REGUT

Description

Transforms an image from one coordinate space to another, based on user-defined transformation data.

Parameters

Name	Type	Length	Value range
Input: Input raster image channel(s) *	Raster port	1 - 1024
Output: Output transformed image channel(s) *	Raster port	1 - 1024
Resampling Method	String	0 - 1	NEAR | BILIN | CUBIC | 8PT | 16PT Default: NEAR
InputDBUTC: Input user transformation channel(s) *	Raster port	2 - 2	1 -
Apply georeferencing to transformed layer(s)	String	0 - 1	ON | OFF Default: OFF
Working Memory Size	Float	0 - 1	0 - Default: 0.0
Report	String	0 - 192	See parameter description

* Required parameter

Parameter descriptions

Input: Input raster image channel(s)

Specifies the image channels from the input file (FILI) to correct.

Duplicate channels are NOT allowed.

Output: Output transformed image channel(s)

Specifies the channels in the output file (FILO) to receive the corrected image data.

Duplicate channels are NOT allowed.

Resampling Method

Specifies the resampling method to use during the registration process.

InputDBUTC: Input user transformation channel(s)

Specifies the channels from the output file (FILO) that contain the user-supplied transformation values.

The first of these channels should contain the X pixel coordinate of the corresponding pixel on the input image; the second channel should contain the Y line coordinate of the corresponding pixel on the input image.

That is, to assign pixel 2,3 on the output image (DBOC), the function will fetch the values from DBUTC at the same pixel (2,3). The first value fetched (DBUTC[1]) will be used as the pixel value (x'), and the second value fetched (DBUTC[2]) will be used as the line value (y'). These values will then be used to sample a pixel from the input channel (DBIC).

Apply georeferencing to transformed layer(s)

Specifies whether the input user transformation coordinates (DBUTC) are assumed to be in georeferenced coordinates.

Working Memory Size

Specifies the amount, in megabytes (as a floating-point number), of internal memory allocated to REGPRO.

The default value of 0.0 Mbytes allows REGUT to automatically determine the appropriate amount of memory to allocate. If the user-entered value is less than 0.25 MB, the memory size will be rounded up to 0.25 MB. This parameter must not have a negative value.

Report

Specifies where to direct the generated report.

Available options are:

• LOG: generates a report on the terminal (default)
• <modulename.RPT>: appends a report to the module's RPT file
• DISK: generates a report on file "IMPRPT.LST"

Details

REGUT transforms an image from one coordinate space to another, based on user-supplied transformation data.

REGUT performs a user-defined image warping (registration). This function operates in a manner similar to REG.

Selected input image channels (DBIC) from the input file (FILI) are registered/corrected using a user-defined transformation (DBUTC). The registered image is stored in the specified output image channels (DBOC) in the output file (FILO).

The user-defined transformation is provided as two channels on the output file (FILO). The user transformation channels (DBUTC) specify the pixel/line, or georeferenced X/Y positions on the input file that should be transformed to that pixel on the output file. The values of DBUTC[1], and DBUTC[2] are treated as georeferenced if USEGEO is "ON", and as pixel/line coordinates if it is "OFF" (default).

In other words, for every pixel location on the output channel (DBOC), REGUT finds the pixel values at the same pixel location on the input user-transformation channel (DBUTC). These pixel values provide an x,y pixel location on the input channel (DBIC). The pixel value at this x,y location on DBIC is then read into the original pixel location on DBOC.

Thus, if the top-left pixel in the output file's DBUTC channels contained the values 4 and 10, the pixel value at (4,10) on the input file would get transformed into the top-left pixel of the output channel.

The user transformation is typically set up using modeling equations or a specialized transformation setup function. Also, when imported, some data sets (such as NASA EOSDIS HDF files) include two channels that contain the lat/long locations of each pixel. These can be transformed through modeling equations to refer to source pixels in lat/long on other databases.

REGUT only outputs actual resampled pixels to the output channels (DBOC). While this allows mosaicking of more than one image into the same channels, it does require the user to CLEAR the channels initially (see CLR).