Method for chroma upsampling with luma reference
AssigneeHimax Technologies Limited
InventorJung-Chung Hsu
Life of this patent
Estimating the term…
Abstract
Chroma upsampling is performed by setting a chroma of a target pixel according to luma of neighboring pixels. When a luma of the target pixel differs from the luma of both of the reference pixels, the chroma of the target pixel is set to a value of (k*C1+(m−k)*C3+m/2) shifted n bits to the right. In this formula, n is an integer, m is equal to 2n, and k is equal to {0˜m, min(abs(abs(Y1−Y2)*k−abs(Y2−Y3)*(m−k)))}. Since luma are considered, and a precise calculation is used in this method, the calculations required are simplified and reduced, and video quality is improved.
Claims11
A chroma upscaling method comprising:
- comparing a luma Y1 of a first reference pixel and a luma Y2 of a target pixel for equality, and comparing a luma Y3 of a second reference pixel and the luma Y2 of the target pixel for equality;
- and
- if the luma Y1 of the first reference pixel is not equal to the luma Y2 of the target pixel and the luma Y2 of the target pixel is not equal to the luma Y3 of the second reference pixel, setting a chroma C2 of the target pixel based on a chroma C1 of the first reference pixel and a chroma C3 of the second reference pixel, as:
- C2=(k*C1+(m−k)*C3+m/2)>>n;
- wherein n is a positive integer, m=2n, “>>” represents a shift calculation, and
- k={0˜m, min(abs(D1*k−D2*(m−k)))},
- where D1=Abs(Y1−Y2), D2=Abs(Y2−Y3).
A chroma upscaling method comprising:
- comparing a luma Y1 of a first reference pixel and a luma Y2 of a target pixel for equality, and comparing a luma Y3 of a second reference pixel and the luma Y2 of the target pixel for equality;
- and
- if the luma Y1 of the first reference pixel is not equal to the luma Y2 of the target pixel and the luma Y2 of the target pixel is not equal to the luma Y3 of the second reference pixel, setting a chroma C2 of the target pixel based on a chroma C1 of the first reference pixel and a chroma C3 of the second reference pixel, as:
- C2=(D2*C1+D1*C3+(D1+D2)/2)/(D1+D2);
- wherein D1=Abs(Y1−Y2), and D2=Abs(Y2−Y3).
Dependencies are inferred from the claim text.