Nov 12 2008

opencv image undistort

Published by Martijn at 19:31 under PhD lab book

  • Implemented undistortion by using cvInitUndistortMap and cvRemap functions. This is useful because the first function gives aundistortion lookup table which can be used to transform any point in a distorted image, for exampletracking kernels.
  • In the end it works, major problem with disappearing values and incorrect pointersseems to be due to¬† an old OpenCV version. Installed 1.0, fixed a lot of problems… System doesn’t crash any longer…
  • Undistorted image doesn’t look right… Only lower half is transformed, and resulting in merely blurred image.
  • Possibly camera center not well defined. Seems like vhl lib, which mainly uses OpenCV implementation, does extra transformation to intrinsic camera values. Some kind of compensation on the frame size, which results in a slightly different parameter: “double y = (v - offY - cy) * fy_inv;” instead of “float y = (v - fy)*fy_inv;”

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