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Merge pull request #1083 from lovell/attention-smartcrop-early-resize

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Smartcrop (attention): resize at start of pipeline to improve performance/accuracy
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John Cupitt 2018-09-21 15:25:48 +01:00 committed by GitHub
commit 847009f81b
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1 changed files with 17 additions and 13 deletions
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30
libvips/conversion/smartcrop.c
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@ -204,6 +204,18 @@ vips_smartcrop_attention( VipsSmartcrop *smartcrop,
int x_pos;
int y_pos;
/* The size we shrink to gives the precision with which we can place
* the crop
*/
hscale = 32.0 / in->Xsize;
vscale = 32.0 / in->Ysize;
sigma = VIPS_MAX( sqrt( pow( smartcrop->width * hscale, 2 ) +
pow( smartcrop->height * vscale, 2 ) ) / 10, 1.0 );
if ( vips_resize( in, &t[17], hscale,
"vscale", vscale,
NULL ) )
return( -1 );
/* Simple edge detect.
*/
if( !(t[21] = vips_image_new_matrixv( 3, 3,
@ -214,7 +226,7 @@ vips_smartcrop_attention( VipsSmartcrop *smartcrop,
/* Convert to XYZ and just use the first three bands.
*/
if( vips_colourspace( in, &t[0], VIPS_INTERPRETATION_XYZ, NULL ) ||
if( vips_colourspace( t[17], &t[0], VIPS_INTERPRETATION_XYZ, NULL ) ||
vips_extract_band( t[0], &t[1], 0, "n", 3, NULL ) )
return( -1 );
@ -260,22 +272,14 @@ vips_smartcrop_attention( VipsSmartcrop *smartcrop,
vips_ifthenelse( t[10], t[13], t[11], &t[16], NULL ) )
return( -1 );
/* Sum, shrink, blur and find maxpos.
/* Sum, blur and find maxpos.
*
* The size we shrink to gives the precision with which we can place
* the crop, the amount of blur is related to the size of the crop
* The amount of blur is related to the size of the crop
* area: how large an area we want to consider for the scoring
* function.
*/
hscale = 32.0 / in->Xsize;
vscale = 32.0 / in->Ysize;
sigma = VIPS_MAX( sqrt( pow( smartcrop->width * hscale, 2 ) +
pow( smartcrop->height * vscale, 2 ) ) / 10, 1.0 );
if( vips_sum( &t[14], &t[17], 3, NULL ) ||
vips_resize( t[17], &t[18], hscale,
"vscale", vscale,
"kernel", VIPS_KERNEL_LINEAR,
NULL ) ||
if( vips_sum( &t[14], &t[18], 3, NULL ) ||
vips_gaussblur( t[18], &t[19], sigma, NULL ) ||
vips_max( t[19], &max, "x", &x_pos, "y", &y_pos, NULL ) )
return( -1 );