[Insight-users] Question on registration of cryogenic RGB images

[Fucang Jia]

Hi, everyone,

At first I thank Luis's help.

Recently I obtained 1399 cryogemic RGB color image, which were produced with 
a high-precision scanner.
These images have different resolution, which are as follows:

1-66         2733 x 3179
67-89        2417 x 3010
90-544       2240 x 3010
545-644      2241 x 3011
645-673      2178 x 3011
674-682      2105 x 3041
683-702      2071 x 3041
703-989      2105 x 3041  ( same with 674-682th )
990-1034     2148 x 3086
1035-1286    2155 x 3110
1287         2163 x 3110
1288-1290    2294 x 3071
1291-1399    2155 x 3110

The image difference is mainly translation and rotation. I want to align the 
second image to the first image, the third to the second, etc. So this is a 
2D registration problem.

The computer is somewhat old, PIII 500 with 640Mb Ram.

Here is several problem I concern:

1. The resolution is different, should I downsampled the image to the 
minimum 2071 x 3010? Or a smaller resolution
such as 500 x 750, because finally I want to visualize the three dimensional 
structure by Marching Cubes or Dividing Cubes in this computer.

2. The image is RGB color, but most of registration algorithm is useful for 
gray scale image, the simplest method is convert RGB image to gray image, or 
only use one channel (red, green, blue), which method is more accurate? I 
noticed that Dr.Luis once said that he would like to implement a 
registration for color image, but I do not know whether this method was 
included in ITK already.

3. The images were not homogenous in brightness, that is to say, the 
brightness of each image have more or least
difference, I think this will induce difficulty in registration. And the 
target area is very small contrast to the entire image. So should I first 
segment the image before registration?

I am confused by these huge images, any advice would be very appreciated!

Fucang

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