PTZ Camera Calibration via Wide-Angle Optical Center Mapping
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Solution Overview
Problem
Existing security systems face challenges in coordinating wide field of view cameras with pan, tilt, zoom (PTZ) cameras, leading to inadequate resolution and increased costs due to the difficulty in reliable calibration, especially when targets are fast-moving or when multiple PTZ cameras are required to monitor large areas.
Innovation Solution
A method that determines the optical center and magnification ratio between the wide field of view camera and the PTZ camera, using a pan and tilt model to control the PTZ camera for enhanced viewing, allowing for automatic or semi-automatic target tracking and focusing, thereby improving calibration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single wide field of view camera is used to monitor a large area, then the coverage area is improved, but the image resolution for identifying targets deteriorates
Solution Approach 1:
The patent combines a wide field of view camera for area monitoring with a PTZ camera for detailed target observation. The system merges the functions of both cameras, allowing the wide camera to capture large areas while the PTZ camera provides magnified views of specific targets, thus resolving the contradiction between coverage area and image resolution.
Solution Approach 2:
The system creates a multi-functional monitoring setup where the wide field camera serves as the primary monitoring device while the PTZ camera acts as a supplemental device for detailed observation. This universal approach allows the system to handle both area surveillance and target identification functions simultaneously.
2Measurement precision
If multiple PTZ cameras are deployed to monitor large areas, then the target identification capability is improved, but the system cost and complexity increase dramatically
Solution Approach 1:
The patent merges one wide field of view camera with a single PTZ camera to achieve the monitoring capabilities that would otherwise require multiple PTZ cameras. The wide camera covers the entire area while the single PTZ camera provides detailed views on demand, reducing system complexity and cost.
Solution Approach 2:
The system uses the wide field camera as a guide to direct the PTZ camera to targets of interest. Instead of deploying multiple PTZ cameras to cover all areas simultaneously, the wide camera captures the entire scene and the PTZ camera 'copies' the detailed view of specific targets, reducing the number of expensive PTZ units needed.
3Measurement precision
If manual calibration procedures are used to coordinate wide field and PTZ cameras, then the calibration accuracy can be improved, but the time consumption and operational complexity increase
Solution Approach 1:
The system enables self-service calibration by allowing operators to simply click on targets in the wide field camera view, and the system automatically calculates and applies the appropriate pan, tilt, and zoom parameters for the PTZ camera. This eliminates the need for complex manual calibration procedures while maintaining accuracy.
Solution Approach 2:
The calibration process uses feedback from the wide field camera images to automatically adjust the PTZ camera parameters. The system continuously monitors the relationship between the wide camera view and PTZ camera view, using this feedback to maintain accurate coordination without requiring frequent manual recalibration.
4Reliability
If traditional calibration methods are used with fast moving targets, then the calibration process becomes unreliable, but using faster calibration methods reduces accuracy
Solution Approach 1:
The system performs preliminary calibration by establishing the geometric relationship between the wide field camera and PTZ camera before actual monitoring begins. This preliminary setup includes determining the optical center, magnification ratio, and pan-tilt model parameters, which are then used to quickly and reliably coordinate the cameras during operation, even with fast-moving targets.
Solution Approach 2:
The calibration system is designed to be dynamic and adaptive, automatically adjusting to moving targets in real-time. The pan-tilt model and magnification ratio calculations are continuously updated based on the current state of the wide field camera view, allowing the system to maintain accurate coordination even when targets are moving rapidly across the field of view.
Data Source
AI summary
A method for capturing surveillance images includes of a secured area has a first camera with a first field of view and a second camera with a second field of view. An optical center is determined for the second field of view. A magnification ratio is determined between a target located in the first field of view relative to the second field of view. A pan and tilt model is determined that provides a relationship between a first camera coordinates and pan and tilt values to position the second camera at the optical center. A target is captured in the first field of view and the second camera is controlled to record the target in the second field of view with the second field of view being an enhanced view relative to the first field of view.