Parent Topic: NGCLUS
PARAMETERS
NGCLUS is controlled by the following global parameters:
Name Prompt Count Type
FILE Database File Name 1-64 Char
DBIC Database Input Channel List 1-4 Int
DBOC Clustering Result Output Channel 0-1 Int
MASK Area Mask (Window or Bitmap) 0-4 Int
HTLN Histogram Table Length 0-1 Int
NBIT Number of Bits of Resolution 0-1 Int
SAMPRM Minimum Sample Threshold 0-1 Int
SMOOTH Smoothing Parameter 0-1 Int
GRID Grid Sample Increments (X,Y) 0-2 Int
SIGGEN Generate Signatures: YES/NO 0-4 Char
REPORT Report Mode: TERM/OFF/filename 0-64 Char
FILE
Specifies the name of the PCIDSK image file for which a histogram
file will be generated.
EASI>FILE="filespec"
DBIC
Specifies the input image channels on FILE for which a histogram
file will be generated.
EASI>DBIC=i,j,k,l
- Up to 4 channels can be specified.
- Ranges of channels can be specified with negative values. For
example: {1,-4} is internally expanded to {1,2,3,4}.
DBOC
Specifies the output channel for the clustering results. If no value
is specified, results will not be saved. For signature generation,
DBOC must be specified.
EASI>DBOC=i | results saved to channel i
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=b | process only under bitmap
| stored in segment b
EASI>MASK= | process entire channel
GRID
Specifies the sampling restriction grid.
EASI>GRID=Npix,Nlin | samples every Npix pixel on
| every Nlin line
EASI>GRID=k | Npix = Nlin = k
EASI>GRID= | defaults to 4,4
SIGGEN
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 class other images.
EASI>SIGGEN="YES" | generate signatures
EASI>SIGGEN="NO" | no signature generated
REPORT
Specifies the file to which the generated report should be appended.
EASI>REPORT = "filename"
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
EASI>REPORT= | defaults to terminal output
NGCLUS generates a report of the total number of clusters and
pixels.
HTLN
Valid Values: x >= 0
Default: <none>
Specifies the maximum number of unique entries that the histogram
table may contain. This number defaults to values carefully selected
to suit your system. This subject is discussed further in the
DETAILS section below.
EASI>HTLN=100
NBIT
Valid Values: 1 <= x <= 8
Default: 6
Specifies the number of high-order bits used per byte of data in
constructing the histogram table. The default of 6 is recommended
for normal 8-bit data. Note that in general, using more bits per
byte does not correspond to increased accuracy; instead, it may make
the clustering unstable.
EASI>NBIT=7
EASI>NBIT= | defaults to 6
SAMPRM
Valid Values: x >= 0
Default: 5
Specifies the minimum number of samples allowed in a clustering,
allowing the user to eliminate clusters with very few samples. If
the number of samples in a cluster is less than SAMPRM, each sample
inside the cluster will be merged into a neighbouring cluster.
EASI>SAMPRM=4
EASI>SAMPRM= | defaults to 5
SMOOTH
Valid Values: x >= 1
Default: 5
Specifies the histogram threshold. If the histogram value of a
vector is less than SMOOTH, the value will be replaced by the
average histogram value of the vector and its neighbours.
EASI>SMOOTH=3
EASI>SMOOTH= | defaults to 5
Parent Topic: NGCLUS
About PCI Help Gateway