3D ToF Camera Calibration for Industrial Safety Compliance
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Solution Overview
Problem
Existing 3D depth-sensing technologies, such as 3D ToF cameras, are not safety-rated and cannot be used in safety-critical applications like machine guarding or collaborative robotics due to the lack of compliance with industry-recognized safety standards and robustness in handling complex industrial environments.
Innovation Solution
A system utilizing 3D ToF cameras with redundant optical paths, temperature compensation, and error detection mechanisms to generate accurate depth maps, meeting safety standards by incorporating calibration data and error correction, ensuring reliable operation in industrial settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3D ToF cameras are used for depth sensing, then measurement precision is improved, but reliability deteriorates due to lack of safety standard compliance
Solution Approach 1:
The patent divides the safety assurance into separate functional components: calibration subsystem, temperature compensation subsystem, error detection subsystem, and safety certification subsystem. Each component independently addresses specific reliability concerns while maintaining the core depth sensing functionality.
Solution Approach 2:
The patent implements calibration before deployment, storing calibration data in non-volatile memory. Temperature compensation parameters are pre-computed and stored. These preliminary actions ensure that when the system operates, it already has the necessary correction data, preventing reliability issues before they occur.
2Reliability
If calibration data is stored in non-volatile memory, then reliability is improved, but device complexity increases
Solution Approach 1:
The calibration data is stored within the camera module's own non-volatile memory, allowing the camera to serve itself by retaining calibration information without requiring external storage systems. This self-service approach improves reliability while minimizing additional complexity.
3Measurement precision
If temperature compensation is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent compensates for temperature effects by changing the calibration parameters dynamically based on temperature sensor readings. Instead of adding complex hardware, the system adjusts software parameters (calibration offsets, gain values) according to temperature conditions, improving precision while keeping the added complexity manageable.
4Reliability
If error detection mechanisms are added, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements error detection through feedback mechanisms where the system continuously monitors calibration validity and depth measurement quality. When errors are detected (e.g., out-of-range values, calibration drift), the system provides feedback to trigger recalibration or correction routines, improving reliability through a manageable feedback loop rather than complex error correction hardware.
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 provides reliable and safe operation by accurately detecting objects and hazards, adhering to safety standards, and optimizing machinery control, thereby enhancing safety and efficiency in industrial environments.
Implementation Method 1
3D time-of-flight cameras
Implementation Method 2
A light source illuminates the object being inspected or measured. This light source may be part of the camera, as in active sensing systems, or independent of the camera, such as a lamp illuminating the field of view of the camera
Data Source
AI summary
Systems and methods utilize one or more 3D cameras (e.g., ToF cameras) in industrial safety applications. The 3D camera generates a depth map that may be used by external hardware and software to classify objects in a workcell and generate control signals for machinery. To facilitate sensor-specific calibration and coordination among sensors in a workcell, the sensors may store calibration data in a boot file that is loaded upon start-up. During initialization, the calibration data is loaded and, as the sensor operates, corrections are made to sensed data (e.g., pixel depth values) using the calibration data.