AND OR

CENTER:Color Demosaicing of Single-Sensor
Sampled Images

Color Demosaicking

What's That?

parrots_BMXaai150dpi.png

A single-chip CCD or CMOS sensor with the Bayer-pattern color filter array is the most popular imaging device for digital cameras. A target scene is focused by an optical lens system onto the CFA to be sampled.

  • Blurring takes place on a captured image due to an optical system.
  • A mosaic picture created by CFA sampling has to be restored by interpolating missing color values.
  • Quantization noise introduced by digitization has to be minimized to produce a visually-pleasing picture.

Color demosaicing is a kind of restoration problems. In the right-hand figure, a mosaic picture shown in the top is changed into a visually-natural picture shown in the bottom. Evaluation of various demosaicing methods is not so simple, because quality has to be demonstrated in the sense of the human visual perception.

  • We have developed a novel scheme, iterative asymmetric average interpolation referred to as iaai. Sharpness restoration is a selling point.
cfa_imaging.jpg

Demonstrations

This is a magnified view.
Note that every small step is equal to the pixel pitch.
originaliaaiACPI
alef13x8.png
alef13x8iaai.png
alef13x8acpi.png
 
  • False color is weak.
  • Sharpness in the original picture is recovered by IAAI after a few iterations.
PSNR of R/G/B in dB19.09/19.26/19.1012.47/12.77/12.45
originaliaaiACPI
sluntsB.png
slunts_iaai.png
slunts_acpi.png
 
http://telecom0.eng.niigata-u.ac.jp/pub/dem_sample.jpg
OriginalAAI, Asymmetric Average Interpolation
IAAI, Iterative AAIAdaptive Color-Plane Interpolation

References

  1. Yoshihisa Takahashi, Hisakazu Kikuchi, Shogo Muramatsu, Yoshito Abe, and Naoki Mizutani, A New Color Demosaicing Method Using Asymmetric Average Interpolation and Its Iteration, IEICE Trans. on Fundamentals, Vol. E88-A, No. 8, pp. 2108-2116, Aug. 2005.
  2. Yoshihisa Takahashi, Hisakazu Kikuchi, Shogo Muramatsu, and Naoki Mizutani, Iterative Asymmetric Average Interpolation for a Single CCD Mosaic Image, ITC-CSCC 2005, pp. 199-200, Cheju, July 4-7, 2005. (invited paper)
  3. Y. Takahashi, H. Kikuchi, S. Muramatsu, Y. Abe, and N. Mizutani, A Proposal of Demosaicing and Its Iteration Using Asymmetric Average Interpolation, Proc. 2004 SIP Symp., D3-4, pp. 1-6, Yatsugatake, Nov. 2004. (in Japanese)

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Last-modified: 2014-07-29 (Tue) 20:44:04 (1594d)