sod_img sod_sharpen_filtering_image(sod_img input);
Spatial filtering of image data. That is, apply a sharpening filter by 8-neighbor Laplacian subtraction. This works only on grayscale images. If you want to convert the colorspace of your input picture to the gray color model, call sod_grayscale_image() or sod_grayscale_image_3c() before.
Processed image is returned in an instance of the sod_img object. if something goes wrong during processing, then an empty image is returned via sod_make_empty_image(). Once done, you must release the memory allocated to this object via sod_free_image() to avoid memory leaks.