Lidar Blooming Detection via Active Passive Distance Comparison
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lidar systems face issues with blooming, leading to inaccurate distance measurements due to overexposure or crosstalk, particularly when detecting highly reflective targets, which can result in false-positive results and hinder accurate three-dimensional representation of the environment.
Innovation Solution
A method and device that utilize both active and passive lidar measurements to determine distances, combining signal propagation time analysis with triangulation of two-dimensional intensity measurements to detect blooming by comparing first and second distance values, with the passive measurement being performed before or after the active measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active lidar measurement is used to determine distance based on signal propagation time, then distance measurement can be obtained, but blooming occurs when detecting highly reflective targets causing inaccurate distance measurements
Solution Approach 1:
The patent introduces a passive measurement as an intermediary method to detect and identify blooming effects. By using passive measurement (detecting reflected light without active emission) as a mediator, the system can recognize when active measurement is compromised by blooming, allowing for correction or rejection of inaccurate distance measurements without requiring complete elimination of the blooming physical effect.
Solution Approach 2:
The system implements feedback by comparing results from active and passive measurements. When the passive measurement indicates blooming conditions (through characteristics like intensity patterns or temporal correlations), the system uses this feedback to adjust or reject the active measurement results, thereby maintaining measurement precision despite the presence of blooming effects.
2Reliability
If passive measurement is added to detect blooming, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling the lidar system to perform both active measurement (for distance) and passive measurement (for blooming detection) using the same hardware components. The single lidar system serves multiple functions: it actively emits and detects light for distance measurement while simultaneously passively detecting reflected light patterns that indicate blooming, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The system merges active and passive measurement capabilities into a unified processing framework. By combining the evaluation of active measurement results with passive measurement indicators within the same processing unit, the patent achieves reliable blooming detection while avoiding the need for completely separate measurement systems, thus managing device complexity effectively.
3Measurement precision
If multiple measurements are performed to detect blooming, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent applies preliminary action by performing passive measurement continuously or in rapid succession with active measurement, so that blooming detection capabilities are ready and data is prepared in advance. This allows the system to quickly compare active and passive measurement results without requiring separate, time-consuming measurement sequences, thereby maintaining high precision while minimizing time loss.
Solution Approach 2:
The system uses periodic action by alternating between active and passive measurement cycles in a rhythmic sequence. This periodic switching allows both measurement types to be performed systematically without requiring simultaneous operation, enabling efficient time management while maintaining the precision needed for accurate blooming detection through regular comparison of measurement results.
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
Enables reliable detection of blooming, preventing false results in lidar measurements, ensuring safe operation of automated and autonomous vehicles and robots by providing accurate three-dimensional environmental representation.
Implementation Method 1
The distance determination is based on the determination of the signal propagation time of the laser pulses
Implementation Method 2
a passive measurement in which an environment is detected by means of at least one lidar, in which the at least one lidar detects exclusively light radiation present in the environment
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
The invention relates to a method for identifying blooming in a lidar measurement. According to the invention, a distance to a lidar reflection point (R) is ascertained in an active measurement and a passive measurement. Furthermore, a first distance value is ascertained in the active measurement based on a signal time-of-flight of a laser pulse and a second distance value is ascertained in the passive measurement based on triangulation of two-dimensional intensity measurements performed from different measurement positions, with blooming being inferred when the second distance value exceeds the first distance value by a predefined extent. A passive measurement based on two-dimensional intensity measurements is in this case understood to mean capturing an environment by way of at least one lidar, in which the at least one lidar captures light radiation present exclusively in the environment without actively emitting laser radiation. The passive measurement is based on two two-dimensional intensity measurements, with for example a first intensity measurement being performed by way of the lidar (1) located at a first position at the first time t1 and a second intensity measurement being performed by way of the same lidar (1) at the second time t2, later in time than the first measurement, and at a second position, which is different from the first position. A relative position of the lidar (1) with respect to the lidar reflection point (R) changes between the two times t1, t2 due to the movement of the platform. In an alternative embodiment, the two intensity measurements are performed by a first lidar and a second lidar arranged at a different position.