Imatest’s Norman Koren presents his vision for challenges in automotive image quality testing including resolving low-contrast scenarios.

A Camera Monitor System (CMS) consists of a camera, an image processing pipeline, and a monitor for viewing the camera image. Examples include automotive side and rear view mirror replacement systems and medical endoscopes (where the doctor views the endoscope image on the monitor). Although there are good reasons to test the components separately (this lets you find out where degradations occur), sometimes the complete system needs to be tested. for example, camera 1 output (shown below) may not be available. Testing the complete system requires a high-quality camera whose resolution is considerably better than that of the CMS camera […]

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This is a professional grade miniaturized target for assessing color, tone, and white balance in addition to measuring resolution and Spatial Frequency Response (SFR) or Modulation Transfer Function ( MTF) for digital cameras/scanners using edge gradient analysis of ISO 12233 and ISO 16067. All target patches are made in cooperation with Munsell Color Services from the same pigmented color paints as the GretagMacbeth™ ColorChecker®. At center are 12 spectrally neutral gray patches for assessing correct exposure and white balance. (These are NOT ink-jet, photographic, or electro-photographic generated colorants). The slanted edges can be used to reliably measure SFR or MTF out to 3000 dot-per-inch or 60 cy/mm with the appropriate software. Five line visual hyperbolic wedges are also included to aid in visual assessment of limiting resolution to 850 dpi.

Although Imatest is primarily orientated toward testing cameras, it includes several tests for monitors (displays). It can measure the sharpness of all sorts of displays, including flat panels, projectors, heads up displays (HUDs), virtual & augmented reality head-mounted displays (HMDs) . It can also measure display defects, as described in Testing display defects with Imatest Blemish Detect, as well as the sharpness of Camera Monitor Systems (CMS).    This post describes how to measure monitor sharpness. It applies to a large variety of displays and monitors. The technique is similar to CMS measurements, but there are a few differences. Please note […]

Imatest is pleased to announce that they will attend the 2017 IS&T Electronic Imaging conference from January 29 – February 2, 2017. Join us as we discuss, learn about and share the latest developments in electronic imaging technology. You can also email us to set up an appointment in advance.

Imatest’s Checkerboard module is our new flagship module for automated analysis of sharpness, distortion and chromatic aberration from a checkerboard (AKA chessboard) pattern. The big benefit of using the checkerboard is that there are looser framing requirements than with other kinds of test targets. While checkerboard lacks the color and tone analysis provided by SFRplus and eSFR ISO, these features are not available on the high precision chrome on glass substrate, so the checkerboard is the optimal pattern for this test.

Autofocus plays a major role in many camera system applications with variable focus, including consumer electronic devices. Camera systems must be able to focus at a variety of distances. Optical systems on cameras only allow a certain range of distances from the camera to be in focus at once (this is often known as the depth of field, or depth of focus).

The updated Imatest Spilled Coins Cross test charts use cross-correlation calculation texture metrics to provide improved stability for images with nonlinear noise reduction. Users can now more accurately differentiate between noise and texture. Random/Dead Leaves Cross, which runs under the interactive Rescharts interface, measures SFR (Spatial Frequency Response) or MTF (Modulation Transfer Function) from random scale-invariant (or approximately scale-invariant) test charts, including “Dead Leaves” and “Spilled Coins” charts.

For lenses that focus out at long distances, to verify ability to focus on distant objects you will need a target system that produces an image that is at or beyond the hyperfocal distance of your lens. You can use our chartfinder utility to determine the size of your imaging plane at a distance based on your lens’ angular field of view. Jump to: Collimator Fixture  |  IMTS Target Projection | IBTS Stray Light/Target Projector Version | Projection Collimators | Multi-collimator systems  | Physical Targets Virtual Target Projection Systems A collimator lens (also known as a close-up lens or relay lens) can change […]

Image Quality Factors are also called Key Performance Indicators (KPIs). Sharpness Noise Dynamic-Range Color Accuracy Distortion Uniformity Chromatic Aberration Stray Light (Flare) Color Moiré Artifacts Compression   Image Quality Factor Video Series   Summary table— Image quality factors and corresponding test charts and modules Sharpness   Noise   Dynamic range, tone, & contrast   Color accuracy Lens Distortion   Uniformity   Blemishes   ISO Sensitivity Lateral Chromatic Aberration   Stray Light (Flare)   Color Moiré   Artifacts Data compression losses   Dmax   Color gamut    Texture Detail   Overview of image quality and Imatest measurements  Image quality is one […]

Noise reduction and sharpening           Original | NR+Sharpening Software (especially operations performed during RAW conversion) can cause significant visual artifacts, including oversharpening “halos” and loss of fine, low-contrast detail. These artifacts result from nonlinear (nonuniform) signal processing (so-called because it varies with the signal). Images may be sharpened (MTF boosted) in the proximity of contrasty features like edges and blurred (lowpass filtered) in their absence. This generally improves measured performance (both sharpness from slanted-edges and noise/Signal-to-Noise Ratio (SNR) from chart patches), but it may result in a degradation of perceived image quality, for example, a “plasticy” cartoon-like appearance of skin even […]

  Original | Barrel-distorted Lens (optical) distortion is an aberration that causes straight lines to curve near the edges of images. It can be troublesome for architectural photography and photogrammetry (measurements derived from images). The simplest approximation is the 3rd order equation, ru = rd + krd3 where rd is the distorted and ru is the undistorted radius. Depending on the sign of k, it can be either “barrel” (shown on the right) or “pincushion.” A mixture known as “mustache” distortion may occur for complex lenses which are better described by a 5th order approximation (ru = rd+ h1rd3+ h2rd5) . Lens distortion and coefficients for correcting […]

Resolution Testing Fisheye (highly barrel-distorted) lenses can be effectively tested with several Imatest modules. SFRplus with pre-distorted test charts. If chart parameters are entered, distortion and Field of View (FoV) are calculated. eSFR ISO with pre-distorted test charts. Distortion and FoV are not currently calculated. Beyond around 160° it becomes increasingly difficult to fill the image plane with a planar test chart.   We introduced SFRreg as a flexible target and analysis system for testing the resolution of ultra-wide cameras. (It can also be used for long-distance and depth of field testing) Example of an ultra-wide camera test setup: See […]

The quality of a camera lens determines how an image forms on a sensor. Lens quality is tested to verify the lens is designed, built, and focused correctly. Once a highly tedious process, Imatest has since refined the testing practice with several solutions, including highly accurate and specific test charts and fixtures. Testing Distance – Sharpness – Chromatic Aberration – Lens Flare Geometric Calibration – Relevant Standards – Supply Chain Image Quality   Testing Distance To determine what size of test chart is needed, use the Imatest Chart Finder that can also calculate the imaging plane based on the sensor […]