I want to find DCT of a gray scale image. How to do it?

The gray scale image is divided into 8*8 blocks. How to find DCT of EACH 8*8 block and display dct of one block? Further, how to quantize the dct of each block?

[Chandvi Arora]

And what is the diiference between dctmtx and blockprocing the dct statement?

[Deo Kelvin]

hello..can I ask for your coding? I am new to Matlab and my problem is the same as yours. You can send it to my email [e-mail]. Thank you in advance, I really appreciate your kindness. @Chandvi Arora

Answer 1

[Walter Roberson]

blockproc() the dct2() call.

[Chandvi Arora]

Since I am a beginner can you please help me with the blockproc:-

img_dct = dct2(grayImage);
C= blockproc(grayImage,[8 8],@dct2);

This is what I have as my code for dct and I also want to display dct matrix of a single 8*8 matrix, of many 8*8 blocks in the image. Please help me out.

[Walter Roberson]

C = blockproc(grayImage, [8 8], @(block) dct2(block.data));

[Chandvi Arora]

Variable C will contain the DCT right? And now how to find its idct?

[Chandvi Arora]

C = blockproc(grayImage, [8 8], @(block) dct2(block.data)); This statement gives an output as in the attached image. please guide me through.

[Walter Roberson]

 iC = blockproc(C, [8 8], @(block) idct2(block.data));