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small bugfix in im_gradcor + better comments/docs

This commit is contained in:
John Cupitt 2008-01-08 13:57:52 +00:00
parent f7cb74ff65
commit 8e7f9e9381
2 changed files with 18 additions and 5 deletions
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4
libsrc/convolution/convol_dispatch.c
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@ -702,7 +702,7 @@ grad_x_vec( im_object *argv )
*/
static im_function grad_x_desc = {
"im_grad_x", /* Name */
"x component of gradient of image",
"horizontal difference image",
IM_FN_PIO | IM_FN_TRANSFORM, /* Flags */
grad_x_vec, /* Dispatch function */
IM_NUMBER( one_in_one_out ), /* Size of arg list */
@ -721,7 +721,7 @@ grad_y_vec( im_object *argv )
*/
static im_function grad_y_desc = {
"im_grad_y", /* Name */
"y component of gradient of image",
"vertical difference image",
IM_FN_PIO | IM_FN_TRANSFORM, /* Flags */
grad_y_vec, /* Dispatch function */
IM_NUMBER( one_in_one_out ), /* Size of arg list */

19
libsrc/convolution/im_gradcor.c
View File

@ -1,6 +1,18 @@
/* @(#) Like im_spcor(), but with a new metric. Docs to follow.
/* @(#) Like im_spcor(), but with a new metric.
* @(#)
* @(#) Returns 0 on sucess and -1 on error.
* @(#) takes the gradient images of the two images, and takes the dot-product
* @(#) correlation of the two vector images.
* @(#)
* @(#) (vector images are never really used, the two components are
* @(#) calculated separately)
* @(#)
* @(#) The vector expression of this method is my (tcv) own creation. It is
* @(#) equivalent to the complex-number method of:
* @(#)
* @(#) ARGYRIOU, V. et al. 2003. Estimation of sub-pixel motion using
* @(#) gradient cross correlation. Electronics Letters, 39 (13).
* @(#)
* @(#) It's suitability for sub-pixel alignment is not (yet) tested.
*
* Copyright: 2007 Nottingham Trent University
*
@ -153,7 +165,8 @@ int im_gradcor_raw( IMAGE *large, IMAGE *small, IMAGE *out ){
IMAGE *ygrad= im_open_local( out, FUNCTION_NAME ": ygrad", "t" );
IMAGE **grads= im_allocate_input_array( out, xgrad, ygrad, NULL );
return im_grad_x( small, xgrad )
return ! xgrad || ! ygrad || ! grads
|| im_grad_x( small, xgrad )
|| im_grad_y( small, ygrad )
|| im_generate( out, gradcor_start, gradcor_gen, gradcor_stop, (void*) large, (void*) grads );
}