research.m1stereo.tv/gitweb/ - melted/blob - src/modules/effectv/image.c

   1 /*
   2  * EffecTV - Realtime Digital Video Effector
   3  * Copyright (C) 2001-2006 FUKUCHI Kentaro
   4  *
   5  * image.c: utilities for image processing.
   6  *
   7  */
   8
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include "utils.h"
  12
  13
  14 /*
  15  * Collection of background subtraction functions
  16  */
  17
  18 /* checks only fake-Y value */
  19 /* In these function Y value is treated as R*2+G*4+B. */
  20
  21 int image_set_threshold_y(int threshold)
  22 {
  23         int y_threshold = threshold * 7; /* fake-Y value is timed by 7 */
  24
  25         return y_threshold;
  26 }
  27
  28 void image_bgset_y(RGB32 *background, const RGB32 *src, int video_area, int y_threshold)
  29 {
  30         int i;
  31         int R, G, B;
  32         const RGB32 *p;
  33         short *q;
  34
  35         p = src;
  36         q = (short *)background;
  37         for(i=0; i<video_area; i++) {
  38                 /* FIXME: endianess */
  39
  40                 R = ((*p)&0xff0000)>>(16-1);
  41                 G = ((*p)&0xff00)>>(8-2);
  42                 B = (*p)&0xff;
  43                 *q = (short)(R + G + B);
  44                 p++;
  45                 q++;
  46         }
  47 }
  48
  49 void image_bgsubtract_y(unsigned char *diff, const RGB32 *background, const RGB32 *src, int video_area, int y_threshold)
  50 {
  51         int i;
  52         int R, G, B;
  53         const RGB32 *p;
  54         const short *q;
  55         unsigned char *r;
  56         int v;
  57
  58         p = src;
  59         q = (const short *)background;
  60         r = diff;
  61         for(i=0; i<video_area; i++) {
  62                 /* FIXME: endianess */
  63
  64                 R = ((*p)&0xff0000)>>(16-1);
  65                 G = ((*p)&0xff00)>>(8-2);
  66                 B = (*p)&0xff;
  67                 v = (R + G + B) - (int)(*q);
  68                 *r = ((v + y_threshold)>>24) | ((y_threshold - v)>>24);
  69
  70                 p++;
  71                 q++;
  72                 r++;
  73         }
  74
  75 /* The origin of subtraction function is;
  76  * diff(src, dest) = (abs(src - dest) > threshold) ? 0xff : 0;
  77  *
  78  * This functions is transformed to;
  79  * (threshold > (src - dest) > -threshold) ? 0 : 0xff;
  80  *
  81  * (v + threshold)>>24 is 0xff when v is less than -threshold.
  82  * (v - threshold)>>24 is 0xff when v is less than threshold.
  83  * So, ((v + threshold)>>24) | ((threshold - v)>>24) will become 0xff when
  84  * abs(src - dest) > threshold.
  85  */
  86 }
  87
  88 /* Background image is refreshed every frame */
  89 void image_bgsubtract_update_y(unsigned char *diff, RGB32 *background, const RGB32 *src, int video_area, int y_threshold)
  90 {
  91         int i;
  92         int R, G, B;
  93         const RGB32 *p;
  94         short *q;
  95         unsigned char *r;
  96         int v;
  97
  98         p = src;
  99         q = (short *)background;
 100         r = diff;
 101         for(i=0; i<video_area; i++) {
 102                 /* FIXME: endianess */
 103
 104                 R = ((*p)&0xff0000)>>(16-1);
 105                 G = ((*p)&0xff00)>>(8-2);
 106                 B = (*p)&0xff;
 107                 v = (R + G + B) - (int)(*q);
 108                 *q = (short)(R + G + B);
 109                 *r = ((v + y_threshold)>>24) | ((y_threshold - v)>>24);
 110
 111                 p++;
 112                 q++;
 113                 r++;
 114         }
 115 }
 116
 117 /* checks each RGB value */
 118
 119 /* The range of r, g, b are [0..7] */
 120 RGB32 image_set_threshold_RGB(int r, int g, int b)
 121 {
 122         unsigned char R, G, B;
 123         RGB32 rgb_threshold;
 124
 125         R = G = B = 0xff;
 126         R = R<<r;
 127         G = G<<g;
 128         B = B<<b;
 129         rgb_threshold = (RGB32)(R<<16 | G<<8 | B);
 130
 131         return rgb_threshold;
 132 }
 133
 134 void image_bgset_RGB(RGB32 *background, const RGB32 *src, int video_area)
 135 {
 136         int i;
 137         RGB32 *p;
 138
 139         p = background;
 140         for(i=0; i<video_area; i++) {
 141                 *p++ = (*src++) & 0xfefefe;
 142         }
 143 }
 144
 145 void image_bgsubtract_RGB(unsigned char *diff, const RGB32 *background, const RGB32 *src, int video_area, RGB32 rgb_threshold)
 146 {
 147         int i;
 148         const RGB32 *p, *q;
 149         unsigned a, b;
 150         unsigned char *r;
 151
 152         p = src;
 153         q = background;
 154         r = diff;
 155         for(i=0; i<video_area; i++) {
 156                 a = (*p++)|0x1010100;
 157                 b = *q++;
 158                 a = a - b;
 159                 b = a & 0x1010100;
 160                 b = b - (b>>8);
 161                 b = b ^ 0xffffff;
 162                 a = a ^ b;
 163                 a = a & rgb_threshold;
 164                 *r++ = (0 - a)>>24;
 165         }
 166 }
 167
 168 void image_bgsubtract_update_RGB(unsigned char *diff, RGB32 *background, const RGB32 *src, int video_area, RGB32 rgb_threshold)
 169 {
 170         int i;
 171         const RGB32 *p;
 172         RGB32 *q;
 173         unsigned a, b;
 174         unsigned char *r;
 175
 176         p = src;
 177         q = background;
 178         r = diff;
 179         for(i=0; i<video_area; i++) {
 180                 a = *p|0x1010100;
 181                 b = *q&0xfefefe;
 182                 *q++ = *p++;
 183                 a = a - b;
 184                 b = a & 0x1010100;
 185                 b = b - (b>>8);
 186                 b = b ^ 0xffffff;
 187                 a = a ^ b;
 188                 a = a & rgb_threshold;
 189                 *r++ = (0 - a)>>24;
 190         }
 191 }
 192
 193 /* noise filter for subtracted image. */
 194 void image_diff_filter(unsigned char *diff2, const unsigned char *diff, int width, int height)
 195 {
 196         int x, y;
 197         const unsigned char *src;
 198         unsigned char *dest;
 199         unsigned int count;
 200         unsigned int sum1, sum2, sum3;
 201
 202         src = diff;
 203         dest = diff2 + width +1;
 204         for(y=1; y<height-1; y++) {
 205                 sum1 = src[0] + src[width] + src[width*2];
 206                 sum2 = src[1] + src[width+1] + src[width*2+1];
 207                 src += 2;
 208                 for(x=1; x<width-1; x++) {
 209                         sum3 = src[0] + src[width] + src[width*2];
 210                         count = sum1 + sum2 + sum3;
 211                         sum1 = sum2;
 212                         sum2 = sum3;
 213                         *dest++ = (0xff*3 - count)>>24;
 214                         src++;
 215                 }
 216                 dest += 2;
 217         }
 218 }
 219
 220 /* Y value filters */
 221 void image_y_over(unsigned char *diff, const RGB32 *src, int video_area, int y_threshold)
 222 {
 223         int i;
 224         int R, G, B, v;
 225         unsigned char *p = diff;
 226
 227         for(i = video_area; i>0; i--) {
 228                 R = ((*src)&0xff0000)>>(16-1);
 229                 G = ((*src)&0xff00)>>(8-2);
 230                 B = (*src)&0xff;
 231                 v = y_threshold - (R + G + B);
 232                 *p = (unsigned char)(v>>24);
 233                 src++;
 234                 p++;
 235         }
 236 }
 237
 238 void image_y_under(unsigned char *diff, const RGB32 *src, int video_area, int y_threshold)
 239 {
 240         int i;
 241         int R, G, B, v;
 242         unsigned char *p = diff;
 243
 244         for(i = video_area; i>0; i--) {
 245                 R = ((*src)&0xff0000)>>(16-1);
 246                 G = ((*src)&0xff00)>>(8-2);
 247                 B = (*src)&0xff;
 248                 v = (R + G + B) - y_threshold;
 249                 *p = (unsigned char)(v>>24);
 250                 src++;
 251                 p++;
 252         }
 253 }
 254
 255 /* tiny edge detection */
 256 void image_edge(unsigned char *diff2, const RGB32 *src, int width, int height, int y_threshold)
 257 {
 258         int x, y;
 259         const unsigned char *p;
 260         unsigned char *q;
 261         int r, g, b;
 262         int ar, ag, ab;
 263         int w;
 264
 265         p = (const unsigned char *)src;
 266         q = diff2;
 267         w = width * sizeof(RGB32);
 268
 269         for(y=0; y<height - 1; y++) {
 270                 for(x=0; x<width - 1; x++) {
 271                         b = p[0];
 272                         g = p[1];
 273                         r = p[2];
 274                         ab = abs(b - p[4]);
 275                         ag = abs(g - p[5]);
 276                         ar = abs(r - p[6]);
 277                         ab += abs(b - p[w]);
 278                         ag += abs(g - p[w+1]);
 279                         ar += abs(r - p[w+2]);
 280                         b = ab+ag+ar;
 281                         if(b > y_threshold) {
 282                                 *q = 255;
 283                         } else {
 284                                 *q = 0;
 285                         }
 286                         q++;
 287                         p += 4;
 288                 }
 289                 p += 4;
 290                 *q++ = 0;
 291         }
 292         memset(q, 0, width);
 293 }
 294
 295 /* horizontal flipping */
 296 void image_hflip(const RGB32 *src, RGB32 *dest, int width, int height)
 297 {
 298         int x, y;
 299
 300         src += width - 1;
 301         for(y=0; y<height; y++) {
 302                 for(x=0; x<width; x++) {
 303                         *dest++ = *src--;
 304                 }
 305                 src += width * 2;
 306         }
 307 }
 308