INP is the name of the input image file.
SIZE specifies the portion of the input image which is to be processed by the program. It contains 4 integers: (Starting Line, Starting Sample, Number of Lines, Number of Samples). These can also be specified separately by the parameters SL, SS, NL, and NS.
If the input data is in 3-D format, BANDS specifies the starting band desired, and the number of bands to be processed. Note that the output histogram will be an aggregate of all bands requested.
See SIZE.
See SIZE.
For 3-D data, this parameter denotes the first band to be included in the processing.
See SIZE.
See SIZE.
For 3-D data, this parameter denotes the number of bands to be included in the processing.
FORMAT specifies the input image data type and may have any of four values: BYTE, HALF, FULL, or REAL. If FORMAT isn't specified, each image will be treated as being in the data format specified by its system label.
SPIKES=N specifies that the printed histogram will be normalized in frequency such that the N-th most frequent value is printed as the full width on the page. All values which occur more frequently will also be represented by a full width bar, ranked by number on the right side. SPIKES may have any value from 1 to 9, inclusive; the default is 1
SINC=N specifies that every N-th sample in the chosen area is to be used. The default is for every value to be used. Note that if INC is specified, this parameter is ignored. (INC specifies SINC and LINC.)
LINC=N specifies that every N-th line in the chosen area is to be used. The default is for every value to be used. Note that if INC is specified, this parameter is ignored. (INC specifies SINC and LINC.)
INC=N specifies that every N-th sample in both dimensions in the chosen area is to be used. Use of this keyword speeds histogram compilation. The default is for every pixel in the area to be used. This keyword overrides any values of SINC or LINC that are specified separately.
AREA is used to specify the portion(s) of the input image which is/are to be graphed. If AREA is not specified, the program will use the entire image as determined by the label of the input file. Several areas may be specified using the one keyword.
NOHIST - Only the statistical data (mean, standard deviation, minimum,
maximum, and number of pixels) is printed. No histogram is formed.
NORMAL - (Default) An 80 column wide histogram is formed, with DN values
running vertically.
WIDE - A 132 column wide histogram is formed, with DN values running
vertically.
SCREEN - A 22 row by (up to) 80 column histogram is formed, with DN values
running horizontally. The is designed to fit within a single
screen. Byte is the only permissible data format for this option.
WINDOW - A line plot of the histogram data is formed, using a window and
run through IDL software. It requires a terminal with windowing
software. After the plot is displayed, the user is given the
option of also producing a hardcopy plot of the data.
WBAR - A bar graph of the histogram data is formed, using IDL and
windowing software. This is the window equivalent of the BAR
option.
This keyword is used to generate a plot on the printer. It may be used with any of the MODE options. However, if MODE is defaulted and PPLOT is specified, no histogram is output to the terminal or log file. The WINDOW and WBAR options automatically ask the user whether a printed plot is desired.
This title is placed beneath printed plots. It has no effect if PPLOT is not specified. In addition to this line of annotation, two other caption lines are always generated for pen plots. One line contains the histogram statistics, while the other lists the file name, area, linc, and sinc.
NOCUM specifies that the percentages printed for each bin in the WIDE format are the percentage of the pixels in each bin, instead of the cumulative percentage of all bins up to and including the current one, which is the default. If the wide-format option has not been specified, this keyword is ignored.
BINS specifies the maximum number of buckets to be used in sorting image pixels. The default is 256. Note that the range spanned by these bins is determined by the LIMITS parameter, and defaults to (0,255) for byte, (-32768,32767) for non-byte. The value of the midpoint of each bin is printed on the output histogram lines.
LIMITS specifies the upper and lower bounds of the histogram. The defaults are 0 and 255 for byte data, and -32768 and 32767 for halfword or fullword integer and real data.
Exclude 0 DN pixels from the mean and standard deviation values reported at the end of the histogram. This does not affect the histogram itself.
Under normal operation a single histogram is produced, including all bands specified by the BANDS parameter. If the BYCHAN keyword is used, a separate histogram for each requested band is produced.
PAUSE specifies that the program is to pause when the screen is filled in interactive mode. Default is for the program not to pause every 23 lines. This parameter has no effect in batch mode.
This is an output parameter. When HIST has completed running, this parameter contains the mean value of the last histogram. This value may be used by subsequent programs within a procedure by declaring MEAN as a local real variable in the procedure.
This is an output parameter. When HIST has completed running, this parameter contains the value of the standard deviation for the last histogram. This value may be used by subsequent programs within a procedure by declaring SIGMA as a local real variable in the procedure.
This is an output parameter. When HIST has completed running, this parameter contains the minimum value for the last histogram. This value may be used by subsequent programs within a procedure by declaring MIN as a local real variable in the procedure.
This is an output parameter. When HIST has completed running, this parameter contains the maximum value for the last histogram. This value may be used by subsequent programs within a procedure by declaring MAX as a local real variable in the procedure.