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I am using SimpleCV to stitch images. I have made some changes in SimpleCV's GitHub code and eventually got the image transformed correctly. But the problem is, the color of the image after getting transformed is changed.

I have used these images https://i.stack.imgur.com/TyJpO.jpg. The output of my code is: https://i.stack.imgur.com/iAxkL.jpg

This is my code:

from SimpleCV import *
import cv2
import cv

img1 = Image("s.jpg")
img2 = Image("t.jpg")

dst = Image((2000, 1600))

# Find the keypoints.
ofimg = img1.findKeypointMatch(img2)

# The homography matrix.
homo = ofimg[1]
eh = dst.getMatrix()

# transform the image.
x = Image(cv2.warpPerspective(np.array((img2.getMatrix())), homo,
  (eh.rows, eh.cols+300), np.array(eh), cv.INTER_CUBIC))

# blit the img1 now on coordinate (0, 0).
x = x.blit(img1, alpha=0.4)
x.save("rishi1.jpg")
fireant
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Rishi
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1 Answers1

3

It seems you're using an old revision of SimpleCV. In the latest version the way to get the homography matrix is [1]:

ofimg[0].getHomography()

Edit:

It seems the color problem you're mentioning is due to the change of color space. So please change the line you warp the image to:

x = Image(cv2.warpPerspective(np.array((img2.getMatrix())), homo,
  (eh.rows, eh.cols+300), np.array(eh), cv.INTER_CUBIC), colorSpace=ColorSpace.RGB).toBGR()

I suspect what's happening is that the returned image after warping is in the BGR color space while SimpleCV by default uses the RGB color space. Please let me know how it goes.

fireant
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  • I am using the latest version of SimpleCV from github. I did it like that because I made some change in the code of SimpleCV. Before that the homography matrix itself was wrong. But now the image is perfectly transformed, but the color of the transformed image changes. In the findkeypointMatch function I changed some code. Here is the change I performed https://github.com/ingenuitas/SimpleCV/pull/63/files. But the color problem was before also. – Rishi Apr 16 '12 at 17:06
  • I edited the answer. I cant run exactly your code, but wrote a similar script and found the problem to be the inverted colorspace. – fireant Apr 18 '12 at 05:54