Image Pickup Apparatus Chromatic Aberration and Distortion Correction
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Solution Overview
Problem
Current image pickup apparatuses face challenges in cost-effectively correcting chromatic aberration of magnification and distortion, especially for high-definition images with high frame rates, due to the need for expensive memory with multiple ports or large capacity, which limits the increase in pixel rate and frame rate.
Innovation Solution
The apparatus employs a chromatic aberration correction device using multiple low-capacity, low-latency SRAMs for each color component and a shared high-capacity, high-latency DRAM for distortion correction, allowing for efficient coordinate conversion of pixel data to address both issues without the need for expensive memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chromatic aberration of magnification and distortion are simultaneously corrected by independently converting coordinates of each color component of RGB, then correction accuracy is improved, but memory cost and device complexity increase significantly
Solution Approach 1:
The patent segments the correction process into two distinct stages: chromatic aberration correction (independent per color component) and distortion correction (shared across color components). This segmentation allows each stage to use optimized memory structures appropriate to its specific requirements, reducing overall system complexity while maintaining correction accuracy.
Solution Approach 2:
The patent makes the distortion correction memory universal by having it serve all color components (R, G, B) simultaneously. This single memory structure handles distortion correction for all colors, eliminating the need for separate memory structures for each color component and significantly reducing device complexity and cost.
2Productivity
If a large capacity memory with small latency such as SRAM is used for random access to correct chromatic aberration of magnification and distortion, then correction performance is improved, but device cost increases significantly
Solution Approach 1:
The patent applies different memory quality characteristics to different correction tasks: low-latency SRAM is used locally for chromatic aberration correction where speed is critical, while high-capacity DRAM is used for distortion correction where capacity is more important than speed. This local optimization of memory quality reduces overall device cost while maintaining correction performance.
Solution Approach 2:
The patent replaces expensive large-capacity SRAM with a combination of smaller SRAM modules and DRAM. The system uses affordable DRAM for the distortion correction function, accepting that DRAM has higher latency but compensating through architectural design, thereby significantly reducing device cost while maintaining adequate correction performance.
3Ease of manufacture
If a single port DRAM is used to simulate a 3 port RAM by boosting driving frequency for time sharing, then device cost is reduced, but pixel rate improvement is limited due to access latency
Solution Approach 1:
The patent segments the correction functions so that chromatic aberration correction (which requires high speed) and distortion correction (which requires large capacity) are performed separately. This segmentation allows the system to use a single port DRAM for distortion correction without bottlenecking the overall pixel rate, as the high-speed chromatic aberration correction uses appropriate memory structures.
Solution Approach 2:
The patent employs dynamic memory allocation and access strategies where the system adaptively manages memory access patterns. By dynamically coordinating between SRAM and DRAM access and optimizing the timing of read/write operations, the system achieves high pixel rates despite using cost-effective single port DRAM for distortion correction.
4Ease of manufacture
If distortion correction is performed by shared coordinate conversion for each color component of RGB, then memory cost is reduced, but chromatic aberration of magnification correction capability is lost
Solution Approach 1:
The patent segments the correction functions into distinct stages: first chromatic aberration correction using independent coordinate conversion for each color component, then distortion correction using shared coordinate conversion. This segmentation preserves chromatic aberration correction capability while utilizing cost-effective shared memory for distortion correction.
Solution Approach 2:
The patent performs chromatic aberration correction as a preliminary action before distortion correction. By first correcting chromatic aberration for each color component independently, the system ensures that subsequent shared distortion correction does not compromise chromatic aberration correction capability, as the chromatic aberration has already been addressed.
Data Source
AI summary
An image pickup apparatus including a chromatic aberration of magnification correction device to correct chromatic aberration of magnification of an image by converting coordinates of pixel data of multiple color components of the image using multiple first coordinate conversion memories corresponding to the multiple color components and a distortion correction device to correct distortion of the image corrected with regard to the chromatic aberration of magnification by converting coordinates of the pixel data of multiple color components of the image at one time using a second coordinate conversion memory shared by the multiple color components.