Documentation - Current v26.1

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 and metrics - 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

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 vs. Siemens star MTF calculations: 2024 white paper 

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 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

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

Other Image Quality Factors

Stray light (flare) 

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

Imatest Instructions – general

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

Simatest ISP/Camera simulator

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

Slanted-Edge sharpness modules

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

Using SFR Part 1 - Setting up and photographing SFR targets

SFR results: Auto Focus (AF) plot

Table of slanted-edge MTF modules with automatic region detection  (interactively or as Auto (batch) analyses)
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.

Feature	SFRplus	eSFR ISO	SFRreg	Checkerboard
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

Pre-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

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

Slanted-edge results Part 3 - eSFR ISO edge results

Multi-ROI summary – Edge and MTF – Chromatic Aberration – Acutance/SQF – Histograms & noise – Image, Geometry, Distortion, FoV – 3D Plots – Lens style MTF plot – Edge roughness – Point Spread Function – Summary – CSV & JSON output

Slanted-edge results Part 4 - eSFR ISO other results (tones, color, wedge, etc.)

Tonal response and gamma - Image, Geometry, Distortion, FoV - Radial distortion - Summary and EXIF data - Color analysis - Detailed noise plot - Wedge aliasing & MTF - Multi-wedge plot - Summary - Links

 

SFRreg – Automated analysis of registration mark patterns

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

target projection - Chart arrays for fisheye lenses - Center Chart - Obtain and photograph chart -  Lighting - Distance - Exposure - Tips - Links

Using SFRreg Part 2 - Running SFRreg

Selecting files – Setup window – ROI selection & analysis area - Speeding up runs - More settings window – Secondary Readout – Settings area – Gamma – Chart contrast ratio – Auto mode window – Warnings - Clipping – Summary

Slanted-edge results Part 3  - SFRreg edge results

Multi-ROI summary – Edge and MTF – Chromatic Aberration – Acutance/SQF – Histograms & noise – Image, Geometry, Distortion, FoV – 3D Plots – Lens style MTF plot – Edge roughness – Point Spread Function – Summary – CSV & JSON output

Slanted-edge results Part 4 - SFRreg other results (tones, color, distortion, etc.)

Tonal response and gamma - Image, Geometry, Distortion, FoV - Radial distortion - Summary and EXIF data - Color analysis - Detailed noise plot - Summary - Links

 

Checkerboard – Automated analysis of checkerboard patterns

Using Checkerboard Part 1 - Checkerboard patterns and how to photograph them

Obtain and photograph chart -  Lighting - Distance - Exposure - Tips - Links

Using Checkerboard Part 2 - Running Checkerboard

Selecting files – Setup window – ROI selection & analysis area - Edge ID Files - Speeding up runs - More settings window – Secondary Readout  – Settings area – Gamma – Chart contrast ratio – Auto mode window – Warnings - Clipping – Summary

Slanted-edge results Part 3 - Checkerboard edge results

Multi-ROI summary – Edge and MTF – Chromatic Aberration – Acutance/SQF – Histograms & noise – Image, Geometry, Distortion, FoV – 3D Plots – Lens style MTF plot – Edge roughness – Point Spread Function – Summary – CSV & JSON output

Slanted-edge results Part 4 - Checkerboard other results (distortion, etc.)

Image, Geometry, Distortion, FoV - Radial distortion - Distortion Contour plot - Summary and EXIF data - Summary - Links

Other (sharpness analyses – Log F-Contrast, Star, Random, Wedge

Using Rescharts - Analysis of resolution-related charts

Introduction - Getting started - The Rescharts window - resolution analyses - Slanted-edge SFR - SFRplus - Log frequency (simple) - Log frequency-contrast - Star - Wedge - Random/Dead Leaves - Focus Score

Log Frequency - Analysis of log frequency-varying charts

Introduction - Photographing, running - Color moire - Output - Pattern - MTF - Comparisons - Calculation details - Nyquist, aliasing

Log F-Contrast - Analysis of charts that vary in log frequency and contrast

Introduction - Creating, printing - Photographing, running - Output - Pattern - MTF - MTF/contrast contours - MTFnn

Sharpness and Texture Analysis using Log F‑Contrast from Imaging-Resource – comparing of several different cameras.

Star Chart - Analysis of the Siemens star chart

Introduction - Creating, photographing, running - Output - MTF - MTFnn, MTFnnP - MTF contours - Equations

Random/Dead Leaves - Scale-invariant test charts (including Imatest Spilled Coins)
           for measuring texture sharpness

Introduction - Obtaining - Photographing - running - Automatic ROI detection - Output - MTF - MTFnn, MTFnnP - Power Spectral Density - Equations & Scale-invariance

Texture examples - More details of Imatest Spilled Coins texture sharpness measurements

Images used in Random/Dead Leaves - Spilled Coins vs. Slanted edge MTF

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 logarithmic, hyperbolic, or trapezoidal wedge patterns with the Wedge and eSFR ISO modules

Introduction - Recommendations - Instructions - Results - Stability - Limitations & Comparisons - Calculation details - MTF/Nyquist & Aliasing - Logarithmic wedges 

Logarithmic wedges - A superior design with the same frequency distribution as Bode of standard frequency response plots.

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.

Introduction – Examples – Prepare the test – Range and Increment – Acquire the images – Analyze – Run FocusField - FocusField Settings – Results – Curvature of Field – Depth of Field (DoF) – Longitudinal (Axial) CA – Lens focal length – Stereo (3D) compatibility 

Image Stabilization/Sharpness Compare - SFRplus postprocessor for analyzing (Optical) Image Stabilization
          and comparing sharpness of different images

Introduction - Operation - Metrics - Results

Batchview - Postprocessor for viewing summaries of SFR, SFRplus, eSFR ISO, or Checkerboard results

Introduction - Preparation - Instructions

Find Sharpest Files - Find the sharpest files in a batch

Introduction - Operation - Details - Example - Plot 

MTF Compare - Compare MTFs of different cameras and lenses (now used infrequently)

Introduction - Instructions 

Tone, color, and spatial modules

Tone, Color, Noise, and Dynamic Range

Using Color/Tone Interactive – Interactive analysis of color & grayscale test charts

Introduction - Getting started - Supported charts - Reference files - The Color/Tone Setup window - Displays and options

Using Color/Tone Auto (Multitest) - Fixed (batch-capable) analysis of color & grayscale test charts

Introduction - Getting started - Reference files - Results

Color/Tone/eSFR ISO Noise - including chroma, sensor (raw), and visual noise

Chroma noise - Imatest Dynamic range - Image sensor (raw) noise and Dynamic Range - Temporal noise – ISO 15739 & CPIQ Visual Noise – ISO 15739 SNR and Dynamic Range – f-stop noise & scene-referenced SNR 

Image Sensor Noise – measurement and modeling - using raw files for image sensor Dynamic Range and Simatest camera/ISP simulator

Experimental technique - Raw files – Black level offset - Noise model – Dynamic Range – EMVA 1288 – Closing the loop

Color/Tone Test Chart Reference & Guide - A guide to the color & monochrome charts used by Color/Tone.

Chart list – Layout – Numbering – Media/materials – Reference values and files - Color charts - ColorGray-42 - DR36+Color - Monochrome (B&W) charts  

Color/Tone Special Charts (OBSOLETE) - Additional charts, including ISO OECF and noise chats and circles arranged on a square  Instructions - Patch numbering - Examples

Color Correction Matrix (CCM) Calculate a matrix (usually 3x3) for correcting image colors (often from raw images)

Introduction - Math - Calculating in Color/Tone Setup - Saturation - Applying the matrix  1. in Color/Tone  2. in Image Processing  3. externally with program code

Contrast Detection Probability (CDP)  - Based on IEEE p2020 automotive image quality standard

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.

Using Gamutvision instructions - Using Gamutvision Part 2: Displays - Gamutvision Table of Contents/Site Map 
Black point compensation demystified - Round trips for evaluating printer profile quality 

Using Colorcheck (legacy module; not recommended – use Color/Tone instead)

What Colorcheck does - Colorchecker colors - Photographing target - Running Colorcheck - Colorchecker reference sources - Output - Temporal noise - Auto White Balance (AWB) - Saving - Links

Colorcheck/Color/Tone Appendix - Color difference algorithms and reference formulas

Color difference formulas - Color ellipses (Delta-C ab, Delta-C 94, Delta-C 2000, etc.) - Color difference visualizer - Chroma correction (corr) - Algorithm - Grayscale and Exposure error (fix in 5.1+)

Using Stepchart (legacy module; not recommended– use Color/Tone instead)

Photographing the chart - Running Stepchart - Output - Temporal noise - Auto Exposure (AE) - Saving - Dynamic range - Algorithm

Stepchart: Special and ISO charts  Photographing chart - Instructions - Patch order

Dynamic Range (postprocessor) - Calculate Dynamic Range from several Color/Tone Auto or Stepchart images

Introduction - Operation - Results - Dynamic Range background (f-stop/scene-referenced noise)

Measuring test chart patches - with a Spectrophotometer and one of two software packages

Spectrophotometer- Babelcolor Patch Tool - SpectraShop 4 - Patch order

Spatial and Uniformity (Flat field) modules

Using Flatfield, Part 1 - Measure lens vignetting and image nonuniformity

Instructions - Results

Using Flatfield, Part 2 - Features in Imatest Master and IS (not in Studio)

Input dialog box - Hot and dead pixels - Color shading - Flatfield profiles - Grid plot - Polynomial fit -  Histograms - Noise detail - Spot detection

Using Flatfield-Interactive - Interactive measurement of vignetting and sensor nonuniformity (can be used with direct image acquisition)

Instructions - Results

Using Flatfield Blemish Detect - Measure visible sensor defects

The Human Visual System - Algorithm - Instructions - Input dialog - Results

Flatfield INI Reference

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

Testing method - Defective pixels - Luminance nonuniformity - Color nonuniformity - Summary

Dot Pattern - Analysis of a grid of circular dots

Introduction - Setup - Results

Miscellaneous modules and utilities

Lighting Control - Set up and control DMX lights (Kino Flo) and Lightboxes; monitor lighting conditions with an Imatest Spectral Sensor.

Arbitrary Charts - Analyze a chart layout you have designed yourself. 

Introduction - Analyses & Output - INI settings - Chart Definition Files - Chart Definition Utility

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.

Auto White Balance (AWB) - Auto Exposure (AE) - Auto Focus (AF)

Test Charts - Create test charts for high quality inkjet printers

Introduction - Bitmap patterns - SVG patterns - Options

SVG Test Charts - Scalable Vector Graphics charts for MTF and other measurements

Introduction: m x n squares - Squares and wedges - USAF 1951 chart - Operation - Options - Output figure - Printing

Using Screen Patterns - Monitor patterns for Light Falloff, SFR, Distortion, and monitor calibration

Introduction - Light Falloff - SFR - Distortion - Monitor calibration - Monitor gamma - Zone plate - SMPTE color bars - Slanted edges - Colorchecker-Stepchart - Squares (checkerboard)

Rename Files - using EXIF data

Starting - 1. Select folder - 2. Select files - 3. Rename options - 4. Preview - 5. Rename files

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.).

Operation - Image processing blocks - Displays and analysis - Optical Character Recognition (OCR) - Face and People Detection

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)

Managing Supply Chain Image Quality with Imatest

Introduction - R&D - Manufacturing - Combining - Guidelines - Accuracy - Quality Staircase - Challenges - Equipment Verification - Failure Analysis - External Quality

Imatest IT Test Items & Modules

Imatest IT-EXE instructions - Running Imatest IT (Industrial Testing)-EXE

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

Imatest IT-C instructions - Running Imatest IT (Industrial Testing)-C

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

Imatest IT-C++ instructions - Running Imatest IT (Industrial Testing)-C++

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

Imatest IT-Python instructions - Running Imatest IT (Industrial Testing)-Python

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

Imatest IT-.NET (C#) instructions - Running Imatest IT (Industrial Testing)-.NET (C#)

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

Imatest IT-.NET (Visual Basic) instructions - Running Imatest IT (Industrial Testing)-.NET (Visual Basic)

Introduction - Installation - Step 1: Capture Images - Step 2: Configure INI File - Step 3: Call Imatest IT Modules - Step 4: Process Results - Error Handling - Sample Code - Advanced Topics - Troubleshooting

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)

INI file structure - INI File Monitor - [api] (for Imatest IT) - [dcraw/LibRaw] - [rdraw] (Generalized Read Raw) - Secondary Readouts - Miscellaneous

SFRplus and eSFR ISO INI file reference

SFR INI file reference | SFRplus INI file reference | eSFR ISO INI file reference | SFRreg INI file reference | Checkerboard INI file reference

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)

Introduction - Setup - Utilities

Operator Console - User interface for production environments

Imatest IT Knowledge Base - Articles about Imatest IT

Debugging Imatest IT

Speeding up Imatest IT with INI file settings 

Appendix

FAQ - Frequently Asked Questions

Cross-reference tables - Tables to help you navigate Imatest

Suppliers - Image quality factors - Modules - Test charts - Test images

Version comparison: Studio vs. Master - Which is right for you?

Troubleshooting - What to do when Imatest doesn't work

Installation problems - Problems after install - Missing DLLs - Runtime problems - Corrupted INI file - Command (DOS) window - A module has stopped working - Diagnostics runs - Path conflicts

Imatest Change Log - Imatest release history

Default INI Folder - Location on your computer of resource files used by Imatest

INI file reference

Glossary

License - The Imatest End User License Agreement (EULA)

Glosario en Espanol

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Index of the Table of Contents
Image quality — Sharpness — Other IQ factors — IQ Utilities —  Getting started — Imatest Instructions – general — 
Troubleshooting —  Knowledge Base highlights — Slanted-Edge sharpness modules — Other sharpness modules —
Tone, Color, Noise & Dynamic Range modules — Spatial & Uniformity modules —
Miscellaneous modules and utilities — Industrial Testing edition — Appendix