1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/** \file
* \brief Histogram Based Operations
*
* See Copyright Notice in im_lib.h
* $Id: im_histogram.cpp,v 1.1 2008/10/17 06:16:33 scuri Exp $
*/
#include <im.h>
#include <im_util.h>
#include <im_math.h>
#include "im_process_pon.h"
#include "im_process_ana.h"
#include <stdlib.h>
#include <memory.h>
static void iExpandHistogram(const imImage* src_image, imImage* dst_image, int low_level, int high_level)
{
int i, value;
imbyte re_map[256];
memset(re_map, 0, 256);
int range = high_level-low_level+1;
float factor = 256.0f / (float)range;
for (i = 0; i < 256; i++)
{
if (i < low_level)
re_map[i] = 0;
else if (i > high_level)
re_map[i] = 255;
else
{
value = imResample(i - low_level, factor);
re_map[i] = (imbyte)IM_BYTECROP(value);
}
}
imbyte* dst_map = (imbyte*)dst_image->data[0];
imbyte* src_map = (imbyte*)src_image->data[0];
int total_count = src_image->count*src_image->depth;
for (i = 0; i < total_count; i++)
dst_map[i] = re_map[src_map[i]];
}
void imProcessExpandHistogram(const imImage* src_image, imImage* dst_image, float percent)
{
unsigned long histo[256];
imCalcGrayHistogram(src_image, histo, 0);
unsigned long acum, cut = (unsigned long)((src_image->count * percent) / 100.0f);
int low_level, high_level;
acum = 0;
for (low_level = 0; low_level < 256; low_level++)
{
acum += histo[low_level];
if (acum > cut)
break;
}
acum = 0;
for (high_level = 255; high_level > 0; high_level--)
{
acum += histo[high_level];
if (acum > cut)
break;
}
if (low_level >= high_level)
{
low_level = 0;
high_level = 255;
}
iExpandHistogram(src_image, dst_image, low_level, high_level);
}
void imProcessEqualizeHistogram(const imImage* src_image, imImage* dst_image)
{
int i, value;
imbyte re_map[256];
memset(re_map, 0, 256);
unsigned long histo[256];
imCalcGrayHistogram(src_image, histo, 1);
float factor = 256.0f / (float)src_image->count;
for (i = 0; i < 256; i++)
{
value = imResample(histo[i], factor);
re_map[i] = (imbyte)IM_BYTECROP(value);
}
imbyte* dst_map = (imbyte*)dst_image->data[0];
imbyte* src_map = (imbyte*)src_image->data[0];
int total_count = src_image->count*src_image->depth;
for (i = 0; i < total_count; i++)
dst_map[i] = re_map[src_map[i]];
}
|
