Time of Flight Sensor Temperature Deviation Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional time of flight sensors face significant challenges in effectively compensating for temperature-dependent deviations in distance measurement due to the temperature variability affecting the light source, particularly when using a modulated light source, leading to inaccurate distance calculations.
Innovation Solution
The implementation of a time of flight sensor system that incorporates a reference pixel to pre-store temperature compensation and correction parameters, allowing for calibration of distance measurements by calculating a temperature compensation and correction based on a reference phase-distance relationship at a reference temperature, which is then applied at the operating temperature to eliminate deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a modulated light source is used in the time of flight sensor, then the sensor can perform distance measurement, but temperature dependency causes detection deviation and reduces measurement accuracy
Solution Approach 1:
A reference pixel is introduced as an intermediary element that does not measure the target object but instead measures the light source's own emission characteristics. This reference pixel serves as a mediator to detect temperature-induced variations in the light source, allowing the system to compensate for these variations when measuring the target object, thereby resolving the contradiction between measurement accuracy and temperature stability.
Solution Approach 2:
The system changes the operational parameters by measuring the phase of the light source emission at different time points using the reference pixel. By calculating the difference in phase values at different time points, the system derives temperature compensation parameters that correct for temperature-induced deviations, thus maintaining measurement accuracy across varying temperatures.
2Measurement precision
If temperature compensation methods are implemented, then detection accuracy can be improved, but the device complexity increases
Solution Approach 1:
The reference pixel is designed to serve multiple functions: it measures the light source emission characteristics, provides temperature compensation data, and enables correction of detection deviations. This multi-functionality allows the system to achieve temperature compensation without adding separate dedicated components, thereby improving detection accuracy while minimizing the increase in device complexity.
Solution Approach 2:
The reference pixel enables the light source to serve itself by providing real-time feedback on its own emission characteristics. The reference pixel measures the light source's phase and intensity variations, and this self-measured data is used to compensate for temperature effects, creating a self-correcting system that improves accuracy without requiring external calibration equipment or complex additional structures.
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 effectively compensates for temperature-induced deviations, ensuring accurate distance measurements by calibrating the phase and distance using stored temperature compensation and correction values, thereby improving the reliability of the sensor across varying temperature conditions.
Implementation Method 1
The light source is arranged in a first accommodation space, and configured to illuminate light according to a light source driving signal
Implementation Method 2
A time interval from the light source 11 emits light till the light sensor 13 receives the reflected light from the object is called a time of light (TOF) Ttof
Implementation Method 3
The light sensor includes a first pixel, arranged in the first accommodation space, and a second pixel, arranged in a second accommodation space adjacent to the first accommodation space, and configured to generate output signals according to a sampling signal
Data Source
AI summary
There is provided a time of flight sensor including a light source, a first pixel, a second pixel and a processor. The first pixel generates a first output signal without receiving reflected light from an external object illuminated by the light source. The second pixel generates a second output signal by receiving the reflected light from the external object illuminated by the light source. The processor calculates deviation compensation and deviation correction associated with temperature variation according to the first output signal to accordingly calibrate a distance calculated according to the second output signal.