Projector Keystone Correction Using Acceleration and Distance Sensors
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Solution Overview
Problem
Existing projectors, particularly ultra short throw beam projectors, face challenges in keystone correction due to errors in optical axis calibration and require complex image processing, leading to image warping and size variation based on screen distance, which is exacerbated by the need for wide-angle lenses and precise angle measurement.
Innovation Solution
An electronic apparatus utilizing an acceleration sensor and distance sensors to adjust image size and perform keystone correction without an image sensor, calculating angles and correcting image warping by using a processor to adjust the image's posture and size based on detected distances and angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an image sensor is used to photograph the screen for keystone correction, then the warped angle can be calculated, but calibration errors occur and a large amount of calculation is required
Solution Approach 1:
The patent extracts the angle measurement function from the image sensor system and implements it using separate acceleration sensors and distance sensors. This removes the need for complex calibration between optical axes and measurement axes, as each sensor type independently measures specific parameters (acceleration for angle, distance for position) without requiring mutual calibration.
Solution Approach 2:
The patent replaces the optical-mechanical image sensor system with an electro-mechanical sensor system (acceleration sensors and distance sensors). This substitution eliminates the need for optical calibration and reduces computational complexity by using direct sensor measurements rather than image processing to determine angles.
2Length of moving object
If an ultra short throw beam projector is used, then the distance between the projection surface and the projector is reduced, but warping becomes severe and calibration becomes difficult
Solution Approach 1:
The patent introduces acceleration sensors and distance sensors as intermediary devices that indirectly measure the projection geometry. Instead of directly measuring angles from the projector's perspective (which is difficult at ultra-short distances), these sensors act as intermediaries to capture acceleration and distance data that can be used to calculate the warped angle through software processing.
3Shape
If keystone correction is performed, then image warping is reduced, but the size of the image varies according to the distance between the screen and the projector
Solution Approach 1:
The patent implements dynamic image size adjustment by continuously monitoring the distance between the projector and screen using distance sensors. The system automatically adapts the image size parameters based on the measured distance, ensuring that the corrected image maintains optimal dimensions regardless of projection distance variations.
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
Effectively corrects keystone distortion and adjusts image size to fit the screen optimally, reducing hardware complexity and improving user satisfaction by displaying images in maximum size and resolution without warping.
Implementation Method 1
obtaining an angle by which the electronic apparatus rotated
Implementation Method 2
obtaining an angle by which an image output by the electronic apparatus is warped based on the screen
Data Source
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AI summary
An electronic apparatus projecting an image is disclosed. The electronic apparatus includes a main body, a projector, a plurality of sensors including an acceleration sensor that detects a sensing value, and a plurality of distance sensors that detect a distance value between the electronic apparatus and a screen, a support connected to the main body, and a processor configured to identify a vertical angle by which the electronic apparatus is tilted, based on a sensing value detected by the acceleration sensor, identify a rotation angle by which the electronic apparatus is rotated based on a distance value detected by the plurality of distance sensors, perform a function corresponding to a keystone correction on an image to provide a modified image, identify a size of the modified image based on the vertical angle or the rotation angle, and control the projector to project the modified image based on the size of the modified image.