本文主要是介绍YUV422与RGB互相转,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
YUV422与RGB互相转换(经验证在IPNC与PC上都可以)
前一段时间在DM8168中进行颜色空间的转换,在网上找了些程序,自己也根据网上的改了下,由于能力问题,实在是不好意思说做了好几天才弄出来,主要是因为YUV<—>RGB有各种各样的转换公式。在多次的实验修改后,终于找到了对的公式,共享出来,以便需要的人选择。
在监控系统中大多采用YUV的颜色空间,原因不说了,网上搜YUV转RGB各种介绍。
在TI的视频英语达芬奇系列中(这里只测试了DVR、IPNC),
采用如下公式:
yCbCr<-->rgb
Y’ = 0.257*R' + 0.504*G' + 0.098*B' + 16
Cb' = -0.148*R' - 0.291*G' + 0.439*B' + 128
Cr' = 0.439*R' - 0.368*G' - 0.071*B' + 128
R' = 1.164*(Y’-16) + 1.596*(Cr'-128)
G' = 1.164*(Y’-16) - 0.813*(Cr'-128) - 0.392*(Cb'-128)
B' = 1.164*(Y’-16) + 2.017*(Cb'-128)
转换效果图如下
第一幅是原图YUV,第二幅是转为RGB后存为bmp,反转是因为BMP图像是从最下面一行开始存取的原因,最下面一副是转回YUV的图像。
代码如下,代码中YUV采用YUYVYUYV的格式,RGB为RGBRGBRGB.....
http://download.csdn.net/detail/guo8113/7318031(代码下载)
- #ifndef _RGB2YUV__
- #define _RGB2YUV__
- #include <iostream>
- using namespace std;
- #define TUNE(r) ( r < 0 ? 0 : (r > 255 ? 255 : r) )
- static int RGB_Y[256];
- static int RGBR_V[256];
- static int RGBG_U[256];
- static int RGBG_V[256];
- static int RGBB_U[256];
- static int YUVY_R[256];
- static int YUVY_G[256];
- static int YUVY_B[256];
- static int YUVU_R[256];
- static int YUVU_G[256];
- static int YUVU_B[256];
- static int YUVV_R[256];
- static int YUVV_G[256];
- static int YUVV_B[256];
- static int coff_rv[256];
- static int coff_gu[256];
- static int coff_gv[256];
- static int coff_bu[256];
- //直接采用公式浮点计算方式
- //仅RGB2YUV采用了查表法,所以有一部分表是没有用到的
- void InitTable()
- {
- int i;
- for(i = 0;i<256;i++)
- {
- //初始化表,放大256倍
- RGB_Y[i] = 298 * (i - 16);
- RGBR_V[i] = 408 * (i - 128);
- RGBG_U[i] = 100 * (128- i);
- RGBG_V[i]= 208*(128-i);
- RGBB_U[i] =517 * (i - 128);
- //y=0.257*r+0.504*g+0.098*b+16
- //u = -0.148*r - 0.291*g + 0.439*b + 128
- //0.439*r - 0.368*g - 0.071*b + 128
- YUVY_R[i]=66*i;
- YUVY_G[i]=129*i;
- YUVY_B[i]=25*i;
- YUVU_R[i]=-38*i;
- YUVU_G[i]=-74*i;
- YUVU_B[i]=112*i;
- YUVV_R[i]=112*i;
- YUVV_G[i]=-94*i;
- YUVV_B[i]=-18*i;
- /*所用公式(此公式不适用)
- *pRGB = (unsigned char)(1.0*y + 8 + 1.402*(v-128)); pRGB++; // r
- *pRGB = (unsigned char)(1.0*y - 0.34413*(u-128) - 0.71414*(v-128)); pRGB++; // g
- *pRGB = (unsigned char)(1.0*y + 1.772*(u-128) + 0); pRGB++ ;
- */
- coff_rv[i] = (8+1.402*(i-128))*256;
- coff_gu[i] = -0.34413*(i-128)*256;
- coff_gv[i] = -0.71414*(i-128)*256;
- coff_bu[i] = 1.772*(i-128)*256;
- /*应该使用如下公式:
- Y’ = 0.257*R' + 0.504*G' + 0.098*B' + 16
- Cb' = -0.148*R' - 0.291*G' + 0.439*B' + 128
- Cr' = 0.439*R' - 0.368*G' - 0.071*B' + 128(标红的两组公式是可逆的转换)
- R' = 1.164*(Y’-16) + 1.596*(Cr'-128)
- G' = 1.164*(Y’-16) - 0.813*(Cr'-128) - 0.392*(Cb'-128)
- B' = 1.164*(Y’-16) + 2.017*(Cb'-128)
- */
- }
- }
- void YUV2RGB422(unsigned char *pRGB, unsigned char *pYUV,int size)
- {
- unsigned char y, u, v,y1;
- int r,g,b;
- unsigned int i=0;
- unsigned int loop = size>>1;
- while(loop-- >0)
- {
- y = *pYUV; pYUV++;
- u = *pYUV; pYUV++;
- y1 = *pYUV;pYUV++;
- v = *pYUV; pYUV++;
- r = 1.164*(y-16) + 1.596*(v-128);
- g = 1.164*(y-16) - 0.813*(v-128) - 0.392*(u-128);
- b = 1.164*(y-16) + 2.017*(u-128);
- *pRGB = TUNE(r);pRGB++;
- *pRGB = TUNE(g);pRGB++;
- *pRGB = TUNE(b);pRGB++;
- r = 1.164*(y1-16) + 1.596*(v-128);
- g = 1.164*(y1-16) - 0.813*(v-128) - 0.392*(u-128);
- b = 1.164*(y1-16) + 2.017*(u-128);
- *pRGB = TUNE(r);pRGB++;
- *pRGB = TUNE(g);pRGB++;
- *pRGB = TUNE(b);pRGB++;
- }
- }
- //size 为图片的大小
- void RGB2YUV422(unsigned char *pRGB, unsigned char *pYUV,int size)
- {
- unsigned char r,g,b,u,v,u1,v1,r1,g1,b1;
- //unsigned char *YUVBuff;
- //unsigned char* p;
- //p = YUVBuff;//
- int loop = size/2;
- int i;
- for( i=0;i<loop;i++)
- {
- r = *pRGB; pRGB++;
- g = *pRGB; pRGB++;
- b = *pRGB; pRGB++;
- r1 = *pRGB; pRGB++;
- g1 = *pRGB; pRGB++;
- b1 = *pRGB; pRGB++;
- //new method --- right
- int y = ((YUVY_R[r] + YUVY_G[g] + YUVY_B[b] + 128) >> 8) +16;
- u = ((YUVU_R[r] + YUVU_G[g] + YUVU_B[b] + 128) >> 8) + 128;
- v = ((YUVV_R[r] + YUVV_G[g] + YUVV_B[b] + 128) >> 8) + 128;
- int y1 = ((YUVY_R[r1] + YUVY_G[g1] + YUVY_B[b1] + 128) >> 8)+16;
- u1 = ((YUVU_R[r1] + YUVU_G[g1] + YUVU_B[b1] + 128) >> 8) + 128;
- v1 = ((YUVV_R[r1] + YUVV_G[g1] + YUVV_B[b1] + 128) >> 8) + 128;
- *pYUV++ = TUNE(y);
- *pYUV++ =(TUNE(u)+TUNE(u1))>>1;
- *pYUV++ = TUNE(y1);
- *pYUV++ = TUNE(v);
- }
- }
- void inline Yuv2RgbPixel(unsigned char y,unsigned char u,unsigned char v,
- unsigned char* rgbPixel)
- {
- int r = (RGB_Y[y] + RGBR_V[v] + 128) >> 8;
- int g = ((RGB_Y[y] + RGBG_V[v] +RGBG_U[u]+ 128)>>8 );
- int b = ((RGB_Y[y] + RGBB_U[u]+128 )>>8);
- *rgbPixel=TUNE(r);rgbPixel++;
- *rgbPixel=TUNE(g);rgbPixel++;
- *rgbPixel=TUNE(b);
- }
- void YUV2RGB(unsigned char *pRGB, unsigned char *pYUV,int size)//444
- {
- unsigned char y, u, v;
- for(int i=0;i<size;i++)
- {
- y = *pYUV; pYUV++;
- u = *pYUV; pYUV++;
- v = *pYUV; pYUV++;
- Yuv2RgbPixel(y,u,v,pRGB);
- pRGB += 3;
- }
- }
- void inline Rgb2YuvPiexl(unsigned char r,unsigned char g,unsigned char b,unsigned char* pYUV)
- {
- int y = ((YUVY_R[r] + YUVY_G[g] + YUVY_B[b] + 128) >> 8) + 16;
- int u = ((YUVU_R[r] + YUVU_G[g] + YUVU_B[b] + 128) >> 8) + 128;
- int v = ((YUVV_R[r] + YUVV_G[g] + YUVV_B[b] + 128) >> 8) + 128;
- *pYUV = TUNEY(y);pYUV++;
- //*pYUV = u < 0 ? 0 : (u > 255 ? 255 : u);pYUV++;
- *pYUV =TUNE(u);pYUV++;
- *pYUV = TUNE(v);
- }
- void RGB2YUV(unsigned char *pRGB, unsigned char *pYUV,int size)
- {
- unsigned char r,g,b,y,u,v;
- for(int i=0;i<size;i++)
- {
- r = *pRGB; pRGB++;
- g = *pRGB; pRGB++;
- b = *pRGB; pRGB++;
- Rgb2YuvPiexl(r,g,b,pYUV);
- pYUV +=3;
- }
- }
- #endif
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