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another 2x faster on hough_line

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This commit is contained in:
John Cupitt 2018-02-02 09:12:31 +00:00
parent 59afb52f7c
commit ce1f236c4d
2 changed files with 8 additions and 8 deletions
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3
ChangeLog
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@ -3,7 +3,8 @@
- remove jpeg thumbnail from EXIF if "jpeg-thumbnail-data" has been removed by - remove jpeg thumbnail from EXIF if "jpeg-thumbnail-data" has been removed by
user user
- hough_line scales width to 0 - 180, not 0 - 360 - hough_line scales width to 0 - 180, not 0 - 360
- hough_line is 2x faster - hough_line is 4x faster
- hough_circle is 2x faster
5/1/18 started 8.6.2 5/1/18 started 8.6.2
- vips_sink_screen() keeps a ref to the input image ... stops a rare race - vips_sink_screen() keeps a ref to the input image ... stops a rare race

13
libvips/arithmetic/hough_line.c
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@ -72,13 +72,13 @@ vips_hough_line_build( VipsObject *object )
int i; int i;
if( !(hough_line->sin = VIPS_ARRAY( object, width, double )) ) if( !(hough_line->sin = VIPS_ARRAY( object, 2 * width, double )) )
return( -1 ); return( -1 );
/* Map width to 180 degrees. /* Map width to 180 degrees, width * 2 to 360.
*/ */
for( i = 0; i < width; i++ ) for( i = 0; i < 2 * width; i++ )
hough_line->sin[i] = sin( VIPS_PI * i / width ); hough_line->sin[i] = sin( 2 * VIPS_PI * i / (2 * width) );
if( VIPS_OBJECT_CLASS( vips_hough_line_parent_class )->build( object ) ) if( VIPS_OBJECT_CLASS( vips_hough_line_parent_class )->build( object ) )
return( -1 ); return( -1 );
@ -111,13 +111,12 @@ vips_hough_line_vote( VipsHough *hough, VipsImage *accumulator, int x, int y )
double yd = (double) y / statistic->ready->Ysize; double yd = (double) y / statistic->ready->Ysize;
int width = hough_line->width; int width = hough_line->width;
int height = hough_line->height; int height = hough_line->height;
unsigned int *data = guint *data = (guint *) accumulator->data;
(unsigned int *) VIPS_IMAGE_ADDR( accumulator, 0, 0 );
int i; int i;
for( i = 0; i < width; i++ ) { for( i = 0; i < width; i++ ) {
int i90 = (i + width / 2) % width; int i90 = i + width / 2;
double r = xd * hough_line->sin[i90] + yd * hough_line->sin[i]; double r = xd * hough_line->sin[i90] + yd * hough_line->sin[i];
int ri = height * r; int ri = height * r;