The large LED based video screens used in stadiums, arenas, outdoor advertising and large, bright indoor displays are typically constructed from a number of smaller modules. During manufacture of these displays, it is important to ensure that the output characteristics of each module are well matched, otherwise the final display will appear to be a patchwork or appear grainy. The primary output characteristics that must be controlled in order to achieve visual consistency are color and brightness.

Accurate calibration of LED display module color and brightness requires the ability to measure each LED within the assembly and the overall panel output characteristics. The traditional method for performing this task, based on a spot colorimeter and x-y translation system, does not offer the speed, consistency, or flexibility necessary for production applications. To meet the needs of LED screen manufacturers, Radiant Imaging created the PM-LED™ Correction. This system offers superior speed, accuracy and repeatability, as well as reduced sensitivity to alignment over previously available instrumentation.

PM-LED™ Correction utilizes our PM-1400 Series Imaging Colorimeter to precisely measure the luminance and chromaticity of each pixel of an LED panel. System software that has been developed for each customer then automatically sends correction coefficients to the panel control electronics. These adjust each LED to achieve any predetermined level of chromaticity and luminance uniformity, such as those for NTSC specifications or requirements.

Once installed in their venue, the output of LED displays typically change with time. The PM-LED™ Correction system can also be fitted with telescopic optics and used for on-site testing and correction of displays. It is the only system capable of on-site testing.