Documentation - Previous v23.2

View Release Notes

For beginners: We recommend these web pages for getting started:

Introduction to the new Imatest Main Window (New in 2021.2)
Image Quality Factors - Using Imatest - Getting started - Imatest Updates and Features 
VIDEOS - Online training - Consulting - News 

Index of the Table of Contents
Offline documentationDownload the website for offline view (with a web browser)
Image Quality 
IQ factors (KPIs) measured by Imatest, with links to detailed descriptions and instructions.
Sharpness Introductions to sharpness and sharpening; comparisons of different charts; chart quality limitations & how to overcome them
Other IQ factors  Noise, SNR, Temporal noise, Dynamic Range (DR),  Chromatic Aberrations, Distortion, Veiling glare, Shannon information capacity, etc.
IQ Utilities  Image Processing, SSIM, Image Statistics, Radial geometry 
Getting started Why Imatest?, Test charts, Lighting, Image capture technique, Setting up your lab, Using Imatest software
Start using Imatest software Installation, Using Imatest, Image file formats & devices, Activation/Deactivation
General InstructionsSpecial standards, Supported devices, Test manager, Raw files, Test lab, INI files, Pass/Fail Monitor
Acquiring imagesFiles, formats, devices, and utilities for acquiring images
Knowledge Base highlights Links to articles for troubleshooting, activation, and general advice on operation.
Troubleshooting What to do when Imatest doesn't work as expected
Slanted-Edge sharpness modules SFR (manual ROIs), SFRplus, eSFR ISO, SFRreg, Checkerboard (auto ROI detection)
The four auto-detection slanted-edge sharpness module are compared here.
Other sharpness modules Log F-Contrast, Star, Random/Dead Leaves/Spilled coins, Wedge, Sharpness utilities & postprocessors
Sharpness utilities & postprocessorsMTF Compare, Image stabilization, Batchview, Find ShGarpest Files
Tone, Color, Noise & Dynamic Range modules Color/Tone (Interactive & Auto), CCM (Color Correction Matrix), CDP, Contrast Resolution, Colorcheck, Stepchart, Measuring patches, Gamutvision for evaluating ICC color profiles and gamut mapping.
Spatial & Flat field modules Flatfield, Flatfield Interactive, Distortion, Dot pattern, Testing displays
Miscellaneous modules and utilities Lighting Control, Arbitrary charts, Device Manager, Auto White Balance/Exposure/Focus (AWB, AE, AF), Printing & displaying test charts, Rename Files, Educational Apps, Database
Industrial Testing edition  Modules, Instructions for various interfaces (EXE, C, C++, Python, .NET), INI file reference, Pass/Fail, Operator Console, Speedup
AppendixFAQ, Versions, Troubleshooting, Change Log, INI file reference, License

Image Quality

General — Introduction to Image Quality Factors (Key Performance Indicators – KPIs)

Image quality factors - Overview and Imatest measurements  Recommended for getting started.

Introduction - Summary table - Image quality factors - Sharpness - Texture - Noise - Information capacity - Tonal response - Dynamic range - Color accuracy - Distortion - Uniformity - Blemishes - Exposure accuracy/ISO sensitivity - Lateral chromatic aberration - Stray light (flare) - Veiling glare - Color moiré - Software artifacts - Data compression - Printer quality factors

Sharpness

Sharpness - What is it and how is it measured?

Introduction - MTF - MTF equation - Spatial frequency units - Summary metrics- MTF measurement matrix - comparing measurement techniques - Slanted-Edge measurements - Why a slanted edge? - Clipping - Noise reduction - Interpreting MTF50 - AutoFocus (AF) Speed - Calculation details - Slanted-edge algorithm - Imatest vs. ISO calculation - Links

Sharpening - and Standardized Sharpening for comparing cameras

Introduction - Examples - Oversharpening/Undersharpening - Examples - Unsharp masking (USM) - Links - Standardized sharpening

Comparing sharpness in different cameras - The application: "Image-centric" (for pictorial images) or "object-centric" (for medical, machine vision, etc.) strongly affects how images are compared.

Validating the Imatest slanted-edge calculation

Slanted-edge versus Siemens Star - A comparison of sensitivity to signal processing

Introduction - Images - Raw results - Slanted-edge results - Sinusoidal (Log F-Contrast and Siemens star) results - Extreme sharpening - Summary - Conclusions

Slanted-edge versus Siemens Star, Part 2 - Results for four additional cameras

Slanted-edge measurement consistency and repeatability - comparing different ISO speeds and ROI sizes. Incomplete, but still useful.

Nyquist frequency, aliasing, and Color Moire - introducing a color aliasing metric derived from hyperbolic wedges.

Diffraction, optimum aperture, and defocus - Lens aberrations – Diffraction – Pixel response limits and Q – Defocus 

Display (Monitor) Sharpness - Display the chart - Capture the image - Analyze - Results - TV Lines - Monitor gamma - CMS systems

Camera Monitor Systems (CMS) – for automotive mirror replacement systems and some endoscopes

LSF (Line Spread Function) correction factor for slanted-edge MTF measurements

Correcting nonuniform illumination in slanted-edge MTF measurements for nonuniformity perpendicular to the edge

Compensating camera MTF measurements for chart and sensor MTF

Introduction - Calculation - MTF compensation files - Applying the compensation - Sensor MTF compensation for measuring lens MTF - Chart MTF measurements

Chart Quality Calculator - determine the suitability of a chart (based on MTF measurements for specific media & print methods) for a specific application
Test chart suitability for MTF measurements - charts for determining the MTF measurement suitability of several media types (inkjet and photographic; reflective and transmissive). Based on Chart Quality Calculator results.
Implicit sharpness assumption (diffraction) - Chart suitability display - Inkjet matte - B&W photo paper - Color LVT | B&W LVT - MTF suitability calculations
Chart Quality Index (CQI) - older (now deprecated) method that relates chart quality and size to MTF measurements. Replaced by Chart Quality Calculator. The Chart Finder is an interactive website for selecting chart size and media.
Reflective Chart Quality Comparison: Inkjet vs. Photographic
Transmissive Chart Quality Comparison
MTF curves and Image appearance - Correlating measurement with appearance
Introduction - The Slanted-edge test - Reference image - Sharpened images - Blurred images - Sharpened + blurred images - Observations - Sharpness ranking - Links
Acutance and SQF (Subjective Quality Factor): perceptual sharpness measurement
Introduction - Acutance and MTF - Meaning of Acutance & SQF - Measuring Acutance & SQF - The SQF equation - CSF - Links
 

Other Image Quality Factors

Gamma, Tonal Response, and related concepts – why it’s used, how to measure it, and much more
Introduction – Encoding vs. Display gamma – Why logarithms? – How gamma-encoding increases Dynamic Range  – Expected gamma values – Gamma and MTF – Which patches are used to calculate gamma? – Why gamma ≅ 2.2? – Tone mapping – Contrast: ratio, Weber, Michelson – Logarithmic color spaces – Monitor gamma
Dynamic Range - a general introduction with links to Imatest modules that calculate it.
Sensor vs. System DR – Flare, Charts, Exposure – DR definitions – Transmissive chart – Lightbox – How to measure DR – Minimizing reflections – Contrast Resolution chart – Tips and recommendations – Offsets – More on Flare – Flare light – limited DR – F-stop noise & scene-referenced SNR
Chromatic Aberration - (Lateral Chromatic Aberration) AKA Color fringing
Introduction - Measurement - Demosaicing - Correction for non-tangential edges - Purple fringing
Distortion - Methods and Modules 
Veiling glare
Introduction - Target - Stepchart measurement - Results - ISO 9358 - ISO 18844 measurements with Uniformity - Contrast Resolution two exposure method 
Color correction matrix
Introduction - Math - Color/Tone Interactive - Saturation - Applying the matrix 
ISO Sensitivity and Exposure Index
Introduction – Incident light measurement – Modules – Equations – Raw files – Saturation-Based  –  Standard Output  –  Related documents 
 
Information capacity news, video, and links are on Solutions - Image Information Metrics.

Three November 2023 white papers (too many?) contain the latest information capacity measurements and results, including Edge SNRi and filter design. Until Imatest 24.1 is released in spring, 2024, they are available in the Imatest 24.1 Pilot Program.

Introduction to Image Information Metrics is the most concise introduction to image information capacity and related metrics, with a minimum number of equations and minimal technical detail. We may shrink it further for use in a brochure for marketing.

Image Information Metrics in Imatest is a concise and readable introduction to image information capacity and related object and edge detection metrics with moderate technical detail.

Image Information Metrics and Applications: Reference (41 pages) has all the equations and technical detail, but it may be difficult to read. It's the reference for the other documents.

The Siemens star method, introduced in 2020, is slower but better for observing the effects of image processing artifacts (demosaicing, data compression, etc.).
 
Shannon information capacity from Siemens stars (2020) - a figure of merit that combines sharpness and noise
Meaning - Results - Summary
Information capacity measurements from Slanted edges: Equations and Algorithms (2023) - figures of merit that combine sharpness and noise, conveniently measured from any slanted-edge, including NPS, NEQ, and SNRi. 

Image quality utilities let you degrade, enhance, examine, or analyze any image (not just test charts)

Image Processing - Simulate several image processing operations (degradations: blur and noise; enhancements: sharpen, bilateral filter, tone mapping, etc.) and observe their effects on appearance and measurements (MTF, SSIM, etc.).
SSIM: Structural Similarity Index - Measure image quality degradation and artifacts from signal processing such as compression. Also, measure PSNR.
Image Statistics - Interactively observe image statistics: cross sections, means, noise, SNR, histograms, and frequency spectra.
Radial Geometry - Add or correct distortion, lateral chromatic aberration, or rotation to images.

Getting Started with Image Quality Testing

Why Imatest?   |   Test Charts   |   Lighting   |   Image Capture Technique   |   Setting up Your Lab   |   Using Imatest Software 
Sample images for several modules from Github

Start Using Imatest Software

Installation - and getting started
Using Imatest - Getting started - Introduction and general instructions  Recommended for beginners.
Activation/Deactivation - Activating Imatest and moving it from one computer to another
Knowledge base — contains several links to help solve activation issues.
 
Please note:  Each Imatest license can be activated on only one computer at a time, but the activation can be easily moved between computers, especially if they’re online. You can install Imatest– and keep it installed– on as many computers as you like (Macintosh as well as Windows– your license works for both; you never have to uninstall it). To move the activation to another computer, you’ll need to deactivate it on the old computer then activate it on the new one, following the instructions above. You may do this as often as you like.

Imatest Instructions – general

Session Logging - Log level controls for display and log files
Target Detection Settings - Settings for guiding automatic detection of targets if default detection fails.
Skype video specification support - Instructions and suggestions
Building a test lab - How to build a testing lab
Saving and retrieving Regions of Interest (ROIs) -  How to save and retrieve ROIs in named files for future use.
Saved settings - Imatest-v2.ini and INI files for use with Imatest IT
Pass/Fail Monitor - Realtime display and update of pass/fail results (useful with Imatest IT)

Acquiring images - Files, formats, devices, and utilities

Autobatch - Combine several test images (from different modules) for a single device into an automatic batch run.
The Imatest Functional Interface - A simplified interface for running tests with consistent settings
Raw files - Imatest modules can analyze raw files directly or after demosaicing.
 

Knowledge Base highlights - Links to articles for troubleshooting, activation, and general advice on operation.

A module that formerly worked has stopped working
How to store and retrieve region (ROI) selections 
New 2019 Imatest Licensing – Update Required to Activate
There are many more links like these on the full Knowledge Base.
 
Troubleshooting - What to do when Imatest doesn't work
Reporting a crash - Do this first - Installation problems - Version 3.6+ changes - Problems after install - Missing DLLs - Runtime problems - Corrupted INI file - A module has stopped working - Error reporting - Command (DOS) window - Diagnostics runs - Path conflicts

Slanted-Edge sharpness modules

SFR – Basic analysis of slanted-edges (manual ROI selection)

Using SFR Part 1 - Setting up and photographing SFR targets
Using SFR Part 2 - Running Imatest SFR
SFR results: - Chromatic Aberration, Noise, and Shannon capacity plot

SFR results: Auto Focus (AF) plot

Table of slanted-edge MTF modules with automatic region detection  (Rescharts or batch-capable fixed modules)
All support ISO-compliant MTF (sharpness) analysis, Lateral Chromatic Aberration (LCA), and information capacity for chart contrast ratios between 2:1 and 10:1, with the ISO-standard 4:1 preferred.
FeatureSFRplus
eSFR ISO
eSFRiso_enhanced_200W		SFRreg
Optikos_Meridian_200W		Checkerboard
checkerboard_ideal_framing-200W
Sharpness map detail  High  Medium  Depends on arrangement  High
ISO-standard chart design–♦––
Color analysis♦♦  (only for SFRreg center chart)–
Tonal response (OECF)♦♦  (only for SFRreg center chart)–
Noise analysis  Limited♦  Limited  Limited
Distortion♦ Good  Limited–♦ Best
Geometry (rotation,
FoV, keystone, etc.)		♦♦–♦
Features and
recommended uses		Imatest's original automatically-detected chart, in use since 2009. Robust and versatile. Some white space recommended above and below top and bottom bars. More spatial and distortion detail than eSFR ISO.
ISO-standard chart design. Includes wedge analysis and (optional) color patches. Supports detailed noise analysis.

Several individual charts are typically placed around the image field. For
- extreme fisheye lenses (>180º)
- target projection systems
- Charts at different distances to test focus & depth of field.
- extreme high resolution cameras (>36MP)

Relatively insensitive to framing: can zoom in or out as long as distance is large enough so chart quality is not an issue and there are detectable corners. Well-suited for through-focus measurements. Very accurate distortion measurements.

♦ denotes strong support;  – denotes no support.

SFRplus – Automated analysis of slanted-edges

Using SFRplus Part 1 - The SFRplus chart: features and how to photograph it
Using SFRplus Part 2 - Running SFRplus
sfrplus_predistort_200WPre-distorted and special charts for Fisheye Lenses - with many applications such as automotive rear view cameras
              Includes SFRplus, eSFR ISO, and SFRreg charts.  Previewing pre-distortion

eSFRiso_enhanced_200WeSFR ISO – Automated analysis of the ISO 12233:2014 Edge SFR chart

Using eSFR ISO Part 1 - The ISO 12233:2014 E-SFR chart: features and how to photograph it

SFRreg – Automated analysis of registration mark patterns

  • Optikos_Meridian_200WTest at infinity focus with Long Range projection systems
  • Test imaging systems with ultrawide fisheye lenses (>180 degrees)
  • Test at very long camera-to-chart distances
  • Test at variable distances for Depth of Field.
Using SFRreg Part 1 - Registration mark patterns and how to photograph them
 

Checkerboard – Automated analysis of checkerboard patterns

checkerboard_ideal_framing-200WUsing Checkerboard Part 1 - Checkerboard patterns and how to photograph them
Using Checkerboard Part 2 - Running Checkerboard

Other (Rescharts) sharpness modules – Log F-Contrast, Star, Random, Wedge

Using Rescharts - Analysis of resolution-related charts
Log Frequency - Analysis of log frequency-varying charts
Log F-Contrast - Analysis of charts that vary in log frequency and contrast
Star Chart - Analysis of the Siemens star chart
Random/Dead Leaves - Scale-invariant test charts (including Imatest Spilled Coins)
           for measuring texture sharpness
Texture examples - More details of Imatest Spilled Coins texture sharpness measurements
Dead Leaves measurement issue - Illustrates challenges posed by extreme signal processing
Random/Dead Leaves cross method  - Also called the Spilled Coins cross-correlation method.
Wedge Analysis - Analysis of hyperbolic or trapezoidal wedge patterns with the Wedge and eSFR ISO modules

Sharpness utilities & postprocessors

FocusField - Use batch results from a range of distances (or apertures) to measure Curvature of Field,
          Longitudinal (Axial) Chromatic Aberration, Depth of Field, and lens focal length.
Image Stabilization/Sharpness Compare - SFRplus postprocessor for analyzing (Optical) Image Stabilization
          and comparing sharpness of different images
Batchview - Postprocessor for viewing summaries of SFR, SFRplus, eSFR ISO, or Checkerboard results
Find Sharpest Files - Find the sharpest files in a batch
MTF Compare - Compare MTFs of different cameras and lenses (now used infrequently)

Tone, color, and spatial modules

Tone, Color, Noise, and Dynamic Range

New Imatest Dynamic Range film chart with Dmax = base+3.4Using Color/Tone Interactive (Multicharts) - Interactive analysis of color & grayscale test charts
Using Color/Tone Auto (Multitest) - Fixed (batch-capable) analysis of color & grayscale test charts
Color/Tone/eSFR ISO Noise - including chroma, sensor (raw), and visual noise
Contrast Detection Probability (CDP)  - Based on IEEE p2020 automotive image quality standard
Color/Tone Special Charts - Additional charts, including ISO OECF and noise chats and circles arranged on a square
Color Correction Matrix (CCM) Calculate a matrix (usually 3x3) for correcting image colors (often from raw images)
Nonuniformity Correction in grayscale and color chart modules for Color/Tone Auto or Setup, Stepchart, and Colorcheck
Dynamic Range - a general introduction with links to Imatest modules that calculate it.
Contrast Resolution - A special transmissive chart for measuring the visibility of low contrast features in larger fields over a wide dynamic range. Analyzed with Color/Tone Interactive or Auto.
Gamutvision - A module for exploring ICC profiles and gamut mapping — illustrates how colors change when images are moved between files and devices.
Colorcheck/Color/Tone Appendix - Color difference algorithms and reference formulas
Dynamic Range (postprocessor) - Calculate Dynamic Range from several Color/Tone Auto or Stepchart images
Measuring test chart patches - with a Spectrophotometer and one of two software packages

Spatial and Uniformity (Flat field) modules

Light Falloff contour plotUsing Flatfield, Part 1 - Measure lens vignetting and image nonuniformity
Using Flatfield, Part 2 - Features in Imatest Master and IS (not in Studio)
Using Flatfield-Interactive - Interactive measurement of vignetting and sensor nonuniformity (can be used with direct image acquisition)
Using Flatfield Blemish Detect - Measure visible sensor defects
Flatfield statistics - Measure PRNU & DSNU with methods based on EMVA-1288: Separate fixed-pattern (spatial) noise from temporal noise by processing multiple identical images.
Lightbox Comparison Guide - Comparing lightbox brightness and uniformity
Testing flat screen displays - with Imatest Blemish Detect
Using Distortion  (legacy module: not recommended for new work. Often fails with strongly distorted images. Checkerboard is now Imatest's recommended module for measuring distortion: it is accurate, robust, and works well with strongly barrel-distorted ("fisheye") lenses.
Dot Pattern - Analysis of a grid of circular dots

Miscellaneous modules and utilities

Lighting Control - Set up and control DMX lights (Kino Flo) and Lightboxes; monitor lighting conditions with an Isolight puck.
Arbitrary Charts - Analyze a chart layout you have designed yourself. 
Device Manager - Connect to cameras, adjust settings and acquire images into interactive modules.
Video: Dynamic measurements - These can also be performed with direct image acquisition.
Test Charts - Create test charts for high quality inkjet printers
SVG Test Charts - Scalable Vector Graphics charts for MTF and other measurements
Using Screen Patterns - Monitor patterns for Light Falloff, SFR, Distortion, and monitor calibration
Rename Files - using EXIF data
Image Processing - Simulate several image processing operations (degradations: blur and noise; enhancements: sharpen, bilateral filter, tone mapping, etc.) and observe their effects on appearance and measurements (MTF, SSIM, etc.).
\
Image Statistics - Interactively observe image statistics: cross sections, means, noise, SNR, histograms, and frequency spectra.
Database - Collect and store important information on image capture conditions, device state, and EXIF metadata
Composite Chart - Create a synthetic test chart from several individual image files. Can be used for Photon Transfer Curves.
Educational Apps - Learning resource for image quality factors and measurements. 

Imatest IT – Industrial Testing (non-GUI)

Imatest IT-EXE instructions - Running Imatest IT (Industrial Testing)-EXE
Imatest IT-C instructions - Running Imatest IT (Industrial Testing)-C
Imatest IT-C++ instructions - Running Imatest IT (Industrial Testing)-C++
Imatest IT-Python instructions - Running Imatest IT (Industrial Testing)-Python
Imatest IT-.NET (C#) instructions - Running Imatest IT (Industrial Testing)-.NET (C#)
Imatest IT-.NET (Visual Basic) instructions - Running Imatest IT (Industrial Testing)-.NET (Visual Basic)
Imatest IT Parallel (IT-P) - Accelerating Imatest IT by performing tests in parallel
Imatest INI file reference - Reference to INI files for IT/EXE and IT/DLL users (sections used in several modules)
Direct Read Mode - Pass image data directly into Imatest IT, without writing to a file on disk
Implementing Pass/Fail - Setting up Pass/Fail criteria and Pass/Fail Reference. For Imatest IT and GUI versions.
Pass/Fail Monitor - Realtime display and update of pass/fail results (useful with Imatest IT)
Operator Console - User interface for production environments
Imatest IT Knowledge Base - Articles about Imatest IT

Appendix

FAQ - Frequently Asked Questions
Cross-reference tables - Tables to help you navigate Imatest
Version comparison: Studio vs. Master - Which is right for you?
Troubleshooting - What to do when Imatest doesn't work
Imatest Change Log - Imatest release history
Default INI Folder - Location on your computer of resource files used by Imatest
License - The Imatest End User License Agreement (EULA)