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PK DC - PeaK search - Center of gravity, output to Doc. file

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PURPOSE

Searches for local peaks in a picture.

SEE ALSO

PK [Peak search]
PK 3 [Peak search - 3D]
PK 3D [Peak search - 3D, output to doc. file]
PK C [Peak search - center of gravity]
PK D [Peak search - output to doc. file]

USAGE

.OPERATION: PK DC X11,X12,X13,X14,X15,X16,X17

[The first three optional output parameters (in this example X11,X12,X13) specify registers that are to receive the coordinates and the value of the largest peak found in this operation (real values). X14 contains the ratio of the first peak relative to the peak # specified for that ratio (option ORIGIN OVERRIDE). The last two registers (here X15 and X16) return the non-integer coordinates according to a 9-point parabolic fit, X17 contains the value of the maximum.]

.INPUT1 FILE: PIC001
[Enter the name of the image file.]

.ENTER # 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 (NSAM/2 + 1, NROW/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, Spider asks for the next two specifications:

.NEW ORIGIN COORDINATES: 1,1
[Enter the new origin coordinates.]

.ENTER PEAK NUMBER FOR RATIO: 1
[Enter the number of the peak relative to which the heights of the other peaks are calculated. This ratio is printed out and listed in the document file along with the other parameters of the peaks.]

.ELLIPSE AXES (X,Y) FOR CGR CALCULATION: 2.5,3.5
[Enter the axes of the ellipse limiting the area around each peak, that is used for the center of gravity calculation. (default for Y=0 is X=Y, assuming a circular area)]

.POSITIVITY ENFORCED? (Y/N): N
[If 'Y' is answered first the minimum in the area used for the CGR calculation is determined and subtracted from all pixels in that area]

.NEIGHB.DIST.: 5.0
[Only peaks with a distance larger than the specified neighborhood distance will be written into a document file. The specification of a minimal neighborhood distance does not affect the printed output.]

.EDGE EXCL. WIDTH X,Y : 4,3
[enter the minimum distance (in pixels (integer)) of peaks towards the edge of the image. The program uses the length of the ellipse half-axes for the edge exclusion if values lower than the ones for the CGR elliptical area are given]

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

[In the above example, the computer 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 X11-X17 are specified, and will be written into the document file. The registers can be used as input to a subsequent 'SH' (SHIFT) operation.

NOTES

  1. Neighborhood exclusion and edge exclusion affect only the peaks which are entered into the document file. The results file still contains all peaks originally found.

SUBROUTINES

SPEAK, SPEAKC

CALLER

UTIL1

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