IMGHASH

Description

IMGHASH computes a hash number that represents a window of image values from a specified image channel. This hash number is used as a checksum for software testing.

Parameters

Name	Type	Caption	Length	Value range
FILE *	String	Input file name	1 - 192
DBIC *	Integer	Input raster channel(s)	1 -
DBIW	Integer	Raster input window	0 - 4	Xoffset, Yoffset, Xsize, Ysize
REPORT	String	Report mode	0 - 192	Quick links
MONITOR	String	Monitor mode	0 - 3	ON, OFF Default: ON

* Required parameter

Parameter descriptions

FILE

Specifies the name of the GDB-supported file containing the image data for which the hash number will be computed.

DBIC

Specifies the channel(s) or layer(s) in the input file to be processed.

Ranges of channels or segments can be specified with negative values. For example, {1,-4,10} is internally expanded to {1,2,3,4,10}. When you are not specifying a range in this way, only 48 numbers can be specified explicitly.

DBIW

Specifies the raster window (Xoffset, Yoffset, Xsize, Ysize) that is read from the input layers. If DBIW is not specified, the entire layer is used by default. Xoffset, Yoffset define the upper-left starting pixel coordinates of the window. Xsize is the number of pixels that define the window width. Ysize is the number of lines that define the window height.

REPORT

Specifies where to direct the generated report.

Available options are:

• TERM: generates a report on the terminal (default)
• DISK: generates a report on file "IMPRPT.LST"
• OFF: turns off report generation
• <filename>: appends a report to the specified file

MONITOR

The program progress can be monitored by printing the percentage of processing completed. A system parameter, MONITOR, controls this activity.

Available options are:

• ON: Turns the monitor ON (default)
• OFF: Turns the monitor OFF (recommended if running in batch or background mode)

Details

IMGHASH computes a hash value for a window of image data in a GDB-supported file. This function is primarily used for the construction of test procedures.

The hash function results in a value between 0 and 32767 being placed into the IMSTAT parameter.

The hash function is computed based on imagery returned by GDBIntChanIO();therefore, all floating point data is truncated to integer before being fed into the hash function.

Example

Compute and display the hash values for each of the channels of irvine.pix.

EASI>FILE="irvine.pix"
EASI>DBIC=1,2,3,4,5,6,7,8,9,10,11
EASI>DBIW=

EASI>RUN IMGHASH
EASI>PRINT IMSTAT