| .TH IM_CORREL 3 "13 May 1991" |
| .SH NAME |
| im_correl \- search for image match |
| .SH SYNOPSIS |
| #include <vips/vips.h> |
| |
| int |
| .br |
| im_correl( IMAGE *ref, IMAGE *sec, |
| .br |
| int xref, int yref, int xsec, int ysec, |
| .br |
| int hwindowsize, int hsearchsize, |
| .br |
| double *correlation, int *x, int *y ) |
| |
| .SH DESCRIPTION |
| im_correl() is the base image-searching function used by the mosaicing |
| functions im_lrmosaic() and im_tbmosaic(), and by the matching funtions |
| im_match_linear() and im_match_linear_search(). |
| |
| It finds the position of the secondary image |
| .B sec |
| within |
| .B ref. |
| It searches the area around |
| .B xsec |
| , |
| .B ysec |
| for the best match for the area around |
| .B xref |
| , |
| .B yref. |
| It searches an area of size |
| .B hsearchsize |
| for a match of size |
| .B hwindowsize. |
| The position of the best match is returned, together with the correlation at |
| that point. |
| |
| Only the first band of each image is correlated. ref and sec may be very large |
| --- the function extracts and generated just the parts needed. Correlation is |
| done with im_spcor(); the position of the maximum is found with im_maxpos(). |
| .SH SEE ALSO |
| im_fastcor(3), im_spcor(3), im_maxpos(3), im_match_linear(3), im_lrmosaic(3). |
| .SH AUTHOR |
| J.Cupitt \- 22/02/93 |
| .SH COPYRIGHT |
| The National Gallery and Birkbeck College, 1989-1996. |
