Projector Keystone Correction Using Gravity and Distance Sensors
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Solution Overview
Problem
Existing projectors, particularly ultra short throw beam projectors, face challenges in precise keystone correction due to the close proximity of the projection surface, requiring complex calibration and prone to errors with existing methods using image sensors.
Innovation Solution
An electronic apparatus utilizing a combination of an acceleration sensor and a plurality of distance sensors arranged to face each other, allowing for precise calculation of rotation angles without the need for a separate image sensor, enabling accurate keystone correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an image sensor is used to calculate rotation angle for keystone correction, then the projector can automatically correct warping, but calibration complexity increases and measurement precision decreases due to optical axis alignment errors
Solution Approach 1:
The patent replaces the optical-based image sensor system with a mechanical sensor system (acceleration sensor and distance sensors). This substitution eliminates the need for optical axis calibration while directly measuring the projection angle through mechanical sensing, thereby improving measurement precision without sacrificing automation.
Solution Approach 2:
The patent introduces distance sensors as intermediary elements between the projector and the projection surface. These sensors measure the actual projection distance and angle directly, serving as a mediator that provides accurate angular information without requiring complex optical calibration procedures.
2Adaptability or versatility
If a wide-angle lens camera is used to view the entire screen in ultra short throw projection, then the field of view increases, but calibration difficulty increases and measurement precision decreases
Solution Approach 1:
The patent replaces the wide-angle lens camera system with a combination of acceleration sensor and distance sensors. This mechanical sensing approach directly measures the projection angle without being affected by the optical distortions and calibration difficulties inherent in wide-angle lenses, thereby maintaining field of view coverage while improving measurement precision.
Solution Approach 2:
The patent extracts the angle measurement function from the imaging system and places it in a separate sensing system. By taking out the measurement function from the wide-angle camera, the system avoids the calibration issues associated with wide-angle lenses while still achieving comprehensive screen coverage through the projector's optical system.
3Measurement precision
If multiple sensors are used to improve measurement accuracy, then rotation angle measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple sensors (acceleration sensor for tilt detection and distance sensors for projection distance measurement) into a unified sensing system. This combination allows the system to calculate the projection angle through coordinate transformation of integrated data from both sensor types, achieving high measurement precision while managing device complexity through functional integration.
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 precise keystone correction even in narrow spaces by accurately measuring rotation angles, reducing errors, and improving the display quality of projected images.
Implementation Method 1
an acceleration sensor for detecting a posture of the electronic apparatus
Implementation Method 2
a plurality of distance sensors for measuring distances to a projection surface
Data Source
Figure 2A
Figure 2B
Figure 3
AI summary
An electronic apparatus and a method for controlling thereof are provided. The electronic apparatus includes a projection part, an acceleration sensor, a plurality of distance sensors arranged on one surface of the electronic apparatus facing a projection surface, a memory storing at least one instruction, and a processor, wherein the plurality of distance sensors are arranged side by side on left and right sides on one surface of the electronic apparatus, and are arranged to be rotated by a first angle to face one another, and the processor is configured to calculate a first rotation angle and a second rotation angle for the direction of gravity of the electronic apparatus based on sensing values acquired by using the acceleration sensor, calculate a third rotation angle of the electronic apparatus for the projection surface based on sensing values acquired by using the plurality of distance sensors and the first angle, and perform keystone correction based on the first to third rotation angles.