Opportunistic Structured Light for Handheld Projectors
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Solution Overview
Problem
Existing hand-held projectors face challenges in dynamically tracking the relative surface depth and orientation during video projection, leading to issues like keystone distortion, reduced brightness, and contrast due to the need for synchronized projector and camera operations when using structured light.
Innovation Solution
The method involves opportunistically placing structured light in a subset of projected frames, allowing for dynamic estimation of the projection surface's depth and orientation, which is then used for keystone correction, focus adjustment, and size manipulation without interrupting the video stream, using a handheld projection device with a projector and camera system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured light frames replace video frames, then depth and orientation tracking is enabled, but brightness and contrast of projected video deteriorate
Solution Approach 1:
The patent applies partial action by injecting structured light patterns into only a subset of video frames rather than replacing entire frames. This selective injection maintains video brightness and contrast while still providing sufficient depth measurement data for tracking surface geometry and orientation during projection.
Solution Approach 2:
The structured light patterns are injected locally into specific portions of the video stream where they can be detected by the camera for depth computation, while the rest of the video content maintains its original quality. This allows depth tracking functionality to be added without degrading overall video presentation quality.
2Measurement precision
If entire video frames are replaced with structured light frames, then complete depth map acquisition is achieved, but video quality and viewing experience deteriorate
Solution Approach 1:
The system performs partial depth map acquisition by processing only selected frames with structured light injection. This provides sufficient depth information for keystone correction and focus adjustment without sacrificing overall video quality, achieving the right balance between measurement completeness and presentation quality.
3Reliability
If structured light is injected into all frames, then continuous depth tracking is achieved, but processing complexity and synchronization requirements increase
Solution Approach 1:
The patent implements periodic structured light injection at selected frame intervals rather than continuous injection in every frame. This periodic approach maintains reliable depth tracking capability while significantly reducing the processing complexity and synchronization burden on the projector-camera system.
4Measurement precision
If high-speed synchronized projector-camera operation is used, then accurate structured light capture is achieved, but device complexity and cost increase
Solution Approach 1:
The system achieves adequate structured light capture accuracy by processing only a subset of frames rather than requiring high-speed synchronized operation for every frame. This reduces the performance requirements for projector-camera synchronization while maintaining sufficient measurement precision for practical applications.
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
This approach maintains the viewing experience by minimizing contrast loss and ensuring accurate projection without requiring high-speed, perfectly synchronized projector and camera operations, allowing for real-time correction and adjustment of projected content.
Implementation Method 1
projecting a structured light pattern in at least one portion of a frame being projected by the handheld projection device
Implementation Method 2
The reflection of the pattern is captured by a camera and the depth profile of the environment can be computed based on triangulation
Data Source
AI summary
A method for using structured light in a handheld projection device is provided that includes projecting a structured light pattern in at least one portion of a frame being projected by the handheld projection device, wherein the at least one portion of the frame is a subset of the frame, capturing an image of the projected frame, computing scene depth information based on the structured light pattern in the captured image, and using the scene depth information in processing of a subsequent frame of the video stream.