TOF Camera Depth Mapping With Safe IR Exposure Control
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Solution Overview
Problem
Camera devices using the Time of Flight (TOF) method face challenges in ensuring both human safety and maintaining high resolution of depth maps, as excessive infrared light output can be harmful and reducing its intensity or duration compromises depth map resolution.
Innovation Solution
A camera device with dual transmission/reception devices and a control unit that alternately turns on/off light-emitting units to reduce infrared exposure, generating high-resolution depth maps by synthesizing overlapping and non-overlapping areas using asymmetrical light distributions and optical axes, and employing an angle control member to adjust the recognition range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the intensity or output time of the IR light is increased to improve depth map resolution, then the resolution of the depth map is improved, but the safety for the human body is compromised
Solution Approach 1:
The patent divides the imaging area into multiple regions (first area, second area, overlapping area, non-overlapping area) and uses different transmission/reception devices for different regions. This segmentation allows the system to concentrate IR light output on specific areas of interest, improving depth map resolution in critical regions while limiting overall IR exposure to safe levels.
Solution Approach 2:
The patent implements asymmetrical light distribution where different regions receive different amounts of IR light based on their importance. The overlapping area, which is critical for depth perception, receives enhanced light distribution, while non-critical areas receive reduced exposure. This local quality approach maintains high resolution where needed while ensuring safety overall.
2Object-affected harmful factors
If the intensity or output time of the IR light is limited to ensure human safety, then the safety for the human body is improved, but the resolution of the depth map is reduced
Solution Approach 1:
The control unit alternately turns on and off the first and second light-emitting units in a periodic manner. This periodic action allows the system to accumulate sufficient light signal data over time while keeping the instantaneous IR light exposure within safe limits. The alternating operation enables the camera to capture multiple frames and synthesize them into a high-resolution depth map without exceeding safety thresholds.
Solution Approach 2:
The patent merges data from multiple transmission/reception devices and combines information from overlapping and non-overlapping areas to generate the final depth map. By integrating signals from both the first and second light-receiving units, the system achieves high resolution through data fusion while each individual emitter operates at safe intensity levels.
3Measurement precision
If multiple transmission/reception devices are used to improve depth map resolution, then the resolution of the depth map is improved, but the device complexity increases
Solution Approach 1:
Each transmission/reception device is designed to perform multiple functions: emitting IR light, receiving reflected light, and contributing to both overlapping and non-overlapping area imaging. The light-emitting units and light-receiving units are configured to serve dual purposes, reducing the need for separate dedicated components and thereby limiting overall device complexity despite using multiple devices.
Solution Approach 2:
The patent employs asymmetrical optical axes and asymmetrical light distributions in the configuration of multiple transmission/reception devices. This asymmetric arrangement optimizes the coverage of overlapping and non-overlapping areas, allowing the system to achieve high resolution with a minimized number of components rather than using symmetric, redundant configurations.
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 solution ensures safety by reducing infrared exposure while maintaining high-resolution depth maps, particularly within the human eye's primary field of view, minimizing unnecessary data and calculations, and achieving depth map quality similar to human perception.
Implementation Method 1
a distance to an object is calculated by measuring TOF, that is, the time of reflection by shooting light
Implementation Method 2
a first input light signal which is a signal in which the first output light signal is reflected from an object
Data Source
AI summary
A camera device according to one embodiment of the present invention comprises: a first transmission/reception device including a first light-emitting unit for outputting a first output light signal, and a first light-receiving unit for receiving a first input light signal obtained through the reflection of the first output light signal from an object; a second transmission/reception unit including a second light-emitting unit for outputting a second output light signal, and a second light-receiving unit for receiving a second input light signal obtained through the reflection of the second output light signal from the object; a depth information generation unit for generating depth information about the object by using the first input light signal received in the first light-receiving unit and the second input light signal received in the second light-receiving unit; and a control unit for controlling the first transmission/reception device, the second transmission/reception device and the depth information generation unit, wherein: the first input light signal is an input light signal for a first area of the object, and the second input light signal is an input light signal for a second area of the object; the depth information includes first depth information about an overlapping area of the object in which the first area and the second area overlap, and second depth information about a non-overlapping area of the object in which the first area and the second area do not overlap; and the resolution of the first depth information is higher than the resolution of the second depth information.