Image Feature Point Separation for Accurate Object Recognition
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Solution Overview
Problem
Existing image processing systems inaccurately recognize object positions and movements due to the extraction of feature points that include both the object and distant scene outlines, leading to deteriorated recognition accuracy when the object moves relative to the camera.
Innovation Solution
An image processing apparatus that uses a camera, vehicle speed sensor, gyro sensor, and ECU to extract and differentiate line segments and feature points based on a threshold value, distinguishing between object and distant scene outlines by calculating positional variations and associating feature points accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature points are extracted from both object and distant scene outlines together, then the quantity of feature points increases, but recognition accuracy deteriorates due to erroneous association between object and distant scene feature points
Solution Approach 1:
The patent segments feature points into two distinct categories: object feature points and distant scene feature points. This segmentation is achieved by classifying line segments based on their motion characteristics - object line segments exhibit significant positional changes between frames, while distant scene line segments show minimal movement. By separating these categories, the system maintains a large quantity of feature points for processing while preventing erroneous associations between object and background features, thus preserving recognition accuracy.
Solution Approach 2:
The patent extracts and isolates object feature points from the mixed set of feature points by identifying and removing distant scene feature points. This is accomplished by comparing line segment positions across consecutive frames and filtering out those with minimal displacement, which are characteristic of distant background elements. The extraction process retains only the moving object feature points for association and recognition, eliminating the harmful influence of stationary background features while maintaining sufficient feature point quantity for robust recognition.
2Ease of manufacture
If intersection points between object and distant scene outlines are used as feature points, then feature point extraction becomes simpler, but position accuracy deteriorates due to feature point movement on object outline
Solution Approach 1:
The patent applies local quality by treating different regions of the image differently based on their motion characteristics. Instead of uniformly processing all line segments, the system identifies local regions corresponding to moving objects versus stationary distant scenes by analyzing positional changes. Object line segments in moving regions are processed with one set of rules (expecting significant displacement), while distant scene line segments in stationary regions are processed with different rules (expecting minimal displacement). This localized differentiation ensures accurate position tracking for objects while filtering out erroneous features from the distant scene.
Solution Approach 2:
The patent changes the parameter used for feature point selection from static geometric properties to dynamic motion-based properties. Instead of relying solely on geometric features like intersection points which remain stationary in the image coordinate system, the system uses positional variation between frames as the key parameter. Line segments are classified and feature points are selected based on whether their position changes significantly between consecutive frames, transforming the selection criterion from a static geometric parameter to a dynamic motion parameter that inherently distinguishes objects from background.
Data Source
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Figure 3A~3B
AI summary
An object recognizer (24) of an image processing apparatus (1) separately extracts a first feature point (P1a(t1), P1b(t1)) and a second feature point (P1a(t2), P1b(t2)) of a first line segment (L1(t1)) and a second line segment L1(t2) for which a difference in positions is equal to or greater than a threshold value and the first feature point (P2(t1)) and the second feature point (P2(t2)) of the first line segment (L2(t1)) and the second line segment (L2(t2)) for which the difference in positions is smaller than the threshold value, and determines a corresponding point (P) in a second captured image (F2), the corresponding point being a point that corresponds to the first feature point (P1a(t1), P1b(t1)) of the first line segment (L1(t1)) for which the difference in positions is equal to or greater than the threshold value as the second feature point (P1a(t2), P1b(t2)) of the second line segment (L1(t2)) corresponding to the first line segment (L1(t1)) for which the difference in positions is equal to or greater than the threshold value to recognize an object.