gen_psf_defocus

gen_psf_defocus ( : Psf : PSFwidth, PSFheight, Blurring : )

Generate an impulse response of an uniform out-of-focus blurring.

gen_psf_defocus generates an impulse response (spatial domain) of an uniform out-of-focus blurring and writes it into an image of HALCON image type 'real'. Blurring specifies the extent of blurring by defining the "blur radius" (out-of-focus blurring maps each image pixel on a small circle with a radius of Blurring - specified in "number of pixels"). If specified less than zero, the absolute value of Blurring is used. The result image of gen_psf_defocus encloses an spatial domain impulse response of the specified blurring. Its representation presumes the origin in the upper left corner. This results in the following disposition of an NxM sized image:

first rectangle ("upper left"):
(image coordinates xb = 0..(N/2)-1, yb = 0..(M/2)-1)
   - conforms to the fourth quadrant of the Cartesian coordinate system, 
     encloses values of the impulse response 
     at position x = 0..N/2 and y = 0..-M/2
second rectangle ("upper right"):
(image coordinates xb= N/2..N-1, yb = 0..(M/2)-1)
   - conforms to the third quadrant of the Cartesian coordinate system, 
     encloses values of the impulse response 
     at position x = -N/2..-1 and y = -1..-M/2
third rectangle ("lower left"):
(image coordinates xb = 0..(N/2)-1, yb = M/2..M-1)
   - conforms to the first quadrant of the Cartesian coordinate system, 
     encloses values of the impulse response 
     at position x = 1..N/2 and y = M/2..0
fourth rectangle ("lower right"):
(image coordinates xb = N/2..N-1, yb = M/2..M-1)
   - conforms to the second quadrant of the Cartesian coordinate system, 
     encloses values of the impulse response 
     at position x = -N/2..-1 und y = M/2..1

This representation conforms to that of the impulse response parameter of the HALCON-operator wiener_filter. So one can use gen_psf_defocus to generate an impulse response for Wiener filtering.

Parameters

`Psf` (output_object)	image `->` object : real
Impulse response of uniform out-of-focus blurring.

`PSFwidth` (input_control)	integer `->` integer
Width of result image.
Default value: 256
Suggested values: 128, 256, 512, 1024
Typical range of values: `1 <= PSFwidth`

`PSFheight` (input_control)	integer `->` integer
Height of result image.
Default value: 256
Suggested values: 128, 256, 512, 1024
Typical range of values: `1 <= PSFheight`

`Blurring` (input_control)	real `->` real
Degree of Blurring.
Default value: 5.0
Suggested values: 1.0, 5.0, 10.0, 15.0, 18.0

Result

gen_psf_defocus returns 2 (H_MSG_TRUE) if all parameters are correct.

Parallelization Information

gen_psf_defocus is reentrant and processed without parallelization.

Possible Predecessors

simulate_motion, gen_psf_motion

Possible Successors

simulate_defocus, wiener_filter, wiener_filter_ni

References

Reginald L. Lagendijk, Jan Biemond: Iterative Identification and Restoration of Images, Kluwer Academic Publishers Boston/Dordrecht/London, 1991

M. Lückenhaus:"Grundlagen des Wiener-Filters und seine Anwendung in der Bildanalyse"; Diplomarbeit; Technische Universität München, Institut für Informatik; Lehrstuhl Prof. Radig; 1995.

Module

Foundation