Object Detection Using Pulse Width for Saturated Signal Reflection
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Solution Overview
Problem
Existing object detection systems face difficulties in accurately detecting the intensity of reflected light when the signal is in a saturated region, making it challenging to determine the distance to a target object, especially when the reflected light is strong.
Innovation Solution
An object detection apparatus is configured with a light emitting unit, a light receiving unit, a distance calculation unit, a saturation determination unit, a pulse detection unit, a falling slope detection unit, and a reflection characteristic acquisition unit, which calculates the reflection characteristic using the pulse width or falling slope of the light reception signal even when it is saturated, allowing for accurate detection of the signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the light receiving unit receives strong reflected light, then the detection range is improved, but the light reception signal becomes saturated and intensity detection accuracy deteriorates
Solution Approach 1:
The patent applies dynamics by making the measurement method adaptive rather than fixed. The system dynamically switches between different measurement approaches (signal intensity for non-saturated signals, pulse width for saturated signals) based on the saturation determination unit's assessment. This dynamic adaptation allows the system to maintain measurement precision across varying detection ranges and light intensities.
Solution Approach 2:
The patent changes the measurement parameter based on signal saturation status. When the light reception signal is not saturated, the system measures signal intensity. When saturated, it switches to measuring pulse width. This parameter change strategy resolves the contradiction by selecting the appropriate measurement parameter for each operating condition, maintaining accuracy across the full detection range.
2Device complexity
If the signal intensity is measured directly in saturated regions, then the measurement process is simplified, but the measurement precision deteriorates due to saturation
Solution Approach 1:
The system dynamically selects the measurement approach based on saturation detection. The saturation determination unit assesses whether the signal is saturated and dynamically switches the measurement method accordingly. This dynamic selection adds complexity only when necessary (in saturated regions), while maintaining simplicity in non-saturated conditions.
Solution Approach 2:
The patent introduces an intermediary measurement parameter (pulse width) that serves as a mediator when direct signal intensity measurement fails due to saturation. The pulse width provides an indirect but accurate way to determine reflected light characteristics in saturated regions, resolving the precision problem without requiring complete system redesign.
3Measurement precision
If the pulse width or falling slope is used to calculate reflection characteristic in saturated regions, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent makes the detection apparatus multi-functional by enabling it to perform both signal intensity measurement (for non-saturated signals) and pulse width/falling slope measurement (for saturated signals). The saturation determination unit acts as a dispatcher that routes to the appropriate measurement function, making the system universally capable of handling all signal conditions without requiring separate dedicated systems.
Solution Approach 2:
The system performs preliminary saturation determination before selecting the measurement method. By assessing the saturation status first, the system can pre-select the appropriate measurement approach, avoiding unnecessary complexity in non-saturated conditions while ensuring precision is maintained in saturated regions. This preliminary action prevents premature application of complex measurement methods.
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 the detection of differences in reflected light intensity even in saturated regions, improving the accuracy of distance measurement and object detection.
Implementation Method 1
measures a distance to a distance measurement target object by projecting pulsed light to the distance measurement target object, receiving reflected light from the target object, and measuring a time from when the pulsed light is projected to when the reflected light is received
Implementation Method 2
a light receiving unit (80) that receives reflected light (Rz) corresponding to the emission light (Lz)
Data Source
AI summary
A light emitting unit emits emission light toward a predetermined emission range. A light receiving unit receives reflected light corresponding to the emission light. A distance calculation unit calculates a distance to the object using a time from the emission of the light to reception of the reflected light. A pulse detection unit detects at least one of a pulse width of the light reception signal at a predetermined threshold or a falling slope of the light reception signal. A reflection characteristic acquisition unit acquires a reflection characteristic including at least one of a reflection intensity or a reflectance of the object. When the light reception signal is saturated, the reflection characteristic acquisition unit acquires the reflection characteristic using at least one of the pulse width or the falling slope.