Light source control method for vision machine, and vision machine
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Solution Overview
Problem
Vision machines, particularly TOF cameras on mobile robots, suffer from limited viewing angles and interference due to the positioning of infrared light sources, leading to blind zones and inaccurate obstacle detection.
Innovation Solution
The implementation of multiple light sources around the lens, controlled based on spatial information, to enhance the field of view and reduce interference, allowing for improved illumination and image acquisition of objects at various angles and heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single infrared light source is arranged below the lens with axis parallel to optical axis, then the structure is simple and compact, but the field of view is limited and blind zones are created
Solution Approach 1:
The single light source is divided into multiple light sources (at least two) arranged around the lens. Each light source covers a specific angular range, and together they provide comprehensive illumination across the entire field of view, eliminating blind zones while maintaining manageable system complexity.
Solution Approach 2:
The light sources are arranged in a circular pattern around the lens in the horizontal plane, transitioning from a single-point arrangement to a distributed circular arrangement. This dimensional change allows light to be emitted from multiple angles simultaneously, expanding the effective field of view without significantly increasing vertical space requirements.
2Device complexity
If a single infrared light source is used, then the device is simple, but interference signals are generated due to light reflection on the ground
Solution Approach 1:
The illumination task is segmented across multiple light sources positioned at different angular locations. This segmentation allows the system to illuminate only the necessary portions of the scene from appropriate angles, reducing ground reflections that would otherwise create interference signals in the camera's field of view.
Solution Approach 2:
Each light source is positioned to provide localized illumination from its specific angle, with its axis directed appropriately to illuminate the intended area while avoiding ground reflection paths that would enter the camera lens. This local optimization of illumination quality reduces harmful interference.
3Ease of operation
If the light source FOV and lens FOV are used for obstacle avoidance, then the system is simple to operate, but large blind zones are created resulting in inability to accurately sense obstacles
Solution Approach 1:
The obstacle detection function is segmented across multiple light sources, each contributing to coverage of specific angular sectors. The controller integrates information from all light sources to create a comprehensive obstacle map, maintaining simple operation while achieving complete 360-degree coverage without blind zones.
Solution Approach 2:
The multiple light sources collectively provide universal coverage of the entire surrounding environment, enabling the vision machine to detect obstacles from all directions. The system maintains ease of operation through automated control while achieving multi-directional sensing capability that eliminates blind zones.
4Illumination intensity
If the infrared light source illuminates only the area in front of the lens, then the illumination is focused, but objects at various angles and heights cannot be properly illuminated
Solution Approach 1:
The illumination function is segmented across multiple light sources positioned at different angular locations around the lens. Each light source maintains focused illumination in its specific direction while collectively providing comprehensive coverage of objects at various angles and heights, resolving the contradiction between focus and coverage.
Solution Approach 2:
The light sources are arranged in a circular pattern around the lens, adding angular dimensionality to the illumination system. This allows light to be emitted from multiple directions simultaneously, enabling proper illumination of objects at various angles and heights while maintaining focused illumination characteristics in each direction.
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
Expands the sensing range and improves the ability to detect obstacles by providing flexible illumination, enhancing the overall image acquisition quality and depth information of objects, especially those below the optical axis of the lens.
Implementation Method 1
an infrared light source is used to illuminate the surrounding environment
Implementation Method 2
the camera lens captures the infrared light reflected from the surface of the object
Implementation Method 3
an image sensor module for converting optical signals into electrical signals
Implementation Method 4
determines a distance between the object and the lens by calculating TOFs of the emitted light and the received light
Data Source
Figure 1~2b
Figure 2c~4b
Figure 4c~5a
AI summary
A control method for light sources of a vision machine and the vision machine. The control method includes the following steps: activating at least one first light source among n light sources to sense spatial information of an object in a field of view; and selectively activating the n light sources according to the spatial information of a sensed object; wherein the n light sources are distributed on a periphery of a front mirror surface of a lens of the vision machine, and n is a natural number greater than or equal to 2. The embodiment of the present disclosure enlarges the field of view of the vision machine, capable of providing corresponding light illumination based on environmental requirements, reducing the interference signal caused by reflection of a single light source, expanding the sensing range of the vision machine, and improving the sensing ability.