R-CNN Object Detector Small Object Detection via Pyramidic Feature Maps

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Solution Overview

Problem

Conventional R-CNN methods are inadequate for detecting small objects in images as they rely on the smallest feature map generated after multiple convolution operations, which is insufficient for precise object representation.

Innovation Solution

The method involves generating multiple feature maps through sequential convolution operations and upsampling blocks to create pyramidic feature maps, allowing for the detection of small objects without additional computational load by using feature maps of varying scales.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple feature maps of varying scales are generated through upsampling blocks, then detection precision for small objects is improved, but device complexity increases

Engineering Contradiction:
Improvedetection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The feature extraction process is segmented into multiple parallel pathways, each producing feature maps at different scales. Instead of using a single feature map, the system divides the detection task across multiple scaled feature maps, allowing small objects to be detected on appropriately-scaled maps while maintaining overall system precision without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a scale dimension to the feature maps by applying upsampling operations. Feature maps are generated not only through sequential convolutional layers but also by expanding their spatial dimensions through upsampling blocks, creating a multi-scale representation that improves small object detection while managing complexity through structured dimensional transformation

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

2Reliability

If multiple feature maps are used for detection, then small object detection capability is improved, but computational load increases

Engineering Contradiction:
Improvesmall object detection capabilityVSAvoidcomputational load
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Different regions of the feature pyramid are utilized based on their scale-appropriate qualities. Small objects are detected on upsampled feature maps where they occupy sufficient pixel density, while larger structures are detected on original-scale maps. This local optimization ensures computational resources are focused where they provide maximum detection value, improving small object detection capability without uniformly increasing computational load across all detection tasks

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system applies upsampling and feature map generation selectively rather than uniformly to all detection scenarios. By generating additional scaled feature maps only when and where small objects are present in the input image, the system achieves improved small object detection capability while avoiding the computational overhead of processing full multi-scale feature pyramids in every detection case

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10304009B1Learning method and testing method for object detector based on R-CNN, and learning device and testing device using the same
Publication Date: 2019.05.28 STRADVISION
  • US10304009B1 patent drawing
  • US10304009B1 patent drawing
  • US10304009B1 patent drawing

AI summary

A method for learning an object detector based on an R-CNN by using a first to an n-th filter blocks respectively generating a first to an n-th feature maps through convolution operations in sequence, and a k-th to a first upsampling blocks respectively coupled with the first to the n-th filter blocks is provided. The method includes steps of: a learning device instructing the k-th upsampling block to the first upsampling block to generate a (k−1)-st pyramidic feature map to the first pyramidic feature map respectively; instructing an RPN to generate each ROI corresponding to each candidate region, and instructing a pooling layer to generate a feature vector; and learning parameters of the FC layer, the k-th to the first upsampling blocks, and the first to the n-th filter blocks by backpropagating a first loss generated by referring to object class information, object regression information, and their corresponding GTs.