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    <p>This is an extremely broad question, here is a general outline of one way you could do it...</p> <ul> <li><p>Find strong <em>features</em> or <em>corners</em> on both images using <code>cvGoodFeaturesToTrack()</code></p></li> <li><p>Pass the features you found into <code>cvFindCornerSubPix()</code> to get more precise floating point representations of the locations of strong <em>features</em></p></li> <li><p>Calculate the optical flow between the two images using the sub-pixel features from the last step using <code>cvCalcOpticalFlowPyrLK</code> or another optical flow function. (I like <code>cvCalcOpticalFlowPyrLK()</code>)</p></li> </ul> <p><em>This is where it gets tricky</em>... in order to rectify images it helps to have some knowledge about the intrinsic camera properites (field of view, focal length) especially if you are planning to do some kind of 3d reconstruction or compute disparity correspondence. Since you didn't mention anything about a calibrated camera set up I will continue on the <em>uncalibrated</em> algorithm.</p> <ul> <li><p>You will need to find the Fundamental Matrix which encodes all aspects of the scene used to compute a rectification matrix. Use <code>cvFindFundamentalMatrix()</code> to do this.</p></li> <li><p>Armed with the Fundamental Matrix you must now find the Homography Matrix, which will map both images to the same plane. Use <code>cvStereoRectifyUncalibrated()</code> to do this. Although the name would suggest that it is rectifying your images it is NOT, it just returns homography matrices that you can USE to rectify your images.</p></li> <li><p>Finally, using the Homography matrices from the last step you can rectify both images by calling <code>cvInitUndistortRectifyMap()</code> to get a remap matrix and then pass that into <code>cvRemap()</code> to do the actual remapping.</p></li> </ul> <p>I must warn you that there are <em>many</em> parameters that go into <em>each</em> of these library calls and you will have to manipulate <em>many</em> matrices and <em>many</em> images, not to mention without the intrinsic camera calibration details you will have to make many assumptions that could drastically affect your results... It is no easy task.</p> <hr> <p>I would recommend buying and/or reading <a href="http://oreilly.com/catalog/9780596516130">Learning OpenCV</a> if you want to learn more, it is far beyond the scope of a short paragraph on stackoverflow to expect to learn all of this :)</p>
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    1. POImage Rectification
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    1. COIsnt there any given piece of code that I could use directly?I know its asking too much but the thing is rectification is a small part of my project and I dont want to spend too much time on it .
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    2. COI _highly_ doubt you will find anything that you can just 'drop in' to your existing code without modification. Search for examples of 'Stereo Rectification' or 'Stereo Calibration', these might help you. It would also help if you explained what you are trying to do instead of just asking for code.
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    3. COWe are trying to do some stereo reconstruction given images of an object from 4 viewpoints.In particular we are trying to implement a paper (I added link to original post).In this pairwise stereo rectification is a small part hence I wanted to do this part fairly quickly.
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