Determine a histogram of features along all threshold values.
The operator ::shape_histo_all carries out 255 threshold operations within Region with the gray values of Image. The entry i in the histogram corresponds to the number of connected components/holes of this image segmented with the threshold i (Feature = 'connected_components', 'holes') or the mean value of the feature values of the regions segmented in this way (Feature = 'convexity', 'compactness', 'ansisometry'), respectively.
The histogram can also be displayed directly as a graphic via the operators ::set_paint(WindowHandle,'component_histogram') and ::disp_image.
The operator ::shape_histo_all expects a region and exactly one gray value image as input. Because of the power of this operator the runtime of ::shape_histo_all is relatively large!
|
Region (input_object) |
region -> Hobject: HRegion |
| Region in which the features are to be examined. | |
|
Image (input_object) |
image -> Hobject: HImage ( byte ) |
| Gray value image. | |
|
Feature (input_control) |
string -> HTuple.char * |
| Feature to be examined. | |
| Default value: 'connected_components' | |
| List of values: 'connected_components', 'convexity', 'compactness', 'anisometry', 'holes' | |
|
AbsoluteHisto (output_control) |
histogram-array -> HTuple.double * / long * |
| Absolute distribution of the feature. | |
|
RelativeHisto (output_control) |
histogram-array -> HTuple.double * |
| Relative distribution of the feature. | |
/* Simulation von shape_histo_all mit Merkmal 'connected_components': */
my_shape_histo_all(Hobject Region,Hobject Image,
long AbsHisto[], double RelHisto[])
{
long i,sum;
Hobject RegionGray,Seg;
reduce_domain(Region,Image,&RegionGray);
for (i=0; i<256; i++) {
threshold(RegionGray,&Seg,(double)i,255.0);
connect_and_holes(Seg,&AbsHisto[i],_);
clear_obj(Seg);
}
clear_obj(RegionGray); sum = 0;
for (i=0; i<256; i++)
sum += AbsHisto[i];
for (i=0; i<256; i++)
RelHist[i] = (double)AbsHisto[i]/Sum;
}
If F is the area of the input region and N the mean number of connected components the runtime complexity is O(255 * (F + sqrt(F) * sqrt(N)).
The operator ::shape_histo_all returns the value H_MSG_TRUE if an image with the defined gray values is entered. The behavior in case of empty input (no input images) is set via the operator ::set_system('no_object_result',<Result>), the behavior in case of empty region is set via ::set_system('empty_region_result',<Result>). If necessary an exception handling is raised.
::histo_to_thresh, ::threshold, ::gen_region_histo
::connection, ::convexity, ::compactness, ::connect_and_holes, ::entropy_gray, ::gray_histo, ::set_paint, ::count_obj
Image filters
