Calculate the average of maximum and minimum inside any mask.
The operator midrange forms the average of maximum and minimum inside the indicated mask in the whole image. Several margin controls (Margin) can be chosen for filtering:
0...255 pixels outside of the image edges are assumed constant (with the indicated gray value). -1 Continuation of edge pixels. -2 Cyclic continuation of image edges. -3 Reflection of pixels at the image edges.The indicated mask (= region of the mask image) is put over the image to be filtered in such a way that the center of the mask touches all pixels once.
Image (input_object) |
image(-array) -> object : byte |
Image to be filtered |
Mask (input_object) |
region -> object : byte |
Region serving as filter mask. |
ImageMidrange (output_object) |
image(-array) -> object |
Filtered output image |
Margin (input_control) |
integer -> integer |
Margin control: 0...255 (constant), -1 (edge pixels continued), -2 (cyclic continuation), -3 (reflection). | |
Default value: -3 | |
Range of values: -3 <= Margin <= 255 |
read_image(:Image:'fabrik':) > draw_region(:Region::) > midrange(Image,Region:Midrange:-3:) > disp_image(Midrange:::).
For each pixel: O(sqrt(F) * 5) with F = area of the mask.
If the parameter values are correct the operator midrange returns the value TRUE. The behavior in case of empty input (no input images available) is set via the operator set_system(::'no_object_result',<Result>:). If necessary an exception is raised.
read_image, draw_region, circle, rectangle1
threshold__, dyn_threshold__, regiongrowing__
circle, rectangle1, min1__, max1__, range__
R. Haralick, L. Shapiro; "Computer and Robot Vision"; Addison-Wesley, 1992, Seite 319