Image compression using DCT

[Quantas]

Trying to perform an image compression using DCT and show the DCT coeffecients using LabVIEW 7.1!

Not sure how to go about?!

[Stephanie B]

Hi Quantas,

This question was answered on another post and is copied below:

http://forums.ni.com/ni/board/message?board.id=170&message.id=203935&requireLogin=False

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I found in one of the Readme files, that the DCT.vi is one of the new transforms that was added in LabVIEW 8.0, so it is not available in LabVIEW 7.0.  I tried looking at the DCT.vi in LabVIEW 8.0 and found that it doesn't do much more than make a call to a dll.  If you have LabVIEW 8.0 on the same computer, you could use a Call Library Function Node to make the VI yourself. 

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[Quantas]

the query related to a 2d image and so, discrete cosine transformation relate to a 2d dct transformation! the obvious part...

how does one go about implementing this in 7.1

[titi_nicolas]

what is exactly your problem: 1) understanding the basics of DCT and how to compress the image or 2) how to implement this in labview?

For the technical parts of the first point, you can find plenty of info on the web.

If you know what you have to do then it is very easy to implement it in labview. You start with a 2D array (the image) and then apply the DCT that gives you a new 2D array of coefficients. The key of compression is in playing with this array (which is related to point 1, and not with labview itself).

[sigma10]

how I can compress an image by DCT?