Projection Surface Edge Detection Using Brightness Gradient Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing projection technologies face challenges in accurately detecting the edges of a projection surface due to secondary reflections from surrounding surfaces, particularly when using white light, which decreases the accuracy of feature point extraction.
Innovation Solution
Projecting a pattern with decreasing or stepwise brightness from the center to the edge of the projection surface, or an annular pattern with increasing brightness on the outer side, to suppress secondary reflections and enhance edge detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white light is projected to increase brightness near the edge of the projection surface, then the brightness in the vicinity of the edge is improved, but the accuracy of extracting feature points decreases due to secondary reflection from surrounding objects
Solution Approach 1:
The patent applies local quality by creating a brightness gradient where the center of the projection surface is brighter than the edges. This is achieved by projecting a pattern where luminance decreases from the center toward the periphery, ensuring that edge regions receive sufficient illumination for detection while the overall gradient prevents secondary reflections from surrounding objects from interfering with feature point extraction accuracy
Solution Approach 2:
The patent changes the luminance parameter across the projection surface by implementing a controlled brightness gradient. The projection pattern modifies the light intensity distribution so that brightness decreases continuously or stepwise from the center to the edge, transforming the uniform illumination into a gradient pattern that suppresses secondary reflections while maintaining edge visibility
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 proposed method effectively reduces the impact of secondary reflections, maintaining high accuracy in detecting the edges of the projection surface and improving the precision of image correction.
Implementation Method 1
the accuracy of extracting the four first feature points Fa10 to Fa13 from the first captured image IM1 sometimes decreases to the contrary because of the influence of secondary reflection of the white light from an object present around the projection surface 90
Data Source
AI summary
A projection apparatus includes a projector configured to project an image onto a projection surface, a processing device, and a camera. In a first period, the processing device causes the projector to project a first pattern in which the brightness continuously decreases in a first direction that is a direction from the center of the projection surface toward an edge of the projection surface. The processing device causes the camera to capture the image of the projection surface and the first pattern projected onto the projection surface in the first period to acquire a first captured image. Then, the processing device detects a plurality of first feature points indicating edges of the projection surface in the first captured image.