Distance Camera Intensity Correction for Detector Tolerance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing distance measurement technologies face challenges in achieving high precision due to manufacturing tolerances in detector elements, leading to ambiguous distance values and requiring fast electronics for time-of-flight measurements, which can be affected by manufacturing variations.
Innovation Solution
A distance camera with a photo element, trigger generator, light source, and intensity sensor that uses a correction value function to accurately determine distance values by interpolating sampling points and storing parameters in a memory unit, allowing for precise distance imaging even with variations in individual photo elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time of flight measurement with fast electronics is used to achieve high precision distance measurement, then measurement precision is improved, but manufacturing tolerances of detector elements cause different picture elements to measure different distance values
Solution Approach 1:
The patent changes the parameter of light intensity to resolve the contradiction. By measuring the intensity of light pulses at different known distances and establishing an intensity-correction relationship, the system compensates for manufacturing tolerances in detector elements. Each picture element's unique intensity characteristics are calibrated and stored, allowing correction of distance measurements to achieve uniformity across all elements while maintaining high precision.
2Measurement precision
If correction values for each picture element are stored to compensate for manufacturing tolerances, then measurement precision is improved, but memory requirements and device complexity increase
Solution Approach 1:
The patent reduces device complexity by changing from storing multiple correction values per picture element to storing a single intensity characteristic parameter per element. By using intensity as the basis for correction, the system maintains high measurement precision while minimizing memory requirements and processing complexity.
Solution Approach 2:
The patent uses a reference intensity measurement at a known distance to create a correction model for each picture element. This copied intensity characteristic is stored and used to correct all distance measurements from that element, eliminating the need for multiple correction values and simplifying the overall system.
3Productivity
If periodic light intensity modulation is used for distance measurement, then measurement speed is improved, but ambiguous distance measurement results occur
Solution Approach 1:
The patent uses periodic light pulse emission to maintain high measurement speed. By emitting light pulses at regular intervals and measuring the intensity of reflected pulses, the system achieves both fast measurement cycles and unambiguous distance determination through intensity-based correction.
Solution Approach 2:
The patent changes from phase-based distance measurement (which causes ambiguity) to intensity-based measurement with temporal gating. By measuring light intensity at specific time windows corresponding to expected flight times, the system resolves distance ambiguity while maintaining high measurement speed through rapid pulse repetition.
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 high-precision distance measurements with a high repetition rate, correcting for manufacturing tolerances and reducing memory access, enabling accurate distance imaging across a range of centimeters with minimal storage needs.
Implementation Method 1
at least one photo element... for detecting light pulses back reflected from the object
Implementation Method 2
light pulses having a predetermined temporal intensity profile... reflected back toward the device
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A distance camera for determining a distance value Rabs between an object and the distance camera within a predetermined distance range comprisesw at least one photo element (9), a trigger generator for activating the photo element (9) during a temporal integration gate (30, 31), a light source for illuminating the object with light pulses (28) having a predetermined temporal intensity profile with a duration Tp, and an intensity sensor for determining the intensity Ip (6) of the light pulses (29) arriving on the photo element (9), wherein the integration gate (30) has a predetermined delay to the light pulse emission start point in time in order to capture the light pulses (29) back reflected from the object such that either To or To+Tp is between an integration start point in time T1b (20) of the integration gate and an integration end point in time T1e (21) of the integration gate (30), with To being the first point in time when the light pulse (29) arrives on the photo element (9), wherein the photo element (9) is adapted to output a signal value U (25) at the integration end point in time T1e (21) with the signal value U (25) depending on the intensity Ip (6) and the duration of the light pulse (29) arriving on the photo element (9) during its activation, wherein the camera comprises a memory unit for storing predetermined parameters (10) of an explicit correction value function Δ = f(Ip) (5) for the photo element (9), and an evaluation unit for determining a raw distance value Rraw from the signal value U (25) and the intensity Ip (6) and adding the raw distance value Rraw and the correction value Δ(Ιp) (7) so as to obtain the distance value Rabs.