Interactive Analysis of Resolution-Related Charts New in Imatest 2020.1 : Shannon information capacity from Siemens Star charts  Introduction – Supported charts – SFR – SFRplus – eSFR ISO – SFRreg – Checkerboard Getting Started – Rescharts Window  –   Rescharts modules Slanted-edge SFR – SFRplus – Log frequency (simple) – Log frequency-contrast – Star – Wedge  Random/Dead Leaves – Focus Score Introduction Imatest™ Rescharts is a highly-interactive interface for running several Imatest modules that can analyze images of several different test charts for resolution-related parameters such as sharpness (i.e., Spatial Frequency Response SFR, which is equivalent to Modulation Transfer Function MTF), color moiré, and fine detail lost to software noise reduction. All Rescharts modules can […]

Running eSFR ISO – Rescharts eSFR ISO – eSFR ISO setup window – Speeding up – More Settings window – Secondary Readouts – Gamma – Auto mode settings – Warnings – eSFR ISO summary Running eSFR ISO Imatest eSFR ISO performs highly automated measurements of several key image quality factors using one of three versions of the ISO 12233:2014 Edge SFR chart: Standard, Enhanced, or Extended. This document shows how to run eSFR ISO in Rescharts and how to save settings for automated runs. Part 1 introduced eSFR ISO and explained how to obtain and photograph the chart. Part 3 […]

Imatest eSFR ISO results Imatest eSFR ISO performs highly automated measurements of several key image quality factors using one of three versions of the ISO 12233:2014 Edge SFR chart: Standard, Enhanced, or Extended. Unlike most other modules, the user never has to manually select Regions of Interest (ROIs). Image quality factors include Sharpness, expressed as Spatial Frequency Response (SFR), also known as the Modulation Transfer Function (MTF), Noise, measured from the grayscale patches surrounding the center of the chart, includes all types of noise calculated by Color/Tone Interactive and Color/Tone Auto (standard pixel noise, chroma noise, scene-referenced noise, sensor (raw) […]

Direct image acquisition allows images to be captured directly from a variety of devices without first being stored as files. It has several important applications. Introduction – Direct data reload for realtime analysis – Signal averaging By continuously reloading images, it can be used for realtime (or near-realtime) image analysis, where “realtime” means that analysis appears to be instant in the timeframe of human perception. It is especially valuable for focusing with slanted-edges (which can be analyzed faster than other MTF patterns) or with cropped areas of arbitrary images.   It is very useful for signal averaging — a technique […]

Two operating modes – Charts –  ISO 12233:2014 Compliance – Advantages  Imatest eSFR ISO performs highly automated measurements of several key image quality factors using versions of the new ISO 12233:2014 E-SFR (Edge SFR) test chart that may be purchased from the Imatest store (recommended) or printed on a high-quality inkjet printer. Region of Interest (ROI) selection is automatic, based on user-entered criteria (similar to  SFRplus, which it closely resembles). Image quality factors include: Sharpness, expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function (MTF) Lateral Chromatic Aberration Distortion  Simple low-order calculations; less accurate than the SFRplus or Checkerboard). […]

Imatest Checkerboard performs highly automated measurements of sharpness (expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function (MTF)), Lateral Chromatic Aberration, and optical distortion from images of checkerboard patterns (with a recommended tilt angle of 2-7 degrees). The primary advantage of Checkerboard (as compared to Imatest’s other automatically-detected modules) is that it is relatively insensitive to framing. You can zoom in our out as much as you like, as long as there are detectable corner features.  This document illustrates Checkerboard results. Part 1 introduced Checkerboard and explained how to obtain and photograph the chart. Part 2 showed […]

Selecting files – Setup window – ROI selection & analysis area – Edge ID Files More settings window – Secondary Readout  – Settings area – Auto mode window Warnings – Clipping – Summary    Using Checkerboard Part 1 – Checkerboard patterns and how to photograph them Running Checkerboard (Interactive and Auto mode settings) Imatest Checkerboard performs highly automated measurements of sharpness (expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function (MTF)), Lateral Chromatic Aberration , and optical distortion from tilted checkerboard images.The primary advantage of Checkerboard is that the field of view, i.e., the framing, does not need to be tied to the chart size (as it […]

Measure visible sensor defects The Human Visual System – Algorithm – Instructions – Settings window – Filtering and threshold – Display options – Defective pixels – Tuning – Results Flatfield Blemish Detect detects visible sensor defects (typically blurred (dark) spots caused by dust in front of the image sensor, but light blemishes can also be detected). To ensure that only visible blemishes are flagged— and blemishes below the threshold of visibility are not— the image is filtered by a response function derived from the Human Visual System (HVS). Filter settings are adjustable for a wide range of applications and viewing conditions.  The IT version of […]

The Pass/Fail monitor (introduced In Imatest 4.0) provides a real-time indication of whether a device has passed or failed a test. It saves the trouble of digging through results— in figures or CSV or JSON files. Key features: It can stay open while modules run, displaying results immediately after calculations are complete. It works best on systems with a high resolution screen or dual screens. It interfaces with most Imatest analysis modules. It can be extremely valuable for developing and testing Pass/Fail criteria for Imatest IT (Industrial Testing). It can call several utilities for helping with this process. It displays […]

Introduction Part 1 of this page illustrates images analyzed in Random Scale-invariant & Dead Leaves. The images are not shown original size; they’ve been resized to be approximately equal in magnification with respect to the original chart image— with enough magnification to show the results of the camera optics and image processing. Part 2 demonstrates how demosaicing is the cause of a commonly observed discrepancy between Spilled Coins and slanted-edge MTF measurements. Part 1: Images used in Random / Dead Leaves Original pattern (cropped from the middle of the chart), for reference. Original pattern (reduced from file used to print […]

This document contains reference data intended to help Imatest users implement test plans that include automatically-detected slanted-edge modules. It describes the most important JSON results, which can be used for Pass/Fail criteria, as well as the key settings needed to get these results.Settings windows and recommended settings Settings for slanted-edge modules Slanted-edge modules can be run in either Setup (interactive) or Auto (batch-capable) mode. You can make settings in Setup mode; Auto mode uses saved settings from Setup mode.  When you run one of  the four auto-detection slanted-edge SFR modules (eSFR ISO, SFRplus, Checkerboard, and SFRreg) in Setup mode, the […]

Introduction: Starting in version 4.5, Imatest is capable of performing the cross-correlation based texture blur measurement which is under consideration for ISO 19567-2: Texture Analysis on Stochastic Pattern. This is a texture-blur-analysis method originally proposed in Description of texture loss using the dead leaves target: Current issues and a new intrinsic approach by Kirk et al at Image Engineering.  This method starts from the same principles as the so-called “Direct” method of Cao et al which is the Power Spectral Density-based method described on the Random Module page. The main difference is the Direct method makes use of assumed statistical properties […]

Overview Starting in Imatest 4.4, it is possible to perform basic analysis of a video system’s ability to auto focus (AF), auto white balance (AWB) or auto expose an image (AE). Combined, these three tests may be referred to as AAA analysis. Currently, temporal analysis is only compatible with the following modules: Auto Focus: SFR Auto White Balance: Colorcheck Auto Exposure: Stepchart When you select one of these modules and read a video file, the fourth option in the Imatest Video Reader, plot metric with respect to time, will be made available. Selecting this option begins the appropriate setup for […]

Test Charts creates test chart files for printing on high quality inkjet printers. This page focuses on Scalable Vector Graphics (SVG) charts, many of which are used for measuring sharpness (MTF) with Imatest SFR, SFRplus, eSFR ISO, Checkerboard, and SFRreg. (Bitmap charts are described elsewhere.) SVG charts can be printed any size at a printer’s maximum quality (i.e., resolution) with no limitations, and they generally require much less storage than bitmap images. The SVG charts designed for automated testing with SFRplus and eSFR ISO (based on ISO 12233:2014/2017) have numerous advantages over the familiar but obsolete ISO 12233:2000 chart. Most […]

 Analyze the Siemens Star chart New in Imatest 2020.1 (Feb. 2020)  Shannon information capacity can be calculated from images of the Siemens star, with much better accuracy than slanted-edges. The old slanted-edge method has been deprecated.   The white paper, “Camera information capacity: a key performance indicator for Machine Vision and Artificial Intelligence systems“, which briefly introduces information theory, describes the camera information capacity measurement, then shows results (including the effects of artifacts) is now available for download. Imatest 5.0: Half-stars (rotated by multiples of 45º) can now be analyzed. A star-only pattern (without density patches, etc.) can be selected in […]

Analysis of random scale-invariant patterns, including the Spilled Coins (Dead Leaves) Pattern, for measuring texture sharpness Introduction – Obtaining – Photographing – Running – Automatic ROI detection – Output  MTF – MTFnn, MTFnnP – Power Spectral Density – Equations & Scale-invariance   Introduction  Random/Dead Leaves, which runs under the interactive Rescharts interface or as a fixed (non-interactive, batch-capable) module, measures SFR (Spatial Frequency Response) or MTF (Modulation Transfer Function) from random scale-invariant (or approximately scale-invariant) test charts, including “Dead Leaves” and “Spilled Coins” charts. It is primarily used to measure the effects of signal processing on image texture. Dead leaves/Spilled Coins charts are of increasing interest because their statistics resemble those of natural […]

A comparison of sensitivity to signal processing: Results for additional cameras This page contains additional Slanted-edge, Siemens Star, and Log F-Contrast results for four cameras, in support of claims in Slanted-edge versus Siemens Star that Siemens Star MTF measurements are nearly as sensitive to sharpening as low-contrast (4:1) slanted-edge measurements. The Siemens Star’s high contrast (specified at >50:1) makes it quite sensitive to saturation and to “shoulders” (regions of reduced contrast) in camera tonal response. Slanted-edge MTF measurements are stable, reliable, and more representative of perceived image sharpness under a wide range of conditions (in addition to their many well-known […]

A comparison of sensitivity to signal processing In this page we address concerns about the sensitivity of slanted-edge patterns to signal processing, especially sharpening, and we correct the misconception that sinusoidal patterns, such as the Siemens star, are insensitive to sharpening, and hence provide more robust and stable MTF measurements. The Siemens Star is of particular interest because, along with the slanted-edge, it is included in the ISO 12233:2014 standard.  To summarize our results, we found that sinusoidal patterns are sensitive to sharpening, though often less so than low contrast (4:1) slanted-edges. The relatively high contrast of the Siemens Star […]

Instructions and comments We are updating this page for the latest Skype/Lync specification. An index of of the Skype/Lync specifications can be found on  http://technet.microsoft.com/en-us/lync/gg278181.aspx. This document contains instructions for using Imatest with the Skype Hardware Certification Specification — For all Skype Video Devices Version 5.0. It also contains comments and suggestions (some of which we hope might be adopted in a future release of the spec). The Skype spec uses only a tiny fraction of Imatest’s powerful capabilities. To learn more, see Image Quality Factors and SFRplus (which allows many factors to be measured from a single image). In […]

Instructions and comments Under development We are updating this page for the latest Skype for Business Video Capture Specification, December 2016. An index of of the Skype/Lync specifications can be found on https://technet.microsoft.com/en-us/office/dn788953 This document contains instructions for using Imatest with the Skype for Business Video Capture Specification, which has two versions: personal solutions (Document Number: H100693) and conferencing devices (Document Number: M1023160), published December 2016. “Skype for Business V3.0” appears on a watermark, and 3.0 is indicated in the Revision History (Section 1). It also contains comments and suggestions for running Imatest. The Skype spec uses only a tiny […]