lib/ccv_swt.c

ccv_swt

void ccv_swt(ccv_dense_matrix_t* a, ccv_dense_matrix_t** b, int type, ccv_swt_param_t params)

Compute the Stroke-Width-Transform image.

a : the input matrix.
b : the output matrix.
type : the type of the output matrix, if 0, ccv will default to CCV_32S | CCV_C1.
params : a ccv_swt_param_t structure that defines various aspect of the SWT function.

up2x : upscale the image for better accuracy.
direction : SWT direction. (black to white or white to black).
size : parameters for Canny edge detector.
low_thresh : parameters for Canny edge detector.
high_thresh : parameters for Canny edge detector.
max_height : the maximum height for a letter.
min_height : the minimum height for a letter.
aspect_ratio : the maximum aspect ratio for a letter.
variance_ratio : the inner-class variance when grouping letters.
thickness_ratio : the allowable thickness variance when grouping letters.
height_ratio : the allowable height variance when grouping letters.
intensity_thresh : the allowable intensity variance when grouping letters.
distance_ratio : the allowable distance variance when grouping letters.
intersect_ratio : the allowable intersect variance when grouping letters.
elongate_ratio : the allowable elongate variance when grouping letters.
letter_thresh : the allowable letter threshold.
breakdown : if breakdown text line into words.
breakdown_ratio : apply OSTU and if inter-class variance above the threshold, it will be break down into words.

ccv_array_t* ccv_swt_detect_words(ccv_dense_matrix_t* a, ccv_swt_param_t params)

Return array of regions that are potentially text area.

a : the input matrix.
params : a ccv_swt_param_t structure that defines various aspect of the SWT function.