3D Time-of-Flight Camera Simultaneous Distance and Speed Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional 3D time-of-flight cameras require separate measurements for distance and speed, resulting in reduced signal-to-noise ratio, increased measurement time, and higher costs due to the need for multiple light sources and image sensors, while also being sensitive to background light and level differences.
Innovation Solution
A 3D time-of-flight camera system that simultaneously measures distance and speed using the same receiving pixel, with an evaluation unit processing signals from multiple charge stores to determine phase shifts and Doppler shifts, allowing for the creation of depth and speed maps from a single measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate measurements are performed for distance and speed using conventional time-of-flight cameras, then measurement accuracy can be maintained, but measurement time increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent combines distance and speed measurements into a single simultaneous measurement process using the same receiving pixel. The evaluation unit processes signals from multiple charge stores to extract both distance (from phase shift) and speed (from Doppler shift) information from the same incoming light, eliminating the need for separate measurement cycles and thereby reducing measurement time while maintaining accuracy.
Solution Approach 2:
The receiving pixel is designed to perform multiple functions simultaneously - it captures both distance and speed information from the same incoming light signal. The charge stores are configured to accumulate signals that contain both phase shift (distance) and Doppler shift (speed) information, making the single pixel universal for both measurement types.
2Measurement precision
If separate measurements for distance and speed are performed, then accurate data can be obtained, but the signal-to-noise ratio is reduced
Solution Approach 1:
By merging the distance and speed measurements into a single simultaneous process using the same receiving pixel and the same incoming light signal, the patent maximizes the utilization of the available signal. This prevents the signal loss that would occur with sequential measurements, thereby maintaining a high signal-to-noise ratio while obtaining both distance and speed information with accurate precision.
3Adaptability or versatility
If multiple light sources and image sensors are used for separate distance and speed measurements, then measurement completeness is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs a single light source and a single image sensor where each receiving pixel serves multiple purposes. The same transmitted light is used for both distance and speed measurements, and the same receiving pixel processes both types of information simultaneously through its multiple charge stores, thereby achieving complete measurement functionality without increasing device complexity.
Solution Approach 2:
The evaluation unit merges the processing of distance and speed information into a single integrated system. Instead of having separate processing chains for distance and speed, the patent combines them in one evaluation unit that simultaneously extracts both parameters from the signals accumulated in the charge stores, reducing overall system complexity.
4Measurement precision
If conventional time-of-flight measurement is used, then distance information can be obtained, but the system remains sensitive to background light and level differences
Solution Approach 1:
The receiving pixel is segmented into multiple charge stores that separately accumulate signals during different time intervals or with different modulation phases. This segmentation allows the evaluation unit to process and compare signals in a way that cancels out background light effects and level differences, thereby maintaining distance measurement precision while reducing sensitivity to harmful environmental factors.
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 approach doubles measurement speed, improves signal-to-noise ratio, and reduces costs by utilizing the same receiving pixel for both measurements, providing more robust results against background light and level variations without the need for additional light sources or sensors.
Implementation Method 1
A lighting unit (12) emits transmitted light (16) whose amplitude is modulated periodically with a frequency fs
Implementation Method 2
An image sensor (26) with a large number of receiving pixels (26a) generates a respective receiving signal (26c) from them
Implementation Method 3
evaluates these receiving signals in order to obtain a phase shift between the transmission and reception light for each receiving pixel (26a) and thus a distance value
Implementation Method 4
a Doppler shift of the receiving light (22) relative to the frequency fs and thus a speed value
Data Source
Figure 1~2
Figure 3~4b
AI summary
A 3D time-of-flight camera (10) for capturing three-dimensional image data from a detection area (18) is described. The camera comprises an illumination unit (12) for generating transmitted light (16) that is periodically modulated with a frequency fs, an image sensor (26) with a plurality of receiving pixels (26a) for generating a corresponding received signal, and an evaluation unit (28) for measuring distance and velocity using the received signals. The receiving pixels (26a) and/or the evaluation unit (28) are configured for simultaneous measurement of distance and velocity using the same receiving pixel (26a).