Level 2 Help for XFORM

INP

 Input file names (can be byte, halfword, I*4, or R*4)


OUT

 Output file names (can be byte, halfword, I*4, or R*4)


SIZE

 The standard VICAR size field: starting line, starting sample,
 number of lines, and number of samples
 (if MSS is specified, the size field refers to one band, not to the
 entire image.)


MATRIX

 MATRIX = (M11,M12...)   The matrix values are real numbers and are 
 entered in row order. The column number is the number of input data
 sets or bands, the row number is the number of output data sets or bands


FORMAT

 Valid keyword values: BYTE, HALF, FULL, REAL.
 This specifies the output data format. 


MSS

 MSS=NI            Denotes that the input data set is in MSS format with
 NI interleaved inputs.  limit: NI <= 32


USEBANDS

 If the input is a single file of multichannel data, the USEBANDS parameter
 is used to specify which bands are to be used as input, and the order that
 must be used to be consistent with the MATRIX parameter.  The default is to
 use all bands, in ascending order.


PRESET

 Offset  = 0 and gain = 1 for all output bands.


GAIN

    GAIN=Q                   For all output bands, 
 or GAIN=(Q1,Q2,Q3,...)      The nth output band is scaled by  gain Qn. 


OFFSET

    OFFSET=P                 For all output bands,
 or OFFSET=(P1,P2,P3,...)    The nth output band is scaled by offset Pn.


AREA

 AREA=(SL,SS,NL,NS)     Indicates area to be sampled for auto-scaling.


INC

 INC=N		For auto-scaling, every Nth sample of every Nth line is used.


LINC

 LINC=N		For auto-scaling, every Nth line is used.


SINC

 SINC=N		For auto-scaling, every Nth sample is used.


PERCENT

 PERC=P       P percent saturation is to be allowed in output histograms,
 one-half at each end. (default=1)


LPERCENT

 LPER=L      L percent saturation is to be allowed in output histograms
 at the low end. (default=0.5)


HPERCENT

 HPER=H      H percent saturation is to be allowed in output histograms
 at the high end. (default=0.5)


SPREAD

 SPREAD=S      Output histograms are to have a spread of s. (default=full
 range of data type)  See also parameter FIRM.


FIRM

 Specify FIRM to cause the output to be clipped so that SPREAD and CENTER
 apply firmly.  Otherwise (the default) SPREAD and CENTER apply approximately.


CENTER

 CENTER=C      Output histogram is to be centered about c. (default=SPREAD/2
 for byte data, =0 otherwise.)


EXCLUDE

 EXCLUDE=E     This keyword instructs the program to ignore input pixels of 
 value e when determining saturation points.  The algorithm used simply 
 zeros the histogram bin which results from each input DN level e.
 However, other combinations of input DNs will in general also contribute
 to this bin and will be erroneously ignored. Therefore, this keyword should 
 only be used if a large contribution from spurious value (e.g., zero)
 is expected.


HISTSIZE

In the auto-scale mode, a histogram is first formed to determine the range
of the output data without rescaling. This parameter allows the user to 
specify the number of bins used to form the histogram of each output band.
While this feature is rarely needed for byte data, the user may want to
adjust this (and the related RANGE parameter) for other data types, if the
unscaled output range is uncertain.


RANGE

In the auto-scale mode, a histogram is first formed to determine the range
of the output data without rescaling. This parameter allows the user to 
specify the range of the bins used to form the histogram of each output band.
While this feature is rarely needed for byte data, the user may want to
adjust this (and the related HISTSIZE parameter) for other data types. The
auto-scaling algorithm works best when the histogram bins span only the
actual range of the data. Therefore, if it is known that the transformation
will produce values only within a certain range, that range should be 
specified here.