can i use OpenCV for dumping jepg coefcients DC and AC

asked 2013-11-18 10:16:30 -0500

nadeem gravatar image

in my research i need to be able to prepare and extract some features from pictures for being use for classification and now i am looking into tools for this purpose. I am looking into libjpeg and want to ask here if also can use OpenCV since it may has something already done and easy to use to save time and effort any suggestions on the direction i should take?

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Actually your question is somewhat unclear, but it seems to me you are looking for the features2D and machine learning modules of openCV.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-11-20 04:56:30 -0500 )edit

yes i will be using machine learning (svm) and for that i will look at the picture from low level at dct for extracting features so i need to know if i used opencv i will be able to dump dct matrix and be able to analyze dct for 8x8 block and extract features from it. so i will not use pixel values for features

nadeem gravatar imagenadeem ( 2013-11-20 07:24:43 -0500 )edit

What you mean by dct?

StevenPuttemans gravatar imageStevenPuttemans ( 2013-11-20 08:29:30 -0500 )edit

okey i mean the dc and ac matrix for each MCU in image. i read that by using libjpeg this function jpeg_read_coefficients() will read the entire image into a set of virtual coefficient-block arrays. and then i an use those arrays to access the matrices and do my analysis on them an extract features to be used later in svm (planing to use libsvm).

nadeem gravatar imagenadeem ( 2013-11-20 12:10:13 -0500 )edit

O okay, i am sorry but I have no experience with this format, so guess I will not be able to help you.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-11-21 02:08:49 -0500 )edit