ToF-Based Projector Keystone Correction With Low Computing Load
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Solution Overview
Problem
Existing projectors require high computing power and resources for keystone correction, leading to increased equipment costs and poor user experience due to the lack of fast and real-time correction capabilities.
Innovation Solution
Incorporating a Time-of-Flight (ToF) sensor, calculation unit, and control unit to sense distances between measurement points on a projection surface, calculate offset angles, and perform keystone correction operations to automatically correct geometric distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image comparison and analysis is performed using a processing circuit to obtain keystone correction parameters, then correction accuracy is improved, but computing resources and computing time increase significantly
Solution Approach 1:
The patent extracts the distance measurement function from the complex image processing system and implements it separately using a ToF sensor. This separates the geometric parameter acquisition (distance) from the image processing, allowing correction parameters to be obtained through simple distance ratios rather than complex image comparison and analysis, thereby reducing computing resources while maintaining correction accuracy
Solution Approach 2:
The patent replaces the mechanical/image-based correction approach with a time-based measurement system. Instead of capturing and analyzing images to determine geometric relationships, the system uses the ToF sensor to measure distances and calculate offset angles through time-of-flight calculations, substituting complex image processing with simpler temporal measurements
2Productivity
If high computing power is provided in the processing circuit to improve correction speed, then real-time correction capability is improved, but equipment cost increases
Solution Approach 1:
The patent replaces expensive high-performance processing circuits with a more economical approach using a ToF sensor and simplified calculation unit. The system achieves real-time correction capability not through powerful computation but through efficient measurement and straightforward distance ratio calculations, reducing equipment cost while maintaining correction speed
Solution Approach 2:
The patent changes the fundamental measurement parameter from image data to distance data. By measuring distances directly with the ToF sensor and using distance ratios to determine offset angles, the system transforms a computationally intensive image processing problem into a simple mathematical calculation, achieving real-time correction with lower-cost components
3Device complexity
If manual keystone correction operation is performed, then device complexity is reduced, but correction time and user operation burden increase
Solution Approach 1:
The patent implements automatic keystone correction by having the system self-measure the projection surface distances using the ToF sensor and self-calculate the correction parameters based on distance ratios. The control unit automatically generates control signals for the projection module without requiring manual user operation, achieving both system simplicity and fast correction time
Solution Approach 2:
The patent performs preliminary distance measurement and correction parameter calculation before the actual projection. The ToF sensor measures distances to the projection surface in advance, and the calculation unit computes offset angles based on these distances, so that when projection begins, the correction is already prepared, eliminating correction time during operation
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 fast and effective keystone correction by reducing computational demands, providing high-quality projection images with reduced geometric distortion.
Implementation Method 1
a ToF sensor (120) is configured to sense a plurality of distances between a plurality of measurement points on a projection surface and the projector
Data Source
AI summary
The invention provides a projector and a correction method thereof. The projector includes a ToF sensor, a calculation unit, a control unit, and a projection module. The ToF sensor senses distances between measurement points on a projection surface and the projector in a distance measurement operation. The calculation unit is coupled to the ToF sensor. The calculation unit calculates at least one distance ratio corresponding to at least one direction according to the distances, and obtains at least one offset angle in the at least one direction according to the at least one distance ratio. The control unit is coupled to the calculation unit and the ToF sensor. The projection module is coupled to the control unit. The control unit performs a keystone correction operation of the projection module according to the at least one offset angle.