9 May 2006 (Boca Raton, Fla.) -- A new DPC Processor utility, available from high-performance machine-vision camera manufacturer Imperx, gives users control over the process for correcting defective pixels in their camera’s CCD. All Lynx-series Camera-Link and GigE cameras have on-board defective-pixel correction capability using pixel correction tables developed at the factory from final-test measurements. Some power users, however, want to create their own pixel-correction tables because their application requires modified pixel-selection criteria.
Defective pixels are classified as “dark” (low sensitivity), “light” (high sensitivity) or “hot” (sensitivity increases with exposure time) relative to the average responsiveness of all pixels on the CCD. Such variations are usually at least annoying, and can be devastating, depending on their application’s requirements.
Imperx camera software uses a Defective Pixel Map (DPM) file stored in the camera’s internal non-volatile memory (NVM) to correct the values put out for up to 128 defective pixels. The system uses a correction algorithm based on coefficients in the DPM file to calculate the digital value the camera would have put out for each defective pixel, had that pixel worked properly.
While all Imperx Lynx cameras are capable of making these defective-pixel corrections, the factory-developed DPM files use criteria (such as thresholds for classifying pixels as “dark”) that work well for most applications, but may not be ideal for a given application.
Imperx’ DPC Processor utility steps users through the process of building their own DPM files. All the user has to do is set the camera up to view a blank screen lit evenly with an adjustable illumination level. The DPC Processor main dialog window provides all of the controls required to set thresholds and control the test. Additional dialog windows allow the user to upload the new DPM File to the camera’s NVM.
