A picture can say more than 1000 words comparing camera...

A picture can say more than 1000 words – comparing camera images Jürgen Bretschneider, 2015

Allied Vision Profile

Foundation: 1989, Headquarters: Stadtroda (Germany)

Employees: > 300 (2015)

Know how:

– Development and production of high-quality digital cameras for industrial and scientific imaging

Research & Development

– Hardware- and software development of digital cameras for the visible and the infrared spectrum

– Standard cameras and also camera solutions for OEM customers

Production

– Company-owned production sites (cleanroom) in Stadtroda and Osnabrück (Germany), Burnaby BC (Canada)

Service

– Consulting teams for distribution and support, worldwide, 24/5

Quality standards

– Compliance with ISO-9001 and ISO 13485

Measurement setup (Ulbricht sphere)

EMVA 1288 standard unified method of measuring a camera’s imaging performance

Ulbricht sphere for C-/ CS- and F-Mount-cameras with homogeneous light source at 632 nm, 529 nm, 448 nm and 850 nm (NIR)

Camera as „black box“ (only pixel size and exposure time must be known)

All measurements use cameras without protection or filter glass

Calibration of the light source and setup of light intensity initially

> 50 measured points to generate curves for sensitivity, linearity, temporal and spatial noise

EMVA 1288 camera data sheet provides measured and derived EMVA data based on 5 cameras of the same type

R, G, B, NIR

Simplified EMVA 1288 related camera model

Photon Shot Noise

photons

Digital value

Temporal: dark noise, quantization noise Spatial: Dark Signal Non-Uniformity (DSNU) Photo Response Non-Uniformity (PRNU)

Noise

- - -

- - -

-

Signal

Description of characteristic EMVA 1288 values

• Sensitivity threshold: point where signal equals temporal dark noise • Saturation capacity: number of electrons that each pixel of an sensor holds, before reaching non-linear response • Dynamic range (DYN): Ratio of the maximum signal (saturation capacity) to the minimum signal (temporal dark noise) • Maximum signal-to-noise ratio (SNR): Ratio of the maximum signal (saturation capacity) to all noise sources • Noise: Unwanted statistical variations of signal produced by the image sensor (temporal dark noise, photon shot noise and spatial noise, like DSNU and PRNU)

NoiseShot Photon NoiseDark

Capacity Saturationmax

SNR

NoiseDark

Capacity SaturationDYN

Description of characteristic EMVA 1288 values

Dark noise

Sensitivity threshold

Saturation capacity

Saturation point

Maximum signal

Dark noise + Photon Shot

noise

SNR at saturation Slope = Quantum Efficiency

Sensitivity threshold (SNR=1)

Caused by irradiance: - Photon shot noise (temporal)

- PRNU (spatial)

Noise SNR bit

48 db 8

24 db 4

Irradiance independent: - Dark noise (temporal)

- DSNU (spatial)

60 db 10 Gain

EMVA 1288 DATA Prosilica GT2750

Photon transfer method: Noise as a measuring tool (example Manta G-223C)

System gain 1/K: 2.561 [e-/DN] Quantum efficiency: 49.205 [%] Sat. Capacity: 10028 [e-] | 20380 [p~] dark noise: 4.608 [DN] | 11.779 [e-] SNR max: 40.012 [dB] | 6.646[bits] Sensitivity threshold: 20.001 [e-] | 40.811 [p~] Dynamic Range DR: 52.065 [dB] | 8.648 [bits]

measured data: System Gain, QE, Temporal Dark Noise, Saturation Capacity, derived data: Sensitivity Threshold, DNR, SNRmax

Temporal dark noise

System Gain QE

Saturation Capacity

Spatial nonuniformity DSNU and PRNU (MG-223C)

DSNU = 4.422 [DN] | 11.326 [e-] PRNU = 1.192 [%]

Deviation Outliers

Model

Model

Spectrogram Method: analyse spatial nonuniformity DSNU and PRNU (vertically and horizontally)

logarithmic histograms of spatial variations – find outlier (Defect Pixels)

Sensitivity curves of selected sensors QE = f (λ)

Manta G-235B (CMOS IMX174LLJ) Manta G-235C (CMOS IMX174LQJ)

448 nm 529 nm 632 nm

Sensitivity estimation: S~QE/dark noise

529 nm 850 nm (NIR)

EMVA data of selected Allied Vision cameras

0

10

20

30

40

50

60

70

80

Sensitivitythreshold

[e-]

QuantumEfficiency

[% @ 529 nm]

SaturationCapacity

[e- *1000]

SNR max [db] DNR max [db] Pixel area [µm²]

Manta G-235C Manta G-223C Mako G-503C

Mako G-192C Global Shutter Mako G-192C Rolling Shutter Manta G-201C

Manta G-145C

appears brightest?

1

1

1

lowest threshold?

Low-light performance of selected Allied Vision cameras

Title Presentation | dd/mm/yyyy | 12

Camera Manta G-235C IMX 174

Manta G-223C CMV 2000

Mako G-503C MT9P006

Mako G-192C GS EV76C570

Mako G- 192C RS EV76C570

Manta G-201C ICX274

Manta G-145C ICX285

Pixel area 34,34 µm² 30,25 µm² 4,84 µm² 20,25 µm² 20,25 µm² 19,36 µm² 41,60 µm²

camera Sensitivity threshold

Manta G-235C 7,07 e- 11.5 [ p~]

Manta G-223C 20.001 [e-] 40.811 [p~]

Mako G-503C 6.072 [e-] 12.157 [p~]

Mako G-192C Global Shutter

22,8 [e-] 62 [p~]

Mako G-192C Rolling Shutter

9 [e-] 28 [p~]

Manta G-201C 9,5[e-] 30 [p~]

Manta G-145C

22,5 [e-] 56,92[p~]

1 MG-503C – really

so sensitive?

Comparing images at low-light condition

Mako G-192C GS Mako G-192C RS

Mako G-503C Manta G-201C

Manta G-223C Manta G-235C

Manta G-145C

Test setup: • Neon tube

5000K • Kowa LM12SC

12mm 1" F1,8 • Camera @

24dB, 300us, Gamma 0,45

Comparing images at low-light condition



Manta G-223C Manta G-235C Test setup: • Neon tube


12mm 1" F1,8 • Camera @

24dB, 300us, Gamma 0,45

Manta G-145C

1

2

3 4

5 6

7

Low-light performance adapted to photons/µm²

Title Presentation | dd/mm/yyyy | 15 Sensitivity threshold (SNR = 1) will be reached earlier at less photons

camera

light densitiy photons/µm² @ Sensitivity threshold

Manta G-235C 0,33 p/µm²


Mako G-503C 2,51 p/ µm²


3,06 p/µm²


1,38 p/µm²



Low-light performance adapted to photons/µm²

Title Presentation | dd/mm/yyyy | 16 Sensitivity threshold (SNR = 1) will be reached earlier at less photons

camera

light densitiy photons/µm² @ Sensitivity threshold



Mako G-503C 2,51 p/ µm²


3,06 p/µm²


1,38 p/µm²



QE

Bright-light condition – 1. high-speed application (shortest shutter time) and 2. high variation in light (high SNR)

camera Saturation capacity (@529 nm)

Manta G-235C 32700 [e-] | 53030 [p~]

Manta G-223C 10028 [e-] | 20380 [p~]

Mako G-503C 4677,3 [e-] | 9300 [p~]


5900 [e-] | 16390 [p~]


10000 [e-] | 27027 [p~]

Manta G-201C 7200 [e-] | 19650 [p~]

Manta G-145C 16600 [e-] | 45996 [p~]

MG-503C – really appears brightest?

Comparing images at bright-light condition




Manta G-145C



12mm 1" F1,8 • Camera @ 4ms

Gamma 1,0

Application task: need for bright image at shortest possible shutter time, SNR isn´t an issue



Mako G-503C

Manta G-201C


Manta G-145C



12mm 1" F1,8 • Camera @ 4ms

Gamma 1,0

115

155

87

111 221

143

164

7

6 5

4 3

2 1

Bright-light performance adapted to photons/µm²

camera

light densitiy photons/µm² @ Saturation capacity

Manta G-235C

1572 p/ µm²

Manta G-223C

674 p/ µm²

Mako G-503C 1921 p/ µm²

Mako G-192C GS

809 p/ µm²

Mako G-192C RS

1315p/µm²

Manta G-201C

1015 p/µm²

Manta G-145C

1105 p/µm²


12.5 ms/ 0 db gain/ Gamma 0.45 8.5 ms/ 0 db gain/ Gamma 0.45

Test setup: • Neon tube 5000K • Kowa LM12SC 12mm 1" F1,8 • images adjusted to 250 DN

Application task: high variation in lighting condition, high dynamic scenes, high SNR is needed

Manta G-235C Mako G-503C

115

225

80

195

What about Dynamic at low illuminated image parts?

Title Presentation | dd/mm/yyyy | 22

Manta G-235C Mako G-192C GS Mako G-192C RS

SNR max 45 dB (7.5 bits) SNR max 38 dB (6.3bits) SNR max 40 dB (6.6 bits)

Signal-to-Noise Ratio (SNR)

39 31

19

Noise!

CCD artifacts – blooming and smear

Blooming: Charge overflow (> full well capacity) between neighboring pixels Corrective action: reduction of

the incoming light

Smear: During readout photons generate a charge in the vertical shift register Corrective action : increase of the exposure time, use of a mechanical or LCD shutter, use of flash illumination

blooming and smear – test images of CCD and CMOS sensors

Mako G-192C (EV76C570) Mako G-503C (MT9P006)

Manta G-145C (ICX 285) Manta G-201C (ICX 274) Manta G-223C (CMV2000)

Manta G-235C (IMX 174)

Global Shutter efficiency – unwanted sensitivity

Shutter efficiency = (1 - parasitic light sensitivity)

Define how much the stored pixel value is distorted by incoming light during readout phase of the sensor when the shutter is closed

Former CMOS global shutter sensors are affected by higher parasitic light sensitivity reduces the ability to use very short integration times to freeze motion

E.g. datasheet of the CMOS sensor IBIS5-A-1300 specifies a parasitic sensitivity < 1% up to 400µs at 40 ms readout time

In case of long exposure times, like 20 ms, parasitic sensitivity 400 µs is negligible, but in case of 2µs shutter time this leads to a strong vertical increase in brightness

Nowadays CMOS global shutter sensors provide ratio of 1:2000 or better shutter efficiency

IBIS5-A-1300:

Global Shutter efficiency of selected sensors

Mako G-223B (CMV 2000) shutter time: 1µs

Marlin F-131B (IBIS5-A-1300) shutter time: 2µs

Mako G-030C (CMV300) shutter time: 83 µs

Manta G-145B (ICX 285AL) shutter time: 20 µs

parasitic sensitivity up to 400 µs! (readout time: 40 ms)

Meaning of measured values: Background and pitfalls

Quantum Efficiency QE = f (λ) - Measured for monochrome cameras only at 529 nm and for color cameras at 632 nm, 529 nm, 448 nm - Please use sensitivity curve to estimate how the camera performs at other wavelengths

Signal response vs. sensitivity: - Grey value generated at a certain exposure time has nothing to do with sensitivity - For purposes of comparison you have to consider Photon Shot Noise and Dark Noise

Saturation capacity vs. sensitivity: - The lower the achievable saturation capacity, the earlier the maximum output level is reached - This does not mean, that a low saturation capacity implies a high sensitivity - Comparing Sensitivity threshold and saturation capacity of different cameras you have to consider Pixel area for

the incoming light - light density photons/µm²

Gain: - Higher gain does not mean increased sensitivity, since signal and noise are increased in the same ratio - Applying gain reduces the achievable saturation capacity of a camera - In case of sufficient image quality it is used to shorten the shutter time to prevent motion blur

Tolerances: - Due to manufacturing tolerance of the sensor and camera electronics a real camera may differs from the EMVA1288 test results. The uncertainty in measurement of the QE values is up to 10%

EMVA1288 results and real application demands

You always have to reconsider the optical set-up (lens, filters) and suitable Lighting - Consider Quantum Efficiency is a function of the wavelength

Low-light applications: - Camera qualified with low Sensitivity threshold and high QE - Compare light densitiy photons/µm² @ Sensitivity threshold - Sensors with low temporal dark noise allows more gain without loosing to much

image quality at shorter shutter time

Bright-light applications:

a) High-speed application - Need for a bright image at shortest possible shutter time, (SNR isn´t an issue, 4- 6 bit sufficent) camera is qualified with Low value of light densitiy photons/µm² @ Saturation capacity

- Higher QE means less illumination or shorter shutter speed

b) High variation in lighting condition: - High SNR and large saturation capacity are needed for dynamic scenes with

different lighting situations

Thank You/Q&A

Allied Vision Technologies GmbH Taschenweg 2a 07646 Stadtroda Germany

www.alliedvision.com

http://www.alliedvision.com/

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