Projector Auto-Focusing Using Stereo Camera Plane Estimation
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Solution Overview
Problem
Existing projector technologies face challenges in accurately adjusting focusing when obstructions or walls are present between the projector and the target, leading to errors in distance measurement and focusing adjustment based on brightness or contrast.
Innovation Solution
A projector system that uses a stereo camera to measure distance and estimate a plane corresponding to the target using regression analysis, allowing for precise focusing adjustment by approximating the target as a plane and correcting image projection based on calculated distance and plane data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distance measurement is performed using light reception intensity or brightness/contrast detection, then focusing adjustment can be achieved, but measurement errors occur when obstructions or walls are present between the projector and target
Solution Approach 1:
The patent introduces an intermediary plane (projection surface) as a reference for distance measurement. Instead of directly measuring distance to the target object, the system measures the distance to the projection surface where the image is displayed, and uses this intermediate measurement to calculate the actual distance to the target. This intermediary approach avoids the interference of obstructions and walls that directly block the measurement path.
Solution Approach 2:
The patent transitions from one-dimensional brightness/contrast detection to three-dimensional spatial coordinate measurement. By using the projection surface as a reference plane and measuring distances in three-dimensional space, the system can accurately determine target position even when traditional one-dimensional detection methods fail due to obstructions or walls.
2Ease of operation
If brightness or contrast is used for focusing adjustment, then automatic focusing can be achieved, but focusing errors occur when obstructions or walls are present
Solution Approach 1:
The patent uses the projection surface as an intermediary reference plane for focusing adjustment. Instead of relying on brightness or contrast of the target object (which may be obscured by obstructions or walls), the system measures the projection surface distance and uses this intermediate data to calculate the correct focusing position, thereby maintaining automatic focusing capability while improving accuracy.
Solution Approach 2:
The patent replaces the optical-based brightness/contrast detection mechanism with a spatial coordinate-based measurement system. By substituting the mechanical/optical detection of brightness variations with three-dimensional position measurement using the projection surface as reference, the system achieves more reliable automatic focusing that is not affected by obstructions or walls.
3Device complexity
If simple brightness or contrast detection is used, then the device complexity is low, but measurement precision deteriorates in the presence of obstructions or walls
Solution Approach 1:
The patent introduces a projection surface as an intermediary reference element that simplifies the measurement process. Instead of using complex obstruction-detection algorithms or multiple sensors, the system uses the known projection surface as a stable reference plane, maintaining relatively simple device complexity while significantly improving measurement precision in environments with obstructions or walls.
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
Enables accurate focusing adjustment even with obstructions or nearby walls, improving image projection quality by correctly estimating the target plane and adjusting the focus without being affected by brightness variations or uneven surfaces.
Implementation Method 1
a projector is a device for projecting an image onto a target
Implementation Method 2
measuring a distance to a target from the light reception intensity of the reflected light
Data Source
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AI summary
A projector includes an image taking part that takes an image of an area that includes a target onto which an image is projected; a distance measuring part that calculates, from taken image data obtained by the image taking part, distance data concerning a distance between the target and the image taking part; a plane estimation part that estimates, from the distance data, a plane corresponding to the target; and a focusing adjustment part that adjusts focusing of the image to be projected, based on information concerning the plane.