SIMD Median Filtering Using Diagonal Array Selection

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Solution Overview

Problem

Conventional median filtering methods require excessive processing power and inefficiency in signal processing due to the need to calculate the median value of all pixel values within a sliding window, which reduces throughput in image processing.

Innovation Solution

A method that sorts each column and row of a high-order array in ascending order, selects values from the diagonal portion, and calculates the median value of the resulting low-order array to efficiently determine the median of a high-order array, particularly utilizing SIMD processors for parallel processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If all pixel values in a sliding window are processed to calculate the median value, then the accuracy of median filtering is improved, but the processing power requirement increases excessively

Engineering Contradiction:
Improvemedian filtering accuracyVSAvoidprocessing power requirement
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The sliding window is divided into multiple blocks, and each block is processed independently to determine candidate median values. This segmentation reduces the computational complexity from processing all N pixels to processing smaller blocks of size M, where M < N. The final median is determined by comparing these candidate values, achieving both accuracy and efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of processing all pixel values in the sliding window, the invention processes only a selected subset of blocks and their representative values. This partial action approach maintains sufficient filtering accuracy by focusing computation on critical regions while reducing overall processing power requirements.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If all pixel values in a sliding window are processed to calculate the median value, then the completeness of noise reduction is improved, but the processing efficiency decreases

Engineering Contradiction:
Improvenoise reduction completenessVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The image processing is divided into multiple sliding windows that are processed in parallel. Each window is further segmented into blocks for median calculation. This hierarchical segmentation enables parallel processing across multiple processors or cores, improving productivity while maintaining complete noise reduction coverage through systematic processing of all windows.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The image is pre-divided into multiple sliding windows before processing begins. This preliminary organization allows for efficient parallel processing and reduces the computational burden on individual processors, thereby improving overall processing efficiency without compromising noise reduction completeness.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If conventional median filtering methods are used, then the noise reduction quality is maintained, but the throughput is reduced

Engineering Contradiction:
Improvenoise reduction qualityVSAvoidthroughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The processing is segmented into multiple independent sliding windows that can be processed simultaneously. Each window maintains the traditional median filtering quality through proper block selection and comparison, while the parallel processing of multiple windows significantly increases overall throughput.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a new dimension of parallel processing by dividing the image into multiple sliding windows that can be processed concurrently. This dimensional expansion from sequential to parallel processing maintains noise reduction quality in each window while dramatically improving overall throughput.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9898805B2Method for efficient median filtering
Publication Date: 2018.02.20 TEXAS INSTRUMENTS INC
  • US9898805B2 patent drawing
  • US9898805B2 patent drawing
  • US9898805B2 patent drawing

AI summary

A method is disclosed for efficiently calculating a median value of a high-order array in a Single Instruction Multiple Data (SIMD) processor. Values of the high-order array are sorted vertically in each column followed by sorts on each individual row. After the sort, selective diagonal values of the sorted high-order array are used to form a low-order array to calculate the median of the high-order array. The median calculation using selective diagonal values of the high-order array in a low-order array significantly improves SIMD processor efficiency and throughput.