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watermark Embedding in Blocks

조회 수: 6(최근 30일)
amitesh kumar
amitesh kumar 2011년 3월 7일
답변: cui 2021년 9월 13일
hello everyone i want to embed watermark in image of size 512*512 & watermark size is 64*64. first of all i am converting original image into 8*8 block. then i want to convert watermark also into 8*8 block and embed it into four block only[16*4 = 64(its my watermark size)]. As i am converting original image into total 4096 block.i want to embed watermark into 64 blocks only. can any one elaborate the coding part for it.my part is as follows
%embedding watermark
for R22=1:64
Block2(:,:,xx:yy)=Block2(:,:,xx:yy)+ aa*Block5(:,:,1:64);
xx=64*(R22)+1;
yy=xx+63;
end;
Here consider Block2 as the blocked original image. aa is the embedding constant and Block5 is named to the watermark image. as here clear that its start embedding again after 64 block. but i want it should embed only first 64 block, not in whole image. thanx in advance

채택된 답변

Walter Roberson
Walter Roberson 2011년 3월 7일
I think that in some places you mean "pixels", but that possibly in other places you do mean "blocks". Could you go back over your wording and check it?
Your current code is equivalent to the loop-less
Block2 = Block2 + aa * repmat(Block5(:,:,1:64),1,1,64))
but I am not clear as to what your target is.

추가 답변(2개)

Saira Khalid
Saira Khalid 2018년 7월 3일
can you tell what is the initial value of xx and yy? @ amitesh kumar
  댓글 수: 5
Walter Roberson
Walter Roberson 2018년 7월 6일
You have not converted your image into an 8 x 8 x (number of blocks) array. For example you could use https://www.mathworks.com/matlabcentral/fileexchange/25763-tile and then
Block2 = cat(3, tiles{:})

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cui
cui 2021년 9월 13일

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