Color difference ellipses
Starting with Imatest 4.2, Imatest’s two-dimensional color displays— CIELAB a*b*, CIE 1931 xy chromaticity, etc.— in Multicharts, Multitest, Colorcheck, SFRplus, and eSFR ISO can display ellipses that assist in visualizing perceptual color differences. You can select between MacAdam ellipses (of historical interest), or ellipses for ΔCab (familiar but not accurate), ΔC94, and ΔC00 (recommended).
Measuring Multiburst pattern MTF with Stepchart
Measuring MTF is not a typical application for Stepchart— certainly not its primary function— but it can be useful with […]
LSF correction factor for slanted-edge MTF measurements
A correction factor for the slanted-edge MTF (Edge SFR; E-SFR) calculations in SFR, SFRplus, eSFR ISO, SFRreg, and Checkerboard was […]
A Study of Slanted-Edge MTF Stability and Repeatability
by Jackson K.M. Roland Abstract The slanted-edge method of measuring the spatial frequency response (SFR) as an approximation of the modulation […]
Slanted-Edge versus Siemens Star: A comparison of sensitivity to signal processing
This post addresses concerns about the sensitivity of slanted-edge patterns to signal processing, especially sharpening, and corrects the misconception that […]
Sharpness and Texture Analysis using Log F‑Contrast from Imaging-Resource
Imaging-resource.com publishes images of the Imatest Log F-Contrast* chart in its excellent camera reviews. These images contain valuable information about […]
No Perfect Lens, No Perfect Lens Test
Roger Cicala of LensRentals.com has completed the second part of his two part series investigating lens testing.
Transmissive Chart Quality Comparison
Imatest currently sells several transmissive (backlit) test charts, which have a range of substrates, each with specific properties and qualities […]
Measuring Test Chart Patches with a Spectrophotometer
Using Babelcolor Patch Tool or SpectraShop 4 This post describes how to measure color and grayscale patches on a variety of […]
Measuring the Effects of Tilt
Summary: The physical lens-to-sensor tilt angle is difficult to measure from images, but the effects of tilt on image quality are […]
Slanted Edge Noise reduction (Modified Apodization Technique)
For measurement of sharpness, the main driver of variation is noise. A powerful noise reduction technique called modified apodization is […]
Advances in Testing Infrared Camera Systems
New infrared test charts and analysis software modernize testing of infrared cameras Once viewed as exotic devices, infrared camera systems […]
Blemish Detection Now Available
Version 3.6 of Imatest’s Master Edition delivers sophisticated blemish detection capabilities based on the human visual system’s ability to detect […]
Image Quality Google Tech Talk
Norman Koren’s Google TechTalk, Image Quality Measurement: Real world challenges, is now available online. For a clearer view of the […]