Topology-Preserving Binary Image Downsampling via Skeleton Enhancement

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Solution Overview

Problem

Existing methods for downsampling binary images often result in significant loss of detailed features and are complex and slow, failing to effectively preserve the topology of the images.

Innovation Solution

A method that generates a gray-scale image from a binary image, enhances skeleton pixel values to differentiate them more significantly from background pixels, downsamples the gray-scale image, and then converts it back to a binary image, using conventional interpolation and thresholding techniques to minimize detail loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If conventional downsampling methods are used on binary images, then the downsampling process is fast and simple, but the topology and detailed features of the image are significantly lost

Engineering Contradiction:
Improvetopology preservationVSAvoiddownsampling process complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The method performs preliminary actions by converting the binary image to grayscale and enhancing skeleton pixels before downsampling. This preprocessing ensures that topological features are emphasized and preserved during the subsequent downsampling operation, avoiding the need for complex post-processing to restore topology.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method applies local quality enhancement by selectively manipulating only the skeleton pixels in the grayscale image, giving them different weights or values compared to other pixels. This localized treatment preserves topological features without requiring complex global processing, maintaining simplicity while improving topology preservation.

Inventive Principle:
Principle #3Local quality

2Loss of information

If adaptive crossing number methods are used for downsampling, then topology is preserved, but the processing speed becomes slow

Engineering Contradiction:
Improvetopology preservationVSAvoiddownsampling processing speed
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The method extracts only the essential skeleton pixels from the binary image and performs enhancement only on these extracted elements. By focusing computation on the critical skeleton structures rather than processing the entire image with complex adaptive algorithms, the method achieves fast processing speed while preserving topology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The method creates a grayscale copy of the binary image and performs all complex operations on this copy rather than modifying the original binary image directly. This copying approach allows for simple, fast downsampling operations while the skeleton enhancement in the grayscale copy ensures topology preservation, avoiding the computational burden of adaptive methods on the original data.

Inventive Principle:
Principle #26Copying

3Loss of information

If redundant pixel removal with path scoring is used, then aliasing is minimized, but the complexity and computational time increase significantly

Engineering Contradiction:
Improvealiasing reductionVSAvoidprocessing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The method changes the parameter representation by converting binary values to grayscale values and applying weight factors to skeleton pixels. This parameter transformation allows standard, fast downsampling algorithms to effectively preserve topology and reduce aliasing without requiring complex iterative path scoring and pixel removal processes.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8942491B2Topology-preserving downsampling of binary images
Publication Date: 2015.01.27 KONICA MINOLTA SYSTEMS LABORATORY INC
  • US8942491B2 patent drawing
  • US8942491B2 patent drawing
  • US8942491B2 patent drawing

AI summary

A binary image downsampling method, including the steps of generating a gray-scale image from a binary image having a background and one or more foreground portions, locating skeleton pixels in the one or more foreground portions, manipulating values of certain foreground pixels in the gray-scale image such that the differences between the values of the skeleton pixels and the background pixels become more significant, downsampling the gray-scale image with the manipulated values of the certain foreground pixels, and generating a downsampled binary image from the downsampled gray-scale image.