exposure will begin. Exposure will continue for the length of time specified in the SHUTTER control register. 5. At the end of the specified exposure time, frame readout and transmission will take place. 6. Repeat steps 3, 4, and 5 each time that you want to capture a frame. 7. Frame exposure and transmission stop when the ISO_EN/CONTINUOUS_SHOT control register is set to Recommended Methods for Controlling Exposure Start If a camera user requires close control of exposure start, there are several general guidelines that must be followed: the camera should be placed in continuous shot mode. the user must use an external trigger signal to start exposure and must set the camera to react to a rising edge of the trigger signal (i.e., active high). the user must monitor the trigger ready signal and the integrate enabled signal (see Sections 3.3 and 3.4 for an explanation of these signals). a rising edge of the external trigger signal must only occur when the trigger ready signal is high. Assuming that these general guidelines are followed, the reaction of the camera to a rising external trigger signal will be one of two cases. In case one, the rising edge of ExTrig occurs when the camera is not transferring a captured frame from the sensor to the image buffer. In case two, the rising edge of ExTrig occurs when the camera is transferring a captured frame from the sensor to the image buffer. BASLER A101f 3-5

22 Operation and Features Case 1 - Exposure Start When the Camera is not Transferring a Frame After each exposure is complete, there is a time period of 80.7 ms. during which the captured frame is transferred from the CCD sensor to the camera s image buffer. If the ExTrig signal rises after this time period has ended as shown in Figure 3-3: The start of exposure will occur between 3 and 6 µs after the rise of ExTrig. For a given camera, the delay in the start of exposure will be consistent from frame to frame. (The size of the delay will vary slightly from camera to camera, but will always be in the 3 to 6 µs range.) The IntEn signal will rise between 2 and 3 µs after the start of exposure. For a given camera, the delay in the rise of IntEn will be consistent from frame to frame. (The size of the delay will vary slightly from camera to camera, but will always be in the 2 to 3 µs range.) The actual length of exposure will be equal to the programmed exposure time plus 4 µs. To know when frame transfer to the buffer is taking place, the user must monitor the integrate enabled signal. The frame transfer time period begins on the falling edge of the integrate enabled signal and lasts for 80.7 ms. TrigRdy ExTrig 3 µs 6 µs 3 µs 6 µs Exposure Exposure Frame N Exposure Frame N µs 3 µs Exposure Frame N µs 3 µs IntEn Frame Transfer 80.7 ms Frame N Transfer to the Image Buffer 80.7 ms Frame N +1 Transfer to the Image Buffer TIMIN CHARTS ARE NOT DRAWN TO SCALE Figure 3-3: Exposure Start After Frame Transfer The camera can be programmed to react to a rising edge of the ExTrig signal or to a falling edge of the ExTrig signal. We strongly recommend that you program the camera to react to the rising edge of the signal (i.e., active high). If falling edge triggering is used, the time between the falling edge of the ExTrig signal and the actual start of exposure is excessively long (at least 90 µs). This occurs due to the characteristics of the opto-coupler on the camera s ExTrig input. 3-6 BASLER A101f

23 Operation and Features Case 2 - Exposure Start When the Camera is Transferring a Frame After each exposure is complete, there is a time period of 80.7 ms. during which the captured frame is transferred from the CCD sensor to the camera s image buffer. If the ExTrig signal rises during this time period as shown in Figure 3-4: The start of exposure will occur between 3 µs and 86 µs after the rise of ExTrig. The delay in the start of exposure will vary from frame to frame but will always fall in the 3 to 86 µs range. 1 The IntEn signal will rise between 2 and 3 µs after the start of exposure. For a given camera, the delay in the rise of IntEn will be consistent from frame to frame. (The size of the delay will vary slightly from camera to camera, but will always be in the 2 to 3 µs range.) The actual length of exposure will be equal to the programmed exposure time plus 4 µs. To know when frame transfer to the buffer is taking place, the user must monitor the integrate enabled signal. The frame transfer time period begins on the falling edge of the integrate enabled signal and lasts for 80.7 ms. TrigRdy ExTrig 3 µs 3 µs µs 86 µs Exposure Exposure Frame N Exposure Frame N µs 3 µs Exposure Frame N µs 3 µs IntEn Frame Transfer 80.7 ms Frame N Transfer to the Image Buffer 80.7 ms Frame N + 1 Transfer to the Image Buffer TIMIN CHARTS ARE NOT DRAWN TO SCALE Figure 3-4: Exposure Start During Frame Transfer 1 This variability in the start of exposure is commonly referred to as an exposure start jitter. It occurs because when the camera is transferring an image, exposure can only start at certain fixed points during the frame transfer process. If an exposure is triggered when the transfer process is very near to one of these fixed points, the exposure start delay can be as little as 3 µs. If an exposure is triggered when the transfer process is very far from one of these fixed points, the start delay can be as much as 86 µs. If you need very close control of exposure start time, you should trigger exposure start when the camera is not transferring a frame as shown on page 3-6. The camera can be programmed to react to a rising edge of the ExTrig signal or to a falling edge of the ExTrig signal. We strongly recommend that you program the camera to react to the rising edge of the signal (i.e., active high). If falling edge triggering is used, the time between the falling edge of the ExTrig signal and the start of exposure will be excessively long (at least 90 µs). This occurs due to the characteristics of the opto-coupler on the camera s ExTrig input. BASLER A101f 3-7

24 Operation and Features 3.3 Trigger Ready Signal The trigger ready signal is not defined in the 1394 Trade Association Digital Camera Specification. Trigger ready is a special feature of Basler cameras. One possible way to control the camera is to perform an image exposure followed by charge read out and frame transfer and to wait until frame transfer is complete before beginning the next exposure. This situation is illustrated in Figure 3-5. Frame 1 Exposure Frame 2 Exposure Frame 3 Exposure Frame 1 Transfer Frame 2 Transfer Frame 3 Transfer Read Out Read Out Read Out Figure 3-5: Exposure Between Frame Transfers While the method of control shown above may be useful in many situations, it is not workable if your objective is to achieve maximum frame rate. To achieve maximum frame rate, most of the exposure for each frame must take place while the previous frame is being transferred out of the CCD array. This situation is illustrated in Figure 3-6. Frame 1 Exposure Frame 2 Exposure Frame 3 Exposure Frame 4 Exposure Frame 1 Transfer Frame 2 Transfer Frame 3 Transfer > 100 ns > 100 ns > 100 ns Read Out Read Out Read Out Read Out Figure 3-6: Exposure During Frame Transfer A point to notice when looking at Figure 3-6 is that exposure must not end during frame transfer; the end of exposure for the next frame must occur at least 100 ns after the transfer of the current frame. (For example, the exposure for frame two must end at least 100 ns after frame one transfer is complete.) This situation poses a problem when you are controlling exposure with an ExTrig signal, that is, how will you know when to toggle the ExTrig signal and begin exposure so that the exposure will end at least 100 ns after the last frame transfer. This problem is addressed by the trigger ready signal. The trigger ready signal will go high at the earliest moment that you can begin exposure and still be sure that the exposure will end at least 100 ns after the transfer of the last frame. 3-8 BASLER A101f

25 Operation and Features For better understanding of the use of trigger ready signal, consider an example. Assume that you will set the exposure time to 20 µs for every exposure and that you want to begin exposing as early as possible during transfer of the previous frame. In this case, the trigger ready signal will go high 20 µs before the earliest allowable end of exposure. This situation is illustrated in Figure µs 20 µs 20 µs Trigger Ready Frame Transfer Frame 1 Transfer Frame 2 Transfer Frame 3 Transfer > 100 ns > 100 ns > 100 ns Figure 3-7: Trigger Ready Signal If you monitor the trigger ready signal, and toggle ExTrig when the trigger ready signal goes high, the exposure will end at the earliest allowable point. Figure 3-8 illustrates how the ExTrig signal should toggle if you want your 20 µs exposure time to overlap frame transfer as much as possible. (Note that the trigger ready signal goes low when exposure starts.) ExTrig 20 µs exposure 20 µs exposure 20 µs exposure Trigger Ready 20 µs 20 µs 20 µs Frame Transfer Frame 1 Transfer Frame 2 Transfer Frame 3 Transfer >100 ns >100 ns >100 ns Figure 3-8: Using Trigger Ready to Time the ExTrig Signal What Happens if you Toggle ExTrig while TrigRdy is Low As explained above, the trigger ready signal is designed to ensure that exposure ends after the previous frame transfer is complete. But what happens if you toggle ExTrig while the trigger ready signal is low. In this case, the camera will remember that ExTrig has toggled and will delay the start of exposure until the trigger ready signal goes high. BASLER A101f 3-9

26 Operation and Features 3.4 Integrate Enabled Signal The Integrate Enabled (IntEn) signal goes high when exposure begins and goes low when exposure ends. This signal is especially useful when you are operating a system where either the camera or the object being imaged is movable. For example, assume that the camera is mounted on an arm mechanism and that the mechanism can be used to move the camera to view different portions of a product assembly. Typically, you do not want the camera to move during exposure. In this case, you can monitor the IntEn signal to know exactly when exposure is taking place and thus know when to avoid moving the camera. 3.5 Version Information A101f cameras include an advanced feature called Extended Versions that allows the user to read the version numbers of the firmware and several other elements in the camera. The version numbers are contained in an ASCII character string located in the EXTD_VERSIONS advanced features register. The extended versions register and the layout of the information contained in the character string are described in detail on page Extended versions is an advanced feature and may not be supported by the camera driver software that you are using BASLER A101f

27 Operation and Features 3.6 ain and Brightness The major components in the camera electronics include: a CCD sensor, a VC (Variable ain Control), and an ADC (Analog to Digital Converter). The pixels in the CCD sensor output voltage signals when they are exposed to light. These voltages are amplified by the VC and transferred to the ADC which converts the voltages to digital output signals. Two parameters, gain and brightness are associated with the VC. As shown in Figures 3-9 and 3-10, increasing or decreasing the gain increases or decreases the amplitude of the signal that is input to the ADC. Increasing or decreasing the brightness moves the signal up or down the measurement scale but does not change the signal amplitude. The default gain and brightness are set so that with optimal lighting and exposure, the linear output range of the CCD sensor maps to the input range of the ADC. Under these conditions, black will produce a gray value of 1 from the ADC and white will produce a gray value of 254. For most applications, black should have a gray value of 1 and white should have a gray value of 254. Attempt to achieve this by varying exposure and illumination rather than changing the camera s gain. The default gain is the optimal operating point (minimum noise) and should be used if possible. input signal to ADC [V] Figure 3-9: ain input signal to ADC [V] offset increasing gain increases the amplitude of the input signal light intensity [µj/cm 2 ] increasing brightness moves the input signal up the measurement scale light intensity [µj/cm 2 ] Figure 3-10: Brightness Because increasing gain increases both signal and noise, the signal to noise ratio does not change significantly when gain is increased. BASLER A101f 3-11

28 Operation and Features ain settings in more detail The output signals from the pixels in the CCD sensor normally range from 0 Volts when the pixels are exposed to no light to 0.4 Volts when they are exposed to bright light. Within that range, the sensor characteristics are linear. Saturation starts at 0.4 Volts. Further exposure results in a higher sensor output signal but linearity is no longer guaranteed. The default factory gain is set for an amplification factor of 5.0 (14 db). At this setting, the sensor s normal linear output range of 0 V V is amplified to 0 V V. The peak-to-peak input range of the ADC is 0 V V. Thus when the gain is at factory default, the amplified output of the sensor maps directly to the input voltage range of the ADC. ain is adjustable and can be programmed on a decimal scale that ranges from 0 to 511 (0x000 to 0x1FF). However, only the settings from 0 to 319 (0x000 to 0x13F) are effective. Settings greater than 319 will not increase the gain and should not be used. The settings result in the following amplification: 0 = 4.5 db 319 = 34.5 db In between, the change in db setting is linear. The gain can be adjusted in steps of db. The desired 14 db default gain is achieved when the gain is programmed to 101 (0x065). You should find that the default gain setting on your camera is near to this value. Reducing the gain below 101 results in mapping more than the linear operating range of the sensor to the ADC. Increasing the gain to more than 101 maps a smaller portion of the sensor s linear output signal to the ADC. If you know the decimal number setting for the gain on your camera, the equivalent decibel value can be calculated as follows: db = DN BASLER A101f

29 Operation and Features 3.7 Binning Binning increases the camera s sensitivity to light by summing the charges from adjacent pixels into one pixel. There are three types of binning available: horizontal binning, vertical binning and full binning. With horizontal binning, pairs of adjacent pixels in each line are summed (see Figure 3-11). With vertical binning, pairs of adjacent pixels from two lines are summed. Full binning is a combination of horizontal and vertical binning in which four adjacent pixels are summed. When horizontal binning is active, image resolution decreases to 650 pixels (H) by 1030 pixels (V). When vertical binning is active, resolution decreases to 1300 (H) by 515 (V). With full binning, resolution decreases to 650 (H) by 515 (V). Horizontal binning is enabled by setting the CUR_V_FORMAT control register to 7 and the CUR_V_MODE control register to 1. Vertical binning is enabled by setting the CUR_V_FORMAT control register to 7 and the CUR_V_MODE control register to 2. Full binning is enabled by setting the CUR_V_FORMAT control register to 7 and the CUR_V_MODE control register to 3. Charges from adjacent pixels in each line are summed and reported out as a single pixel. Charges from adjacent pixels in two lines are summed and reported out as a single pixel. Charges from groups of four pixels are summed and reported out as a single pixel. Horizontal Binning Figure 3-11: Binning Vertical Binning Full Binning Binning is only available on the A101f monochrome camera. Using horizontal or vertical binning generally increases the camera s sensitivity by up to two times normal. Full binning increases sensitivity up to four times normal. After switching on binning, the image might look overexposed. Reduce the lens aperture, light intensity, or exposure in this case. With horizontal binning active, frame grabbers often require the information that the horizontal resolution is 650. With vertical binning active, they often require the information that the vertical resolution is 515. With full binning active, they often require the information that the horizontal resolution is 650 and the vertical resolution is 515. With vertical or full binning active (horizontal binning has no effect), the maximum allowed frame rate increases to frames/sec. BASLER A101f 3-13

30 Operation and Features 3.8 Area of Interest (AOI) The area of interest (AOI) feature allows you to specify a portion of the CCD array and during operation, only the pixel information from the specified portion of the array is transferred out of the camera. The area of interest is referenced to the top left corner of the CCD array. The top left corner is designated as column 0 and row 0 as shown in Figure The location and size of the area of interest is defined by declaring a left-most column, a width, a top row and a height. Reference position is the top left corner of the image. For example, suppose that you specify the left column as 10, the width as 16, the top row as 4 and the height as 10. The area of the array that is bounded by these settings is shown in Figure The camera will only transmit pixel data from within the area defined by your settings. Information from the pixels outside of the area of interest is discarded. Starting Row Height in Rows Column 0 1 Row 0 Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 14 Row 15 Row 17 Row 18 Row The camera will only transmit the pixel data from this area. Starting Column Width in Columns Figure 3-12: Area of Interest The AOI feature is enabled by setting the CUR_V_FORMAT control register to 7 and the CUR_V_MODE control register to 0. The location of the area of interest is defined by setting a value for the left field and a value for the top field within the IMAE_POSITION control register that has been established for Format_7, Mode_0. The size of the area of interest is defined by setting a value for the width field and a value for the height field within the IMAE_SIZE control register that has been established for Format_7, Mode_0. To use the entire CCD array on the A101f, set the value for left to 0, the value for top to 0, the value for width to 1300 and the value for height to BASLER A101f

31 Operation and Features On the A101fc color camera: the setting for Left must be 0 or an even number. the setting for Top must be 0 or an even number. the setting for Width must be an even number. the setting for Height must be an even number. On all cameras, the sum of the setting for Left plus the setting for Width must not exceed On all cameras, the sum of the setting for Top plus the setting for Height must not exceed On all cameras, the AOI must contain at least 6144 pixels (width x height) Changes to the Frame Rate With AOI When the area of interest (AOI) feature is used, the maximum allowed frame rate depends on the number of rows included in the area of interest. The maximum allowed frame rate increases as the number of rows included in the area of interest decreases. The formula below can be used to calculate the maximum allowed frame rate when the AOI feature is used: 1,000,000 µs Frames/sec. = µs + [( Rows in AOI) x 5.44 µs] + [(Rows in AOI + 1) x µs] µs Table 3-1 shows the maximum allowed frame rates for a variety of AOI sizes. Rows in AOI Highest Frame Rate Rows in AOI Highest Frame Rate Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec Frames/sec. Table 3-1: Maximum Allowed Frame Rates The examples in Table 3-1 assume that you are using the maximum allowed packet size. If you use a smaller packet size, you will not be able to achieve the stated frame rates. See Section for more details. BASLER A101f 3-15

32 Operation and Features 3.9 Test Images The test image mode is used to check the camera s basic functionality and its ability to transmit an image via the video data cable. The test image mode can be used for service purposes and for failure diagnostics. In test mode, the image is generated with a software program and the camera s digital devices and does not use the optics, CCD sensor, VC, or ADC. Three different test images are available. Test images are an advanced feature. The test images are enabled by setting the ImageOn field of the TEST_IMAE advanced features register (see page 4-13). To enable test image one, set the field to 1. To enable test image two, set the field to 2. To enable test image three, set the field to 3. To disable the test image feature, set the field to 0. When a test image is active, the gain, brightness, and exposure time have no effect on the image. Test Image one As shown in Figure 3-13, test image one consists of lines with several gray scale gradients ranging from 0 to 255. If the camera is operating at full 1300 x 1030 resolution when the test images are generated: the first line starts with a gray value of 0 for the first pixel, the second line starts with a gray value 1 for the first pixel, the third line starts with a gray value of 2 for the first pixel, and so on. (If the camera is operating at a lower resolution when the test images are generated, the basic appearance of the test pattern will be similar to Figure 3-13, but the staring pixel values on each line will not be as described above.) The mathematical expression for test image one is: grayvalue = [ x + y ] MOD256 Figure 3-13: Test Image One 3-16 BASLER A101f

33 Operation and Features Test Image Two As shown in Figure 3-14, test image two consists of lines with several gray scale gradients ranging from 0 to 255. If the camera is operating at full 1300 x 1030 resolution when the test images are generated: lines 1, 2, 3, and 4 start with a gray value of 0 for the first pixel, lines 5, 6, 7, and 8 start with a gray value of 1 for the first pixel, lines 9, 10, 11, and 12 start with a gray value of 2 on the first pixel, and so on. (If the camera is operating at a lower resolution when the test images are generated, the basic appearance of the test pattern will be similar to Figure 3-14, but the staring pixel values on each line will not be as described above.) The mathematical expression for test image two is: [ x + y ] grayvalue = MOD 256, round off all values 4 Figure 3-14: Test Image Two Test Image Three Test image three (not shown) is similar to test image one, but it is not stationary. The image moves by 1 pixel from right to left whenever a one-shot, multi-shot or continuous-shot command signal is sent to the camera. Test Images are an advanced feature and may not be supported by the camera driver software that you are using. BASLER A101f 3-17

34 Operation and Features 3.10 Low Smear In applications where a CCD sensor is under constant illumination, highcontrast images may show smearing. Smearing is an unwanted effect that converts dark pixels into brighter ones. With the help of the low smear feature on the A101f, smearing is reduced on the upper part of the image. The effect of the low smear feature is illustrated in Figure The low smear feature cannot be activated or deactivated. Low smear is active all of the time, however, the feature operates best at lower frame rates. Figure 3-15: Full Smear (left), Low Smear (right) A two step process must be used to calculate the maximum frame rate that you can use and still see the full effect of the low smear feature. First, you must use this formula to calculate the frame transfer time based on the size of the area of interest (AOI): T(f) = 43 µs + [ ( AOIH) x 5.44 µs ] + [ (AOIH + 1) x µs ] µs where: T(f) = frame transfer time AOIH = number of rows in the AOI Second, you must use this formula to calculate the maximum allowed frame: 1,000,000 µs Frames/sec T(f) + [ (AOIH + AOIT) x 7.1 µs ] + T(e) where: T(f) = frame transfer time AOIH = number of rows in the AOI AOIT = number of rows above the AOI T(e) = exposure time 3-18 BASLER A101f

35 Operation and Features To better understand these calculations, let s look at an example. Suppose that you are working with an 800 (H) x 600 (V) area of interest, that there are 215 rows above the AOI and that you want a 2 ms. exposure. The calculations would look like this: T(f) = 43 µs + [ ( ) x 5.44 µs ] + [ ( ) x µs ] µs T(f) = ms and: Frames/sec. 1,000,000 µs ms + [ ( ) x 7.1 µs ] + 2 ms Frames/sec. = 17.2 So in this case, you can run the camera at up to 17.2 frames per second and still see the full effect of the low smear feature. If the camera s actual frame rate is higher than the maximum allowed frame rate, the smearing will come back. When you exceed the maximum allowed frame rate by a small amount, the upper part of the image will show partial smearing (see Figure 3-16). As the frame rate is increased, the smearing will become worse. Figure 3-16: Full Smear (left), Partial Smear (middle), Low Smear (right) BASLER A101f 3-19