3D Dither Pattern Generation for Gradation Expansion
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Solution Overview
Problem
Existing image signal processing devices face challenges in expanding gradation beyond two bits while adding dither data, often resulting in side effects due to large dither pattern blocks and long frame periods, necessitating a solution that minimizes these issues while maintaining high-quality gradation expansion.
Innovation Solution
An image signal processing device and method that employs a three-dimensional dither pattern with two-dimensional blocks arranged in the frame direction, using a storage device to store dither data with dither values assigned to each dot, and an adder to select and add dither patterns, along with a lower bit reduction unit to manage overflow, ensuring even distribution and reduced side effects by prioritizing addresses with the smallest spatiotemporal density values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the block size of dither pattern is increased to expand more than two bits of gradation, then the gradation expansion capability is improved, but side effects such as visual discomfort and periodicity become more prominent
Solution Approach 1:
The patent transitions from conventional two-dimensional dither patterns to three-dimensional dither patterns by adding the time dimension (frame direction). This allows dither values to be distributed across multiple frames, effectively reducing the block size within each frame while maintaining the capability to expand more than two bits of gradation. The three-dimensional structure enables better control over spatial and temporal distribution of dither values, minimizing visual discomfort and periodicity.
Solution Approach 2:
The patent divides the dither pattern into smaller two-dimensional blocks arranged in the frame direction. Instead of using a single large block, the dither pattern is segmented into multiple smaller blocks that are distributed across different frames. This segmentation reduces the visual impact of each individual block while maintaining the overall gradation expansion capability through temporal distribution.
2Measurement precision
If dither data with large block size and long frame period is added to image signal, then higher bit expansion is achieved, but visual discomfort and periodicity increase
Solution Approach 1:
The patent employs periodic action by distributing dither values across multiple frames in a systematic manner. The three-dimensional dither pattern uses frame direction to create a periodic structure that is less perceptible to the human visual system. By carefully controlling the period and phase of dither value distribution across frames, the patent achieves high gradation precision while minimizing visual discomfort and periodicity artifacts.
Solution Approach 2:
The patent changes the parameters of the dither pattern by introducing temporal distribution across frames. Instead of varying only spatial parameters (block size, dot arrangement), the patent varies the temporal parameter (frame period) to optimize the distribution of dither values. This parameter change enables achieving higher bit expansion with reduced visual artifacts by controlling how dither values evolve over time.
3Object-affected harmful factors
If three-dimensional dither pattern with smaller blocks is used, then side effects are reduced, but the complexity of dither data storage and management increases
Solution Approach 1:
The patent achieves universality by creating a three-dimensional dither pattern structure that serves multiple functions simultaneously. The same basic structure can expand different numbers of bits (more than two bits) while maintaining reduced side effects. The framework is versatile and can be applied to various gradation expansion requirements without fundamentally changing the approach, thus managing complexity while achieving multiple goals.
Solution Approach 2:
The patent applies the nested doll principle by organizing dither data in a hierarchical structure. Two-dimensional blocks are nested within the three-dimensional frame structure. This nesting allows efficient storage and management where smaller two-dimensional patterns are contained within the larger temporal framework. The nested structure enables systematic generation and management of dither data, reducing the apparent complexity while maintaining the benefits of three-dimensional distribution.
Data Source
AI summary
A storage device stores dither patterns composed of three-dimensional block consisting of the number H of dots in a horizontal direction×the number V of lines in a vertical direction×the number F of frame directions. Each value from a minimum value to a maximum value of dither values of n bits is written in each address of the storage device corresponding to each dot. When each value is written into the storage device, processing of obtaining a spatiotemporal density value indicating a degree of density of an address in which a dither value has already been written in a predetermined three-dimensional area centered on each of the addresses in which a new dither value is writable, and processing of selecting an address having the smallest spatiotemporal density value among the addresses in which a new dither value is writable and writing a dither value are repeated.