Optical Ranging Apparatus Synchronizing Signal Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ranging apparatuses based on optical Time Of Flight (TOF) technology require complex drive circuits and are burdensome for the CPU due to the need for precise timing adjustments and calibration when measuring phase delays of reflected light across multiple exposure periods.
Innovation Solution
A ranging apparatus with a synchronizing signal generator, light-emitting and light-detecting units, and a synchronizing signal control unit that simplifies the circuit by maintaining a constant interval for synchronizing signals, allowing exposure periods to be adjusted based on external control signals without changing the timing of the synchronizing signal arrival, thereby reducing the need for calibration and CPU burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the arrival time of synchronizing signals is adjusted for each exposure period to measure phase delays at different phases, then measurement precision is improved, but device complexity increases due to complex drive circuits and calibration requirements
Solution Approach 1:
The patent introduces a synchronizing signal control unit as an intermediary component that manages the timing coordination between light emission and exposure periods. This control unit generates synchronizing signals with progressively delayed arrival times at the image capturing device, enabling phase delay measurement without requiring complex adjustments to the light source timing. The intermediary control unit simplifies the overall system architecture by centralizing the timing control function.
2Measurement precision
If multiple exposure periods with different timing are used to detect phase delay, then measurement precision is improved, but productivity decreases due to increased calibration time and CPU burden
Solution Approach 1:
The patent employs periodic action by using multiple exposure periods with regularly spaced phase delays (e.g., 0°, 90°, 180°, 270°) to measure the reflected light amplitude at different phases. This periodic sampling approach enables accurate phase delay determination through systematic amplitude comparison while maintaining efficient processing. The regular periodic pattern simplifies the calculation algorithm and reduces CPU burden compared to arbitrary timing schemes.
3Adaptability or versatility
If the timing of synchronizing signals is changed for each exposure period, then adaptability is improved, but ease of operation worsens due to calibration requirements
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal arrival times of synchronizing signals for different exposure periods in a table or memory structure. Instead of performing real-time calculations or manual calibration during operation, the system has the timing parameters prepared in advance. This preliminary preparation enables the ranging apparatus to adapt to different measurement conditions while maintaining ease of operation, as the control unit simply retrieves pre-determined timing values rather than computing them on-the-fly.
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
The solution simplifies the circuitry and reduces CPU load by allowing exposure periods to be adjusted without recalibrating the timing, enabling efficient and accurate distance measurement from the ranging apparatus to objects.
Implementation Method 1
a light source 200 in the form of an LED array, for example, for emitting intensity-modulated light (modulated light)
Implementation Method 2
reflected light from an object 202 irradiated with the modulated light from the light source 200
Implementation Method 3
the amount of reflected light R at the time the phase of the modulated light W is 0° is photoelectrically converted into an electric charge
Data Source
AI summary
A first ranging apparatus includes a synchronizing signal generator for generating a synchronizing signal at a constant interval, a light-emitting unit for emitting an intensity-modulated light in response to the synchronizing signal input thereto, a light-detecting unit for detecting a reflected light from an object irradiated with the modulated light, in response to the synchronizing signal input thereto, a calculating unit for calculating the distance up to the object based on the phase difference between the modulated light and the reflected light, and a synchronizing signal control unit for changing an arrival time of the synchronizing signal from the synchronizing signal generator at the light-detecting unit, depending on the number of times that the synchronizing signal is generated. The light-detecting unit samples the amount of the reflected light in exposure periods established at a constant cycle length with reference to a time at which the synchronizing signal is input thereto.