Parent Topic: KCLUS

PARAMETERS

KCLUS is controlled by the following global parameters: 

Name     Prompt                                  Count     Type
FILE     Database File Name                      1-64      Char
DBIC     Database Input Channel List             1-16      Int
DBOC     Database Output Channel                 0-1       Int
MASK     Area Mask (Window or Bitmap)            0-4       Int
NUMCLUS  Number of Cluster Centres               0-1       Int
SEEDFILE Seed File for Initial Centres           0-64      Char
MAXITER  Maximum Number of Iterations            0-1       Int
MOVETHRS Movement Threshold                      0-1       Real
SIGGEN   Generate Signatures: YES/NO             1-4       Char
BACKVAL  Background Grey-level Value             0-1       Real
NSAM     Number of Pixel Values to Sample        0-1       Int
REPORT   Report Mode: TERM/OFF/filename          0-64      Char

FILE

Specifies the name of the PCIDSK image file for which clustering will be performed. 

 EASI>FILE="filespec"

DBIC

Specifies the input channels to be used. These can be 8 bit, 16 bit, or 32 bit real, mixed in any way. 

 EASI>DBIC=i,j,k,l,...

DBOC

Specifies the output channel for the clustering results. If no value is specified, results will not be saved into a channel. For signature generation, DBOC must be specified. 

 EASI>DBOC=j
 EASI>DBOC=                        | results not saved
DBOC can be equal to DBIC. Only the area under MASK is written to DBOC.

MASK

Specifies the area in the input channel which should be processed. This can be one of the following: 

 EASI>MASK=xoff,yoff,xsize,ysize   | process window
 EASI>MASK=                        | process entire channel
 EASI>MASK=b                       | process only under bitmap
                                   | stored in segment b

NSAM

Specifies the number of samples to collect on which to perform the the iterative clustering. This defaults to 262144 if not provided by the user. If the indicated number is large than the total number of pixels in the image then all the pixels in the image will be used.

The time to compute each iteration is proportional to the number of samples used, so using a lot more than the default number of samples can make the clustering process much slower. Also, all the samples are stored in memory, so a large NSAM value can lead to requirements for a lot of memory. With 262144 samples, and five bands of eight bit input data the program would require approximately 1.3MB of memory while with NSAM set to 2000000, it would take 10MB. 

 EASI>NSAM=             | Default to the normal 262144 samples
 EASI>NSAM=1500000      | Use up to 1500000 sample pixels

REPORT

Specifies the file to which the generated report should be appended. 

 EASI>REPORT="filename"
 EASI>REPORT=                      | defaults to terminal output
The following names have special meaning: 

 EASI>REPORT="TERM"        | generates reports on your terminal
 EASI>REPORT="DISK"        | generates reports on file "IMPRPT.LST"
 EASI>REPORT="OFF"         | switches off report generation

NUMCLUS

  Valid Values:   x >= 0
  Default:        16
Specifies the number of cluster centres (classes) desired.

SEEDFILE

  Valid Values:   <filename, 0-64 characters>
  Default:        <none>
Specifies the text file name to read in initial seeds. If no filename is given, seeds will be generated diagonally along the n-dimensional histogram.

MAXITER

  Valid Values:   0 <= x <= 20
  Default:        20
Specifies the maximum number of iterations in calculating the cluster mean positions.

MOVETHRS

  Valid Values:   0.0 <= x <= 1.0
  Default:        0.01
Specifies the movement threshold in percentage of cluster means. If the movement of all cluster means is less than MOVETHRS, the program has converged. For example, for all cluster means, the following situation terminates the program: 

 New cluster mean position - Old cluster mean position
 ----------------------------------------------------- < MOVETHRS
             Old cluster mean position

SIGGEN

  Valid Values:   YES,NO
  Default:        NO
Specifies whether the signature for each cluster will be generated. The user can utilize the signatures as inputs for the MLC (Maximum Likelihood Classification) program to classify other images. 

 YES           | generate signatures
 NO            | no signature generated

BACKVAL

  Valid Values:   See Below
  Default:        <none>
Optionally specifies a background grey level value to be ignored during classification. If this parameter is specified, pixels with the background grey level value will be assigned class 0 (null class).

Parent Topic: KCLUS
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