Occupancy Grid Ray Traversal Using Integer Error Functions
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Solution Overview
Problem
Existing methods for determining cells in occupancy grids, especially when using multiple heterogeneous sensors, face challenges in efficient calculation and memory usage, particularly in 2D or 3D environments, due to the need for floating-point arithmetic and handling of varying sensor resolutions.
Innovation Solution
A method that uses an error function to discretize the space with a spatial step smaller than the grid resolution, allowing for integer arithmetic operations to determine cells crossed by a line segment between a source and target point, thereby reducing computational resources and improving mapping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If floating-point arithmetic is used to determine cells crossed by a line segment in occupancy grids, then measurement precision is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent transforms the computational parameters from floating-point to integer arithmetic. By representing coordinates and line equations using integer math (similar to Bresenham's algorithm), the system maintains cell determination precision while eliminating the computational overhead of floating-point operations. This parameter transformation resolves the contradiction by changing the numerical representation system.
Solution Approach 2:
The patent substitutes the computational mechanism from floating-point arithmetic to integer arithmetic. This substitution replaces a computationally intensive operation with a simpler integer-based calculation system, reducing processing complexity while maintaining the accuracy needed for occupancy grid cell determination.
2Reliability
If multiple heterogeneous sensors are integrated to improve field of view and robustness, then reliability is improved, but computational requirements and memory usage increase
Solution Approach 1:
The patent applies integer arithmetic to the data fusion process from multiple sensors. By representing sensor coordinates, line segments, and cell intersections using integer math, the system can process data from multiple heterogeneous sensors more efficiently. This reduces the computational burden of integrating sensor data while maintaining the reliability benefits of multi-sensor perception.
3Measurement precision
If high-resolution spatial discretization is used to improve accuracy, then measurement precision is improved, but memory requirements increase
Solution Approach 1:
The patent segments the continuous spatial space into discrete integer-coordinate cells in the occupancy grid. By using integer arithmetic to determine which cells are crossed by line segments, the system efficiently represents spatial information at high resolution without requiring continuous memory structures. The segmentation of space into discrete cells with integer coordinates reduces memory requirements compared to continuous representations.
Data Source
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AI summary
The invention relates to a method for perceiving material bodies intended to locate said bodies on an occupancy grid G of at least 2 dimensions, having a first resolution step RG, and comprising a set of cells represented by vertices (commonly called vertices in English) and segments connecting these vertices, the method using an obstacle detection sensor positioned at a source point S, comprising at least the following steps: • Acquisition by said sensor of a measurement of the position of a material body detected at a point F;• Define the coordinates of a point M using a discretized space with a spatial step δ finer than the resolution step RG, • Initialize an integer error parameter representing the position of at least one coordinate of a vertex of the cell containing the source point S in the discretized space relative to a path defined in the observation space, • Calculate the value of the error parameter for at least one vertex of the current grid cell by performing additions or subtractions of integers, • Establish the list {ci} of cells located on the path [SF] or located at a predefined distance from the path [SF].;