Skip to content

Commit

Permalink
Added thresholding in Skeletonization algorithm
Browse files Browse the repository at this point in the history
  • Loading branch information
@alessandrofrancesconi
alessandrofrancesconi committed Jul 22, 2013
1 parent c23c77c commit 984debb
Show file tree
Hide file tree
Showing 3 changed files with 70 additions and 24 deletions.
Binary file modified bin/win32/morphop.exe
View file
Binary file not shown.
93 changes: 69 additions & 24 deletions src/morphop-algorithms.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
#endif

static void do_morph_operation(MorphOperator, GimpPixelRgn*, GimpPixelRgn*, guchar*, guchar*, StructuringElement, SourceTansformation);
static void do_merge_operation(MergeOperation, GimpPixelRgn*, GimpPixelRgn*, GimpPixelRgn*, guchar*, guchar*, guchar*);
static void do_merge_operation(MergeOperation, GimpPixelRgn*, GimpPixelRgn*, GimpPixelRgn*, guchar*, guchar*, guchar*, SourceTansformation);
static gboolean is_black(GimpPixelRgn*, guchar*);
static void fill_black(GimpPixelRgn*, GimpPixelRgn*, guchar*, guchar*);
static void prepare_image_buffers(GimpDrawable*, GimpPixelRgn*, GimpPixelRgn*, guchar**, guchar**, int, int, int, int, gboolean);
Expand Down Expand Up @@ -138,7 +138,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_DILATION, &src_rgn_d, &dst_rgn_d, src_preview_d, dst_preview_d, settings.element, SRC_ORIGINAL);

// save the difference
do_merge_operation(MERGE_DIFF, &dst_rgn, &dst_rgn_d, &dst_rgn, dst_preview, dst_preview_d, dst_preview);
do_merge_operation(MERGE_DIFF, &dst_rgn, &dst_rgn_d, &dst_rgn, dst_preview, dst_preview_d, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_d);
Expand All @@ -152,7 +152,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin

// boundary extraction is the difference between the original image and its erosion
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn, src_preview, dst_preview, settings.element, SRC_ORIGINAL);
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview);
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview, SRC_ORIGINAL);

}
else if (settings.operator == OPERATOR_HITORMISS) {
Expand Down Expand Up @@ -196,7 +196,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn_c, src_preview_c, dst_preview_c, B2, SRC_INVERSE);

// do interception (take only the common values)
do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview);
do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_c);
Expand Down Expand Up @@ -238,8 +238,8 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn, src_preview, dst_preview, B1, SRC_ORIGINAL);
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn_c, src_preview_c, dst_preview_c, B2, SRC_INVERSE);

do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview);
do_merge_operation(MERGE_UNION, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview);
do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview, SRC_ORIGINAL);
do_merge_operation(MERGE_UNION, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_c);
Expand Down Expand Up @@ -282,8 +282,8 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn, src_preview, dst_preview, B1, SRC_ORIGINAL);
do_morph_operation(OPERATOR_EROSION, &src_rgn, &dst_rgn_c, src_preview_c, dst_preview_c, B2, SRC_INVERSE);

do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview);
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview);
do_merge_operation(MERGE_INTERSEPT, &dst_rgn, &dst_rgn_c, &dst_rgn, dst_preview, dst_preview_c, dst_preview, SRC_ORIGINAL);
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_c);
Expand All @@ -310,8 +310,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
*/

// we need some temporary buffers...

// for erosions
// ...for erosions
int drawable_erod_id;
GimpDrawable* drawable_erod;
GimpPixelRgn src_rgn_erod, dst_rgn_erod;
Expand All @@ -329,7 +328,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
#endif
}

// for opening and difference
// ...for opening and difference
int drawable_open_id;
GimpDrawable* drawable_open;
GimpPixelRgn src_rgn_open, dst_rgn_open;
Expand All @@ -339,21 +338,21 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
drawable_open = gimp_drawable_get(drawable_open_id);
prepare_image_buffers(drawable_open, &src_rgn_open, &dst_rgn_open, &src_preview_open, &dst_preview_open, sel_x, sel_y, sel_w, sel_h, is_preview);

// the source/destination region will be the final skeleton.
// the destination region will be the final skeleton.
// start filling it black...
fill_black(&src_rgn, &dst_rgn, src_preview, dst_preview);

do {
// eroded = erosion(img)
do_morph_operation(OPERATOR_EROSION, &src_rgn_erod, &dst_rgn_erod, src_preview_erod, dst_preview_erod, settings.element, SRC_ORIGINAL);
// eroded = erosion(img) [must threshold 'img'!]
do_morph_operation(OPERATOR_EROSION, &src_rgn_erod, &dst_rgn_erod, src_preview_erod, dst_preview_erod, settings.element, SRC_THRESHOLD);
// open = dilate(eroded)
do_morph_operation(OPERATOR_DILATION, &dst_rgn_erod, &dst_rgn_open, dst_preview_erod, dst_preview_open, settings.element, SRC_ORIGINAL);

// diff = img - open
do_merge_operation(MERGE_DIFF, &src_rgn_erod, &dst_rgn_open, &dst_rgn_open, src_preview_erod, dst_preview_open, dst_preview_open);
// diff = img - open [must threshold 'img'!]
do_merge_operation(MERGE_DIFF, &src_rgn_erod, &dst_rgn_open, &dst_rgn_open, src_preview_erod, dst_preview_open, dst_preview_open, SRC_THRESHOLD);

// skel = skel U diff
do_merge_operation(MERGE_UNION, &dst_rgn, &dst_rgn_open, &dst_rgn, dst_preview, dst_preview_open, dst_preview);
do_merge_operation(MERGE_UNION, &dst_rgn, &dst_rgn_open, &dst_rgn, dst_preview, dst_preview_open, dst_preview, SRC_ORIGINAL);

// must update the eroded drawable for the next iteration
if (!is_preview) {
Expand Down Expand Up @@ -400,7 +399,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_DILATION, &dst_rgn_o, &dst_rgn, dst_preview_o, dst_preview, settings.element, SRC_ORIGINAL);

// and subtract it to the original image
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview);
do_merge_operation(MERGE_DIFF, &src_rgn, &dst_rgn, &dst_rgn, src_preview, dst_preview, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_o);
Expand All @@ -426,7 +425,7 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
do_morph_operation(OPERATOR_DILATION, &src_rgn, &dst_rgn_c, src_preview, dst_preview_c, settings.element, SRC_ORIGINAL);
do_morph_operation(OPERATOR_EROSION, &dst_rgn_c, &dst_rgn, dst_preview_c, dst_preview, settings.element, SRC_ORIGINAL);

do_merge_operation(MERGE_DIFF, &dst_rgn, &src_rgn, &dst_rgn, dst_preview, src_preview, dst_preview);
do_merge_operation(MERGE_DIFF, &dst_rgn, &src_rgn, &dst_rgn, dst_preview, src_preview, dst_preview, SRC_ORIGINAL);

if (is_preview) {
g_free(src_preview_c);
Expand Down Expand Up @@ -459,6 +458,21 @@ void start_operation(GimpDrawable *drawable, GimpPreview *preview, MorphOpSettin
}
}

/* do_morph_operation()
*
* Executes erosion or dilation using the given structuring element
*
* - MorphOperator op: the operator, it can be OPERATOR_EROSION or OPERATOR_DILATION
* - GimpPixelRgn* src: source region
* - GimpPixelRgn* dst: destination region
* - guchar* src_prev: source preview buffer (if any)
* - guchar* dst_prev: destination preview buffer
* - StructuringElement element: the structuring element
* - SourceTansformation srctransf: a "source preprocessing" option, it can be:
* - SRC_ORIGINAL (leaves source unchanged)
* - SRC_INVERSE (invert source's colors, used by Hit-or-Miss)
* - SRC_THRESHOLD (makes a threshold, if color < 127 => 0, else => 1, used by Skeletonization)
*/
static void do_morph_operation(
MorphOperator op,
GimpPixelRgn *src, GimpPixelRgn *dst,
Expand Down Expand Up @@ -490,6 +504,7 @@ static void do_morph_operation(
guchar row_buffer_mask[final_elem_size][src->w * src->bpp]; // will store the input pixel in a "big" row (for masking)

guchar this_pixel[src->bpp]; // the visited pixel
guchar this_lum; // the luminosity of the visited pixel
guchar best_pixel[src->bpp]; // the best pixel found to be copied on the center pixel
unsigned int best_lum; // the luminosity of the best pixel

Expand Down Expand Up @@ -556,17 +571,24 @@ static void do_morph_operation(
){
// get this pixel's values
for(i = 0; i < src->bpp; i++) {
if (srctransf == SRC_ORIGINAL) this_pixel[i] = row_buffer_mask[neigh_y][neigh_x + i];
if (srctransf == SRC_ORIGINAL || srctransf == SRC_THRESHOLD) this_pixel[i] = row_buffer_mask[neigh_y][neigh_x + i];
else if (srctransf == SRC_INVERSE) this_pixel[i] = abs(row_buffer_mask[neigh_y][neigh_x + i] - 255);
}

// and calc its luminosity (different ways for different image types)
unsigned int this_lum;
if (image_type == GIMP_RGB_IMAGE || image_type == GIMP_RGBA_IMAGE) {
this_lum = this_pixel[0] * 0.2126 + this_pixel[1] * 0.7152 + this_pixel[2] * 0.0722;
if (srctransf == SRC_THRESHOLD) {
this_lum = (this_lum < 127 ? 0 : 255);
this_pixel[0] = this_pixel[1] = this_pixel[2] = this_lum;
}
}
else {
this_lum = this_pixel[0];
if (srctransf == SRC_THRESHOLD) {
this_lum = (this_lum < 127 ? 0 : 255);
this_pixel[0] = this_lum;
}
}

// now check if this luminosity is better than the best found so far
Expand Down Expand Up @@ -630,20 +652,28 @@ static void do_morph_operation(
* - an "union" (min(Ai - Bi, 255)),
* - an "interseption", taking only the common pixels and setting the others to black.
*
* - MergeOperation op: the merge operation, can be MERGE_DIFF, MERGE_UNION or MERGE_INTERSEPT
* - MergeOperation op: the merge operation, it can be MERGE_DIFF, MERGE_UNION or MERGE_INTERSEPT
* - GimpPixelRgn* a: first input region
* - GimpPixelRgn* b: second input region
* - GimpPixelRgn* dst: destination region
* - guchar* a_prev: first input preview buffer (if any)
* - guchar* b_prev: second input preview buffer
* - guchar* dst_prev: destination preview buffer
* - SourceTansformation srctransf: a "source preprocessing" option applied to a/a_prev, see do_morph_operation()
*/
static void do_merge_operation(MergeOperation op, GimpPixelRgn* a, GimpPixelRgn* b, GimpPixelRgn* dst, guchar* a_prev, guchar* b_prev, guchar* dst_prev)
{
static void do_merge_operation(
MergeOperation op,
GimpPixelRgn* a, GimpPixelRgn* b, GimpPixelRgn* dst,
guchar* a_prev, guchar* b_prev,
guchar* dst_prev,
SourceTansformation srctransf
){
gboolean is_preview = (a_prev != NULL || b_prev != NULL);
guchar row_buffer_a[a->w * a->bpp];
guchar row_buffer_b[b->w * b->bpp];

GimpImageType image_type = gimp_drawable_type (a->drawable->drawable_id);

unsigned int x, y, i;
int ignore_alpha = gimp_drawable_has_alpha(a->drawable->drawable_id) ? 1 : 0;

Expand Down Expand Up @@ -674,6 +704,21 @@ static void do_merge_operation(MergeOperation op, GimpPixelRgn* a, GimpPixelRgn*
}

for (x = 0; x < a->w; x++) {

// preoprocessing on a/a_prev
if (srctransf == SRC_THRESHOLD) {
for(i = 0; i < a->bpp - ignore_alpha; i++) {
if (image_type == GIMP_RGB_IMAGE || image_type == GIMP_RGBA_IMAGE) {
unsigned char this_lum = row_buffer_a[x * a->bpp + 0] * 0.2126 + row_buffer_a[x * a->bpp + 1] * 0.7152 + row_buffer_a[x * a->bpp + 2] * 0.0722;
row_buffer_a[x * a->bpp + 0] = row_buffer_a[x * a->bpp + 1] = row_buffer_a[x * a->bpp + 2] = (this_lum < 127 ? 0 : 255);
break;
}
else {
row_buffer_a[x * a->bpp + i] = row_buffer_a[x * a->bpp + i] < 127 ? 0 : 255;
}
}
}

// merge here, skipping alpha channel if present
for(i = 0; i < a->bpp - ignore_alpha; i++) {
if (op == MERGE_DIFF) {
Expand Down
1 change: 1 addition & 0 deletions src/morphop-algorithms.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ typedef enum {
typedef enum {
SRC_ORIGINAL = 0,
SRC_INVERSE,
SRC_THRESHOLD,

SRC_END
} SourceTansformation;
Expand Down

0 comments on commit 984debb

Please sign in to comment.