cmos image sensor design. m. wäny nov. 2005 emva standard 1288 standard for measurement and...

CMOS Image Sensor Design. M. Wäny Nov. 2005

EMVA Standard 1288

Standard for Measurement and Presentation of Specifications for Machine Vision Sensors and Cameras


Agenda

Motivation

Goals

Approach

Current state & Outlook

Brief presentation of first released module


Motivation

EMVA Standardization Working Group launched in February 2004

Aim is to increase transparency of image sensor & camera specifications

Existing standards from broadcasting industry not suitable for describing performance of image giving systems in machine vision applications

Well-defined standards will increase transparency for customers, prevent unfair comparison of specification sheets, reduce support time, facilitate selection of the “right” camera or image sensor

Increase credibility of the industry


Participating companies

The standardization working group is open to all who constructively participate

Apply for registration at www.emva.org or e-mail to [email protected]


Goals

Elaborate a recommendation for a specification parameter set with clearly defined physical definitions of each parameter

Elaborate a measurement guideline for each of the recommended parameters

Provide information for understanding the implication of the recommended parameters to the performance of machine vision systems and guidelines for conversion of the parameter to other definition systems


Approach

Modular standard framework New modules are to complete the standard rather than to

replace previous versions

Module 1•Sensitivity•Quantum efficiency•Dynamic range•Spatial and temporal noise•Over all system gain

Module 2•Linearity•Artifacts •Defect pixels

Module 3•Color

Module X•More to follow

The modular approach protects investment in measurement equipment, processes and education


Current State

First Module released in August 2005

Logo is available at www.EMVA.org

Full Standard available at www.EMVA.org

Companies “self certify” standard compliance

First cameras characterized according to the standard at vision

PCO: pco.1600; pco.2000; pco.4000

BASLER: A102f; A311f; A312f; A60xf; A631f; A641f


Content of the Standard

Basic Information:This section delivers general information and information regarding the operation point at

which data is acquired.

Vendor name Model name Type of data presented: Typical; Guaranteed; Guaranteed over life time[1] Sensor type (CCD; CMOS; CID etc...) Sensor diagonal in [mm]; Indication of lens category to be used [inch] Resolution; Pixel size (width x height in [µm]) Readout type (CCD only) ; Transfer type (CCD only); Shutter type (CMOS only); Global; Rolling Overlap capabilities; (readout of frame n and exposure of frame n+1 can happen at

the same time). Maximum frame rate at the given operation point. (no change of settings permitted) Others (Interface Type etc..)


Content of Module 1

Camera

Mathematical ModelParameters

ParameterIdentification

Description of Mathematical model


Content of Module 1 Continued

Illumination Setup from Module 1 Homogenous illumination Without lens F-number 8 Definition of temperature

measurements

temperature sensor

Measurement Setup


The photon transfer method

Acquire series of images at increasing number of integrated photons (by variation of the integration time)

Represent mean value and temporal noise over # photons

Permits to determine each parameter independently

[DN]

[#p~]

Imagemean

[DN]

[#p~]

.temp

Content of Module 1 Continued



Measured Quantities Mean of the gray values

(How much light generates how much signal)

Variance of the temporal distribution of the gray values

(How much temporal noise do we have at what signal level)

ji

ijy yN ,

1

ji

Bij

Aijtempy yy

N ,

22.

1

2

1



Derived Quantities Overall system gain(Responsivity of the sensor/camera)

Total Quantum efficiency(QE including FF, glass ML etc..)

Full well capacity(How many electrons are needed for

the saturation signal)

Absolute Sensitivity(How much light equals the read

noise)

Dynamic input Range

darkyy

darktempytempyK.

2..

2.

p

darkyy

K

.

satpsate ..

const.0

.0

pdarkyy

darkyy

d

p min.

min.

.

p

satpinDYN


The spectrogram method

Compute and plot a row and column FFT of the image at 3 illuminations (dark; 50%saturation; 90% saturation)

Extract spatial noise performance from spectrogram.

Permits to get more insight in FPN and temporal noise performance then bare figures.

0

1

2

3

4

5

infinite32.016.010.78.06.45.34.64.03.63.22.92.72.52.32.12.0

period [px]

FF

T A

mp

litu

de

[#p

~]

Content of the Module 1 Continued


The spectrogram method

Derived Quantities Standard deviation of the spatial

offset noise referenced to electrons in [e-].

(Total FPN at a given light level)

Standard deviation of the spatial gain noise in [%].

(Total gain noise “PRNU”)

Signal to Noise Ratio(SNR including all noise contributions)

o

gS

22222pgpod

py

SSNR


Data Presentation

Describe data presentation Present all data in physical units Refer data to photons Present raw data and extracted parameters

Permits the user to check matching of the model to the data and pick parameters relevant to their application


Thank you for your attention

Current standard draftwww.emva.org

Join the working group:[email protected]

Acknowledgements:

Dr. F. Dirks; Dr. G. Holst;

All members of the 1288 Workinggroup

Contact:

Martin Wäny

AWAIBA Lda.

Madeira Technopolo

9020-105 Funchal Madeira

[email protected]

+351 291 723 124 / +49 4102 457 176

www.awaiba.com

cmos image sensor design. m. wäny nov. 2005 emva standard 1288 standard for measurement and...

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