Patent ID: 6567096
Filing Date: 2003-05-20
Classification: G06T

Abstract:
A method of combining a first video image and a second video image to produce a combined video image, said method comprising:selecting a minuend comprising a first minuend component, a second minuend component, a third minuend component and a fourth minuend component from the group consisting of a first pixel value, a second pixel value and a zero pixel value, said first pixel value corresponding to a pixel from said first video image and comprising a red component corresponding to said first minuend component, a green component corresponding to said second minuend component, a blue component corresponding to said third minuend component and an alpha component corresponding to said fourth minuend component, said second pixel value corresponding to a pixel from said second video image and comprising a red component corresponding to said first minuend component, a green component corresponding to said second minuend component, a blue component corresponding to said third minuend component and an alpha component corresponding to said fourth minuend component, said zero pixel value comprising a first zero component corresponding to said first minuend component, a second zero component corresponding to said second minuend component, a third zero component corresponding to said third minuend component and a fourth zero component corresponding to said fourth minuend component; selecting a subtrahend comprising a first subtrahend component, a second subtrahend component, a third subtrahend component and a fourth subtrahend component from the group consisting of said first pixel value, said second pixel value and said zero pixel value, said first subtrahend component corresponding to said first minuend component, said second subtrahend component corresponding to said second minuend component, said third subtrahend component corresponding to said third minuend component and said fourth subtrahend component corresponding to said fourth minuend component; subtracting said first subtrahend component, said second subtrahend component, said third subtrahend component and said fourth subtrahend component from, respectively, said first minuend component, said second minuend component, said third minuend component and said fourth minuend component to produce, respectively, a first difference component, a second difference component, a third difference component and a fourth difference component; selecting a first mixing factor comprising a first mixing component, a second mixing component, a third mixing component and a fourth mixing component, each of said mixing components having the same value, said same value being selected from the group consisting of the alpha component of said first pixel value, the alpha component of said second pixel value and a fixed value; multiplying said first difference component, said second difference component, said third difference component and said fourth difference component by, respectively, said first mixing component, said second mixing component, said third mixing component and said fourth mixing component to produce, respectively, a first product component, a second product component, a third product component and a fourth product component; selecting a blending factor comprising a first blending component, a second blending component, a third blending component and a fourth blending component from the group consisting of said first pixel value, said second pixel value and said zero pixel value, said first blending component corresponding to said first minuend component, said second blending component corresponding to said second minuend component, said third blending component corresponding to said third minuend component and said fourth blending component corresponding to said fourth minuend component; adding said first product component, said second product component, said third product component and said fourth product component to, respectively, said first blending component, said second blending component, said third blending component and said fourth blending component to produce, respectively, a red value, a green value, a blue value and an alpha value for a pixel of said combined video image.