Imatest can correct for nonuniform illumination and lens response (vignetting) in Imatest modules that analyze grayscale and/or color charts, including Color/Tone Setup (formerly Color/Tone Interactive), Color/Tone Auto (formerly Color/Tone Auto), Colorcheck, and Stepchart. Nonuniformity correction involves reading and specifying a second image, taken from a flat-field target (plain gray or white) under identical conditions to the test image.  Note that the correction described in this page is not the same as nonuniformity correction for slanted-edge MTF measurements. Not also that Color/Tone Interactive (a highly interactive module) and Color/Tone Auto (a batch-capable fixed version of Color/Tone Interactive) are recommended for new […]

Imatest 5.2 has several new features that let you use measured chart modulation transfer function (MTF) to do the following: Determine the suitability of a test chart characterized by size (height), print media, and printing technology for camera MTF measurements where the camera is characterized by pixel size, which is typically the number of vertical pixels. This can help determine the appropriate test chart for a specific application. This capability has been enhanced in Imatest 5.2  with the addition of the Chart suitability display. Increase the accuracy of MTF measurements by dividing the measured camera MTF by the appropriately scaled chart […]

Analyses & Output – INI settings – Chart Definition Files – Chart Definition Utility   INI file fields relevant to Arbitrary Charts The following INI fields are currently exposed to the user to control the behavior of the Arbitrary Charts module and its output. They have been organized here by topic, but do not need to be in any particular order or grouping in your INI file itself.    [arbcharts] section Slanted-edge Analysis     Texture Analysis   Star Analysis   Wedge Analysis   Uniformity Grid Analysis   Color/Tone/Noise   Perceptual metrics   Module operation and misc.   [api] section   […]

Analyses & Output – INI settings – Chart Definition Files – Chart Definition Utility   Combine all the features you need to analyze into a single chart Introduction The Imatest™ Arbitrary Charts module analyzes images of custom test charts. A chart-definition file (typically user defined) is needed to describe the chart layout to Imatest software. The Arbitrary Charts module will automatically locate and analyze target features when an observed image of a chart is loaded along with the corresponding definition file.    This module allows users to get a number of measurements out of custom, legacy, or competitors’ charts which are unsupported […]

Analyses & Output – INI settings – Chart Definition Files – Chart Definition Utility   Data outputs from the Arbitrary Charts Module are different from other modules in Imatest: Only JSON files are output, not CSV or XML. The structure of JSON is substantially different than other modules.  If several images are run in a batch, results from all images may be contained in a single JSON. Since the Arbitrary Charts Module is based on the concept of a custom layout of features, there is no fixed structure to the measurement results that the Module produces. Instead, the module simply produces […]

Introduction Watch on YouTube. Imatest IT (Industrial Testing) is a set of Application Programming Interfaces (APIs) that allow developers to access Imatest’s powerful image quality analysis tools in their own custom applications. Imatest IT is available for 64-bit Windows and Linux, and includes libraries for use with C, C++, Python, .NET (including C# and Visual Basic), and LabVIEW, and also contains standalone executables that can be called from a command line or script. The API libraries perform the exact same calculations as the corresponding GUI-based Imatest Master modules. Imatest IT is a complete package that includes the module libraries, support […]

Introduction Introduction – Background – The Contrast Resolution chart – Photographing & analyzing – Tonal response and SNR – Visualization – Analysis – Contrast Resolution Dynamic Range – Tone mapped results – Summary – Verification This page describes the Imatest Contrast Resolution chart and analysis (supported by Imatest 5.0+), which is designed to measure the visibility of low contrast objects in larger fields over a wide range of brightness. These measurements are expressed as the Contrast Resolution Signal-to-Noise Ratio (SNRCR) and Dynamic Range (DRCR). They are of particular interest to the automotive and security industries. This method of dynamic range measurement was inspired […]

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 […]

How Imatest IT/.NET works Imatest IT/.NET (Industrial Testing .NET) is a Microsoft .NET Framework library that allows developers to access Imatest‘s powerful image quality analysis tools via calls to methods residing in a .NET DLL library. The library methods perform the same calculations as the corresponding GUI-based Imatest Master modules.  Imatest IT/.NET is compatible with .NET Framework versions 4.5 and higher.  Fourteen modules are available: SFR   SFRplus   Star Colorcheck   Stepchart   Wedge Uniformity (Light Falloff)   Distortion   eSFR ISO Blemish   Dot Pattern   Multitest OIS   Random     Imatest IT/.NET is a complete package that includes the module libraries, […]

Imatest 4.4+ can evaluate auto-focus (AF) as a measure of MTF with respect to time. This can be performed by using the SFR module with an appropriate video file. Uses/Purpose This metric is intended to be used as a way to measure the time a camera system takes to auto-focus. Rise time and settling time are automatically calculated. This measurement does not provide information about the accuracy or precision of auto-focus. To evaluate those measures, several measurements should be performed on the final, settled images and compared. File Selection and Frame Selection Begin by clicking on SFR from the main window and select a […]

Operation – Image processing blocks – Displays and analysis – Remosaicing – Optical Character Recognition (OCR) Face and People Detection The Imatest Image Processing module, introduced in Imatest 4.4 and significantly enhanced in 4.5 and 5.0, simulates a number of image processing operations, including image degradations such as noise and blurring as well as image enhancements such as applying a Color Correction Matrix, tone mapping (used in High Dynamic Range (HDR) imaging), Unsharp Masking (USM), and bilateral filtering. You can instantly observe the visible effects of these operations by switching between unprocessed and processed images. You can see how processing affects several measurements, including […]

  This page describes details about the implementation of our CPIQ Solution.   For additional details about the initiative, see this presentation assembled by former committee chair Margaret Belska.   Imatest’s CPIQ Implementation Imatest 4.4+  supports IEEE CPIQ P1858TM (Camera Phone Image Quality) 2016 measurements. As members of CPIQ, we are strongly committed to providing convenient CPIQ-compliant and equivalent image quality measurements. NOTE: You should use at least Imatest 4.4.9 for the latest corrections to visual noise calculations. This page has similar order to chapters the CPIQ Standard, “P1858TM/D1 Standard for Camera Phone Image Quality“ document. The first four chapters […]

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 Item   Imatest Module

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 […]

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 does with SFRplus and eSFR ISO). You can zoom in as much as you want as long as there are sufficient edges to analyze, and you can zoom out as far as you want (though the […]

Imatest Checkerboard performs highly automated measurements of sharpness (expressed as Spatial Frequency Response (SFR), Lateral Chromatic Aberration, and optical distortion from images of checkerboard patterns (with a recommended tilt angle of ~5-8 degrees for sharpness measurements). The primary advantages of Checkerboard are: Compared to Imatest’s other automatically-detected sharpness modules:  It is relatively insensitive to framing. You can zoom in or out as much as you like, as long as there are detectable corner features.  Compared to the Distortion (legacy) module:  It works with highly-distorted (fisheye lens) images. Calculations are more accurate, and it contains all results available in Distortion. The […]

Introduced in Imatest 4.2, the Imatest Educational Apps serve to demonstrate mathematical concepts that directly relate to the understanding of image quality factors. The Imatest Educational Apps demonstrate Nyquist sampling theorem, the decomposition of an image’s Fourier transform, the Modulation Transfer Function of a slanted edge, chromatic aberration and signal to noise ratio (SNR). As an educational resource, this utility is available through the main window of your Imatest software. To access the Imatest Educational Apps, go to the Imatest main window and select Help, then Educational Apps…. A Welcome splash screen will open by default. Select the tabs across […]

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 […]