Random Cropping Framework Defends Against Patch Attacks

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Solution Overview

Problem

Machine learning systems, such as deep neural networks, are vulnerable to patch attacks, which can cause misclassification of images due to arbitrary changes in pixel regions, leading to inefficiencies and high computational costs in existing defense mechanisms like sliding window and ablation processes.

Innovation Solution

A random cropping framework is implemented to train machine learning systems, where a digital image is randomly cropped into multiple smaller regions, and the system generates predictions for each crop, evaluating them collectively to determine a majority prediction and output label, thereby defending against patch attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If exhaustive sliding window approach is used to create image blocks, then defense against patch attacks is improved, but processing time and computational cost increase significantly

Engineering Contradiction:
Improvedefense against patch attacksVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the image into multiple blocks and processes them in parallel rather than exhaustively through a sliding window approach. This segmentation allows the system to evaluate multiple regions simultaneously, reducing processing time while maintaining comprehensive coverage for patch attack detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of processing every possible window position exhaustively, the patent selects specific representative blocks from the image. This partial action approach provides sufficient defense against patch attacks without the computational burden of examining every possible region, achieving a balance between security and efficiency.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If sliding window approach with full-size image blocks is used, then patch attack detection capability is improved, but computational expense increases

Engineering Contradiction:
Improvepatch attack detection capabilityVSAvoidcomputational expense
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The image is segmented into multiple discrete blocks that can be processed independently and in parallel. This segmentation reduces the computational burden on each processing unit while maintaining overall detection capability, as each block can be evaluated separately rather than processing the entire image through a sliding window.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts specific representative blocks from the image for analysis rather than processing the entire image. This extraction approach focuses computational resources on key regions that are most likely to contain patches, reducing overall computational expense while maintaining effective patch attack detection.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If ablation process is used to generate image blocks, then digital attack detection is improved, but unnecessary computations are performed

Engineering Contradiction:
Improvedigital attack detectionVSAvoidcomputational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent directly extracts image blocks from the original image without performing an ablation process. This extraction method obtains the necessary image blocks for patch detection without the unnecessary computational steps involved in ablation, improving computational efficiency while maintaining attack detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses simple, direct image block extraction rather than complex ablation processes. This approach treats image block generation as a straightforward, computationally inexpensive operation that can be performed quickly without the overhead of iterative ablation steps, enhancing overall system productivity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If all pixel values can be changed in digital attacks, then attack effectiveness is improved, but real-world realizability decreases

Engineering Contradiction:
Improveattack effectivenessVSAvoidreal-world applicability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent focuses on detecting local patch modifications rather than requiring changes to all pixel values. By concentrating on localized regions where patches are typically applied, the system maintains effectiveness against realistic attacks while avoiding the need for comprehensive pixel manipulation that would be required for full digital attack coverage.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11574143B2Systems and methods with robust classifiers that defend against patch attacks
Publication Date: 2023.02.07 ROBERT BOSCH GMBH
  • US11574143B2 patent drawing
  • US11574143B2 patent drawing
  • US11574143B2 patent drawing

AI summary

A system and method relate to providing machine learning predictions with defenses against patch attacks. The system and method include obtaining a digital image and generating a set of location data via a random process. The set of location data include randomly selected locations on the digital image that provide feasible bases for creating regions for cropping. A set of random crops is generated based on the set of location data. Each crop includes a different region of the digital image as defined in relation to its corresponding location data. The machine learning system is configured to provide a prediction for each crop of the set of random crops and output a set of predictions. The set of predictions is evaluated collectively to determine a majority prediction from among the set of predictions. An output label is generated for the digital image based on the majority prediction. The output label includes the majority prediction as an identifier for the digital image.