Single-Pixel Centroid Detection Using DMD Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional centroid detection methods are limited by low signal-to-noise ratios and high costs associated with area-array cameras, especially in low-light and wide spectral response applications, and are not effective for infrared or terahertz bands, restricting their range of use.
Innovation Solution
A system and method utilizing a single-pixel detector assembly with a Digital Micromirror Device (DMD) and an acquisition and processing unit to generate and load two-dimensional modulation matrices, allowing for direct centroid calculation without imaging, leveraging the DMD's high-speed binary modulation capabilities to enhance detection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-pixel detector is used to improve spectral response range and light sensitivity, then the ability to work in low-light conditions and wide spectral ranges is improved, but the centroid detection speed is reduced due to sequential sampling requirements
Solution Approach 1:
The patent applies periodic action by using the DMD to rapidly switch between different modulation patterns (Hadamard sequences) at high frequency. The DMD modulates the light signal periodically according to pre-defined patterns, enabling the single-pixel detector to sample different spatial frequencies in a periodic manner. This periodic modulation allows the system to reconstruct the centroid position from sequentially sampled data while maintaining high detection speed through rapid pattern switching.
Solution Approach 2:
The patent implements dynamics by making the modulation pattern changeable and adaptive. The DMD dynamically switches between different Hadamard modulation patterns based on the detection requirements. The system adapts the modulation sequence dynamically to optimize the sampling process, allowing the single-pixel detector to efficiently capture the necessary information for centroid calculation while maintaining high speed performance.
2Measurement precision
If traditional area-array camera methods are used to achieve high centroid detection accuracy, then measurement precision is improved, but the system cost increases significantly especially for infrared and terahertz bands
Solution Approach 1:
The patent extracts only the essential information needed for centroid detection from the full image data. Instead of using an area-array camera to capture and process the entire image, the system uses a single-pixel detector to sample only the necessary spatial frequency components through Hadamard modulation. This extraction approach retrieves the centroid position information with minimal sampling, dramatically reducing the detector array size requirement and system cost while maintaining detection accuracy.
Solution Approach 2:
The patent changes the detection parameter from capturing full spatial information (intensity at each pixel location) to measuring integrated light intensity modulated by Hadamard patterns. By transforming the measurement parameter from spatially-resolved intensity to modulated integrated intensity, the system achieves centroid detection accuracy comparable to area-array cameras while using a single-pixel detector, thus reducing device complexity and cost.
3Illumination intensity
If Hadamard transform methods are used to enable single-pixel imaging to work in low-light conditions, then light sensitivity is improved, but the imaging frame frequency is limited
Solution Approach 1:
The patent extracts only the centroid position information from the full image reconstruction process. Instead of reconstructing the complete image which requires all Hadamard coefficients, the system directly calculates the centroid position from the measured light intensities using a simplified formula that involves only the first-order moment calculations. This extraction of essential information reduces the computational burden and allows for higher frame frequencies while maintaining low-light detection capability.
Solution Approach 2:
The patent applies partial action by performing only the necessary calculations for centroid detection rather than full image reconstruction. The system measures a sufficient number of Hadamard coefficients to accurately determine centroid position without acquiring all coefficients needed for complete image reconstruction. This partial sampling approach reduces the number of measurements required, thereby increasing the frame frequency while still achieving accurate centroid detection in low-light conditions.
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 enables fast and accurate centroid detection across a wide spectral range, including low-light conditions, by reducing modulation information requirements and utilizing the DMD's high-speed modulation performance, achieving frame frequencies above 11 KHz.
Implementation Method 1
The DMD modulates an image signal of the target object according to two-dimensional modulation information. Specifically, the DMD is composed of a plurality of micromirrors, and each of the micromirrors may rotate back and forth between a positive angle and a negative angle, to correspond to '0' and '1' states of a microelement of the DMD; and light intensities of the DMD in two reflection directions are complementary.
Data Source
AI summary
Disclosed are a system and a method for detecting a centroid of a complementary single pixel. The system includes a lens group, a single-pixel detector assembly, a Digital Micromirror Device (DMD) and an acquisition and processing unit. The acquisition and processing unit generates two-dimensional modulation matrices A and B which are loaded into the DMD; the lens group processes light reflected or transmitted from a target object, such that an image of the target object is imaged on the DMD; and the acquisition and processing unit is connected with data output ends of two single-pixel detectors in respective, to calculate the centroid of the target object. The DMD modulates an image signal of the target object according to modulation information A and B; the single-pixel detector assembly includes a first single-pixel detector and a second single-pixel detector.