Basler aca-18km Camera Specification Measurement protocol using the EMVA Standard 188 Document Number: BD59 Version: 3
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. All material in this publication is subject to change without notice and is copyright Basler Vision Technologies.
Contacting Basler Support Worldwide Europe: Basler AG An der Strusbek 6-6 96 Ahrensburg Germany Tel.: +9-1-63-5 Fax.: +9-1-63-599 bc.support.europe@baslerweb.com Americas: Basler, Inc. 855 Springdale Drive, Suite 16 Exton, PA 1931 U.S.A. Tel.: +1-877-93-87 Fax.: +1-61-8-768 bc.support.usa@baslerweb.com Asia: Basler Asia Pte. Ltd 8 Boon Lay Way # 3-3 Tradehub 1 Singapore 6996 Tel.: +65-65-7 Fax.: +65-65-73 bc.support.asia@baslerweb.com www.baslerweb.com
CONTENTS Contents 1 Overview 7 Introduction 8 3 Basic Information 9 3.1 Illumination................................... 1 3.1.1 Illumination Setup for the Basler Camera Test Tool......... 1 3.1. Measurement of the Irradiance.................... 1 Characterizing Temporal Noise and Sensitivity 11.1 Basic Parameters................................ 11.1.1 Total Quantum Efficiency....................... 11.1. Temporal Dark Noise.......................... 13.1.3 Dark Current.............................. 1.1. Doubling Temperature......................... 1.1.5 Inverse of Overall System Gain.................... 15.1.6 Inverse Photon Transfer........................ 16.1.7 Saturation Capacity.......................... 17.1.8 Spectrogram.............................. 18.1.9 Non-Whiteness Coefficient...................... 1. Derived Data....................................1 Absolute Sensitivity Threshold...................... Signal-to-noise Ratio.......................... 3..3 Dynamic Range............................ 5.3 Raw Measurement Data............................ 6.3.1 Mean Gray Value............................ 6.3. Variance of the Temporal Distribution of Gray Values........ 7.3.3 Mean of the Gray Values Dark Signal................ 8.3. Variance of the Gray Value Temporal Distribution in Darkness... 9.3.5 Light Induced Variance of the Temporal Distribution of Gray Values 3.3.6 Light Induced Mean Gray Value.................... 31.3.7 Dark Current Versus Housing Temperature............. 3 5 Characterizing Total and Spatial Noise 33 5.1 Basic Parameters................................ 33 5.1.1 Spatial Offset Noise.......................... 33 5.1. Spatial Gain Noise........................... 3 5.1.3 Spectrogram Spatial Noise...................... 35 5.1. Spatial Non-whiteness Coefficient.................. 38 5. Raw Measurement Data............................ 39 5..1 Standard Deviation of the Spatial Dark Noise............ 39 5.. Light Induced Standard Deviation of the Spatial Noise....... Basler aca-18km 5
CONTENTS Bibliography 1 6 Basler aca-18km
1 Overview 1 Overview Basler aca-18km Item Symbol Typ. 1 Unit Remarks Temporal Noise Parameters Total Quantum Efficiency (QE) η 6 % λ = 55 nm Inverse of Overall System Gain 1 K 1.5 e DN Temporal Dark Noise σ d 1 e Saturation Capacity µ e.sat 119 e Derived Parameters Absolute Sensitivity Threshold µ p.min p λ = 55 nm Dynamic Range DYN out.bit 9.8 bit Maximum SNR SNR y.max.bit 6.8 bit Spatial Noise Parameters SNR y.max.db.8 db Item Symbol Typ. Unit Remarks Spatial Offset Noise, DSNU 188 σ o 1.6 e Spatial Gain Noise, PRNU 188 S g 1.3 % Table 1: Most Important Specification Data Operating Point Item Symbol Remarks Video output format 1 bits/pixel Gain Register raw 33 Offset Register raw 16 Exposure time T exp. µs to 5.7 ms Table : Operating Point for the Camera Used 1 The unit e is used in this document as a statistically measured quantity. Basler aca-18km 7
Introduction Introduction This measurement protocol describes the specification of Basler aca-18km cameras. The measurement methods conform to the 188 EMVA Standard, the Standard for Characterization and Presentation of Specification Data for Image Sensors and Cameras (Release A1.3) of the European Machine Vision Association (EMVA) [1]. The most important specification data for Basler aca-18km cameras is summarized in table 1. 8 Basler aca-18km
3 Basic Information 3 Basic Information Basic Information Vendor Basler Model aca-18km Type of data presented Selected samples Number of samples 1 Sensor CMV Sensor type CMOS Sensor diagonal Diagonal 15 mm Indication of lens category to be used C-Mount Resolution 8 x 8 pixel Pixel width 5.5 µm Pixel height 5.5 µm Readout type - Transfer type - Shutter type Pipelined global shutter Overlap capabilities Overlapping Maximum readout rate 18 frames/second General conventions - Interface type Camera Link Table 3: Basic Information Basler aca-18km 9
3.1 Illumination 3.1 Illumination 3.1.1 Illumination Setup for the Basler Camera Test Tool The illumination during the testing on each camera was fixed. The drift in the illumination over a long period of time and after the lamp is changed is measured by a reference Basler A6fc camera. The reference camera provides an intensity factor that was used to calculate the irradiance for each camera measurement. Light Source Item Symbol Typ. Unit Remarks Wavelength λ 55 nm Wavelength Variation λ 5 nm Distance sensor to light source d 8 mm Diameter of the light source D 35 mm f-number f # 8 f # = d D Table : Light Source 3.1. Measurement of the Irradiance The irradiance was measured using an IL17 Radiometer from International Light Inc. (Detector: SEL33 #685; Input optic: W #961; Filter: F #187; regular calibration). The accuracy of the Radiometer is specified as ±3.5%. The measured irradiance is plotted in figure 1..1 'aca-18km' (1 cameras), Irradiance Irradiance [W/m^].1.8.6... 6 8 1 Measurement Figure 1: Irradiance for Each Camera Measurement. The error for each calculated value using the amount of light falling on the sensor is dependent on the accuracy of the irradiance measurement. 1 Basler aca-18km
Characterizing Temporal Noise and Sensitivity Characterizing Temporal Noise and Sensitivity.1 Basic Parameters.1.1 Total Quantum Efficiency Total Quantum Efficiency for One Fixed Wavelength Total quantum efficiency η(λ) in [%] for monochrome light at λ = 55 nm with a wavelength variation of λ = 5 nm. 'aca-18km' (1 cameras), Quantum Efficiency 7 Quantum Efficiency [%] 6 5 3 1 6 8 1 Camera Figure : Total Quantum Efficiency (QE) Item Symbol Typ. Std. Dev. Unit Remarks Total Quantum Efficiency (QE) η 6 TBD % λ = 55 nm Table 5: Total Quantum Efficiency (QE) The main error in the total quantum efficiency η is related to the error in the measurement of the illumination as described in section 3.1. Basler aca-18km 11
.1 Basic Parameters Total Quantum Efficiency Versus Wavelength of the Light Total quantum efficiency η(λ) in [%] for monochrome light versus wavelength of the light in [nm]. 'aca-18km', Quantum Efficiency 7 Quantum Efficiency [%] 6 5 3 1 5 6 7 8 9 1 Wavelength [nm] Figure 3: Total Quantum Efficiency Versus Wavelength of the Light The curve of the total quantum efficiency versus the wavelength as shown in figure 3 was calculated from the single measured total quantum efficiency as presented in section.1.1. For the shape of the curve, the data from the sensor data sheet was used. 1 Basler aca-18km
.1 Basic Parameters.1. Temporal Dark Noise Standard deviation of the temporal dark noise σ d time zero in [ e ]. referenced to electrons for exposure Std. Dev. Temporal Dark Noise [e-] 16 1 8 'aca-18km' (1 cameras), Std. Dev. Temporal Dark Noise 6 8 1 Camera Figure : Temporal Dark Noise Item Symbol Typ. Std. Dev. Unit Remarks Temporal Dark Noise σ d 1 1. e Table 6: Temporal Dark Noise Basler aca-18km 13
.1 Basic Parameters.1.3 Dark Current Dark current N d3 for a housing temperature of 3 C in [e /s]. Not measured!.1. Doubling Temperature Doubling temperature k d of the dark current in [ C]. Not measured! 1 Basler aca-18km
.1 Basic Parameters.1.5 Inverse of Overall System Gain Inverse of overall system gain 1 K in [ e DN ]. Inverse of Overall System Gain [e-/dn] 1 1 1 8 6 'aca-18km' (1 cameras), Inverse of Overall System gain 6 8 1 Camera Figure 5: Inverse of Overall System Gain Item Symbol Typ. Std. Dev. Unit Remarks Inverse of Overall System Gain 1 K 1.5.3 e DN Table 7: Inverse of Overall System Gain Basler aca-18km 15
.1 Basic Parameters.1.6 Inverse Photon Transfer 1 Inverse photon transfer in [ ] p ηk DN. 'aca-18km' (1 cameras), Inverse Photon Transfer Inverse Photon Transfer [p~/dn] 5 15 1 5 6 8 1 Camera Figure 6: Inverse Photon Transfer Item Symbol Typ. Std. Dev. Unit Remarks Inverse Photon Transfer 1 ηk.1 TBD Table 8: Inverse Photon Transfer p DN λ = 55 nm 1 The main error in the inverse photon transfer is related to the error in the measurement of the illumination as described in section ηk 3.1. 16 Basler aca-18km
.1 Basic Parameters.1.7 Saturation Capacity Saturation capacity µ e.sat referenced to electrons in [ e ]. 'aca-18km' (1 cameras), Saturation Capacity 1 Saturation Capacity [e-] 1 1 8 6 6 8 1 Camera Figure 7: Saturation Capacity Item Symbol Typ. Std. Dev. Unit Remarks Saturation Capacity µ e.sat 119 56 e Table 9: Saturation Capacity Basler aca-18km 17
.1 Basic Parameters.1.8 Spectrogram Spectrogram referenced to photons in [p ] is plotted versus spatial frequency in [1/pixel] for no light, 5% saturation, and 9% saturation. 5 'aca-18km' (1 cameras), FFT for No Light FFT Amplitude [p~] 3 1 All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), FFT for No Light FFT Amplitude [p~] 1 3 6 5 3 All Mean..1..3..5 Frequency [Cycles/pixel] Figure 8: Spectrogram Referenced to Photons for No Light 18 Basler aca-18km
.1 Basic Parameters 6 'aca-18km' (1 cameras), FFT for 5% Saturation FFT Amplitude [p~] 5 3 1 All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), FFT for 5% Saturation FFT Amplitude [p~] 1 8 6 All Mean..1..3..5 Frequency [Cycles/pixel] Figure 9: Spectrogram Referenced to Photons for 5% Saturation Basler aca-18km 19
.1 Basic Parameters 1 'aca-18km' (1 cameras), FFT for 9% Saturation FFT Amplitude [p~] 8 6 All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), FFT for 9% Saturation FFT Amplitude [p~] 8 6 1 8 6 All Mean..1..3..5 Frequency [Cycles/pixel] Figure 1: Spectrogram Referenced to Photons for 9% Saturation Basler aca-18km
.1 Basic Parameters.1.9 Non-Whiteness Coefficient The non-whiteness coefficient is plotted versus the number of photons µ p in [p ] collected in a pixel during exposure time. 'aca-18km' (1 cameras), Non Whiteness. 3.5 Non Whiteness 3..5. 1.5 1..5. 5 1 15 5 3 Mean Photon [Photons/pixel] Figure 11: Non-whiteness Coefficient Basler aca-18km 1
. Derived Data. Derived Data..1 Absolute Sensitivity Threshold Absolute sensitivity threshold µ p.min (λ) in [ p ] for monochrome light versus wavelength of the light in [nm]. µ p.min = σ d (1) η Absolute Sensitivity Threshold [p~] 3 5 15 1 5 'aca-18km' (1 cameras), Absolute Sensitivity Threshold 6 8 1 Camera Figure 1: Absolute Sensitivity Threshold Item Symbol Typ. Std. Dev. Unit Remarks Absolute Sensitivity Threshold µ p.min TBD p λ = 55 nm Table 1: Absolute Sensitivity Threshold Basler aca-18km
. Derived Data.. Signal-to-noise Ratio Signal-to-noise ratio SNR y (µ p ) is plotted versus number of photons µ p collected in a pixel during exposure time in [p ] for monochrome light with the wavelength λ given in [ nm]. The wavelength should be near the maximum of the quantum efficiency. A : SNR y = µ y µ y.dark σ y () B : SNR y = ηµ p (ηµp + σ d ) (3) Figure 13 shows the signal-to-noise ratio SNR y for monochrome light with the wavelength λ = 55 nm. 8 'aca-18km' (1 cameras), SNR SNR [bit] 6 A B 6 8 1 1 1 16 Mean Photon [bit] Figure 13: Signal-to-noise Ratio The maximum achievable image quality is given as SNR y.max. SNR y.max = µ e.sat () SNR y.max.bit = ld SNR y.max = log SNR y.max log (5) SNR y.max.db = log SNR y.max 6. SNR y.max.bit (6) Basler aca-18km 3
. Derived Data 'aca-18km' (1 cameras), SNR SNR 1 6 1 6 1 1 1 1 1 1 3 1 1 5 Mean Photon [Photons/pixel] A B Figure 1: Signal-to-noise Ratio Item Symbol Typ. Std. Dev. Unit Remarks Maximum achievable SNR [bit] SNR y.max.bit 6.8.3 bit Table 11: Maximum achievable SNR [bit] Item Symbol Typ. Std. Dev. Unit Remarks Maximum achievable SNR [db] SNR y.max.db.8.1 db Table 1: Maximum achievable SNR [db] Basler aca-18km
. Derived Data..3 Dynamic Range Dynamic range DYN out.bit in [ bit]. DYN out = µ e.sat σ d (7) DYN out.bit = log (DYN out ) (8) 'aca-18km' (1 cameras), Output Dynamic Range 1 Output Dynamic Range [bit] 8 6 6 8 1 Camera Figure 15: Output Dynamic Range Item Symbol Typ. Std. Dev. Unit Remarks Output Dynamic Range DYN out.bit 9.8.1 bit Table 13: Output Dynamic Range Basler aca-18km 5
.3 Raw Measurement Data.3 Raw Measurement Data.3.1 Mean Gray Value Mean gray value µ y (µ p ) in [DN] is plotted versus number of photons µ p in [p ] collected in a pixel during exposure time. 'aca-18km' (1 cameras), Mean Gray Value Bright 1 Mean Gray Value Bright [DN] 1 8 6 5 1 15 5 3 Mean Photon [Photons/pixel] Figure 16: Mean Gray Values of the Cameras with Illuminated Pixels 6 Basler aca-18km
.3 Raw Measurement Data.3. Variance of the Temporal Distribution of Gray Values The variance of the temporal distribution of gray values σ y.temp(µ p ) in [DN ] is plotted versus number of photons µ p in [p ] collected in a pixel during exposure time. Variance Gray Value Bright [DN^] 1 1 1 8 6 'aca-18km' (1 cameras), Variance Gray Value Bright 5 1 15 5 3 Mean Photon [Photons/pixel] Figure 17: Variance Values for the Temporal Distribution of Gray Values with Illuminated Pixels Saturation Capacity The saturation point is defined as the maximum of the curve in figure 17. The abscissa of the maximum point is the number of photons µ p.sat where the camera saturates. The saturation capacity µ e.sat in electrons is computed according to the mathematical model as: µ e.sat = ηµ p.sat (9) Basler aca-18km 7
.3 Raw Measurement Data.3.3 Mean of the Gray Values Dark Signal Mean of the gray values dark signal µ y.dark (T exp ) in [DN] time in [s]. is plotted versus exposure Mean Gray Value Dark [DN] 8 7 6 5 3 1 'aca-18km' (1 cameras), Mean Gray Value Dark 1 3 5 Exposure Time [ms] Figure 18: Mean Gray Values for the Cameras in Darkness 8 Basler aca-18km
.3 Raw Measurement Data.3. Variance of the Gray Value Temporal Distribution in Darkness The variance of the temporal distribution of gray values in darkness σ y.temp.dark(t exp ) in [DN ] is plotted versus exposure time T exp in [s]. Variance Gray Value Dark [DN^] 3.5 3..5. 1.5 1..5. 'aca-18km' (1 cameras), Variance Gray Value Dark 1 3 5 Exposure Time [ms] Figure 19: Variance Values for the Temporal Distribution of Gray Values in Darkness Temporal Dark Noise The dark noise for exposure time zero is found as the offset of the linear correspondence in figure 19. Match a line (with offset) to the linear part of the data in the diagram. The dark noise for exposure time zero σd is found as the offset of the line divided by the square of the overall system gain K. σ d = σ y.temp.dark (T exp = ) K (1) Basler aca-18km 9
.3 Raw Measurement Data.3.5 Light Induced Variance of the Temporal Distribution of Gray Values The light induced variance of the temporal distribution of gray values in [DN ] is plotted versus light induced mean gray value in [DN]. Variance Gray Value (Bright - Dark) [DN^] 8 6 'aca-18km' (1 cameras), Diff. Variance vs Diff. Mean Gray Value 6 8 Mean Gray Value (Bright - Dark) [DN] Figure : Light Induced Variance of the Temporal Distribution of Gray Values Versus Light Induced Mean Gray Value The overall system gain K is computed according to the math- Overall System Gain ematical model as: K = σ y.temp σ y.temp.dark µ y µ y.dark (11) which describes the linear correspondence in figure. Match a line starting at the origin to the linear part of the data in this diagram. The slope of this line is the overall system gain K. 3 Basler aca-18km
.3 Raw Measurement Data.3.6 Light Induced Mean Gray Value The light induced mean gray value µ y µ y.dark in [ DN] is plotted versus the number of photons collected in a pixel during exposure time Kµ p in [ p ]. Mean Gray Value (Bright - Dark) [DN] 1 8 6 'aca-18km' (1 cameras), Difference Mean Gray Value 5 1 15 Mean Photon [Photons/pixel] Figure 1: Light Induced Mean Gray Value Versus the Number of Photons Total Quantum Efficiency The total quantum efficiency η is computed according to the mathematical model as: η = µ y µ y.dark (1) Kµ p which describes the linear correspondence in figure 1. Match a line starting at the origin to the linear part of the data in this diagram. The slope of this line divided by the overall system gain K yields the total quantum efficiency η. The number of photons µ p is calculated using the model for monochrome light. The number of photons Φ p collected in the geometric pixel per unit exposure time [p /s] is given by: Φ p = EAλ (13) hc with the irradiance E on the sensor surface [W/m ], the area A of the (geometrical) pixel [m ], the wavelength λ of light [m], the Planck s constant h 6.63 1 3 Js, and the speed of light c 3 1 8 m/s. The number of photons can be calculated by: µ p = Φ p T exp (1) during the exposure time T exp. Using equation 1 and the number of photons µ p, the total quantum efficiency η can be calculated as: η = hc 1 AT exp E 1 λ µ p µ y.dark. (15) K Basler aca-18km 31
.3 Raw Measurement Data.3.7 Dark Current Versus Housing Temperature The logarithm to the base of the dark current in [e /s] versus deviation of the housing temperature from 3 C in [ C] Not measured! 3 Basler aca-18km
5 Characterizing Total and Spatial Noise 5 Characterizing Total and Spatial Noise 5.1 Basic Parameters 5.1.1 Spatial Offset Noise Standard deviation of the spatial offset noise σ o referenced to electrons in [ e ]. 'aca-18km' (1 cameras), DSNU188 16 DSNU188 [e-] 1 8 6 8 1 Camera Figure : Spatial Offset Noise ( DSNU 188 ) Item Symbol Typ. Std. Dev. Unit Remarks Spatial Offset Noise ( DSNU 188 ) σ o 1.6.7 e Table 1: Spatial Offset Noise ( DSNU 188 ) Basler aca-18km 33
5.1 Basic Parameters 5.1. Spatial Gain Noise Standard deviation of the spatial gain noise S g in [ %]..5 'aca-18km' (1 cameras), PRNU188 PRNU188 [%]. 1.5 1..5. 6 8 1 Camera Figure 3: Spatial Gain Noise ( PRNU 188 ) Item Symbol Typ. Std. Dev. Unit Remarks Spatial Gain Noise ( PRNU 188 ) S g 1.3.3 % Table 15: Spatial Gain Noise ( PRNU 188 ) 3 Basler aca-18km
5.1 Basic Parameters 5.1.3 Spectrogram Spatial Noise Spectrogram referenced to photons in [p ] is plotted versus spatial frequency in [1/pixel] for no light, 5% saturation, and 9% saturation. 5 'aca-18km' (1 cameras), Spatial FFT for No Light FFT Amplitude [p~] 3 1 All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), Spatial FFT for No Light FFT Amplitude [p~] 1 8 6 All Mean..1..3..5 Frequency [Cycles/pixel] Figure : Spectrogram Referenced to Photons for No Light Basler aca-18km 35
5.1 Basic Parameters FFT Amplitude [p~] 6 5 3 1 'aca-18km' (1 cameras), Spatial FFT for 5% Saturation All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), Spatial FFT for 5% Saturation FFT Amplitude [p~] 1 8 6 All Mean 1 8 6..1..3..5 Frequency [Cycles/pixel] Figure 5: Spectrogram Referenced to Photons for 5% Saturation 36 Basler aca-18km
5.1 Basic Parameters 1 'aca-18km' (1 cameras), Spatial FFT for 9% Saturation FFT Amplitude [p~] 8 6 All Mean..1..3..5 Frequency [Cycles/pixel] 'aca-18km' (1 cameras), Spatial FFT for 9% Saturation FFT Amplitude [p~] 8 6 1 8 6 All Mean 1..1..3..5 Frequency [Cycles/pixel] Figure 6: Spectrogram Referenced to Photons for 9% Saturation Basler aca-18km 37
5.1 Basic Parameters 5.1. Spatial Non-whiteness Coefficient The non-whiteness coefficient is plotted versus the number of photons µ p in [p ] collected in a pixel during exposure time. 8 'aca-18km' (1 cameras), Spatial Non-Whiteness Spatial Non-Whiteness 6 5 1 15 Mean Photon [Photons/pixel] Figure 7: Spatial Non-whiteness Coefficient 38 Basler aca-18km
5. Raw Measurement Data 5. Raw Measurement Data 5..1 Standard Deviation of the Spatial Dark Noise Standard deviation of the spatial dark noise in [DN] versus exposure time in [s]. Spatial Std. Dev. Gray Value Dark [DN] 1. 1. 1..8.6... 'aca-18km' (1 cameras), Spatial Std. Dev. Gray Value Dark.5 1. 1.5..5 3. 3.5 Exposure Time [ms] Figure 8: Standard Deviation of the Spatial Dark Noise From the mathematical model, it follows that the variance of the spatial offset noise σ o should be constant and not dependent on the exposure time. Check that the data in the figure 8 forms a flat line. Compute the mean of the values in the diagram. The mean divided by the conversion gain K gives the standard deviation of the spatial offset noise σ o. DSNU 188 = σ o = σ y.spat.dark K The square of the result equals the variance of the spatial offset noise σo. (16) Basler aca-18km 39
5. Raw Measurement Data 5.. Light Induced Standard Deviation of the Spatial Noise Light induced standard deviation of the spatial noise in [DN] versus light induced mean of gray values [DN]. Std. Dev. Gray Value (Bright - Dark) [DN] 5 15 1 5 'aca-18km' (1 cameras), Spatial Gain Noise 6 8 Mean Gray Value (Bright - Dark) [DN] Figure 9: Light Induced Standard Deviation of the Spatial Noise The variance coefficient of the spatial gain noise Sg or its standard deviation value S g respectively, is computed according to the mathematical model as: PRNU 188 = S g = σ y.spat σ y.spat.dark µ y µ y.dark, (17) which describes the linear correspondence in figure 9. Match a line through the origin to the linear part of the data. The line s slope equals the standard deviation value of the spatial gain noise S g. Basler aca-18km
REFERENCES References [1] EUROPEAN MACHINE VISION ASSOCIATION (EMVA): EMVA Standard 188 - Standard for Characterization and Presentation of Specification Data for Image Sensors and Cameras (Release A1.3). 6 Basler aca-18km 1