Geometrically corrects the image using the geometric mapping grid
Performs the geometric rectification of an image as specified by a previously generated mapping grid. Resampling is accomplished using either nearest neighbor interpolation, parametric cubic convolution interpolation, bilinear interpolation, or a user-entered table of resampling weights.
- FRAMNUM
- Frame number. The frame number of the image that is geometrically corrected.
- BAND
- Band number. The band number of the image that is geometrically corrected.
- RESAMP(CC)
- Resampling method. Pixel values in the output image are determined by finding the corresponding location in the input image. The pixel location in the input image is a floating point value, i.e., it can fall between pixels. A method of interpolating a brightness value for that pixel location is therefore needed.
= NN: Nearest neighbor. Nearest neighbor inter- polation uses the brightness value of the pixel closest to the calculated floating point pixel value. = BI: Bilinear. Bilinear interpolation uses a 2 x 2 block of input pixels which surround the calculated floating point pixel value to determine the output pixel brightness value. = CC: Cubic convolution. Cubic convolution interpolation uses a 4 x 4 block of in- put pixels which surround the calculated floating point pixel value to determine the output pixel brightness value. = TABLE: Table-based. Table-based resampling uses a N x M block of input pixels which sur- round the calculated floating point pixel value to determine the output pixel bright- ness value. The dimensions N and M, as well as the resampling kernel (resampling weights), are contained in the user- entered file of resampling weights.
- INRWT(--)
- Input resampling weight table file. File containing externally generated table of resampling weights. This parameter is valid when RESAMP=TABLE. It is ignored for all other resampling methods.
- PCCALPHA(-0.5 )
- Parametric cubic convolution alpha parameter. Commonly used values are -1.0 and -0.5; values -3.0 through 3.0 produce reasonable results. Other values may cause unpredictable results but are permitted for experimental purposes. This parameter is valid when RESAMP=CC. It is ignored for all other resampling methods.
- BACKGRND(0.0 )
- Background value. Gray level fill value assigned to all output pixels which map into locations outside the edges of the input image. If bilinear, cubic convolution, or table-based resampling methods are used, an output pixel is considered to fall outside the input image if any of the input pixels needed for the interpolation are at positions outside the input edges.
Assuming that the LAMS global $IMAGE = ("US1","US2"), GEOMAP reads US13.DAT and geometrically corrects the image using cubic convolution interpolation method according to the geometric grid US1.GGR. This grid was created in MGRID. All background areas are set to 0.0.
Assuming that the LAMS global $IMAGE = ("US1","US2"), GEOMAP reads US12.DAT and geometrically corrects the image using nearset neighbor method according to the geometric grid US1.GGR. This grid was created in MGRID. All background areas are set to 0.0.
Assuming that the LAMS global $IMAGE = ("US1","US2"), GEOMAP reads US13.DAT and geometrically corrects the image using bilinear interpolation resampling and map ping grid US1.GGR. This grid was created in MGRID. All background areas are set to 255.0.
Assuming that the LAMS global $IMAGE = ("US1","US2"), GEOMAP reads US14.DAT and maps this image using the grid US1.GGR and the table US1.TABLE of user-entered resampling weights. All background areas are set to 0.0.
The FRAMNUM image will be geometrically corrected by GEOMAP using the resampling technique as specified by the parameter RESAMP according to the geometric mapping grid created by MGRID. Error Messages: Error messages are displayed from the called routine.User Notes:
- Any changes made to the RESAMPLE function may affect the operation of this routine.
- Related Large Area Mosaicking System (LAMS) procedure functions include MCTP, MCUT, MTIE, MEDIT, MCRN, MAVE, MGRID, and MRAD.