Point Grey Research Knowledge Base

Article 33 - Different color processing algorithms.

Issue:
Different color processing algorithms.

Solution:

Some PGR cameras (e.g. Dragonfly2, Flea2) convert the raw Bayer tiled images produced by the sensor into color on board the camera, while others (e.g. Scorpion, Flea) leave this task to the host computer. The following list enumerates the various color processing / interpolation algorithms accessible through various PGR libraries.

NOTE: Details regarding the PGR-specific implementation of these algorithms is proprietary and cannot be shared with the public. Refer to the Coriander library for Linux (see Related Article below) for details on how to create your own color processing algorithms.

NOTE: Users of cameras that perform on-board color processing can still access the raw Bayer data, which will allow them to apply their own color conversion algorithm or one of the FlyCapture library algorithms. This is done by acquiring images using one of the Format_7 video modes that support Raw8 or Raw16 pixel encoding.

All of the images were generated from the same raw image and are magnified to illustrate the differences. Each image links to the full image from which it was taken:

  • Nearest Neighbor Fast - This is the fastest of all of the provided color processing algorithms. It is generally considered to provide the poorest results.

Nearest Neighbor Fast Sample
Nearest Neighbor Fast Sample

  • Nearest Neighbor - Based on a very similar algorithm to the Nearest Neighbor Fast this algorithm is slower but performs slightly better.

Nearest Neighbour Sample
Nearest Neighbour Sample

  • Edge Sensing - Slower than Nearest Neighbor, this algorithm weights surrounding pixels based on localized edge orientations.

Edge Sensing Sample
Edge Sensing Sample

  • High Quality Linear - Although this is the second-slowest algorithm, it is much faster than Rigorous, and produces comparable results.

Edge Sensing Sample
High Quality Linear Sample

  • Rigorous - This algorithm is the slowest of all of the algorithms, but produces the best color quality.

Rigorous Sample
Rigorous Sample

Related Articles:
1.) Color PGR Imaging Product shows black and white images
2.) Writing color processing software and color interpolation algorithms.
3.) Rigorous color processing with Digiclops and Bumblebee cameras
4.) How is color processing performed on my camera’s images?
5.) Relationship between color processing and number of bits per pixel.
6.) Key differences between imaging cameras.
7.) PGR FlyCapture SDK color processing algorithm performance.
8.) Ladybug SDK Color Processing, Rectification and Stitching Performance Measures


Article ID:
33
Published:
12:00:00 AM
Last Modified:
9/18/2008 3:34:57 PM
Keywords:
color processing, color interpolation, nearest neighbour, edge sensing, rigorous, on-board color processing, high quality linear, hq linear
Issue Type:
Customization

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