Imaging Photometer and Colorimeter

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1 W E B R I N G Q U A L I T Y T O L I G H T. /XPL&DP Imaging Photometer and Colorimeter Two models available (photometer and colorimetry camera) 1280 x 1000 pixels resolution Measuring range 0.02 to 200,000 cd/m² (expandable with density filter) Multiple exposure delivers up to 5 decades of dynamic range Selection of objective lenses for different image sizes Comprehensive software functions (pseudo-color display, polygon analysis, spotmeter, 3D box, profile, and minimum, maximum, mean value, and contrast determination) Windows DLL and LabView drivers for custom software

2 Two-dimensional Luminance and Color Distribution at a Glance Instrument Systems has developed the LumiCam 1300 luminance and colorimetry camera to meet the sophisticated needs of manufacturers and OEM customers in taking measurements at flat-panel displays, LED clusters, and multifunction information displays. The high-resolution CCD image sensor allows complex luminance distributions to be measured within seconds. Typical applications of the LumiCam 1300 are in the automotive, aerospace and general lighting industry. Each of the 1280 x 1000 detector pixels is assigned a calibrated luminance or colorimetry value. The total of these measuring points provides a two-dimensional image that can be used for further evaluation. The Benefits of Imaging Photometry and Colorimetry Substantial time savings with simultaneous recording of an entire image, e.g. a complete control panel. Integrated image processing functions permit new methods of analysis, e.g. automated target and background identification. Short measurement cycles and simple setup of intuitive pass/fail criteria for use in production environments. Compact design and minimum training requirement facilitate a wide range of applications. Windows DLL and LabView driver available for custom software The available LumiCam 1300 Models LumiCam 1300 The integrated V(λ) filter is used for measuring luminance. LumiCam 1300 Color The CIE tristimulus filters are mounted on a motorized filter wheel and are swiveled sequentially into the optical beam path to measure chromaticity..

3 Functional Principle The compact setup of the LumiCam 1300 measuring system creates maximum flexibility and provides users with a wide range of applications. A precision objective lens with downstream V(λ) filter is used to image the specimen under investigation on a CCD sensor with a resolution of 1280 x 1000 pixels. The size of the measurement area is determined by the distance of the specimen to the LumiCam The measuring signals read by each detector pixel are then digitized by the integrated AD converter and transferred to a frame-grabber board in an external computer. Digital data transfer makes the system particularly robust with respect to external interference. The values are then processed using stored calibration data and the result is displayed on the computer monitor. Test specimem Lens Filter CCD- Electronics with Data cable PC with frame-grabber Sensor AD converter board Precise Matching of Spectral Sensitivity with CIE Curves A set of four all-glass filters is used to match the spectral sensitivity of the CCD sensor to the known CIE tristimulus functions X, Y, and Z. Two separate filters are used for the X function with one filter each for the blue and the red ranges of the spectrum. This considerably improves accuracy compared to conventional filter-based colorimeters. The picture on the right shows the deviation of the actual spectral sensitivity functions from the ideal CIE curves. Relative Response 2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0 LumiCam 1300 Color spectral response compared to CIE observer Wavelength [nm] LC X1 LC X2 LC Y LC Z CIE X1 CIE X2 CIE Y CIE Z Accurate Recording of Measurements Each LumiCam 1300 is calibrated individually in the Instrument Systems laboratory in order to determine all the properties of the lens system and the CCD sensor. A complex flatfield correction is performed for every aperture and distance setting of the objective lens. Furthermore, the multi-exposure mode delivers precise measurements for a large dynamic range of the luminance values within an image. Several images are captured with different exposure times. They are then merged to form a complete image.

4 Analysis and Graphical Illustration of Measurement Results Polygon traverse Profile Spotmeter Box In addition to an extensive range of sophisticated analysis tools, LumiCam software offers the option of illustrating the images generated in different false-color displays. A comprehen- The Palette Editor sive library of pre-configured color palettes is available. In addition to this, new palettes can easily be adapted or generated. Data Export into MS-Excel All measuring results can be transferred into MS-Excel and MS-Word using the clipboard function. This facilitates evaluation and documentation in conformity with customer specifications.

5 Analysis Tools in Detail Spotmeter Any number of spotmeters can be positioned in the luminance image. Users can define their position and size. The pixels enclosed by a spotmeter are automatically evaluated for maximum, minimum, and average value of the measured luminance. Additionally, the tristimulus values of the spotmeter pixels are summed up. Average chromaticity and dominant wavelength are then calculated. Polygon traverse Object areas can be generated in any shape using polygons. All pixels within such an object area are classified in a higher range and lower range for brightness on the basis of their luminance values. These areas are designated target and background and are color-coded in the luminance image. The target and background areas enclosed by the polygon are also subject to statistical evaluation for the following calculations: maximum, minimum, and average luminance, standard deviation, and contrast ratio (quotient of target and background average values). Line / Profile The profile function allows easy analysis of the variation in luminance along any path within the captured luminance image. This function is particularly suitable for analyzing sections across an entire display area or for evaluating the change in luminance along the path of a speedometer needle. The software generates an associated luminance profile in a separate window along the selected line. A cursor can be positioned at any point in this profile for further analysis. 3D Box The 3D display provides a particularly impressive visualization of a luminance distribution. Any frame in the luminance image can be selected for this purpose using the mouse. A 3D image can then be displayed in a separate window. The mouse can be used to rotate the object in all three axes. The full range of false-color displays is also available in the 3D box. Furthermore, the rectangular frame in the luminance image can be repositioned and resized at any time using the mouse.

6 Analyzing Color LumiCam 1300 Color offers a full range of colorimetric evaluations in addition to the standard features of the photometer version. The following display modes are available: ƒ Luminance ƒ RGB image ƒ x, y, z and u, v color coordinates ƒ Dominant wavelength ƒ Delta E (the reference color is defined manually or using the Spotmeter) The Delta-E concept was taken from the Lab color difference system, where a Euclidean distance is calculated in a multidimensional color space. The full selection of the color palette is available for all display modes excluding the RGB image (this is a color-coded image by itself). Measurement of Dominant Wavelength The dominant wavelength, rather than the color coordinates, is generally used to analyze color of narrowband spectra that are virtually 100% color-saturated. This is particularly the case with LEDs (aside from white LEDs which, of course, have a broadband spectrum). The LumiCam Software calculates the dominant wavelength from the x,y color coordinates using an algorithm recommended by the CIE. Because the filters do not exactly match the CIE tristimulus functions, a measuring error occurs in the color coordinates for narrowband spectra that is dependent on the wavelength of the radiation. The entire spectral range can be divided into various segments in which the measuring errors vary considerably. The deviation in the range from 560 to 610 nm, for example, is less than 1 nm, because the filters can be precisely matched here. Deviation [nm] Measurement Errors for dominant wavelength of LEDs Dominant Wavelength [nm] Even minute nuances in the color coordinates for the red spectral range result in substantial changes in the dominant wavelength. This leads to a relatively large deviation when dominant wavelength is determined for red LEDs. This dependence is strictly systematic and can therefore be corrected.

7 Technical Specifications LumiCam Model LC Monochrome LC Color Measurement parameter Luminance [cd/m²] Luminance [cd/m²] Chromaticity [x,y,z] and [u,v ] Dominant Wavelength [nm] Camera Pixel resolution 1280 (H) x 1000 (V) effective pixels Refresh rate in life mode Up to 10 images per sec at 10 ms exposure time (depending on PC) Exposure time 1 ms to 30 sec Signal dynamic range 1000:1 in single shot ; up to 250,000:1 in multi-exposure mode Filter match (typical) F 1 = 2.5 % for Y / V(λ) filter F 1 = 3.5% for X and Z filter Lens flare *1 0.2 % at 4 pixel distance; % at a larger distance Luminance measurement Measurement range * cd/m² to 200,000 cd/m² ; can be increased by optional density filter *3 Measurement time at 10 cd/m² *4 3 sec at SNR of 1000:1 ; 1 sec at SNR of 100:1 without autoranging Measurement accuracy ± 4% for standard illuminant A Repeatability *5 ± 0.1 % Linearity ± 1 % Uniformity ± 1.5 % (average of 10 x 10 pixel) Color measurement Measurement time at 10 cd/m² *4 20 sec for standard illuminant A Measurement accuracy for [x,y] ± for standard illuminant A ± for color light *6 Repeatability for [x,y] ± Uniformity for [x,y] ± (average of 10 x 10 pixel) Measurement accuracy for dominant See diagram wavelength Repeatability for dominant wavelength*5 General CCD sensor 2/3 chip ± 0.1 nm for narrowband radiation (e.g. LEDs) CCD smear *7 < 0.02 % AD converter 12 bit Interface PCI frame-grabber board Dimensions 240 mm x 70 mm x 65 mm 275 mm x 120 mm x 135 mm Weight 0.9 kg 3.2 kg Power supply via PC via PC plus 12 V external Environmental conditions 10 to 35 C for operation; 20 to 25 C for specified measurement accuracy max. 70% relative humidity, non-condensing Notes: ** All specifications on the datasheet above relate to the LC mm objective lens. *1 Applicable to small luminous areas. If half the image surface is illuminated, the scattered light from the lens is approximately 1% at a distance of 10 pixels. *2 The minimum value of 0.02 cd/m² is applicable to a signal-to-noise ratio of 10:1. The maximum value of 200,000 cd/m² is applicable to a 1 ms exposure time. *3 Signal attenuation for the ND2 filter is approximately 100 and for the ND4 filter approximately 10,000. *4 The measurement time corresponds to the total time for exposure, data transfer and computation; the specified values are applicable to aperture 1.4 and autoranging mode; the exact measurement time depends on the PC configuration *5 Applicable to twice the standard deviation and at 10 cd/m², autoranging measuring mode, and within a series of measurements. *6 Applicable for color glass set of LMT and for white LEDs. Measuring accuracy depends on the dominant wavelength for monocolor LEDs (see also the diagram showing measuring accuracy for the dominant wavelength of LEDs). *7 Applicable at exposure times greater than 10 ms. There is a larger smear value for shorter exposure times Instrument Systems is continually working to develop and improve products. Any technical changes, errors or misprints do not form grounds for compensation. The company s Terms of Delivery and Payment apply in all other respects.

8 Objective Lens Specifications Order No LC-312 LC-314 LC-316 Focal length 28 mm 50 mm 105 mm Macro Field of view Minimal distance Distance of DUT to lens 18 cm 37 cm 14 cm Distance of DUT to housing 23 cm 42 cm 27 cm Image size [W x H] 55 x 42 mm 61 x 47 mm 8.5 x 6.5 mm Pixel size 42 µm 47 µm 6.5 µm 1 m distance to housing Image size [W x H] 290 x 230 mm 160 x 120 mm 73 x 57 mm Pixel size 230 µm 120 µm 57 µm Note: All values are typical Ordering Information Order No Description Basic unit (without objective lens and calibration) LC Imaging Photometer with 1280x1000 pixel resolution and 12 Bit ADC; incl. PCI frame grabber, software and PC LC Imaging Photometer and Colorimeter with 1280x1000 pixel resolution and 12 Bit ADC; incl. PCI frame grabber, software and PC Optionen LC-110 Delete PC LC mm objective lens LC mm objective lens LC mm objective lens LC-362 Neutral density filter 2 (attenuates light by a factor of 100) LC-364 Neutral density filter 4 (attenuates light by a factor of 10,000) Software SW-510 DLL driver for LumiCam 1300; incl. analysis functions; running under Windows 98/2000/XP SW-515 Labview driver for LumiCam 1300; running under Windows 98/2000/XP (requires SW-510 DLL) Instrument Systems Neumarkter Str. 83, D Munich, Germany Tel.: Fax.: info@instrumentsystems.de