Lidar Receiver Segmentation for Near-Range Reflection Separation
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Solution Overview
Problem
Existing lidar sensors face challenges in distinguishing between reflections from near objects and unwanted reflections from the protective glass and internal components, leading to signal saturation and reduced accuracy in environment detection.
Innovation Solution
The lidar sensor employs a receiving unit with distinct light-sensitive regions for near and distant objects, adjusting sensitivity and transmission energy levels to separate and enhance the signal-to-noise ratio, using a rotating deflecting unit and control unit to manage laser beam emission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective glass is used to protect the interior of the lidar sensor from external influences, then protection from dust and moisture is improved, but unwanted reflections from the protective glass occur that interfere with measurements
Solution Approach 1:
The patent applies the principle of converting harm into benefit by utilizing the protective glass's reflective properties in a controlled manner. A reflector is positioned to redirect the harmful unwanted reflections from the protective glass toward the receiving unit, where they can be distinguished from actual object reflections through temporal filtering and signal processing, thereby converting the harmful reflections into usable information or at least non-interfering signals.
Solution Approach 2:
The patent introduces an intermediary element (the reflector and associated optical components) between the protective glass and the receiving unit. This intermediary system mediates the harmful reflections by redirecting them through a controlled path, allowing the system to distinguish between reflections from the protective glass and reflections from actual objects in the environment.
2Device complexity
If the receiving unit uses a single light-sensitive surface for detecting reflected laser beams, then device complexity is reduced, but the ability to distinguish between near and distant objects is compromised
Solution Approach 1:
The patent applies segmentation by dividing the light-sensitive surface of the receiving unit into multiple distinct regions. Each region is optimized for detecting reflections from objects at specific distance ranges. This segmentation allows the system to distinguish between near and distant objects based on which region detects the signal, thereby improving measurement precision without requiring a completely separate receiving unit for each distance range.
Solution Approach 2:
The patent implements local quality by assigning different detection characteristics to different regions of the light-sensitive surface. Each region has optimized sensitivity and temporal characteristics suited for its specific detection task (near objects vs. distant objects). This allows the single receiving unit to perform multiple detection functions with differentiated local properties.
3Measurement precision
If the lidar sensor uses high transmission energy to detect distant objects, then detection range is improved, but signal saturation occurs due to unwanted reflections from the protective glass
Solution Approach 1:
The patent applies periodic action by using temporal filtering and periodic scanning techniques. The system sends laser pulses periodically and uses the time-of-flight information to distinguish between signals from different distances. By analyzing the temporal pattern of returned signals, the system can identify and filter out unwanted reflections from the protective glass that occur at predictable times, allowing high transmission energy to be used for distant object detection without signal saturation.
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 improves the recognition of near objects by reducing unwanted reflections, enhancing signal clarity, and maintaining temporal resolution for both near and distant object detection.
Implementation Method 1
The transmitting unit is configured to generate pulsed laser beams during the respective measuring processes by the lidar sensor and to emit these via the deflecting unit through the protective window into an environment of the lidar sensor
Implementation Method 2
The deflecting unit is configured to move the laser beams within a field of view of the lidar sensor in order to scan the environment within the field of view. The deflecting unit is also configured to direct portions of the emitted laser beams reflected in the environment to the receiving unit
Implementation Method 3
The receiving unit is configured to receive, within a first time period after the start of the emission of a particular laser beam, reflected portions of a laser light of the particular emitted laser beam within the first light-sensitive region and to generate a first signal that contains time-of-flight information
Data Source
AI summary
A lidar sensor including a transmitting unit, a receiving unit, a protective window, a housing, and a deflecting unit. The transmitting unit generates laser beams during respective measuring processes and emits them into an environment of the lidar sensor, the receiving unit includes at least a first light-sensitive region and a second light-sensitive region, and is configured to receive, within a first time period after the start of the emission of a particular laser beam, reflected portions of the particular laser beam within the first light-sensitive region and, within a second time period, to receive reflected portions of the particular laser beam within the second light-sensitive region.