Vehicle Camera Focal Length Adjustment for License Plate Recognition
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Solution Overview
Problem
Existing vehicle camera systems struggle to clearly capture and recognize license plates during traffic accidents due to vehicle motion, leading to doubts about the authenticity of recognized license plate numbers.
Innovation Solution
A vehicle camera device with a picture-taking module, image analyzing unit, and adjusting unit that captures driving images with a focal length adjustment based on vehicle speed to enhance license plate recognition, increasing the focal length when the detected picture size of the license plate is smaller than a threshold to improve image clarity and recognition accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vehicle camera device uses a fixed focal length to capture driving images, then the device complexity is low and operation is simple, but the license plate recognition accuracy deteriorates when vehicle speed increases causing motion blur
Solution Approach 1:
The patent applies the dynamics principle by making the focal length adjustable rather than fixed. The controlling unit dynamically changes the focal length of the picture-taking module based on real-time vehicle speed detection, allowing the system to adapt to varying motion conditions and maintain clear license plate capture accuracy across different driving speeds.
Solution Approach 2:
The patent implements parameter changes by modifying the focal length parameter in response to vehicle speed. When speed exceeds a threshold, the system increases the focal length to reduce motion blur and improve license plate image quality, directly addressing the contradiction between maintaining simplicity and achieving high recognition accuracy under varying conditions.
2Productivity
If the vehicle camera device captures images at high speed to record traffic accidents, then the productivity is high, but the image clarity deteriorates due to motion blur
Solution Approach 1:
The system dynamically adjusts the focal length based on vehicle speed to maintain image clarity during high-speed capture. The controlling unit receives speed information and modifies the picture-taking module's focal length in real-time, enabling the device to capture clear license plate images even when the vehicle is moving at high speeds, thus resolving the contradiction between capture rate and image quality.
3Measurement precision
If the picture-taking module uses a short focal length to capture wide scenes, then the area covered is large, but the license plate picture size is small reducing recognition accuracy
Solution Approach 1:
The patent applies dynamics by enabling the focal length to change based on detected license plate size. When the system detects that the license plate image is too small (indicating the need for better recognition), it automatically increases the focal length to enlarge the license plate picture size, thereby improving recognition accuracy while maintaining the ability to capture wide scenes when needed.
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
The method effectively increases the recognition rate of license plates by adjusting the focal length in response to vehicle speed, resulting in clearer images and more reliable license plate number identification.
Implementation Method 1
a picture-taking module (110)... captures a driving image with a focal length
Data Source
AI summary
A vehicle camera device is applied in a vehicle. The vehicle camera device performs image recognition of current driving image to obtain a license-plate pattern in the driving image, and when size of the license-plate pattern is less than a threshold, increases a focus according to current speed of the vehicle.