Segment an image using global threshold.

threshold selects the pixels from the input image whose gray values g fulfill the following condition:

             MinGray <= g <=  MaxGray .

All points of an image fulfilling the condition are returned as one region. If more than one gray value interval is passed (tuples for MinGray and MaxGray), one separate region is returned for each interval.

read_image(Image,'fabrik') 
sobel_dir(Image,EdgeAmp,EdgeDir,'sum_abs',3) 
threshold(EdgeAmp,Seg,50,255,2) 
skeleton(Seg,Rand) 
connection(Rand,Lines) 
select_shape(Lines,Edges,'area','and',10,1000000).

Let A be the area of the input region. Then the runtime complexity is O(A).

threshold returns 2 (H_MSG_TRUE) if all parameters are correct. The behavior with respect to the input images and output regions can be determined by setting the values of the flags 'no_object_result', 'empty_region_result', and 'store_empty_region' with set_system. If necessary, an exception is raised.

threshold is reentrant and automatically parallelized (on tuple level, domain level).

histo_to_thresh, min_max_gray, sobel_amp, gauss_image, reduce_domain, fill_interlace

connection, dilation1, erosion1, opening, closing, rank_region, shape_trans, skeleton

class_2dim_sup, hysteresis_threshold, dyn_threshold, bin_threshold, char_threshold, auto_threshold, dual_threshold

zero_crossing, background_seg, regiongrowing

Foundation