Using the result from ros stereo camera calibration tool with opencv rectify.

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For some reason, I am unable to perform calibration of my stereo camera using the opencv stereo calibrate, and hence went for the ROS tool. However, my program uses the intrinsic and extrinsic yml to rectify the images, to get a disparity map. How do I use the result data from the ROS tool, to make it work like the intrinsic and extrinsic yml files . I am new to stereo reconstruction, and not entirely sure how to proceed now.