Interpolation%20of%20RGB%20components%20in%20Bayer%20CFA%20images

1
Interpolation of RGB components in Bayer CFA
images

• CEG4311
• Eric Dubois

2
Demosaicking of Bayer-sampled color images

• Problem Most digital color cameras, capture only
  one color component at each spatial location. The
  remaining components must be reconstructed by
  interpolation from the captured samples.
  Objective Develop algorithms to interpolate each
  color plane (called demosaicking) with best
  quality reconstruction, and with minimal
  computational complexity.

3
Construction of color image from color planes

4
Lighthouse original
5
Lighthouse red original
6
Lighthouse green original
7
Lighthouse blue original
8
Formation of Color planes
9
Lighthouse red subsampled
10
Lighthouse green subsampled
11
Lighthouse blue subsampled
12
Lighthouse Bayer CFA image
13
Color plane interpolation
Green channel bilinear interpolation
GA
GL
GR
GI
GB
14
Color plane interpolation
Red channel bilinear interpolation
RNE
RNW
RC
RSE
RS
RSW
15
Lighthouse red interpolated
16
Lighthouse green interpolated
17
Lighthouse blue interpolated
18
Lighthouse Interpolated color image
19
Lighthouse original
20
Can we do better?

• Color planes have severe aliasing. Better
  interpolation of the individual planes has little
  effect.

21
Lighthouse red interpolated with bilinear
interpolator
22
Lighthouse red interpolated with bicubic
interpolator
23
Can we do better?

• Color planes have severe aliasing. Better
  interpolation of the individual planes has little
  effect.
• We could optically prefilter the image (blur it)
  so that aliasing is less severe.

24
Lighthouse red interpolated with bilinear
interpolator
25
Lighthouse prefiltered red interpolated with
bilinear interpolator
26
Lighthouse Interpolated color image
27
Lighthouse Prefiltered Interpolated color image
28
Lighthouse original
29
Can we do better?

• Color planes have severe aliasing. Better
  interpolation of the individual planes has little
  effect.
• We could optically prefilter the image (blur it)
  so that aliasing is less severe.
• We can process the three color planes together to
  gather details from all three components.

30
Lighthouse Interpolated color image with new
frequency domain method