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Added some functions for running a 3x3 separable filter on part of an image.

This commit is contained in:
Davis King 2011-07-13 11:21:47 -04:00
parent 63ca672c77
commit 0639831a21
2 changed files with 174 additions and 2 deletions
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104
dlib/image_transforms/spatial_filtering.h
View File

@ -102,6 +102,108 @@ namespace dlib
}
}
// ----------------------------------------------------------------------------------------
template <
long size,
typename T,
typename in_image_type
>
inline void separable_3x3_filter_block_grayscale (
T (&block)[size][size],
const in_image_type& img,
const long& r,
const long& c,
const T& fe1, // separable filter end
const T& fm, // separable filter middle
const T& fe2 // separable filter end 2
)
{
// make sure requires clause is not broken
DLIB_ASSERT(shrink_rect(get_rect(img),1).contains(c,r) &&
shrink_rect(get_rect(img),1).contains(c+size-1,r+size-1),
"\t void separable_3x3_filter_block_grayscale()"
<< "\n\t The sub-window doesn't fit inside the given image."
<< "\n\t get_rect(img): " << get_rect(img)
<< "\n\t (c,r): " << point(c,r)
<< "\n\t (c+size-1,r+size-1): " << point(c+size-1,r+size-1)
);
T row_filt[size+2][size];
for (long rr = 0; rr < size+2; ++rr)
{
for (long cc = 0; cc < size; ++cc)
{
row_filt[rr][cc] = get_pixel_intensity(img[r+rr-1][c+cc-1])*fe1 +
get_pixel_intensity(img[r+rr-1][c+cc])*fm +
get_pixel_intensity(img[r+rr-1][c+cc+1])*fe2;
}
}
for (long rr = 0; rr < size; ++rr)
{
for (long cc = 0; cc < size; ++cc)
{
block[rr][cc] = (row_filt[rr][cc]*fe1 +
row_filt[rr+1][cc]*fm +
row_filt[rr+2][cc]*fe2)/256;
}
}
}
// ----------------------------------------------------------------------------------------
template <
long size,
typename T,
typename U,
typename in_image_type
>
inline void separable_3x3_filter_block_rgb (
T (&block)[size][size],
const in_image_type& img,
const long& r,
const long& c,
const U& fe1, // separable filter end
const U& fm, // separable filter middle
const U& fe2 // separable filter end 2
)
{
// make sure requires clause is not broken
DLIB_ASSERT(shrink_rect(get_rect(img),1).contains(c,r) &&
shrink_rect(get_rect(img),1).contains(c+size-1,r+size-1),
"\t void separable_3x3_filter_block_grayscale()"
<< "\n\t The sub-window doesn't fit inside the given image."
<< "\n\t get_rect(img): " << get_rect(img)
<< "\n\t (c,r): " << point(c,r)
<< "\n\t (c+size-1,r+size-1): " << point(c+size-1,r+size-1)
);
T row_filt[size+2][size];
for (long rr = 0; rr < size+2; ++rr)
{
for (long cc = 0; cc < size; ++cc)
{
row_filt[rr][cc].red = img[r+rr-1][c+cc-1].red*fe1 + img[r+rr-1][c+cc].red*fm + img[r+rr-1][c+cc+1].red*fe2;
row_filt[rr][cc].green = img[r+rr-1][c+cc-1].green*fe1 + img[r+rr-1][c+cc].green*fm + img[r+rr-1][c+cc+1].green*fe2;
row_filt[rr][cc].blue = img[r+rr-1][c+cc-1].blue*fe1 + img[r+rr-1][c+cc].blue*fm + img[r+rr-1][c+cc+1].blue*fe2;
}
}
for (long rr = 0; rr < size; ++rr)
{
for (long cc = 0; cc < size; ++cc)
{
block[rr][cc].red = row_filt[rr][cc].red*fe1 + row_filt[rr+1][cc].red*fm + row_filt[rr+2][cc].red*fe2;
block[rr][cc].green = row_filt[rr][cc].green*fe1 + row_filt[rr+1][cc].green*fm + row_filt[rr+2][cc].green*fe2;
block[rr][cc].blue = row_filt[rr][cc].blue*fe1 + row_filt[rr+1][cc].blue*fm + row_filt[rr+2][cc].blue*fe2;
}
}
}
// ----------------------------------------------------------------------------------------
}
@ -109,5 +211,3 @@ namespace dlib
#endif // DLIB_SPATIAL_FILTERINg_H_

72
dlib/image_transforms/spatial_filtering_abstract.h
View File

@ -8,6 +8,8 @@
namespace dlib
{
// ----------------------------------------------------------------------------------------
template <
typename in_image_type,
typename out_image_type,
@ -51,6 +53,76 @@ namespace dlib
- #out_img.nr() == in_img.nr()
!*/
// ----------------------------------------------------------------------------------------
template <
long size,
typename T,
typename in_image_type
>
inline void separable_3x3_filter_block_grayscale (
T (&block)[size][size],
const in_image_type& img,
const long& r,
const long& c,
const T& fe1,
const T& fm,
const T& fe2
);
/*!
requires
- T should be a scalar type
- shrink_rect(get_rect(img),1).contains(c,r)
- shrink_rect(get_rect(img),1).contains(c+size-1,r+size-1)
ensures
- Filters the image in the sub-window of img defined by a rectangle
with its upper left corner at (c,r) and lower right at (c+size-1,r+size-1).
- The output of the filter is stored in #block. Note that img will be
interpreted as a grayscale image.
- The filter used is defined by the separable filter [fe1 fm fe2]. So the
spatial filter is thus:
fe1*fe1 fe1*fm fe2*fe1
fe1*fm fm*fm fe2*fm
fe1*fe2 fe2*fm fe2*fe2
!*/
// ----------------------------------------------------------------------------------------
template <
long size,
typename T,
typename U,
typename in_image_type
>
inline void separable_3x3_filter_block_rgb (
T (&block)[size][size],
const in_image_type& img,
const long& r,
const long& c,
const U& fe1,
const U& fm,
const U& fe2
);
/*!
requires
- pixel_traits<typename in_image_type::type>::rgb == true
- T should be a struct with .red .green and .blue members.
- U should be a scalar type
- shrink_rect(get_rect(img),1).contains(c,r)
- shrink_rect(get_rect(img),1).contains(c+size-1,r+size-1)
ensures
- Filters the image in the sub-window of img defined by a rectangle
with its upper left corner at (c,r) and lower right at (c+size-1,r+size-1).
- The output of the filter is stored in #block. Note that the filter is applied
to each color component independently.
- The filter used is defined by the separable filter [fe1 fm fe2]. So the
spatial filter is thus:
fe1*fe1 fe1*fm fe2*fe1
fe1*fm fm*fm fe2*fm
fe1*fe2 fe2*fm fe2*fe2
!*/
// ----------------------------------------------------------------------------------------
}