PK DR - Peak search - Restricted neighborhood, output to Document file

PURPOSE

Searches for local peaks in an image with neighbourhood exclusion and stores the output in document file.

SEE ALSO

PK	[Peak search]
PK 3	[Peak search - 3D]
PK 3D	[Peak search - 3D, output to Document file]
PK 3R	[Peak search - 3D, Restricted neighborhood, output to Document file]
PK C	[Peak search - Center of gravity]
PK D	[Peak search - output to Document file]
PK DC	[Peak search - Center of gravity, output to Document file]
PK M	[Peak search - Maximum]

USAGE

.OPERATION: PK DR [x],[y],[pk],[ratio],[xp],[yp],[pkp]
[The first three optional output parameters (in this example [x],[y],[pk]) specify registers that are to receive the coordinates (integer values) and the value of the largest peak found in this operation). [ratio] (here) contains the ratio of the first peak relative to the peak # specified for that ratio (option ORIGIN OVERRIDE). The 5th & 6th registers (here [xp],[yp]) return the non-integer coordinates according to a 9-point parabolic fit, and the last register ([pkp] here) contains the value of that maximum.]

.INPUT FILE: PIC001
[Enter the name of the image.]

.ENTER NUMBER OF PEAKS, CENTER ORIGIN OVERRIDE (0/1): 12, 0
[Enter the number of peaks to be searched for. If an origin position other than at the picture's center (NX/2 + 1, NY/2 + 1) is desired, enter '1' in the second position. The system will then allow you to enter the X,Y coordinates of the origin to be used.]

If the option "CENTER ORIGIN OVERRIDE" is specified]:

.NEW ORIGIN COORDINATES: 1, 1
[Enter the new origin coordinates. In this example, SPIDER will find the 12 largest peaks. Their positions will be printed in the RESULTS file, and the value position of the largest peak will be printed to the user's terminal. In addition, the peak positions and values will be put into the temporary registers if output parameters [x],[y],[pk],[ratio],[xp],[yp],[pkp] are specified. The registers can be used as input to a subsequent shift ("SH") operation.

.NEIGHBOURHOOD EXCLUSION DISTANCE : 130
[Enter the neighbourhood distance for peak exclusion. Starting with the highest peak, only peaks with a distance larger than the specified neighborhood distance will be written into a document file. In this case the number of peaks returned may be less than the requested number.

.DOCUMENT FILE: DOC001
[Enter the name of the document file.]

NOTES

1. This routine does NOT find "maximum" location when image has plateaus. It may find the "last" value along the plateau. To overcome this, use low pass filtration first or use 'PK M'.

SUBROUTINES

SPEAKR, PARABL

CALLER

UTIL1