Projector Touch Detection Using IR Brightness Correction
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Solution Overview
Problem
Projectors face challenges in accurately identifying touch inputs due to variations in infrared ray intensity caused by distance from the emitter and lens shading, leading to inaccurate object location detection.
Innovation Solution
A projector system that includes an infrared emitter, camera module, and processors to correct brightness using correction data, accounting for both distance-dependent intensity changes and lens shading, enabling precise touch input detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If infrared ray intensity is used to detect touch input, then touch detection capability is enabled, but detection accuracy deteriorates due to distance-dependent intensity variations and lens shading
Solution Approach 1:
The system performs preliminary calibration to generate correction data before actual touch detection. The correction data compensates for distance-dependent intensity variations and lens shading effects, enabling accurate touch detection throughout the projection area without being affected by these systematic errors
Solution Approach 2:
The system changes the parameter of infrared ray intensity by applying correction values that compensate for distance-related intensity decay and lens shading. This allows the system to maintain consistent detection sensitivity across different locations in the projection area
2Measurement precision
If correction data is generated to account for distance-dependent intensity changes, then detection accuracy is improved, but system complexity increases
Solution Approach 1:
The correction data is generated in advance through calibration procedures and stored for reuse. This preliminary action eliminates the need for complex real-time calculations during touch detection, reducing processing complexity while maintaining high accuracy
Solution Approach 2:
The system performs self-calibration to generate its own correction data without requiring external intervention. This self-service approach simplifies the overall system architecture by integrating the calibration functionality within the projector itself
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
Enhances the accuracy of touch input recognition by equalizing infrared ray intensities and correcting lens shading effects, improving the projector's ability to identify touch inputs accurately.
Implementation Method 1
an infrared emitter, comprising circuitry, configured to output infrared ray to a projection area where the image is projected
Implementation Method 2
based on infrared ray output from the infrared emitter being reflected by an object present in the projection area and received by the infrared camera module
Implementation Method 3
an infrared camera configured to generate an image by photographing the projection area using an image sensor
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A projector is provided. The projector includes: a projection part including a light source configured to project an image, an infrared emitter comprising circuitry configured to emit infrared ray to a projection area where the image is projected, an infrared camera module including an infrared camera configured to generate an image by photographing the projection area using an image sensor, a memory storing correction data including correction values for correcting brightness of the image, and at least one processor configured to: correct brightness of an image obtained through the infrared camera module using the correction data, and identify whether a touch input for the projected image is entered based on the corrected brightness, wherein the correction data is generated based on first correction data and second correction data, the first correction data includes correction values for correcting a decrease in intensity of the infrared ray according to a distance from the infrared emitter, and the second correction data includes correction values for correcting lens shading.