Projection Device Distortion Correction on Uneven Surfaces
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Solution Overview
Problem
Existing projection technologies fail to accurately project images on surfaces with complex unevenness, as they either take too long to measure distances or overlook some unevenness, especially when the surface is complicated.
Innovation Solution
A projection device that includes a storage unit, image output unit, projection unit, image acquisition unit, distortion amount calculating unit, and distortion correction processing unit, which projects a pattern image, captures the distorted image, calculates distortion parameters, and corrects the image in real-time to display it without distortion on uneven surfaces by comparing the captured image with an expected image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distance measurement is performed using triangulation principle, then distance to projection surface can be obtained, but measurement time becomes excessively long
Solution Approach 1:
The patent replaces the optical triangulation measurement system with a time-based electronic measurement system. The measurement unit sends a measurement signal and measures the time until reception of a reflected signal, substituting mechanical/optical triangulation with electronic timing to achieve faster measurement.
Solution Approach 2:
The patent uses signal reflection to create a virtual copy of the measurement process. Instead of physically measuring distance through triangulation, the system sends a signal that bounces off the projection surface and returns, using the time delay of this signal copy to calculate distance.
2Measurement precision
If pattern projection is used for distance measurement, then distance can be measured, but complex unevenness may be overlooked
Solution Approach 1:
The projection device serves multiple functions: it can project measurement patterns for distance measurement, project correction patterns for distortion correction, and display actual content. This multi-functionality allows the system to handle both simple and complex unevenness scenarios using the same device.
Solution Approach 2:
The system uses feedback from the measured distance information and captured images to automatically adjust projection parameters and generate appropriate correction patterns. The measurement results feed into the correction algorithm, creating a closed-loop system that adapts to different surface conditions.
3Manufacturing precision
If keystone correction is used for flat surfaces, then image distortion on flat walls can be corrected, but it cannot handle surfaces with unevenness
Solution Approach 1:
The system dynamically changes projection parameters based on measured distance and surface characteristics. Instead of using fixed keystone correction parameters, the system adjusts projection position, size, and shape parameters according to the actual distance and unevenness detected, enabling adaptation from flat to complex surfaces.
Solution Approach 2:
The patent transitions from static keystone correction to dynamic correction. The system continuously measures distance and captures images, then dynamically generates and applies correction patterns based on real-time surface conditions, allowing adaptation to varying surface geometries.
Data Source
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AI summary
To display an image even on a projection surface having complex unevenness similarly to a flat, a projection device includes: a storage unit storing at least a pattern image for detecting distortion depending on a state of the surface, an expected image associated with a displayed image of the pattern image displayed on a flat, and a desired projection image; a projection unit projecting an image including the pattern image and the desired projection image; an image acquisition unit acquiring a displayed image of the pattern image, and extracting a distortion image; a distortion amount calculating unit calculating a distortion parameter for distortion by comparing the expected image with the distortion image; a distortion correction processing unit correcting the projected desired projection image by using the distortion parameter; and an image output unit outputting, to the projection unit, image data including the corrected desired projection image and the pattern image.