Imager Resolution & The Great Pixel Debate
Sponsored by: Testo Inc.
Imager Resolution & The Great Pixel Debate
Tip written by: Infraspection Institute
Resolution is one of the most important objective specifications for any thermal imaging system. Pixel count is frequently offered as a measure of image quality; however, pixel count is only one of many factors that affect imager resolution.
The Focal Plane Array (FPA) detector assemblies used in modern infrared imagers are made up of several tiny, discrete picture elements or pixels. Each pixel is a discrete infrared detector that collects thermal data. Individual pixels are arranged to form an array that ultimately allows the imager to produce a thermal image.
FPA detectors are commonly specified according to pixel count and ratio. Typical detector sizes for industrial imagers range from 160W by 120H to 320W by 240H; some detectors may have more or less pixels. To determine the total pixel count for a detector; the horizontal and vertical values are multiplied.
Imager manufacturers often cite pixel count as a measure of imager resolution. Imager sales are won and lost as entire ad campaigns focus heavily on this single objective specification. Actually determining resolution is not that simple.
Although resolution generally increases with the number of pixels, there are several other factors that influence image clarity or resolution. These include, but are not limited to, pixel viewing angle, imager optics, signal-to-noise ratio and the imager’s display screen.
When evaluating an imager for resolution, physically try the imager under actual working conditions. Imagers that produce clear images should be sufficient to the task regardless of pixel count.
To better understand imager resolution, read the article, Selecting, Specifying and Purchasing Thermal Imagers available from Infraspection Institute. To obtain a copy of the article, call 609-239-4788 or visit us online at www.infraspection.com.
