Warp Correction Using Single-Ported Memory Pipelining
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Solution Overview
Problem
Conventional camera image processing systems require large buffer spaces and multi-ported memory to achieve high performance warp correction, which is inefficient and costly, especially when aiming for single pixel per clock performance.
Innovation Solution
A system utilizing a single-ported memory with a pipelined architecture that computes and stores warp fields efficiently, allowing for single pixel per clock performance while reducing hardware costs by using adders instead of multipliers and optimizing interpolation calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multi-ported memory is used to achieve single pixel per clock performance, then processing speed is improved, but hardware cost and device complexity increase
Solution Approach 1:
The processing pipeline is divided into multiple stages (warp field computation stage, interpolation parameter computation stage, and output pixel generation stage), with each stage operating on different data and producing intermediate results. This segmentation allows a single-ported memory to be used instead of multi-ported memory, reducing hardware complexity while maintaining single pixel per clock performance.
Solution Approach 2:
The warp field is computed in advance and stored in a single-ported memory before the actual image processing begins. Interpolation parameters are also pre-computed from the warp field. This preliminary computation approach allows the main processing pipeline to proceed efficiently with simpler memory architecture.
2Reliability
If large buffer space is allocated to hold input image data, then processing completeness is improved, but memory usage and hardware cost increase
Solution Approach 1:
The input image processing is divided into line-by-line processing, where only the current line and necessary reference lines are held in buffers. This line-based segmentation reduces the total buffer space required from holding the entire image to holding only a few lines at a time, while still ensuring complete processing of all pixels.
Solution Approach 2:
Instead of buffering the entire input image, the system buffers only the minimum necessary portions (current line and reference lines) required to compute the warp correction. This partial buffering approach reduces memory usage while maintaining processing completeness through systematic iteration over all lines.
3Measurement precision
If 2D bilinear interpolation is used to calculate warp field at missing pixels, then interpolation accuracy is improved, but computational complexity and hardware cost increase
Solution Approach 1:
The interpolation approach is adapted dynamically based on the available data and processing stage. In the warp field computation stage, 1D interpolation is used along scan lines. In the output pixel generation stage, the pre-computed interpolation parameters are applied directly. This dynamic adaptation maintains accuracy while reducing computational complexity compared to full 2D bilinear interpolation.
Solution Approach 2:
The complex 2D bilinear interpolation calculation is replaced by a two-stage process: first computing warp field values with 1D interpolation, then using pre-computed parameters to generate output pixels. This substitution replaces the mechanically complex 2D interpolation with simpler, more efficient calculations that achieve the same accuracy goal.
Data Source
AI summary
An apparatus generally having a first memory, a second memory and a circuit is disclosed. The first memory may be configured to store a warp table. The warp table is generally accessed through a single data port of the first memory. The second memory may be configured to buffer an input image. The input image may have a plurality of input pixels arranged in two dimensions. The circuit may be configured to generate an output image by a warp correction of an input image. The warp correction may be defined by the warp table. The output image may include a plurality of output pixels. At least one of the output pixels may be generated during each clock cycle of the circuit.