LFSR Seed Generation for Frame Buffer-Free Temporal Dithering
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Solution Overview
Problem
Conventional image signal processing apparatuses require expensive frame buffers to perform temporal dithering, making it impossible to achieve high-definition images without them.
Innovation Solution
The use of a linear feedback shift register (LFSR) to produce and update seed values for dithering, eliminating the need for a frame buffer and enabling both spatial and temporal dithering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a frame buffer is used to perform temporal dithering, then image quality is improved, but fabrication cost increases
Solution Approach 1:
The patent uses a linear feedback shift register (LFSR) to generate pseudorandom seed values that replicate the temporal dithering effect previously requiring a frame buffer. The LFSR produces a sequence of seed values that mimics the temporal variation needed for high-quality dithering, achieving the same image quality improvement without the expensive frame buffer hardware
Solution Approach 2:
The invention replaces the expensive, complex frame buffer with a simple, inexpensive LFSR circuit. The LFSR generates new seed values continuously and discards old ones, using minimal hardware resources while maintaining the temporal dithering effect that improves image quality
2Ease of manufacture
If a frame buffer is eliminated to reduce cost, then fabrication cost decreases, but temporal dithering becomes impossible
Solution Approach 1:
The LFSR is configured to automatically generate pseudorandom seed values for temporal dithering without requiring external storage or complex control logic. The feedback mechanism within the LFSR self-generates the sequence of seed values needed for temporal dithering, enabling the system to maintain temporal dithering capability with minimal hardware
Solution Approach 2:
The patent changes the approach from storing actual frame data in a buffer to generating pseudorandom seed values through an LFSR. By changing the parameter generation method from storage-based to algorithm-based, the system achieves temporal dithering without requiring the frame buffer hardware
3Measurement precision
If seed values are generated for every M×N position, then dithering precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the dithering process into spatial and temporal components. The LFSR generates seed values that are applied across M×N positions, but the pseudorandom sequence is generated through a simple linear feedback mechanism rather than complex per-position calculations, reducing device complexity while maintaining precision
Data Source
AI summary
An image signal processing apparatus and a method thereof are disclosed. The image signal processing apparatus includes a random producing unit which produces seed values to a plurality of frames input for a predetermined period by using a linear feedback shift register (LFSR), and a dithering processing unit which carries out a dithering to input image signals by using the seed values produced by the random producing unit. With this construction, the apparatus can carry out the dithering without using a frame buffer, thereby allowing a high-definition image to be realized.