Lidar Conveyor Object Tracking Illumination Independence
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Solution Overview
Problem
Optical means for identifying and tracking objects on conveyors are ineffective in environments with faint or overly bright illumination, degrading performance.
Innovation Solution
A tracking system using a rangefinder, such as a Lidar sensor, captures depth frames to determine object positions, trajectories, and motion characteristics without relying on illumination, employing processing steps to correct for sensor tilt, find bounding boxes, calculate object dimensions, and track centroids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical means are used to identify and track objects on conveyors, then object tracking capability is provided, but performance degrades in environments with faint or overly bright illumination
Solution Approach 1:
The patent replaces optical detection systems with a rangefinder-based detection system. The rangefinder uses time-of-flight measurement of light pulses to determine object positions and trajectories, eliminating dependence on ambient illumination conditions. This substitution of the detection mechanism resolves the contradiction by making tracking reliable regardless of lighting levels.
Solution Approach 2:
The patent changes the detection parameter from optical intensity (which is illumination-dependent) to time-of-flight measurement (which is illumination-independent). By measuring the time for light pulses to travel to and from objects, the system obtains range information that is unaffected by ambient light conditions, thereby resolving the illumination sensitivity issue while maintaining tracking capability.
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 accurate tracking of objects on conveyors regardless of illumination conditions, providing reliable object position, velocity, and acceleration data, and allowing for real-time monitoring of conveyor operations.
Implementation Method 1
A tracking system embodying features of the invention comprises a conveyor conveying objects in a conveying direction on a conveying surface and a rangefinder disposed above the conveyor and scanning a field of view encompassing a portion of the conveyor. At a predetermined repetition rate, the rangefinder captures depth frames constituting an array of pixels whose values indicate the distance from the rangefinder to objects in the field of view.
Data Source
AI summary
A tracking system using a rangefinder, such as a Lidar sensor, to track objects conveyed on a belt conveyor. The rangefinder produces depth frames in a field of view encompassing a portion of a conveyor. The depth frames comprise an array of pixels whose values represent distances from the rangefinder to reflective surfaces in the field of view. The rectangular reflection surfaces of objects are identified and their dimensions and centroids are calculated so that the objects can be tracked from frame to frame. An object's trajectory angle Θi is computed and stored in a tracking buffer array. Conventional smoothing techniques can be used to convert the piecewise linear trajectory (30) into a smooth curved trajectory. If an object is being conveyed on a conveyor belt without slipping on the belt's surface, its component of velocity vx in the x direction can be used as an estimate of the speed of the conveyor belt. The orientation of the object can be tracked from frame to frame to reveal whether the conveyor belt is changing the object's orientation relative to the conveying direction.