Function kernelInvert

deps/leptonica/src/kernel.c:455–477

! * \brief kernelInvert() * * \param[in] kels source kel, to be inverted * \return keld spatially inverted, about the origin, or NULL on error * * * Notes: * (1) For convolution, the kernel is spatially inverted before * a "correlation" operation is done between the kernel and the image. * */

 * </pre>
 */
L_KERNEL *
kernelInvert(L_KERNEL  *kels)
{
l_int32    i, j, sx, sy, cx, cy;
L_KERNEL  *keld;

    PROCNAME("kernelInvert");

    if (!kels)
        return (L_KERNEL *)ERROR_PTR("kels not defined", procName, NULL);

    kernelGetParameters(kels, &sy, &sx, &cy, &cx);
    if ((keld = kernelCreate(sy, sx)) == NULL)
        return (L_KERNEL *)ERROR_PTR("keld not made", procName, NULL);
    keld->cy = sy - 1 - cy;
    keld->cx = sx - 1 - cx;

    for (i = 0; i < sy; i++)
        for (j = 0; j < sx; j++)
            keld->data[i][j] = kels->data[sy - 1 - i][sx - 1 - j];

    return keld;
}


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