histo_2dim🔗
Short description🔗
histo_2dim — Calculate the histogram of two-channel gray value images.
Signature🔗
histo_2dim( region Regions, image ImageCol, image ImageRow, out image Histo2Dim )
Description🔗
The operator histo_2dim calculates the 2-dimensional
histogram of two images within Regions. The gray values
of channel 1 (ImageCol) are interpreted as row index,
those of channel 2 (ImageRow) as column index. The gray
value at one point \(P(g1,g2)\) in the output image
Histo2Dim indicates the frequency of the gray value
combination (\(g1\),\(g2\)) with \(g1\) indicating the line index and \(g2\)
the column index.
Attention🔗
Note that the operator histo_2dim only considers
the given Regions and ignores any previously set domain
of the input images.
Execution information🔗
Execution information
-
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
-
Multithreading scope: global (may be called from any thread).
-
Processed without parallelization.
Parameters🔗
Regions (input_object) region(-array) → object
Region in which the histogram is to be calculated.
ImageCol (input_object) (multichannel-)image → object (byte / direction / cyclic / int1)
Channel 1.
ImageRow (input_object) (multichannel-)image → object (byte / direction / cyclic / int1)
Channel 2.
Histo2Dim (output_object) image → object (int4)
Histogram to be calculated.
Example🔗
(HDevelop)
read_image(Image,'monkey')
get_domain (Image, Domain)
gauss_filter (Image, ImageGauss, 7)
histo_2dim(Domain,ImageGauss, Image,Histo2Dim)
dev_display(Histo2Dim)
read_image(&Image,"monkey")\;
get_domain (Image, &Domain)
gauss_filter(Image,&ImageGauss,7)\;
histo_2dim(Domain,Image,ImageGauss,&Histo2Dim)\;
set_part(WindowHandle,0,0,511,511)\;
disp_image(Histo2Dim,WindowHandle)\;
Complexity🔗
If \(F\) is the plane of the region, the runtime complexity is \(O(F + 256^2)\).
Result🔗
The operator histo_2dim returns the value 2 (H_MSG_TRUE) if both
images have defined gray values. The behavior in case of empty
input (no input images available) 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 is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
decompose3, decompose2, draw_region
Possible successors
threshold, class_2dim_sup, pouring, local_max, gray_skeleton
Alternatives
See also
Module🔗
Foundation