Automatic Keystone Correction in Handheld Projectors
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Solution Overview
Problem
Handheld projectors, such as DLP Pico Projectors, suffer from keystone distortion when not held perfectly perpendicular to the projection surface, requiring manual correction each time the orientation changes, which is inefficient.
Innovation Solution
An automatic keystone correction method that uses initial keystone correction parameters based on a depth image of the projection surface, continuously monitors and adjusts these parameters by computing new ones if necessary, ensuring accurate projection without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual keystone correction is used, then image distortion can be corrected, but the operation becomes complex and time-consuming requiring manual intervention each time orientation changes
Solution Approach 1:
The system uses the projector's built-in camera to automatically detect and measure keystone distortion without external devices. The processor automatically calculates correction parameters from captured images, enabling the system to self-correct distortion without manual intervention.
Solution Approach 2:
The system continuously captures images of the projected content with the camera, analyzes the trapezoidal distortion in real-time, and feeds this information back to the processor which adjusts correction parameters dynamically. This closed-loop feedback ensures continuous accurate correction as orientation changes.
2Measurement precision
If manual keystone correction is used, then distortion can be corrected, but productivity decreases due to repeated manual adjustments
Solution Approach 1:
The keystone correction operates continuously throughout the projection process. The camera continuously captures images and the processor continuously adjusts correction parameters, ensuring uninterrupted accurate projection even as the projector orientation changes during use.
Solution Approach 2:
The system automatically performs all correction operations without requiring user intervention. The built-in camera and processor work together to detect, measure, and correct distortion automatically, eliminating the need for manual adjustments and maximizing productivity.
3Adaptability or versatility
If the projector orientation changes, then adaptability increases, but keystone distortion increases requiring frequent correction
Solution Approach 1:
The keystone correction parameters are dynamic rather than static. The system continuously adapts correction parameters based on real-time detection of projector orientation and distortion levels, allowing the projector to maintain accurate images across varying orientations and positions.
Solution Approach 2:
Real-time feedback from the camera detects changes in orientation and distortion, enabling the processor to dynamically adjust correction parameters. This continuous adaptation maintains image geometric accuracy regardless of how the projector orientation changes.
Data Source
AI summary
A method for automatic keystone correction in a projection system is provided that includes rectifying a first image to be projected using current keystone correction parameters to generate a first rectified image, projecting, by a projector in the projection system, the first rectified image on a projection surface, determining whether or not current keystone correction parameters are providing sufficient keystone correction after the first rectified image is projected, rectifying a second image to be projected using the current keystone correction parameters to generate a second rectified image if the current keystone correction parameters are providing sufficient keystone correction, computing new keystone correction parameters if the current keystone correction parameters are not providing sufficient keystone correction and rectifying the second image to be projected using the new keystone correction parameters to generate the second rectified image, and projecting, by the projector, the second rectified image on the projection surface.