VCSEL Array Illumination Control for 3D Imaging
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Solution Overview
Problem
Existing methods for generating three-dimensional images using projector light sources are limited by inefficiencies in power management, size, and cost, particularly under varying ambient light conditions, which affect the projector's performance and the need for multiple light sources.
Innovation Solution
A method and apparatus that illuminate a target area using a VCSEL array with a diffractive optical element, adjusting illumination intensity based on ambient light conditions, and combining data from depth and RGB sensors to generate three-dimensional images, while optionally using a secondary light source and audio information for motion detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DC to DC converter circuits or switch capacitor voltage and current sources are used to provide projector power, then the projector light source can operate effectively under varying ambient light conditions, but the size and cost of the circuitry increase significantly
Solution Approach 1:
The patent extracts the complex power management functionality from dedicated converter circuits and implements it through a simplified controller that directly controls the VCSEL array operation modes. This removes the need for bulky DC-DC converters and switch capacitor circuits while retaining the ability to adapt to ambient light conditions through mode switching between continuous wave and pulsed operation
Solution Approach 2:
The patent changes the operational parameters of the VCSEL light source by switching between continuous wave mode and pulsed mode with duty cycles less than 10%. This parameter change allows the system to adapt to varying ambient light conditions without requiring complex power management circuitry, as the controller directly adjusts the driving current parameters
2Illumination intensity
If short high power pulses are generated under intense ambient light conditions, then the projected pattern becomes visible at the object, but the light source efficiency decreases due to heating
Solution Approach 1:
The patent implements periodic pulsed operation with duty cycles less than 10%, where the VCSEL array emits high power pulses intermittently rather than continuously. This periodic action allows the light source to recover between pulses, reducing thermal accumulation and maintaining efficiency while still achieving sufficient illumination intensity during the pulse periods for pattern visibility
3Loss of energy
If longer and weaker pulses are generated under moderate ambient light conditions, then the light source efficiency is maximized, but the projected pattern contrast decreases
Solution Approach 1:
The patent implements dynamic control of the VCSEL array by switching between continuous wave mode and pulsed mode with adjustable duty cycles. The controller dynamically selects the optimal operating mode based on ambient light conditions, allowing the system to maintain both efficiency and pattern contrast by adapting the pulse characteristics in real-time rather than using fixed parameters
4Illumination intensity
If still longer pulses and secondary light source are utilized in absence of ambient light, then scattered light upon the object is obtained, but the device complexity and cost increase
Solution Approach 1:
The patent makes the VCSEL array multi-functional by enabling it to operate in both continuous wave mode and pulsed mode with duty cycles less than 10% to serve different ambient light conditions. This universal operation eliminates the need for separate secondary light sources, as the same VCSEL array adapts its operation mode to provide sufficient illumination across all lighting environments, reducing device complexity and cost
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
This approach enhances the efficiency and accuracy of three-dimensional image generation by optimizing light source usage and integrating multiple sensor data, improving image quality and reducing power consumption and system size.
Implementation Method 1
A method and apparatus that illuminate a target area using a VCSEL array
Implementation Method 2
VCSEL array with a diffractive optical element
Data Source
AI summary
A method and apparatus are provided for generating a three dimensional image, wherein the method includes: illuminating a target; capturing an image that comprises an object present at the illuminated target; converting the captured image into data and processing it to determine depth of the object; and generating a three dimensional image of the object whose depth has been determined. Preferably, the illumination intensity applied while illuminating the target, is determined based on the current intensity of ambient light at the target.