Basic Knowledge

Dead pixel indicates the bright or dark flecks in infrared images that do not change with the target, which caused by high or low response rate of single detector element to infrared radiation, it also called as ineffective pixel.

Ghost indicates the bright or dark lines in infrared images that do not change with the target, which caused by the non-uniform response rate of detector element to infrared radiation.

Thermal time constant can be comprehended as the time required by thermal cameras to generate a image with complete and accuracy temperature data. The smaller the thermal time constant, the faster the speed of photo generation, and the faster and moving objects can be captured.

Due to the limits of infrared detector manufacturing process, each detection element on infrared detector has different response rate to infrared radiation, ghost appears on the images, which affects imaging quality. Non-uniformity correction function can effectively prevent the appearance of ghost, and restore the authenticity of the images.

NETD (Noise Equivalent Temperature Difference) indicates that the smallest temperature difference can be detected by infrared detector, which is one of the most important parameters to measure performance of infrared detector/sensor. NETD is typically being expressed in milli-Kelvin (mK). The lower the NETD, the better the imaging quality.

MRTD (Minimum Resolvable Temperature Difference) is the key parameter to comprehensively evaluate the ability of NETD and IFOV in the field of thermal imaging. At a given IFOV value, when observers can just distinguish 4 bands (50% of probability), the temperature difference between the target and background called MRTD. The smaller the MRTD, the better the performance of infrared thermal imagers.

Size of imaging resolution reflects arrangement distribution and total number of detection element on focal plane of detector. The higher the imaging resolution, the clearer the imaging.

Pixel size also known as detection element, it is the smallest unit used by sensor to scan objects, each pixel size indicates a temperature acquisition unit. The smaller the pixel size, the better the imaging quality.

Frame rate is the frequency at which bitmap image consecutively appear in frame on the display screen of the device.

Focal length of lens is the distance from the center of the lens to its focus, usually denoted in F. Its unit is usually expressed in millimeter. The larger the distance, the farther the clear image can be taken.

Measurement accuracy indicates the difference between the measured temperature and actual temperature. The smaller the value, the better the performance of infrared thermal imager.

IFOV also called as spatial resolution. It indicates the actual size of the corresponding objects for each pixel, expressed in radian. The smaller the IFOV, the higher the imaging resolution.