Documentation – Alpha v2021.2

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Tables to help you navigate Imatest modules and charts

Imatest is a complex, rich application involving a great many image quality factors, modules, and test charts. The tables below, for Quality Factor, Module, and Test chart are designed to help navigate the site. A Table of contents is also available.

Image quality factorsModulesTest chartsTest images 
AlgorithmsSuppliers

Image quality factors

Image quality factors have their own page. A brief list of recommended test charts is given in the FAQ.

Quality factor Charts Module Comments
Camera, lens
Color accuracy X-Rite ColorChecker (24-patch) Colorcheck, Color/Tone Color/Tone Interactive or Auto is recommended.
Various color charts listed in Color/Tone Color/Tone IT8.7, ColorChecker SG, ColorGauge, RezChecker, ChromaduMonde 28R, etc.
Rescharts charts with color: SFRplus, eSFR ISO Rescharts
SFRplus
eSFR ISO
Multi-purpose charts primarily designed to map sharpness (MTF) over the image surface. Color and grayscale patterns can be included. Color patches must be measured for accurate results.
Dynamic range Transmissive grayscale stepcharts, especially the Imatest 36-patch Dynamic Range chart. Also some 20-patch OECF charts Stepchart
Color/Tone
Transmissive charts such as the Imatest 36-patch Dynamic Range chart or the Stouffer T4110.
Reflective step charts Dynamic Range Postprocessor to Stepchart or Color/Tone. Not recommended because flare light is not properly accounted for.
Exposure accuracy Any test chart that contains a grayscale step chart, such as the Kodak Q-13/Q-14 Stepchart  
X-Rite ColorChecker Colorcheck  
Lateral chromatic aberration Slanted edge (can be printed from Test Charts) SFR
Rescharts SFR

SFRplus
eSFR ISO
Printable by Test Charts
ISO 12233:2014 Available in a variety of media
Optical (Lens) distortion Checkerboard (recommended), Dot Pattern, SFRplus (all can be printed from Test Charts) Distortion
Checkerboard

SFRplus
Dot Pattern
Distortion – Methods and Modules describes measurements in detail. Distortion is a legacy module: no longer recommended. 
Light falloff (uniformity), vignetting plain, uniformly lit surface Uniformity Best: Screen Patterns with LCD flat screen.
Noise Any grayscale step chart with patches large enough to get reasonable noise statistics. Examples: Kodak Q-13/Q-14, 36-patch Dynamic Range, eSFR ISO, etc. Color/Tone 
eSFR ISO
 
Stepchart
 
Any chart that contains a grayscale, except for ones with very tiny patches such as the Colorchecker SG or IT8.7.
X-Rite ColorChecker Colorcheck  
Sharpness (MTF) from slanted-edges Slanted-edge (can be printed from Test Charts)
ISO 12233:2014 (eSFR ISO)
SFR
Rescharts SFR
L
Printable by Test Charts. Some versions printed on photographic media.
SFRplus chart (highly automated) SFRplus Print or purchase from the Imatest store
ISO 12233:2014 Edge SFR (eSFR ISO) eSFR ISO Print or purchase from the Imatest store
Sharpness (MTF) from other targets Log Frequency, Log F-Contrast,
Star chart, Random scale-invariant, Spilled coins
Log F-Contrast 
Star Chart
Print or purchase from the Imatest store  
Tonal response,  Contrast (Gamma), Noise (as a function of patch density) Grayscale step charts Color/Tone 
Stepchart
Transmissive charts such as the Imatest 36-patch Dynamic Range chart or the Stouffer T4110.
Special charts: ISO-16067-1, QA-62, ISO-14524 OECF, ISO-15739 Noise, 20-patch OECF charts Stepchart Imatest Master only.
ColorChecker, ColorChecker SG, IT8.7, Step Charts Color/Tone  
Veiling glare (lens flare) Reflective step chart with “black hole” Stepchart  
Color moiré Log Frequency Log Frequency Part of Rescharts
Software artifacts Log F-Contrast Log F-Contrast Part of Rescharts
Data compression Log F-Contrast Log F-Contrast Not yet fully supported
Prints
Dmax (deepest black tone) Custom test chart printed from file,
scanned on profiled flatbed scanner
Print Test Gamutvision extracts these properties from ICC profiles.
Color gamut

Modules

Modules are listed on the Tour page.

Module Quality factor Charts Comments
Colorcheck Color accuracy, Tonal response, Contrast, X-Rite ColorChecker-only. Legacy module.  
Distortion Lens distortion Square or rectangular grid  
eSFR ISO Sharpness (MTF), Lateral chromatic aberration, Tonal response, Lens distortion ISO 12233:2014 Edge SFR (E-SFR) chart Highly automated module: no manual ROI selection. Chart available from the Imatest store.
Uniformity Light falloff, vignetting plain, uniformly lit surface  
Color/Tone Interactive

(Interactive
module)
Color accuracy, Tonal response, Contrast, Noise X-Rite ColorChecker, IT8.7, ColorChecker SG, Step charts, special charts: ISO-16067-1, QA-62, EIA Grayscale, ISO-14524 OECF, ISO-15739 Noise, 20-patch OECF charts Interactive module for measuring a large variety of color and grayscale charts.
Color/Tone

(Interactive or Fixed)
Color accuracy, Tonal response, Contrast, Noise   Fixed (batch-capable) module for measuring a large variety of color and grayscale charts (all charts supported by Color/Tone Interactive).
SFR Sharpness (MTF), Lateral chromatic aberration Slanted-edge (printable by Test Charts), ISO 12233 Also measures Subjective Quality Factor (SQF).
SFRplus Sharpness (MTF), Lateral chromatic aberration, Tonal response, Lens distortion SFRplus chart Highly automated module: no manual ROI selection. Chart available from the Imatest store.
Stepchart Tonal response, Contrast, Noise, Dynamic range, Exposure accuracy, Veiling glare (lens flare) Step charts, Special charts: ISO-16067-1, QA-62, EIA Grayscale, ISO-14524 OECF, ISO-15739 Noise, 20-patch OECF charts Special charts in Imatest Master only. Transmissive charts such as the Stouffer T4110 recommended for DR.
Dynamic Range (Postprocessor for Stepchart) Tonal response, Dynamic range Reflective step charts such as the Kodak Q-14/Q-14. Usually more convenient than Stepchart for measuring DR because it doesn’t require a transmission chart, special light source, and darkened room.
Print Test Dmax (deepest black tone), Color gamut Custom test chart printed from file,
scanned on profiled flatbed scanner
Gamutvision extracts these properties from ICC profiles.
Log Frequency Sharpness (MTF), Color moiré Log Frequency (can also use Log Frequency-Contrast chart) Part of Rescharts
Log F-Contrast Sharpness (MTF), Software artifacts Log Frequency-Contrast Part of Rescharts
Star Chart Sharpness (MTF) Star chart Part of Rescharts

Test charts

This list is primarily commercially-available test charts. You can print out additional charts from files generated by the Test Charts module.

Chart Quality factor Module Comments
Recommended charts
Sharpness (MTF), Lateral chromatic aberration, Tonal response, Lens distortion SFRplus Available in the Imatest Store in several sizes, media (transmissive and reflective), and options (pre-distorted, etc.).

 

Designed to measure several key image quality factors from a single image with a high degree of automation: no manual ROI selection. SFRplus operates interactively inside Rescharts or as a fully automated module with no user intervention. Has numerous advantages over the old ISO-12233 chart, listed here.

eSFRiso_enhanced_200W
eSFR ISO

Sharpness (MTF), Lateral chromatic aberration, Tonal response, Lens distortion eSFR ISO Available in the Imatest Store in several varieties, sizes, and media (transmissive and reflective).

 

Designed to measure several key image quality factors from a single image with a high degree of automation: no manual ROI selection. eSFR ISO operates interactively inside Rescharts or as a fully automated module with no user intervention. Has numerous advantages over the old ISO-12233:2000 chart, listed here.


Spilled Coins chart
Texture, Sharpness Random Available from the Imatest Store: Color, Monochrome.

Imatest Master
-only. Color or Black & White available.
dynamic_35_E_200W
36-Patch Dynamic Range
(transmissive)
Tonal response, Noise, Dynamic Range Color/Tone Interactive,
Color/Tone Auto
Available from the Imatest Store.

Imatest Master
-only.

Density range depends on chart variant. Near-circular design minimizes effects of light falloff. Automatic region selection available. Much easier to use than other transmissive stepcharts.

Color accuracy, Tonal response Color/Tone Interactive,
Color/Tone Auto
Available from the Imatest Store.

Imatest Master
-only.
Color accuracy, Tonal response, Noise Colorcheck, Color/Tone Interactive,
Color/Tone Auto
Available from the Imatest Store.

Widely available; consistent pigments. A compatible chart is available from Danes-Picta.

Color accuracy, Tonal response Color/Tone Interactive,
Color/Tone Auto
Available from Wolf Faust

Requires reference file

Dynamic range, Tonal response, Contrast Stepchart, Color/Tone Interactive (Special charts),
Color/Tone Auto
Imatest Master-only.
ISO-15739 Noise target crop
ISO-15739 (Noise)
Dynamic range, Tonal response, Contrast Stepchart, Color/Tone Interactive, 
Color/Tone Auto
 
Q13 grayscale step chart
Step charts (reflective):
Kodak Q-13, Q-14, etc.
Tonal response, Contrast, Noise, Exposure accuracy, Veiling glare Stepchart,
Color/Tone Interactive.
Dynamic Range
Veiling glare is measured with “black hole” next to the Q-13. May be purchased from professional camera stores or Danes-Picta.
Other transmissive
step charts: Stouffer
T4110
, etc.
Dynamic range, Tonal response, Contrast, Noise Stepchart,
Color/Tone Interactive,
Color/Tone
For measuring dynamic range
Log Frequency-Contrast chart
Log Frequency, Log F-Contrast (sine or bar)
Sharpness, Color moiré, Detail lost to software noise reduction

Log Frequency,

Log F-Contrast

MTF can be a check on the slanted-edge method; more direct but less accurate.
Siemens star chart
Siemens star chart
Sharpness Star chart Imatest Master-only. May be created for printing by Test Charts. Will be available on the Imatest store.

Other charts
Sharpness, Lateral chromatic aberration, Subjective Quality Factor (SQF) SFR Printed on high resolution photographic media. Slanted-edge charts printed on a high quality inkjets can perform the same function, but aren’t as fine. No longer supported in the ISO 12233:2014 standard.
The SFRplus chart has numerous advantages, listed here.
  Color/Tone Interactive,
Color/Tone Auto
 
Color accuracy, Tonal response Color/Tone Interactive,
Color/Tone Auto
Imatest Master & Image Sensor-only.
Color accuracy, Tonal response Color/Tone Interactive,
Color/Tone Auto
Imatest Master & Image Sensor-only.
QPcard 201
QPcard 201
Color accuracy, Tonal response Color/Tone Interactive,
Color/Tone Auto
Inexpensive chart

Test images

These images were put online for testing Imatest API/EXE, but they are generally useful for testing Imatest. This is not a comprehensive list of charts, which can be found in the above table.

Module Image file Description
Webcam image of high and medium contrast custom charts created by Test Charts and printed on an Epson R2400 printer: these can have larger regions of interest (ROIs) than the ISO 12233 chart below.
Webcam image of ISO 12233 chart. At this distance the available regions of interest are very small.
Webcam image of the Kodak Q-14 grayscale and X-Rite ColorChecker.
Image of the Stouffer T4110 transmission test chart taken with the Canon Powershot G2. Excellent dynamic range measurement.
(image in Colorcheck, above)
GMB_Q-14_webcam.jpg
Webcam image of the Kodak Q-14 grayscale and X-Rite ColorChecker.
12-patch OECF chart (for API and Imatest Master only ). Available from Imatest Store.
Image of Kodak Q-14 chart with “black hole” cavity for measuring veiling glare (susceptibility to lens flare)
Webcam image of distortion grid.
Image of nearly uniformly illuminated surface taken with the Canon 10-22mm lens on the EOS-20D, f/4.5, 22mm, ISO 1600.
Image Log-Frequency-Contrast chart (cropped), acquired by the EOS-20D camera, 24-70mm f/2.8L lens set at 42mm, f/5.6, ISO 100. Can also be used with Log Frequency.

Algorithms

Module Algorithm link Brief description
Stepchart www.imatest.com/docs/stepchart  
Slanted-edge MTF measurement. The calculation is derived from ISO-12233. The average edge is calculated using a 4x oversampling binning algorithm. MTF is the Fourier transform of the derivative of the differentiated edge (the average line spread function (LSF)). The Imatest algorithm is more immune to noise and lens distortion than the standard ISO algorithm, which can be selected in a checkbox if desired.

Suppliers

Most test charts are available from the Imatest Store.

Supplier Chart(s) and comments Location
Imatest A large variety of charts (sharpness, color, tone, dynamic range) are available on the Imatest store. Boulder, CO USA
Stouffer The Stouffer T4110 transmission step wedge was recommended for single-image Dynamic Range measurements prior to the development of the Imatest 36-patch Dynamic Range chart. Chicago, IL USA
Wolf Faust
(Coloraid.de)
IT8.7 (standard color target with reference file, printed on photographic paper or color transparency film). Used in Color/Tone Frankfurt, Germany