Improvement to the ISO 12233 slanted-edge SFR (MTF) calculation

Introduction Note: MTF (Modulation Transfer Function) and SFR (Spatial Frequency Response) are (almost) synonymous. Older papers mostly use MTF, but […]

Fixed versus Interactive modules

Imatest has two types of analysis module: Fixed (in the left-most column of the Imatest main window) and Interactive (in […]

Detecting traffic lights with RCCB sensors

RCCB (Red-Clear-Clear-Blue) sensors are widely used in the automotive industry because their sensitivity and Signal-to-Noise Ratio (SNR) is better than […]

Scene-referenced noise and SNR for Dynamic Range measurements

The problem — in the post on Dynamic Range (DR), DR is defined as the range of exposure, i.e., scene […]

Logarithmic wedges: a superior design

We introduce the logarithmic wedge pattern, which has several advantages over the widely-used hyperbolic wedges found in ISO 12233 (current […]

Gamma, Tonal Response Curve, and related concepts

Introduction – Encoding vs. Display gamma – Why logarithms?  How gamma-encoding increases dynamic range – Expected gamma values –  Entering gamma […]

Comparing sharpness in cameras with different pixel count

Introduction – Spatial frequency units – Summary metrics – Sharpening  Example – Summary Introduction: The question We frequently receive questions […]

Three optical centers

Customers frequently want to know how we measure the optical center of the image (not to be confused with the […]

Real-time focusing with Imatest Master direct data acquisition

Speed up your testing with real-time focusing in Imatest Master 2020.2. Recent speed improvements allow for real-time focusing and allow […]

Making Dynamic Range Measurements Robust Against Flare Light

Introduction A camera’s Dynamic Range (DR) is the range of tones in a scene that can be reproduced with adequate […]

Correcting nonuniformity in slanted-edge MTF measurements

Slanted-edge regions can often have non-uniformity across them. This could be caused by uneven illumination, lens falloff, and photoresponse nonuniformity […]

Measuring temporal noise

Two temporal noise methods  |  Results  |  Temporal noise image Related pages:  Flatfield Statistics based on EMVA-1288  |  Using Flatfield, […]

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).

SFRreg: SFR from Registration Marks

Imatest SFRreg performs highly automated measurements of sharpness (expressed as Spatial Frequency Response (SFR), also known as Modulation Transfer Function […]

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 […]

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 […]

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 […]

Region Selection bug workaround

Symptoms of problem: Upon selection of a region of interest, program stops working, either not responding or crashing. DOS window […]