Video Signal Processor Pulldown Detection Accuracy
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Solution Overview
Problem
Conventional interlaced-to-progressive scanning converters falsely determine video signals with steep edges moving at a constant speed as 2:2 pulldown signals, leading to image quality deterioration during conversion.
Innovation Solution
A video signal processor with modules for block division, vertical edge detection, and pulldown pattern analysis, which accurately distinguishes between 2:2 pulldown signals and edge images moving at a constant speed by counting moving blocks and integrating difference values, preventing false determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional interlaced-to-progressive scanning converter detects image movement to determine 2:2 pulldown signal, then the conversion process is simple, but false determination occurs when edge images move at constant speed
Solution Approach 1:
The image is divided into multiple blocks, and movement detection is performed independently for each block. This segmentation allows the system to analyze local movement patterns rather than treating the entire image as a single unit, thereby distinguishing between genuine 2:2 pulldown patterns and edge image movements.
Solution Approach 2:
The patent applies different detection criteria and weighting to different regions of the image. By focusing on specific block characteristics and local movement patterns rather than global image movement, the system can identify the distinctive patterns of 2:2 pulldown signals while ignoring misleading edge movements.
2Ease of operation
If field interpolation is used for conversion regardless of image type, then conversion is straightforward, but image quality deteriorates when false 2:2 pulldown determination occurs
Solution Approach 1:
The patent dynamically adjusts the conversion method based on detection results. When 2:2 pulldown is accurately detected, field interpolation is applied; when edge movement is detected instead, alternative conversion methods are used. This dynamic adaptation ensures optimal image quality for different input types while maintaining operational simplicity through automated decision-making.
Data Source
AI summary
According to one embodiment, a video signal processor has a moving block determining module, a vertical edge detector, a moving block number counter, a moving field determining module, a pulldown pattern detector, and a pulldown signal determining module. The moving block determining module divides each field configuring an input video signal into a plurality of blocks, and determines a motion of a block within the plurality of blocks, the block of which the motion is determined having a same spatial position within two fields adjacent to each other. The vertical edge detector detects a vertical edge within each of the plurality of blocks in the each field. The moving block number counter counts a number of moving blocks excluding a block having the vertical edge within a screen based on the detection result of the vertical edge detector and the determination result of the moving block determining module. The moving field determining module determines a motion between the each field based on the counting result of the moving block number counter. The pulldown pattern detector detects a 2:2 pulldown pattern based on the determination result of the moving field determining module. The pulldown signal determining module determines whether the input video signal is a 2:2 pulldown signal depending on the detection result of the pulldown pattern detector.