Image Projector Marker Mapping for Posture-Aware Keystone Correction
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Solution Overview
Problem
Existing projectors face challenges in accurately performing keystone correction due to errors in the correction process, which can lead to image distortion and size variations, especially when the projector's posture is incorrect, and conventional methods require significant computational resources.
Innovation Solution
An electronic apparatus that projects a test image with markers, uses an external device to photograph this image, and applies posture information from sensors like accelerometers and cameras to correct keystone distortion by adjusting the projected image based on the external device's posture and distance information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If keystone correction is performed using image processing methods, then image alignment can be achieved, but calculation complexity and processing time increase significantly
Solution Approach 1:
The patent replaces complex image processing calculations with sensor-based measurement. Instead of using image sensors to photograph and process the projection plane to calculate keystone correction, the system uses posture sensors (accelerometers, gyroscopes, magnetometers) to directly measure the projector's orientation and calculate correction parameters. This substitution of measurement methods dramatically reduces computational complexity while maintaining alignment precision.
Solution Approach 2:
The patent introduces posture sensors as an intermediary between the projector and the correction calculation. The sensors measure posture information (roll, pitch, yaw angles) which serves as intermediate data to calculate the keystone correction parameters. This intermediary approach simplifies the overall system by using direct physical measurements rather than complex image processing chains.
2Reliability
If correction process errors occur, then image distortion and size variation increase, but the conventional correction method lacks robustness against such errors
Solution Approach 1:
The patent implements feedback by continuously monitoring posture information from sensors and using it to adjust correction parameters in real-time. The system uses the measured posture angles (roll, pitch, yaw) as feedback to calculate and apply keystone correction, ensuring that corrections are based on actual device orientation rather than assuming ideal conditions. This feedback mechanism improves reliability by adapting to actual operating conditions.
Solution Approach 2:
The patent applies beforehand cushioning by pre-calculating correction parameters based on sensor data before the actual projection occurs. The system measures posture information in advance and uses this information to determine the necessary correction angles, preparing the correction data beforehand to prevent distortion during projection. This proactive approach ensures accurate correction without relying on post-error correction methods.
3Adaptability or versatility
If the projector is placed on a flat plane, then the projection geometry is simplified, but the system loses adaptability to different projection surfaces and angles
Solution Approach 1:
The patent achieves universality by making the projector adaptable to various projection surfaces and angles through posture sensing. The system can detect and correct for different orientations (front projection, ceiling projection, wall projection at various angles) using the same sensor-based correction mechanism. This multi-functional capability allows a single projector to handle diverse projection scenarios without requiring separate correction systems for each surface type.
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting correction angles based on measured posture information. The system changes the correction parameters (roll angle correction, pitch angle correction, yaw angle correction) according to the actual orientation detected by sensors. This dynamic parameter adjustment allows the system to adapt to different projection geometries by modifying correction values rather than requiring hardware changes or complex surface-specific processing.
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 keystone correction by reflecting posture information, improving user convenience and reducing computational complexity, ensuring precise image alignment and size adjustment.
Implementation Method 1
the roll information and the pitch information are acquired through an acceleration sensor provided in the external device
Implementation Method 2
an image of a projection plane photographed by an external device
Data Source
AI summary
An example electronic apparatus may include an image projector, and a processor configured to control the image projector to project a test image including a plurality of markers onto a projection plane, based on first information indicating a location of the plurality of markers in the test image and second information indicating a location of the plurality of markers in an image of the projection plane photographed by an external device, acquire third information indicating a location of a vertex of the test image in the photographed image, correct the third information based on posture information of the external device, and perform keystone correction based on the corrected third information.