3D ToF Position Sensing with Selective Pixel Depth Sampling

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Solution Overview

Problem

Existing position-determining devices, such as 2D stereo cameras and 3D ToF cameras, face challenges in accuracy, size, processing complexity, and efficiency in determining object positions, particularly in dynamic environments.

Innovation Solution

A 3D time-of-flight camera with a 2D pixel arrangement and a control unit that processes images to recognize objects based on image criteria, determining distance information for a subset of pixels, reducing the need for full 3D representation and enhancing processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If distance information is collected for all pixels in the image, then complete 3D position data is obtained, but processing time increases and efficiency decreases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the complete set of image pixels into multiple subsets, where only selected subsets have their distance information collected and processed. This segmentation allows the system to process only the necessary portion of pixel data rather than all pixels, thereby reducing processing time while maintaining sufficient position determination accuracy for the object of interest.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by collecting distance information for only a subset of pixels rather than all pixels in the image. This partial processing approach is sufficient to determine object position without the need for complete 3D representation of every pixel, thus achieving the measurement goal with reduced computational effort and faster processing.

Inventive Principle:
Principle #16Partial or excessive action

2Volume of moving object

If 3D ToF camera is used for compact design, then device size is reduced, but exposure time increases and quick movements cannot be captured

Engineering Contradiction:
Improvedevice sizeVSAvoidexposure time
Core Design Contradiction:
Volume of moving objectVSDuration of action of moving object

Solution Approach 1:

The patent segments the pixel data processing into subsets, which reduces the total computational load and processing time required. This enables the use of shorter exposure times that can capture quick movements, while still maintaining sufficient data quality for position determination through selective processing of relevant pixel subsets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the processing parameter from complete pixel set analysis to subset analysis, which reduces the amount of data that needs to be processed. This parameter change enables faster processing speeds that can keep up with quick movements captured during shorter exposure times, thus resolving the contradiction between compact device design and movement capture capability.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If complete 3D representation is generated from all pixel data, then comprehensive position information is obtained, but computational complexity and processing load increase

Engineering Contradiction:
Improveposition information completenessVSAvoidprocessing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent extracts only the essential position information needed from the image by processing selected pixel subsets rather than generating complete 3D representations of all pixels. This extraction approach obtains sufficient position data for the object of interest while avoiding the computational complexity associated with processing and storing complete 3D representations of entire scenes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by processing only a subset of pixels to obtain the necessary position information. This partial processing is sufficient to determine object position without the excessive computational complexity of generating complete 3D representations, thus achieving information sufficiency with reduced processing complexity.

Inventive Principle:
Principle #16Partial or excessive action

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 quick and accurate position determination of objects by minimizing redundant information processing, allowing for real-time tracking of moving objects with reduced computational load.

Implementation Method 1

By determining either the round trip time of the radiation or the phase shift of the modulation, the distance of the camera to an object which reflected the radiation to the pixel can be determined

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

By determining either the round trip time of the radiation or the phase shift of the modulation, the distance of the camera to an object which reflected the radiation to the pixel can be determined

Methodology Applied
Scientific EffectPhase shift: Phase Modulation

Data Source

PatentEP3915044B1Position-determining device
Publication Date: 2026.04.15 LELY PATENT NV
  • EP3915044B1 patent drawingFigure 1
  • EP3915044B1 patent drawingFigure 2~4
  • EP3915044B1 patent drawing

AI summary

There is provided a position-determining device,anda milking device therefor,for determining a relative position of an object, comprising a 3D time-of-flight camera with a 2D arrangement of pixels configured to, in particular repeatedly, record an image of a space,anda control unit which is connected there to and comprises an image-processing device. The 3D time-of-flight camera has a controllable light source and is configured both to record a 2D image of the space by means of reflected emitted light and to collect distance information for one or more pixels. The image-processing device is configured to recognise a possible object in the 2D image on the basis of image-processing criteria as a first set of pixels,and to determine distance information for a subset of said pixels, and to determine said relative position by analysing the 2D image and said distance information.Due to the fact that distance information, which is often much more noisy than the 2D brightness information, is determined for far fewer (image) points, the position can be determined more quickly and reliably.