In-Vehicle Camera Speed Estimation via License Plate Analysis
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Solution Overview
Problem
Current vehicle speed detection devices are limited by legal and construction constraints, and are often costly, making it difficult to monitor vehicle speeds effectively across all desired locations.
Innovation Solution
An in-vehicle camera device with an image capturing unit and processing unit that captures sequential vehicle images, performs image analysis to recognize license plate pixels and inclinations, and estimates moving speed based on these parameters and time difference, allowing for dynamic speed limit enforcement without the need for costly speed detection devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stationary posts with speed detection devices are deployed to detect vehicle speeds, then vehicle speed monitoring capability is improved, but deployment flexibility and coverage are limited due to legal regulations and road construction constraints
Solution Approach 1:
Instead of deploying stationary detection devices on road posts, the patent inverts the approach by mounting the speed detection device on a moving vehicle. This allows the system to move to different locations and capture speed data from multiple positions, thereby improving deployment flexibility while maintaining speed detection capability.
Solution Approach 2:
The patent uses an image capturing device and image processing algorithm as intermediaries to indirectly measure vehicle speed. Rather than directly measuring speed with traditional sensors, the system captures images of license plates at different positions and uses image analysis to calculate speed, enabling deployment in locations where traditional speed detection devices cannot be installed.
2Measurement precision
If laser speedometers are used as vehicle speed detection devices, then speed measurement accuracy is improved, but device cost increases significantly
Solution Approach 1:
The patent uses image copying technology by capturing multiple images of the same license plate at different positions and times. These image copies are then processed to extract positional information and calculate speed, replacing the need for expensive laser speedometers while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical/optical laser speedometer system with an image-based measurement system. By substituting the direct optical measurement method with image capture and computational analysis, the system achieves comparable speed measurement accuracy at a lower cost.
3Reliability
If traditional stationary speed detection devices are deployed, then speed enforcement capability is improved, but the system lacks adaptability to dynamically adjust to different locations and speed limits
Solution Approach 1:
The patent implements a dynamic system by mounting the detection device on a moving vehicle rather than a fixed post. This allows the system to dynamically relocate to different positions along the road, adapt to varying speed limits at different locations, and provide flexible speed enforcement coverage that stationary devices cannot achieve.
Data Source
AI summary
A method for estimating a moving speed of a vehicle includes: sequentially capturing, by an image capturing unit, a first driving vehicle image and a second driving vehicle image having a time difference; performing image analysis on the first driving vehicle image to obtain a first pixel area and a first inclination of a first license plate image; performing image analysis on the second driving vehicle image to obtain a second pixel area and a second inclination of a second license plate image; and estimating the moving speed according to the first pixel area, the first inclination, the second pixel area, the second inclination and the time difference.