ToF Camera Casing Step for Optical Misalignment
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Solution Overview
Problem
ToF image-capturing devices face challenges in accurately acquiring distance information due to misalignment of optical axes between the illumination unit and light receiver, leading to overly concentrated dot pattern light within the field of view, causing dot patterns to connect and fail to function as distinct patterns.
Innovation Solution
The design includes a casing with a light receiver at one end and a support at the other, with a light emitter positioned between them to emit patterned light, and a processor to calculate distances based on received patterned light, while excluding areas with overly concentrated light to prevent dot pattern overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the optical axes of the illumination unit and light receiver are misaligned, then the device structure becomes simpler and easier to manufacture, but the dot pattern light becomes overly concentrated in certain areas causing measurement errors
Solution Approach 1:
The patent introduces a third dimension (vertical displacement) to resolve the two-dimensional alignment problem. By allowing the light receiver to be positioned at a different vertical level than the illumination unit, the system accepts optical axis misalignment as a design feature rather than a defect to be eliminated, thereby simplifying manufacturing while maintaining measurement capability through software-based correction
Solution Approach 2:
The patent changes the operational parameters by accepting a range of optical axis misalignments and compensating through image processing algorithms. Instead of maintaining precise mechanical alignment (a physical parameter), the system uses digital processing to correct the dot pattern distortion, transforming a mechanical precision problem into a computational one
2Measurement precision
If the dot pattern light is emitted with high intensity to improve signal-to-noise ratio, then distance information can be acquired more accurately, but the dot patterns may connect and overlap causing loss of pattern distinction
Solution Approach 1:
The patent creates a digital copy of the dot pattern through the light receiver and processes this copy to recover the original pattern information. By capturing the light reflected from the dot pattern and processing the resulting image, the system can distinguish individual dots even when they appear connected in the raw data, thereby preserving pattern information that would otherwise be lost
Solution Approach 2:
The system uses feedback from the captured dot pattern image to adjust and refine the distance measurement. By analyzing the received dot pattern and comparing it with expected patterns, the system can identify and correct for areas where dot connection occurs, using this feedback information to maintain measurement accuracy despite high light intensity conditions
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
This configuration allows for accurate distance measurement by preventing dot pattern overlap and maintaining distinct patterns, enhancing the device's ability to acquire precise distance information even with misaligned optical axes.
Implementation Method 1
The light receiver receives the patterned light reflected from the target object
Implementation Method 2
One of the methods for measuring the distance from an imaging apparatus to an object is known as the Time of Flight (ToF) method, which calculates the distance to the object based on the time taken for light to be emitted, reflected, and then received
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An image-capturing device (1001) includes: a casing (11) elongated in one direction; a light receiver (61) on one end of the casing in said one direction, a support on another end of the casing in said one direction; and a light emitter (21) between the light receiver (61) and the support in said one direction of the casing, to emit patterned light to a target object. The light receiver (61) receives the patterned light reflected from the target object and is preferably able to capture an image covering 360 degrees around the casing in a plane orthogonal to said one direction. The image-capturing device (1001) has a blind spot at the lower portion to prevent light emitted from the light emitter (21) at the lower side relative to the ToF light receiver (61) from directly entering the ToF light receiver (61). The image-capturing device (1001) has a step (11a) in the casing (11) with which the ToF light receiver (61) and the light emitter (21) form a step therebetween in the optical system. The image-capturing device (1001) including the step (11a) in the casing (11) blocks incident light at an angle of view of -60 degrees or less from the ToF light receiver (61), creating a blind spot. This configuration allows the ToF light receiver (61) to avoid receiving patterned light at a maximum angle of view emitted from the light emitter (21).