Why is the lenna image rotated?
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Opened lenna.raw file in figure.
By the way, the image is rotated 90 degrees counterclockwise. It was a 256x256 image, and I printed the image using mat2gray.
I'm curious as to why and how the image is spinning.
please help me thank you.
4 Comments
DGM
on 22 Feb 2022
When you read the image into a rectangular geometry such as in this call:
a = fread(raw,[256,256])
understand that what you're doing is taking the raw data in the file (a vector) and devectorizing it. This is the same as reshaping any other vector.
Consider the example:
myimagevector = 1:25; % pretend this is the image data
myimagematrix = reshape(myimagevector,5,5)
The contents of the vector are placed columnwise into the output geometry. If the original data had been written out row-wise, then the result will be transposed -- not rotated.
@yanqi liu is correct. All you likely need to do is transpose the incoming image.
Accepted Answer
yanqi liu
on 22 Feb 2022
yes,sir,may be check
when read it,should use ' to transposition the matrix
fid = fopen('lena256.raw', 'rb');
x = fread(fid, [256, 256], 'uint8=>double').' ;
fclose(fid);
figure; imshow(x, [])
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