Two-Level CNN Target Detection in Video Sequences

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Solution Overview

Problem

Existing target detection methods in videos suffer from low accuracy due to the reliance on single-frame image analysis, which fails to effectively capture the features of a target over multiple frames, leading to errors in detecting suspected target regions.

Innovation Solution

A target detection method utilizing a pre-trained Convolutional Neural Network (CNN) model with a two-level classifier system, where the first-level classifier identifies candidate target regions and the second-level classifier refines the detection using feature fusion across multiple frames, improving accuracy by considering the correlation between images in a video.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If single-frame image analysis is used for target detection, then the detection speed is fast and the process is simple, but the detection accuracy is low due to inability to capture target features over multiple frames

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection process is segmented into two distinct levels: a first-level classifier for initial candidate region detection and a second-level classifier for refined target detection. This segmentation allows the system to process multiple frames efficiently at the first level while applying more complex analysis only to promising candidates at the second level, thereby improving accuracy without proportionally increasing overall complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first-level classifier performs preliminary detection to identify candidate target regions before the second-level classifier conducts detailed analysis. This preliminary action filters out obvious non-targets early in the process, allowing the more computationally intensive multi-frame analysis to be applied selectively only to regions with potential targets, thus balancing accuracy improvement with computational efficiency

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multi-frame image analysis is used for target detection, then the detection accuracy is improved by capturing target features over multiple frames, but the computational complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidcomputational power consumption
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The system applies multi-frame analysis partially rather than to all frames uniformly. The first-level classifier quickly identifies candidate regions using simplified processing, and only these candidate regions undergo the more computationally demanding second-level multi-frame analysis. This partial application of complex processing significantly reduces overall computational power consumption while maintaining the accuracy benefits of multi-frame analysis where needed

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Different levels of analysis are applied to different regions of the video stream: candidate regions identified by the first-level classifier receive intensive multi-frame local quality analysis at the second level, while non-candidate regions receive minimal processing. This local differentiation ensures high accuracy for potential targets while minimizing computational waste on regions unlikely to contain targets

Inventive Principle:
Principle #3Local quality

3Measurement precision

If single-frame detection is used, then the processing time is short and real-time detection is easier, but the detection accuracy suffers due to feature similarity between different actions at single moment

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The detection system operates periodically across multiple frames rather than analyzing each frame in isolation. By examining targets across a sequence of frames with periodic intervals, the system captures temporal patterns that distinguish different actions (e.g., running vs. walking) even when single-frame appearances are similar. This periodic multi-frame analysis improves accuracy while the two-level structure keeps processing time manageable

Inventive Principle:
Principle #19Periodic action

Data Source

PatentUS10949673B2Target detection method and device
Publication Date: 2021.03.16 HANNO IP LLC
  • US10949673B2 patent drawing
  • US10949673B2 patent drawing
  • US10949673B2 patent drawing

AI summary

Embodiments of the present application disclose a target detection method and device, and relate to the technical field of video processing. The method comprises: obtaining an image sequence to be detected from a video to be detected according to an image sequence determining algorithm based on video timing (S101), extracting a first CNN feature of the image sequence to be detected based on a pre-trained CNN model, performing feature fusion on the first CNN feature based on a second CNN feature to obtain a first fused CNN feature of the image sequence to be detected (S102); inputting the first fused CNN feature into the first-level classifier, and obtaining first candidate target regions of the image sequence to be detected from an output of the first-level classifier (S103); determining a first input region of the second-level classifier based on the first candidate target regions (S104); obtaining a third CNN feature of the first input region based on the first fused CNN feature (S105); inputting the third CNN feature into the second-level classifier, and obtaining a target detection result for the image sequence to be detected based on the output of the second-level classifier (S106).