including raw (image sensor), chroma, and visual noise as well as several types of Dynamic Range calculation News– 2021: Using images of noise to estimate image processing behavior for image quality evaluation  was presented at Electronic Imaging 2021. Noise can be measured anywhere in an image– on edges, etc.– if multiple identical images are acquired. This will lead to some interesting applications. Imatest 5.2: Multicharts (the highly interactive module for measuring color accuracy, tonal response, and noise) has been renamed to Color/Tone Setup, and Multitest (the fixed/batch-capable version of Multicharts) has been renamed to Color/Tone Auto. For now the old […]

Page Contents This page provides an overview of the summary metrics Overview Level-Based Metrics Count-Based Metrics Minimum Measurable Stray Light Overview Similar to how MTF50 (SFR50) and MTF area provide a single number for resolution, stray light also has single number measurements for characterizing stray light performance. These summary metrics fall into two categories: Level-Based: Metrics that are about the amount (level) of the stray light Count-Based: Metrics about the number of pixels (count) that meet a criteria Level-Based Metrics Overview Level-based summary metrics describe the amount (level) of stray light in the image. They include standard summary statistics (e.g., […]

Analysis of wedge patterns with the  Imatest Wedge and eSFR ISO modules News  2021.2 —  Logarithmic wedges: a superior design describes the advantages of logarithmic wedges, which have a much better distribution of spatial frequencies than hyperbolic wedges, allowing a larger maximum/minimum frequency ratio. Supported by Imatest (automatically detected) since 2021, but (as of May 2022) not currently included in standard eSFR ISO charts (though available on request).  2020.2 —  Calculations were greatly sped up in order to improve performance of direct image acquisition. During the testing of the speedup with direct acquisition, we found that Wedge results were unstable during […]

Which version is right for you? Imatest 5.0:  All functions of Imatest Image Sensor have been incorporated into Imatest Master.   Imatest is available in several GUI (Graphic User Interface)-based versions. Studio, with everything individual photographers need to test their cameras and lenses. Studio is only available to individual photographers. Master, the full-featured industrial-strength version for engineers and scientists who develop and evaluate imaging systems. Acquire images directly from several manufacturer’s development systems. Images can be updated and analyzed in real time with the Rescharts, Multicharts, and Uniformity-Interactive modules. As of Imatest 5.0, Image Sensor (IS) has been discontinued. All […]

Introduction Imatest’s slanted-edge algorithms for calculating MTF/SFR are based on ISO 12233 standard, “Photography – Electronic still picture cameras – Resolution measurements”. Although this standard is well-established in industry, we often receive questions regarding its validity. This document describes methods for validating the Imatest slanted-edge method for calculating image sharpness (expressed as Modulation Transfer Function, MTF, which is synonymous in practice with Spatial Frequency Response, SFR). MTF is a measurement of image contrast as a function of spatial frequency. As such, it is a measure of device or system sharpness, which is only indirectly related to perceived image sharpness in […]

Create test chart files for high quality inkjet prints for for screen display Imatest 24.2 (pilot program):  Test charts can now create high quality screen displays.     Although we strongly recommend that customers purchase charts from the Imatest Store, the Imatest Test Charts module allows you to create test chart files for printing on high quality photographic inkjet printers. If you plan to print charts using this module, you should be skilled at fine printing and have a knowledge of color management to obtain optimum chart quality; otherwise we recommend purchasing charts at the Imatest Store. Disclaimer: Although we sell […]

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 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 that contain two light and two dark quadrants). This document illustrates SFRreg results. Part 1 introduced SFRreg and explained how to obtain and photograph the chart. Part 2 showed how to run SFRreg inside Rescharts and how to save settings for automated runs.   SFRreg results When calculations are complete, results are displayed in the Rescharts window, which allows a number of displays to be selected. The following […]

Running SFRreg (Interactive and Auto mode settings) Setup window – ROI numbering – More settings – SFRreg target detection Auto mode settings – Warnings – Summary 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 that contain two light and two dark quadrants). This document shows how to run SFRreg in Rescharts and how to save settings for automated runs. Part 1 introduced SFRreg and explained how to obtain and photograph the chart. Part 3 illustrates the […]

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 […]

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 […]

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 […]

The SFRplus chart: description and how to photograph it Slanted-edge test – Advantages – Obtain chart – Framing – No bars – Lighting Distance – Exposure – Tips – Links 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: […]

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 […]

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 […]

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 […]

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 […]

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 […]