Motion Vector Shifting Device and Method for Motion-Compensated Frame Rate Up-Conversion

High-Quality Frame Rate Up-Conversion Using Neighboring Block Candidate Motion Vector Shifting

This technology is a motion-compensated frame rate up-conversion device that shifts motion vectors obtained from forward and backward unidirectional motion estimation between previous and current frames into bidirectional motion vectors for interpolated frame positions, then selects the final motion vector through refinement and reliability comparison.

Frame rate up-conversion creates new frames between two original frames to play low-frame-rate video smoothly. Early methods simply duplicated previous frames, resulting in jerky motion. Even in methods using motion information, unidirectional motion estimation often caused gaps or overlaps in interpolated frames, while bidirectional motion estimation was prone to finding vectors that did not match actual motion.

This technology uses unidirectional motion vectors from nine neighboring blocks as candidates to shift the best-overlapping vector and fine-tunes movement errors using Small-range Bidirectional Sum of Absolute Differences (SBAD), outperforming existing methods in both objective and subjective image quality metrics. It can be applied to high-refresh-rate TVs, sports broadcast conversion, and streaming player frame interpolation, allowing low-frame-rate sources to be played with smooth motion.

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Key Features:

• A motion estimator that obtains motion vectors by performing forward and backward unidirectional motion estimation on previous and current frames
• A shifter that uses nine blocks adjacent to the current block as candidate unidirectional motion vectors and shifts them into bidirectional motion vectors
• A refiner that removes residual errors of the shifted motion vectors by finding the minimum value of the bidirectional sum of absolute differences within a small search range
• A selector that calculates the reliability of each forward and backward motion vector and selects the vector with higher reliability as the final motion vector

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This invention was developed with support from the Small and Medium Business Administration for resolving technical difficulties in large-capacity image analysis for film inspection equipment.

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