Camera Imaging Control for Vehicle License Plate Tracking

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Solution Overview

Problem

Conventional systems face challenges in capturing high-resolution images of vehicle license plates at wide entrances using a single camera, leading to increased costs and higher likelihood of imaging failure, especially when vehicles enter at high speeds.

Innovation Solution

A camera control apparatus that uses a multi-stage detection area system, where the number of detection areas increases towards the interior of the premises, allowing the camera to track vehicle movement with smaller directional changes, enabling effective imaging even at high speeds without requiring the entire entrance area to be imaged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single camera is used to image the overall entrance, then system cost is reduced, but the resolution required for vehicle number recognition cannot be achieved when the entrance width is relatively wide

Engineering Contradiction:
Improvenumber of camerasVSAvoidimage resolution
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the camera's imaging direction changeable through pan-tilt mechanisms. The camera dynamically adjusts its orientation to track the moving vehicle, allowing a single camera to maintain high resolution on the license plate throughout the vehicle's entry motion, resolving the contradiction between using one camera and achieving sufficient image resolution.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a pan-tilt-zoom camera is used to track a moving vehicle, then image resolution is maintained, but when the vehicle speed is high, the PTZ control cannot keep up with the movement and imaging failure occurs

Engineering Contradiction:
Improveimage resolutionVSAvoidimaging success rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by starting the camera positioning operation early when the vehicle is first detected entering the premises. The camera begins tracking the vehicle's motion in advance, progressively adjusting its imaging direction to follow the vehicle's trajectory. This early start allows the camera to anticipate and maintain proper tracking even when the vehicle moves at high speed, preventing imaging failure.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple detection area groups are used with increasing number of areas from entrance to interior, then the camera can track vehicle position more accurately, but the system complexity increases

Engineering Contradiction:
Improvevehicle position detection accuracyVSAvoiddetection area configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the detection space into multiple detection area groups arranged from the entrance toward the interior. Each group contains a specific number of detection areas, creating a structured grid that systematically covers the vehicle's expected path. This segmented approach enables accurate position detection through simple area identification, resolving the contradiction between detection accuracy and system complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2919160B1Apparatus for controlling imaging of camera and system provided with the apparatus
Publication Date: 2021.04.28 DENSO WAVE INC
  • EP2919160B1 patent drawingFigure 1
  • EP2919160B1 patent drawingFigure 2
  • EP2919160B1 patent drawingFigure 3A~3C

AI summary

In a camera control apparatus, an imaging control unit controls imaging operations of a camera. This camera is able to capture an image of a license plate of a vehicle entering a premises from an entrance thereof. A detection area setting unit sets a planar detection area for detecting a position of the vehicle. A vehicle detecting unit detects the position of the vehicle based on the detection area. The camera is capable of changing the imaging direction thereof. The detection area setting unit sets detection area groups, each of which are composed of a plurality of detection areas aligned in a width direction of the entrance, in multiple stages from the entrance towards the inside of the premises. The imaging control unit performs imaging while changing the imaging direction of the camera based on the position of the vehicle detected by the vehicle detecting unit.