Compressive Scanning Lidar With Programmable Micromirror Array
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LIDAR systems face limitations in size, weight, and power consumption, as well as angular and range resolution, with mechanically scanned systems being large and power-hungry, and flash lidars having limited range and field of view due to their design.
Innovation Solution
A compact and low-cost real-time LIDAR system utilizing a scanned laser beam, a programmable micromirror array, and compressive sensing methods for high-resolution 3D imaging, allowing variable angular resolution and maintaining a high frame rate with low computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanically scanned lidar systems use large rotating mirrors to scan multiple laser beams, then the field of view and scanning capability are improved, but the size, weight, and power consumption increase significantly
Solution Approach 1:
The patent replaces the mechanical rotating mirror system with a fixed mirror and electronic beam steering using a photodiode array and time-gated detection. This substitution eliminates the need for large rotating mirrors while maintaining the ability to scan multiple directions and measure ranges, thereby reducing size and weight while preserving field of view capability
Solution Approach 2:
The patent divides the detection function into multiple independent photodiode elements arranged in an array, where each photodiode detects light from a specific direction. This segmentation allows the system to achieve multi-directional scanning capability without mechanical movement, reducing the need for large rotating components
2Adaptability or versatility
If mechanically scanned lidar systems use large rotating mirrors to scan multiple laser beams, then the field of view is improved, but the power consumption increases
Solution Approach 1:
The patent replaces the power-hungry mechanical rotating mirror system with a static optical arrangement using a photodiode array and electronic timing control. This eliminates the energy required to drive motors and rotate large mirrors, significantly reducing power consumption while maintaining field of view through electronic beam steering and time-gated detection
Solution Approach 2:
The patent uses periodic pulsed laser illumination combined with time-gated photodiode detection to achieve sequential scanning of multiple directions. By using time-multiplexed detection where each photodiode measures reflected light from its specific direction during designated time windows, the system achieves comprehensive angular coverage without continuous mechanical rotation, reducing average power consumption
3Adaptability or versatility
If flash lidars illuminate the entire scene with each pulse, then the field of view is improved, but the range is limited due to reduced power per pixel
Solution Approach 1:
The patent segments the illumination function by using a scanning laser beam that sequentially illuminates different regions of the scene rather than illuminating the entire scene simultaneously. This concentration of laser power on a small spot at a time maintains high power density for long-range detection while achieving full field of view coverage through sequential scanning with multiple photodiodes detecting different angular positions
Solution Approach 2:
The patent employs periodic scanning of the laser beam across the field of view combined with time-gated detection. The laser pulse illuminates a specific angular sector, and the photodiode array detects reflected light from that sector during a specific time window. This periodic sequential illumination and detection maintains high power concentration for long range while covering the entire field of view over the scan period
4Measurement precision
If flash lidars use an array of time-gated photodiodes to image the reflected light, then the angular resolution is improved, but the field of view and range are limited by the number of photodiodes
Solution Approach 1:
The patent makes each photodiode in the array multi-functional by using time-gated detection to enable each photodiode to detect light from multiple different angular directions at different time intervals. During a complete scan cycle, each photodiode sequentially measures reflections from various sectors of the field of view, allowing the system to achieve both high angular resolution and wide field of view with a smaller number of photodiodes
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 achieves improved angular and range resolution, reduced size, weight, and power consumption, with increased optical and computational efficiency, enabling high-resolution imaging of salient regions while maintaining a high frame rate.
Implementation Method 1
a scanning laser for scanning a scene and illuminating a spot in the scene; a photodiode detector for detecting received light reflected from the scene
Implementation Method 2
use time of flight detection of reflected laser pulses to measure the range of each spot along the beam directions
Implementation Method 3
a programmable N-pixel mirror or mask array in an optical path of reflected received light, the programmable N-pixel mirror or mask array optically coupled to the photodiode detector; and means for forming a reconstructed image comprising compressive sensing or Moore-Penrose reconstruction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for increasing resolution of an image formed of received light from an illuminated spot includes measuring a y vector for measurement kernels A1 to AM, where M is a number of the measurement kernels, measuring the y vector including programming a programmable N-pixel micromirror or mask located in a return path of a received reflected scene spot with a jth measurement kernel Aj of the measurement kernels A1 to AM, measuring y, wherein y is an inner product of a scene reflectivity f( α, β ) with the measurement kernel Aj for each range bin ri, wherein α and β are azimuth and elevation angles, respectively, repeating programming the programmable N-pixel micromirror or mask and measuring y for each measurement kernel A1 to AM, and forming a reconstructed image using the measured y vector, wherein forming the reconstructed image includes using compressive sensing or Moore-Penrose reconstruction.