Photographing the chart – Running Stepchart – Settings – Output – Temporal noise Auto-exposure – Saving – Dynamic range (DR) – DR definitions – Algorithm   Stepchart measures the tonal response, noise, dynamic range, and ISO sensitivity of digital cameras and scanners using Reflective grayscale step charts such as the Kodak/Tiffen Q-13 and Q-14 Gray Scales, which have a single row of patches (a linear arrangement), or charts such as the ISO-14524 or ISO-15739 charts, with non-linear (multiple rows; may be circular) patch arrangements, shown below, or Transmissive (backlit) grayscale step charts such as the Imatest 36-patch Dynamic Range or 36-patch […]

Imatest SFRreg performs highly automated measurements of sharpness (expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function (MTF)) and Lateral Chromatic Aberration from images that contain registration mark patterns (circles with two light and two dark quadrants). Unlike standard test charts, these patterns do not need to be located on a flat (planar) surface. Since Region of Interest (ROI) detection is automatic, they may be positioned where needed. Depending on the image source, they offer several advantages. You can Test images at infinity distance (or any distance of choice) using a compact projection system such as a collimator […]

Running SFRplus (Interactive and Auto mode settings) Imatest SFRplus performs highly automated measurements of several key image quality factors using a specially-designed test chart. This document shows how to run SFRplus in Rescharts and how to save settings for automated runs. Part 1 introduced SFRplus and explained how to obtain and photograph the chart. Part 3 illustrates the results. New in Imatest 3.10 SFRplus settings can be updated by clicking Settings, SFRplus Auto settings in the Imatest main window without having to read an image file into Rescharts SFRplus Setup. New in Imatest 3.9 SFRplus can be run without including […]

Imatest SFRplus results Imatest SFRplus performs highly automated measurements of several key image quality factors using the specially-designed SFRplus test chart. 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, Lateral Chromatic Aberration, Distortion (with nearly as detailed output as the Distortion module). Described in detail here. Tonal response (again, with less detail than Stepchart; no noise statistics) Color accuracy, when used with an SFRplus that contains the optional color pattern, located above the […]

The SFRplus chart: description and how to photograph it Watch on YouTube. Download 1080p/720p/540p. Purchase SFRplus Test Charts from the Imatest Store. Imatest SFRplus performs highly automated measurements of several key image quality factors using a specially-designed test chart that may be purchased from the Imatest store (recommended) or printed on a high-quality inkjet printer. The user does not need to manually select Regions of Interest (ROIs). Image quality factors include Sharpness, expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function (MTF), which can be mapped over the entire image, Noise (limited: eSFR ISO has more detailed […]

From the Imatest main window, click on SFR or Rescharts on the upper left. SFR allows you to analyze multiple regions and to run batches of files. Rescharts (1. Slanted-edge SFR) allows you to analyze single regions in a highly-interactive interface. ISO 12233:2000 chart images, which have contrasty (≥40:1) slanted-edges, can be downloaded from dpreview.com reviews, typically in the last page titled “Compared to…,” and from Imaging-resource.com reviews, typically on the page labeled “sample images.” We no longer recommend such high contrast images, because saturation can lead to inaccurate results. 4:1 or 10:1 contrast images are much preferred. Image file […]

Monitor patterns for Light Falloff, SFR, Distortion, and monitor calibration Introduction Screen Patterns displays a variety of test patterns on monitors, preferably on LCD flat screen monitors. It may become more useful as cost-effective ultra-high resolution (4k+) monitors become available. It is opened by clicking on Screen Patterns on the right of the Imatest main window. Most patterns (except perhaps Monitor calibration) perform best with the window maximized. You may need to redraw the pattern after maximizing (or resizing) it by selecting the pattern or changing one of the settings. These patterns are offered as a convenient alternative to the […]

Setting up and photographing SFR test charts Imatest SFR measures spatial frequency response, also known as the Modulation Transfer Function (MTF), of digital cameras using a slanted-edge (light-to-dark) target, as described in Sharpness: What is it and how is it measured? Although it doesn’t provide the as strong a visual indication of MTF as wedge or sinusoidal chats (such as Log Frequency), it provides a more accurate quantitative measurement and uses space much more efficiently. Old ISO 12233:2000 test chart (left) with Imatest SFR cropping indicated by the red rectangle New ISO 12233:2014 test chart (right– supported with a high […]

Running Rescharts slanted-edge modules (Interactive and Auto mode settings) Imatest Rescharts slanted edge modules— SFRplus, eSFR ISO, SFRreg, and Checkerboard— perform highly automated measurements of several key image quality factors using specially-designed test charts. This document shows how to run these modules in Rescharts and how to save settings for automated runs.  Four introductory pages —  SFRplus, eSFR ISO, SFRreg, and Checkerboard — describe each module and explain how to obtain and photograph the chart.  Rescharts Results Part 3 and Part 4 illustrate the results. Selecting files – Setup window – ROI selection & analysis – Edge ID files – Speeding up runs […]

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 […]

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 […]

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). […]

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 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. Blemish detect also includes all […]

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 […]

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 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 […]