Multiple-Exposure Imaging for Vehicle Speed Measurement
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Solution Overview
Problem
Conventional vehicle-traveling control systems face challenges in accurately measuring vehicle speed due to tire wear and varying environmental conditions, leading to measurement errors and uncertainties, especially during turns or braking on icy roads.
Innovation Solution
A moving-body control system that uses a multiple-exposure imaging device to capture images with varying sensitivities within a single frame period, generating multiple-exposure image data to enhance measurement speed and accuracy by detecting motion states such as speed and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wheel rotational speed measurement is used, then vehicle speed can be measured, but measurement accuracy deteriorates due to tire wear and environmental conditions
Solution Approach 1:
The patent replaces the mechanical measurement system (wheel rotational speed sensors) with an optical imaging system. The imaging device captures images of the vehicle's movement through the environment, and the control unit calculates vehicle speed and position by analyzing the displacement of captured features between sequential images, thereby eliminating dependence on mechanical wheel components susceptible to wear and environmental factors
Solution Approach 2:
The patent changes the measurement parameter from wheel rotational speed to visual feature displacement in captured images. By tracking the movement of recognizable environmental features or vehicle-mounted markers between sequential images and calculating displacement, the system determines vehicle speed and position without relying on mechanical wheel parameters that vary with tire wear and road conditions
2Measurement precision
If multiple images are captured to improve measurement accuracy, then speed and direction detection precision improves, but computation time and processing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-identifying and tracking specific feature points or markers in the captured images before performing full speed and direction calculations. The control unit identifies key displacement features in sequential images and uses these pre-selected reference points to efficiently compute motion parameters, reducing the computational burden of processing entire image datasets
Solution Approach 2:
The patent extracts only the essential motion information from captured images by focusing on specific displacement features or markers rather than analyzing complete image data. The control unit identifies and tracks selected feature points between sequential images, extracting only the necessary positional change data required for speed and direction calculation, thereby minimizing computation time while maintaining measurement precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces computation required for determining vehicle speed and direction, improves measurement accuracy, and allows for more precise prediction of motion states, reducing measurement errors and uncertainties.
Implementation Method 1
imaging devices including imaging elements having photoelectric conversion characteristics
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A driving control system comprises: an imaging device that is installed on a moving body and that images a target object in a first frame period a plurality of times to generate a multiple-exposure image data including a first image data and a second image data; and a detecting device that detects a relative motion state of the moving body with respect to the target object, based on the first image data and the second image data included in the multiple-exposure image data, wherein the imaging device images the target object with a first sensitivity in a first exposure period in the first frame period to generate the first image data and images the target object with a second sensitivity in a second exposure period in the first frame period to generate the second image data, the second exposure period being different from the first period, the second sensitivity being different from the first sensitivity.