From b39b9697bcc9270953ecadf11d2bedbc4f87ced6 Mon Sep 17 00:00:00 2001
From: Benjamin Franzke <benjaminfranzke@googlemail.com>
Date: Fri, 20 Apr 2012 13:04:41 +0200
Subject: Add hst: Histogramm based SegmenTation

---
 Makefile |   6 ++-
 hst.c    | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 1 deletion(-)
 create mode 100644 hst.c

diff --git a/Makefile b/Makefile
index 559cdaa..0e7e3a5 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,10 @@ unvignette_LIBS=$(shell pkg-config --libs cairo) -lm
 cvg_CFLAGS=$(shell pkg-config --cflags gtk+-3.0 glib-2.0 gmodule-2.0 opencv)
 cvg_LIBS=$(shell pkg-config --libs gtk+-3.0 glib-2.0 gmodule-2.0 opencv)
 
-PROGS = wimmel wimmel_gl roi capture unvignette cvg
+hst_CFLAGS=$(shell pkg-config --cflags gdk-pixbuf-2.0 glib-2.0)
+hst_LIBS=$(shell pkg-config --libs gdk-pixbuf-2.0 glib-2.0)
+
+PROGS = wimmel wimmel_gl roi capture unvignette cvg hst
 OBJS = $(PROGS:=.o) util.o
 
 all: $(PROGS)
@@ -33,6 +36,7 @@ roi: roi.o
 capture: capture.o
 unvignette: unvignette.o
 cvg: cvg.o
+hst: hst.o
 
 .PHONY: clean all
 
diff --git a/hst.c b/hst.c
new file mode 100644
index 0000000..63516c7
--- /dev/null
+++ b/hst.c
@@ -0,0 +1,126 @@
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <glib.h>
+
+#ifndef INTERVAL
+#define INTERVAL 8
+#endif
+#define BLOCKS (256 / INTERVAL)
+
+struct cell {
+	int i, j, k;
+	int count;
+	struct cell *max;
+};
+
+struct hst {
+	struct cell cells[BLOCKS][BLOCKS][BLOCKS];
+	GList *list;
+};
+
+static inline void
+pixbuf_get(GdkPixbuf *pixbuf, guchar **pixels,
+	   gint *width, gint *height, gint *nch, gint *stride)
+{
+	if (pixels) *pixels = gdk_pixbuf_get_pixels(pixbuf);
+	if (width)  *width  = gdk_pixbuf_get_width(pixbuf);
+	if (height) *height = gdk_pixbuf_get_height(pixbuf);
+	if (nch)    *nch    = gdk_pixbuf_get_n_channels(pixbuf);
+	if (stride) *stride = gdk_pixbuf_get_rowstride(pixbuf);
+}
+
+static gint
+compare_cell(gconstpointer a, gconstpointer b)
+{
+	const struct cell *cell1 = a;
+	const struct cell *cell2 = b;
+
+	return cell1->count - cell2->count;
+}
+
+static void
+add_neighbors(struct hst *hst, struct cell *cell)
+{
+	int i, j, k;	
+
+	for (i = MAX(cell->i - 1, 0); i < MIN(cell->i + 1, BLOCKS); ++i) {
+		for (j = MAX(cell->j - 1, 0); j < MIN(cell->j + 1, BLOCKS); ++j) {
+			for (k = MAX(cell->k - 1, 0); k < MIN(cell->k + 1, BLOCKS); ++k) {
+				if (hst->cells[i][j][k].count <= cell->count &&
+				    hst->cells[i][j][k].max == NULL) {
+				    	hst->cells[i][j][k].max = cell->max;
+					add_neighbors(hst, &hst->cells[i][j][k]);
+				}
+			}
+		}
+	}
+	hst->list = g_list_remove(hst->list, cell);
+}
+
+int
+main(int argc, char *argv[])
+{
+	GdkPixbuf *image;
+	gint x, y, width, height, nch, stride;
+	int i, j, k;
+	guchar *p, *row;
+	int cluster = 0;
+	struct hst hst;
+	struct cell *cell;
+
+	g_type_init();
+
+	if (argc < 2)
+		return 1;
+
+	image = gdk_pixbuf_new_from_file(argv[1], NULL);
+	if (!image)
+		return 1;
+
+	hst.list = NULL;
+	for (i = 0; i < BLOCKS; ++i) {
+		for (j = 0; j < BLOCKS; ++j) {
+			for (k = 0; k < BLOCKS; ++k) {
+				hst.cells[i][j][k].i = i;
+				hst.cells[i][j][k].j = j;
+				hst.cells[i][j][k].k = k;
+				hst.cells[i][j][k].count = 0;
+				hst.cells[i][j][k].max = NULL;
+			}
+		}
+	}
+
+	pixbuf_get(image, &row, &width, &height, &nch, &stride);
+	for (y = 0; y < height; ++y, row += stride)
+		for (x = 0, p = row; x < width; ++x, p += nch)
+			++hst.cells[p[0] / INTERVAL][p[1] / INTERVAL][p[2] / INTERVAL].count;
+
+	for (i = 0; i < BLOCKS; ++i)
+		for (j = 0; j < BLOCKS; ++j)
+			for (k = 0; k < BLOCKS; ++k)
+				hst.list = g_list_insert_sorted(hst.list,
+								&hst.cells[i][j][k],
+								compare_cell);
+
+	while (hst.list) {
+		cell = g_list_nth_data(hst.list, 0);
+		cell->max = cell;
+		add_neighbors(&hst, cell);
+		++cluster;
+	}
+	printf("cluster: %d\n", cluster);
+
+	pixbuf_get(image, &row, &width, &height, &nch, &stride);
+	for (y = 0; y < height; ++y, row += stride) {
+		for (x = 0, p = row; x < width; ++x, p += nch) {
+			cell = &hst.cells[p[0] / INTERVAL][p[1] / INTERVAL][p[2] / INTERVAL];
+
+			p[0] = cell->max->i * INTERVAL;
+			p[1] = cell->max->j * INTERVAL;
+			p[2] = cell->max->k * INTERVAL;
+		}
+	}
+
+	gdk_pixbuf_save(image, argc > 2 ? argv[2] : "hst.tiff", "tiff", NULL, NULL);
+
+	return 0;
+}
-- 
cgit