CMOS sensors almost always have some pixels that don’t have the full dynamic range that they should. Most of these pixels can be corrected with the flat field correction parameters, also implemented in the camera. However, the pixels that cannot be properly corrected with flat field correction are considered defective pixels. These dead or hot pixels, usually stuck dark or bright, are corrected with the defective pixel correction routine. This routine corrects the defective pixel with interpolated values based on neighbouring pixels.
Typical correction methods include averaging with immediate same-colour neighbours, or even going out to the second set of neighbours. Correction can span multiple pixels if by some chance many consecutive pixels in a row are defective. Boundary conditions also exist to handle defective pixels at the edges of the image array.
When to Use
Use this feature when:
- You want to replace dead or hot pixels with interpolated neighbours.
- When the camera is factory calibrated or field calibrated, the FFC Wizard calibration utility will test each pixel and mark it as defective if needed. This is performed after the flat field correction, i.e., only pixels that look defective after flat field correction will be flagged. In most cases increasing exposure time or camera gain before running the FFC Wizard will yield more defective pixels flagged, and therefore more corrected.
- The defective pixel correction routine is always on, and cannot be turned off by a user.
How to use
- All pixels that are flagged as defective will be corrected on the fly as video is streaming.
- There are no settings that the user can adjust.