Pixel-Controlled Projector with Infrared Gesture Detection
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Solution Overview
Problem
Conventional projectors are large, heavy, energy-inefficient, and prone to producing pale colors when sunlight strikes the projection surface, and existing gesture detection methods in miniaturized laser scanners are influenced by the image being projected, making them unsuitable for mobile use and inaccurate in gesture recognition.
Innovation Solution
A projector system that includes a light diode device for emitting visible light, an infrared diode device for emitting infrared radiation, and a radiation intensity detection device to generate actual and setpoint back radiation intensity signals, allowing for precise control of light emission to maintain a constant back radiation intensity, enabling accurate gesture detection by differentiating between image inhomogeneities and object interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional projectors are used, then image projection is achieved, but the devices are large, heavy, and energy-inefficient
Solution Approach 1:
The patent replaces conventional mechanical projector components with a laser scanner system that uses laser diodes and galvanometer mirrors for beam deflection. This substitution enables miniaturization while improving energy efficiency, as laser beams can be switched on only when needed for projection, eliminating the need for continuous illumination sources and complex optical mechanisms found in traditional projectors.
Solution Approach 2:
The invention changes the operational parameters by using pulsed laser emission synchronized with the scanning motion. Instead of continuous light emission, laser beams are activated only during the brief moments when they need to illuminate specific pixels, dramatically reducing overall energy consumption while maintaining effective projection brightness.
2Illumination intensity
If conventional projectors are used, then image projection is achieved, but colors appear pale when sunlight strikes the projection surface
Solution Approach 1:
The patent employs laser diodes that emit highly saturated, monochromatic light in specific color ranges. By using pure wavelength laser beams rather than broad-spectrum light sources, the system produces vivid, intense colors that maintain their saturation and brightness even when projected onto surfaces exposed to ambient sunlight, as the laser's coherent light overpowers the scattered ambient light.
3Volume of moving object
If laser scanners are used for miniaturized projectors, then device size is reduced and energy efficiency is improved, but gesture detection accuracy is influenced by the projected image
Solution Approach 1:
The patent segments the light emission into two distinct components: visible light for image projection and infrared light for gesture detection. By separating these functions into different wavelength bands, the system can detect gestures based on infrared backscatter from objects (such as hands) without the detection being influenced by the visible image content being projected, thereby maintaining both miniaturization benefits and accurate gesture recognition.
Solution Approach 2:
The invention introduces infrared radiation as an intermediary carrier for gesture detection information. Since infrared light is invisible to the human eye and does not interact with the visible image content, it serves as a clean communication channel between the projector and the user's gestures, allowing accurate detection of hand movements and control gestures independent of the projected image.
4Ease of operation
If gesture detection is performed by evaluating luminous intensity differences, then control gestures can be detected, but detection speed and accuracy are influenced by the projected image
Solution Approach 1:
The patent transitions gesture detection from the visible light dimension to the infrared dimension. By detecting backscattered infrared radiation rather than visible light intensity variations, the system operates in a separate spectral dimension where the projected image content has no influence, enabling accurate and rapid gesture detection that is completely independent of the visual content being displayed.
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
The system ensures consistent image projection with constant radiation intensity across pixels, enhancing gesture detection accuracy and reliability, even with non-ideal projection surfaces and varying object reflection properties, making it suitable for mobile applications.
Implementation Method 1
a light diode device (12) for emitting visible light (32) pixel by pixel
Implementation Method 2
an infrared diode device (14) for emitting infrared radiation (34) pixel by pixel
Implementation Method 3
for detecting a back radiation intensity of reflected visible light (42) and reflected infrared radiation (44) pixel by pixel
Data Source
AI summary
A method and a projector for projecting an image pixel by pixel includes a control unit controlling a light diode device for emitting visible light, pixel by pixel, in accordance with the image to be projected and controlling an infrared diode device for emitting infrared radiation pixel by pixel based on the image to be projected and on a back radiation model, in such a way that a setpoint back radiation intensity measuring signal to be expected pixel by pixel for the actual back radiation intensity measuring signal has a predetermined value for predetermined pixels; and a radiation intensity detection device detecting pixel by pixel a back radiation intensity of reflected visible light and reflected infrared radiation and generating pixel by pixel an actual back radiation intensity measuring signal based on the detected back radiation intensities.