Lookup Table Arrangement for Sequential Image Data Access

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Solution Overview

Problem

Existing image processing methods face challenges in achieving real-time processing of image transformations, such as distortion correction and 'Bird View' visualization, due to limitations in hardware components like internal memory size and external RAM clock frequency, leading to stalls and reduced image quality.

Innovation Solution

The method rearranges the entries within the lookup table to enable sequential reading of input memory, allowing the image processing unit to access input image data in a pixel order, reducing the need for external RAM access and minimizing stalls, while maintaining high image quality through bilinear interpolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If generic image processing methods are used with standard hardware, then image transformation can be performed, but processing speed is insufficient for real-time applications due to memory access stalls

Engineering Contradiction:
Improveimage processing speedVSAvoidprocessor stall time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The lookup table is pre-calculated and pre-arranged in sequential order before image processing begins. This preliminary arrangement of memory addresses ensures that during actual processing, the processor can sequentially access input image data without random memory access stalls, thereby improving processing speed while maintaining real-time performance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the arrangement parameter of the lookup table from conventional non-sequential order to sequential order based on input image pixel addresses. This parameter change in memory address sequencing enables continuous cache-friendly access patterns, eliminating processor stalls and achieving real-time processing without hardware modifications

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If lookup table entries are arranged in conventional order, then image transformation logic is simple, but memory access becomes non-sequential causing processor stalls

Engineering Contradiction:
Improvelookup table generation simplicityVSAvoidprocessing efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The invention modifies the arrangement parameter of lookup table entries by sorting them according to sequential input image pixel addresses. This parameter change transforms the memory access pattern from random to sequential, enabling efficient cache utilization and continuous processing without stalls, thereby significantly improving processing efficiency while maintaining operational simplicity

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2997539B1Method and device for processing input image data
Publication Date: 2019.12.11 SMR PATENTS S A R L
  • EP2997539B1 patent drawingFigure 1
  • EP2997539B1 patent drawingFigure 2~3
  • EP2997539B1 patent drawingFigure 4

AI summary

The invention provides a method for processing input image data by an image processing device, to reach a desired visual effect within an output image, wherein input image data are stored within an input memory device and the input image data are transferred based on data of a lookup table into respective output image data stored within an output memory device, the lookup table being generated based on at least one data remapping function to reach the desired visual effect, wherein further the entries within the lookup table are arranged in such a way that when processing the lookup table the input memory device is addressed in a sequential reading order; a computer readable medium having stored thereon program code to carry out the inventive method as well as an image processing device to carry out the method.