Projection Display Distance Measurement Using Dual Optical Paths
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Solution Overview
Problem
Existing projection display apparatuses face challenges in accurately measuring distance to a projection surface without requiring adjustments for lens replacement, zoom changes, or other modifications, especially in projection mapping applications where high precision and real-time image control are necessary.
Innovation Solution
A projection display apparatus that includes a light source unit, a digital micromirror device (DMD) as a light deflector, and a calculator to measure distance by using light that travels along two optical paths, allowing for real-time distance calculation without altering the existing apparatus configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light receiver measures reflected projection light to calculate distance, then distance measurement is achieved, but measurement precision deteriorates when the apparatus configuration changes (lens replacement, zoom changes)
Solution Approach 1:
The system uses its own emitted light as the measurement light source, making the measurement system self-contained and independent of external conditions. The light receiver detects the emitted light after it has been reflected from the projection surface, allowing the apparatus to self-calibrate and maintain measurement precision regardless of configuration changes such as lens replacement or zoom adjustments.
2Measurement precision
If multiple distance measurement points are measured to achieve accurate distortion correction, then measurement precision improves, but device complexity increases
Solution Approach 1:
The projection surface is divided into multiple measurement regions, and the light receiver sequentially measures distance at different points across the surface. By segmenting the measurement task into multiple discrete points and processing them in sequence rather than simultaneously, the system achieves comprehensive distortion correction data without requiring a complex multi-sensor array, thus maintaining relatively simple device architecture while improving measurement precision.
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 and real-time distance measurement to the projection surface, maintaining precision across various configurations and applications, including projection mapping, without the need for adjustments during lens changes or other modifications.
Implementation Method 1
a light source unit configured to emit light for producing the projection light
Implementation Method 2
the at least part of the incident light that has traveled along the first optical path and then has been reflected by the projection surface
Data Source
AI summary
The projection display apparatus includes a light source unit, a light deflector, a first light receiver, a second light receiver, and a calculator. The light deflector deflects at least part of incident light coming from the light source unit to a first optical path so as to produce a projection light, and deflects a remaining part of the incident light to a second optical path. The first light receiver receives the at least part of the incident light that has been reflected by the projection surface. The second light receiver receives the remaining part of the incident light. The calculator calculates a distance from the projection display apparatus to a projection surface based on light reception results obtained by the first light receiver receiving the at least part of the incident light and the second light receiver receiving the remaining part of the incident light.