In February 2014 a new version of the ISO 12233:2014 standard, “Photography — Electronic still picture imaging — Resolution and spatial frequency,” was was released. This new standard defines three test charts. The new Imatest eSFR ISO module preforms a highly automated analysis of the new low (4:1) contrast Edge SFR chart. It is available now in Imatest Master and Image Sensor 4.0. (more…)
We are happy to announce that Imatest Master 3.10-Beta is now available for Mac OS X
We are confident in the stability of the image quality testing algorithms in this version, but have kept the Beta tag on this release since there may be some minor issues that remain to be resolved before we remove the Beta tag. (more…)
Imaging-resource.com publishes images of the Imatest Log F-Contrast* chart in its excellent camera reviews. These images contain valuable information about camera quality— how sharpness and texture response are affected by image processing— but they need to be processed by Imatest to reveal the important information they contain.
*F is an abbreviation for Frequency in Log F-Contrast.
Here at Imatest we recognize that not every company has an in-house team of software engineers to create a user interface for Imatest IT to suit the needs of a production environment. To address this need, we have created the Operator Console, which we are releasing as an open-source Microsoft Visual Studio 2012 project written in C++ on github: Operator-Console . (more…)
In our last chart quality investigation we looked at the fine detail of transmissive (backlit) test charts. Now we will look in to the properties of reflective charts.
Imatest currently offers three types of reflectively-illuminated test chart. Most of the charts we produce are printed on a high quality inkjet printer on matte or semi-gloss (luster) papers. We also have a chart that is produced with a photographic process. We will determine which of these substrates has the sharpest edge and quantify the difference.
Roger Cicala of LensRentals.com has completed the second part of his two part series investigating lens testing.
In the first part: “There is No Perfect Lens“, Roger explored about the sharpness variability that is inherent to consumer-grade lenses:
“My first thought when seeing more variation than expected was our testing methods weren’t accurate. So we refined testing methods, eliminated bad copies, and tested only new copies. The variation was still there.
“Like most people testing lenses, we used Imatest. But maybe a lens-test projector would be better. Nope. Well, the gold standard was MTF measured on an optical bench. So we (despite the vigorous protestations of those-who-manage-the-money) bought an optical bench. It showed a similar amount of copy-to-copy variation.”
In the second part: “There is No Perfect Lens Test, Either”, Roger compares testing using Imatest to the expensive optical bench. He makes some valid constructive criticisms about how a variation in SFRplus region selection can lead to different reviewers having a variation in their test results. Roger also writes about how chart quality can be the limiting factor for measurements, and the importance of testing multiple focus distances. (more…)
Imatest 3.10 Released
The latest version of Imatest has been optimized for speed and includes many improvements and new features. A new image stabilization module allows users to test the efficacy of a camera’s optical image stabilization (OIS). To see a rundown of all of the new additions to version 3.10, take a look at our blog detailing the release. (more…)
The release of version 3.10 of Imatest brings a host of improvements to make image quality testing faster and more relevant to advances in cameras. Look for performance, stability, interface and measurement improvements across the board as well as some excellent new modules and features.
- An Optical Image Stabilization (OIS) module has been added to measure OIS effectiveness using images of the SFRplus chart. This module compares three images: unshaken, shaken without OIS, and shaken with OIS. It can also be used to compare SFRplus images from different imaging systems.
- The new Multitest module can analyze all of the color and grayscale charts supported by the interactive Multicharts module in a non-interactive mode that allows batch runs. (Multitest was called ColorTest in early 3.10 releases.)
- Five existing Rescharts modules─ Random (which supports the new “Spilled Coins” texture chart), Log F-Contrast, Wedge, Star (Siemens), and Any Image Sharpness ─ are now available as non-interactive modules that can be run in batches.
- New hue and saturation displays have been added to the Multicharts color accuracy, tonal response and noise modules.
- The new Random/Dead Leaves module provides stronger support for Dead Leaves-type texture charts, particularly for the new Imatest Spilled Coins chart, which is more uniform and has better scale-invariance resulting in more consistent measurements for different image sizes.
Printed at 600 ppi (pixels per inch) on Epson DisplayTrans using an HP DesignJet Z3100 printer here at Imatest HQ. Produced at sizes up to 1083mm (44 inches) in height.Quality should be very similar to our reflective inkjet materials.
Using Babelcolor Patch Tool or SpectraShop 4
This post describes how to measure color and grayscale patches on a variety of test charts, including Imatest SFRplus charts, the X-Rite Colorchecker, ISO-15729, ISO-14524, ChromaDuMonde CDM-28R, and many more, using a spectrophotometer and one of two software packages.
- Babelcolor PatchTool which works with reflective test charts
- Robin Myers SpectraShop 4 which works with both reflective and transmissive (backlit) test charts
Measurement results are stored in CGATS files, which can be used as reference files for grayscale and color chart analysis in Multicharts, Multitest, Colorcheck, Stepchart, and SFRplus. In many cases, custom reference files provide more accurate results than the default values. (more…)