对比度计算

[e_feeling]

图像亮度、对比度的计算方法？

[topology18]

亮度：light = 1/3(r+g+b)

[ttmmdd]

亮度应是0.3f*R + 0.59f*G + 0.11f*B

[zzwu]

设
Imax = 图像亮度最大值
Imin = 图像亮度最小值

则
对比度 = (Imax-Imin)/256

图像各点亮度上面已给了计算公式.

[e_feeling]

增加减少亮度, 增加减少对比度怎么计算?

[e_feeling]

?

[zzwu]

不知道看看下面的贴能不能解决问题:
http://expert.csdn.net/Expert/FAQ/FAQ_Index.asp?id=179307

[e_feeling]

还有没有?

[e_feeling]

寻找

[e_feeling]

@@

[ljranby]

ttmmdd(老孩子) 你说的是灰度
根据CIE的标准
HSI系统中亮度为I=(R+G+B)/3
对比度S=1-(min(R,G,B)/I)

[e_feeling]

haiyouma
z

[e_feeling]

SFTW

[potlee]

有两个C++Builder的函数，希望有用

调整对比度的函数
void TForm1::DoContrast(int s)
{
int XX;
BYTE *ptr;
Graphics::TBitmap *tmpBitmap=new Graphics::TBitmap();
tmpBitmap->Assign((TPersistent*)Image1->Picture->Graphic);
tmpBitmap->PixelFormat=pf24bit;
for (int y = 0; y < tmpBitmap->Height; y++)
{
ptr =(BYTE *) tmpBitmap->ScanLine[y];
for (int x = 0; x < tmpBitmap->Width*3; x+=3){
XX=((ptr[x+2]-128)*s+12800)/100;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+2]=XX;
XX=((ptr[x+1]-128)*s+12800)/100;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+1]=XX;
XX=((ptr[x]-128)*s+12800)/100;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+0]=XX;
}
}
Image1->Picture->Graphic=tmpBitmap;
delete tmpBitmap;

}
调整亮度的函数
void TForm1::DoBright(int b)
{
int XX;
BYTE *ptr;
Graphics::TBitmap *tmpBitmap=new Graphics::TBitmap();
tmpBitmap->Assign((TPersistent*)Image1->Picture->Graphic);
tmpBitmap->PixelFormat=pf24bit;
for (int y = 0; y < tmpBitmap->Height; y++)
{
ptr =(BYTE *) tmpBitmap->ScanLine[y];
for (int x = 0; x < tmpBitmap->Width*3; x+=3){
XX=ptr[x+2]+b;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+2]=XX;
XX=ptr[x+1]+b;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+1]=XX;
XX=ptr[x]+b;
XX=MAX(XX,0);XX=MIN(XX,255);ptr[x+0]=XX;
}
}
Image1->Picture->Graphic=tmpBitmap;
delete tmpBitmap;
}