Question about efficient mesh warping

edit savecancel

Hi,

I am doing camera de-calibration using barrel distortion.

I have two of 2D point arrays, beforeGrids and afterGrids. beforeGrids are points of distorted grid and afterGrids are just straight lines. Below is my result:

It looks good. But I am looking for a faster way to do the mesh warping. Here is my current dewarping code:

    public static IplImage Dewarp( IplImage image, double distortionParam )
    {
        // create 2D array of points
        CvPoint[][] gridsBefore = GetWarpedGrid( image.Width, image.Height, distortionParam );
        CvPoint[][] gridsAfter = GetStraightGrid( image.Width, image.Height );

        // make lists of point arrays. Each array has 3 points.
        List<CvPoint[]> trianglesBefore = GetTriangles( gridsBefore );
        List<CvPoint[]> trianglesAfter = GetTriangles( gridsAfter );

        // apply affine transform for each triangle (MESH WARPING)
        IplImage result = new IplImage( image.Size, image.Depth, image.NChannels );
        for( int i = 0; i < trianglesAfter.Count; i++ )
        {
            DrawAffineTransformedTriangle( 
                image, ref result, trianglesBefore[ i ], trianglesAfter[ i ] );
        }
        return result;
    }

The problem of this mesh warping method is that it needs to call AffineTransform cols * rows * 2 times which makes it not fast. I have done everything I could do for reducing processing time for using AffineTransform such as setting ROI and reusing objects, but I am still in trouble.

so, I am looking for a faster and smarter way to do mesh warping rather than calling AffineTransform hundreds times.

OpenCV already provides functions like remap() and CalibrateCamera() but I cannot use them because these functions need several camera distortion coefficients and I don't have the data. That's why I used Barrel Distortion which only needs one parameter.

It will be great if someone can tell me how to use remap() and CalibrateCamera() functions using points from Barrel Distortion. Or please give me better idea of doing faster mesh warping.