**PURPOSE**- Computes convolution product between picture and specified matrix (point spread function (PSF)) in real space. PSF is assumed square/cubic. Example.

**USAGE**- .OPERATION: RC

- .INPUT FILE: PIC001

[Enter name of image/volume to be convoluted.].OUTPUT FILE: PIC002

[Enter name of image/volume where convoluted values are placed.].PSF INPUT FILE: PSF001 / * / #

[Enter (1) Name of file where PSF matrix is found,

(2) '*' to indicate that PSF matrix is typed in and not saved,

(3) '#' to indicate that PSF is typed in and is saved.] - If 'PSF INPUT FILE' is an existing PSF file, SPIDER will read in the
SPIDER image format PSF file and print out its values:

.PSF IN USE

-0.1 -0.1 -0.2 -0.1 -0.1

-0.1 -0.1 -0.3 -0.1 -0.1

-0.1 -0.1 3.0 -0.1 -0.1

-0.1 -0.1 -0.3 -0.1 -0.1

-0.1 -0.1 -0.2 -0.1 -0.1

[The convolution product between PIC001 and PSF001 is then computed and written into PIC002.]

- If 'PSF INPUT FILE' is '*', SPIDER will read in the PSF values:

.PSF WIDTH: 5

[Enter linear size of PSF matrix. Number must be odd. See notes regarding range.

Enter matrix, with <PSF WIDTH> numbers per line]

.ROW(1): -0.1 -0.1 -0.2 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.3 -0.1 -0.1

.ROW(1): -0.1 -0.1 3.0 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.3 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.2 -0.1 -0.1

[SPIDER will then normalize the PSF and print out the PSF IN EFFECT. Then the convolution product between PIC001 and PSF001 is then computed and written into PIC002.]

- If 'PSF INPUT FILE' is '#', SPIDER will read in the name of the
- PSF output file and the PSF values:
.PSF OUTPUT FILE: PSF002

[Enter name of file where PSF matrix is to be saved.].PSF WIDTH: 5

[Enter linear size of PSF matrix. Number must be odd. See notes regarding range.

Enter matrix, with <PSF WIDTH> numbers per line]

.ROW(1): -0.1 -0.1 -0.2 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.3 -0.1 -0.1

.ROW(1): -0.1 -0.1 3.0 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.3 -0.1 -0.1

.ROW(1): -0.1 -0.1 -0.2 -0.1 -0.1

[SPIDER will then normalize the PSF and print out the PSF IN EFFECT. Then the convolution product between PIC001 and PSF001 is then computed and written into PIC002.]

**NOTES**

- If PSF has "box" form (i.e., all coefficients of matrix
have equal value), use box convolution ('BC') instead.
- Fourier convolution, 'CN', is the method of choice
for large PSFs (with PSFs as large as the image!).
- 'RC' has been rarely used since it was first written. It is possible that bugs have developed over the years.

**SUBROUTINES**- RCONV, RCNV3_P, RCNV2_P

**CALLER**- UTIL3

© Copyright Notice / Enquiries: spider@wadsworth.org