How to compute the mean of two disjoint region ?
조회 수: 1 (최근 30일)
이전 댓글 표시
Suppose I have to fragment of an image J : J_out_1 et J_out_2.
J_out_1 = J(1:h,startj:i);
J_out_2 = J(1:h,k:endj);
I would like to compute the mean of the union of those two regions , is it possible ?
m_out = mean2(J_out_1 union J_out_2);
Thank you in advance
댓글 수: 0
채택된 답변
Guillaume
2015년 5월 1일
편집: Guillaume
2015년 5월 1일
m_out = mean([J_out_1(:); J_out_2(:)])
would be one way to do it assuming the image has only one colour channel. If they are RGB images:
m_out = mean([reshape(J_out_1, 1, [], 3), reshape(J_out_2, 1, [], 3)])
Note that if the two regions are the same size, you could just concatenate them without any reshaping (by colon or reshape).
추가 답변 (1개)
Image Analyst
2015년 5월 1일
Why not just take the weighted mean of the two?
numerator = numel(J_out_1) * mean2(J_out_1) + numel(J_out_2) * mean2(J_out_2)
denominator = numel(J_out_1) + numel(J_out_2)
m_out = numerator / denominator
If you want, you could make a binary image and use that as a mask to extract all the pixels in just the two regions:
binaryImage = false(size(J));
binaryImage(1:h,startj:i) = true;
binaryImage(1:h,k:endj) = true;
m_out = mean(J(binaryImage))
댓글 수: 2
Image Analyst
2015년 5월 2일
You're welcome. Those ways will also work even if the two subimages don't have the same number of rows. So "h" could be different for each image and they would still work.
참고 항목
카테고리
Help Center 및 File Exchange에서 Feature Detection and Extraction에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!