Patent ID: 8743957

Claim:
An apparatus for video coding using intra prediction, comprising: (a) a computer configured for processing video signals associated with a video coding device comprising an encoder; and (b) programming executable on said computer for direction prediction during intra prediction within the video coding device by performing steps comprising: (i) obtaining image gradient vectors for pixels neighboring a current block; (ii) determining an edge direction for each neighboring pixel by obtaining a perpendicular direction to said image gradient vectors; (iii) discarding edge directions which do not cross block boundaries of said current block and whose norm falls below a minimum threshold; (iv) deriving a dominant edge direction in response to defining an objective function as a summation of projections to a candidate direction and computing a suggested direction of each neighboring pixel; (v) utilizing said dominant edge direction as a direction prediction for use during said intra prediction within the video coding device; (vi) finding an optimum prediction direction θ opt which accounts for curvature in said dominant edge direction θ*; (vii) determining direction adjustment angle Δθ in response to said optimum prediction direction θ opt and said dominant edge direction θ* as Δθ=θ opt −θ*; (viii) quantizing said direction adjustment angle Δθ into a quantized direction adjustment angle; and (ix) encoding said quantized direction adjustment angle as side information within an encoded output of said encoder.