Superpixel and Curtain Modulation for Ambient Light Suppression
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Solution Overview
Problem
Current technologies face challenges in effectively suppressing ambient light and improving signal-to-noise ratio (SNR) in photodetectors, particularly in scenarios involving moving objects and structured illumination, which affects the accuracy of 3D scanning and data acquisition.
Innovation Solution
The implementation of curtain modulation and superpixel modulation techniques, where a light source projects a collimated beam of light that changes orientation, and a photodetector with modulated pixel sensitivity tracks the light source, selectively measuring light in regions with high irradiance while minimizing ambient light impact, using methods such as controlling electric charge storage or attenuating light with spatial light modulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If curtain modulation is used to suppress ambient light, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The photodetector array is divided into multiple independently controllable regions or pixels, allowing selective activation of only those pixels currently receiving the structured light pattern. This segmentation enables ambient light suppression by keeping non-illuminated pixels inactive, thereby improving signal-to-noise ratio while managing device complexity through targeted control.
Solution Approach 2:
The system dynamically adjusts which pixels are active based on the real-time position of the structured light pattern. By continuously updating the active pixel regions to match the moving light pattern, the system maintains high measurement precision throughout the scanning process while avoiding the complexity of having all pixels active simultaneously.
2Measurement precision
If superpixel modulation is implemented to track light source, then data acquisition accuracy is improved, but control complexity increases
Solution Approach 1:
Multiple pixels are grouped into superpixels that are controlled by a single modulation signal. This merging approach simplifies control complexity by reducing the number of independent control signals needed, while still maintaining data acquisition accuracy through the coordinated response of multiple pixels within each superpixel group.
Solution Approach 2:
The superpixel modulation system serves multiple functions: it tracks the moving light source, suppresses ambient light, and enables depth measurement. By designing the control system to handle these multiple functions through a unified superpixel approach, the patent reduces overall control complexity compared to implementing separate systems for each function.
3Object-affected harmful factors
If photodetector pixels are selectively activated, then ambient light suppression is improved, but manufacturing complexity increases
Solution Approach 1:
The system changes the operational state parameter of photodetector pixels between active and inactive modes based on illumination conditions. This parameter change approach allows standard photodetector pixels to be used without requiring specialized manufacturing, as the ambient light suppression is achieved through operational control rather than physical modification during manufacturing.
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 signal-to-noise ratio and improves the accuracy of data acquisition, enabling more precise 3D scanning of moving objects by selectively measuring light where it is most intense and reducing ambient light interference.
Implementation Method 1
a photodetector that measures light reflecting from the scene
Implementation Method 2
a light source that illuminates a scene with collimated light
Data Source
AI summary
An imaging system with a light source controls the sensitivity of pixels to light, by performing both superpixel modulation and curtain modulation. The superpixel modulation may facilitate rapid data acquisition. The curtain modulation may suppress the effect of ambient light. In superpixel modulation, each pixel set may be modulated by a separate superpixel modulation signal that causes sensitivity of the pixel set to light to vary over time, and each superpixel may include a pixel from each pixel set. The curtain modulation may cause pixels in only a small region of the photodetector to be sensitive to light. The curtain modulation may cause the small region to move to track the dot of light, by changing which pixels are in the region. This invention may be used for 3D scanning.