Spatial Information Detection Device Using Random Modulation
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Solution Overview
Problem
Existing spatial information detection devices face challenges in accurately detecting spatial information when unintended objects, such as transparent objects or objects in the vicinity, interfere with the light path, leading to inaccurate measurements due to reflected light from these objects.
Innovation Solution
A spatial information detection device that employs a modulation signal with high and low level periods of randomly selected lengths, a demodulation signal with the same or inverted waveform, and a correction information provision unit to generate and apply correction information, allowing the calculation unit to differentiate between intended and unintended light signals and correct for interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a constant period intensity-modulated light is used for distance measurement, then the phase difference can be measured to calculate distance, but the measurable range is limited to half the period distance (maximum measuring distance)
Solution Approach 1:
The patent applies dynamics by changing the modulation period of the light signal dynamically. The modulation period is varied to be longer than the round-trip time of light to the farthest target, allowing the system to adapt to different distances. This dynamic adjustment of the modulation period enables the system to extend its measurable range beyond the fixed half-period limitation while maintaining phase difference measurement accuracy.
2Measurement precision
If environmental light is eliminated by using difference between light projection period and non-light projection period, then only signal light component is detected, but the detection time is doubled due to alternating periods
Solution Approach 1:
The patent applies preliminary action by performing correlation processing between the received light signal and the modulation signal in advance. This correlation processing enables the system to identify and extract the signal light component without requiring separate light projection and non-light projection periods. The preliminary correlation analysis allows the system to eliminate environmental light interference while maintaining full-time detection capability.
3Speed
If light is emitted continuously to improve detection speed, then response time is reduced, but unintended objects in the vicinity cause interference and reduce measurement accuracy
Solution Approach 1:
The patent applies feedback by using correlation processing to continuously monitor and identify the modulation signal characteristics in the received light. The system compares the received signal with the expected modulation pattern and adjusts its detection accordingly. This feedback mechanism allows the system to maintain continuous light emission for fast response while using correlation analysis to filter out interference from unintended objects and preserve measurement accuracy.
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 enhances the accuracy of spatial information detection by effectively eliminating the effects of unintended objects, improving the detection of distance and reflection intensity by isolating the intended signal from the interference caused by unintended objects.
Implementation Method 1
a light projecting unit configured to emit signal light to a space including a predetermined intended area
Implementation Method 2
a light receiving unit configured to receive light from the space
Data Source
AI summary
The spatial information detection device emits, to a space including an intended area, signal light defined as light modulated with a modulation signal defined as a square wave signal having high and low level periods appearing alternately, each of the periods having its length randomly selected from integral multiples of a unit time period. The device generates signal electric charges by accumulating electric charges generated in response to light from the space in a collection time period determined by a demodulation signal defined as a signal having the same waveform as that of the modulation signal or that of the inverted modulation signal. The device corrects, using correction information regarding an effect caused by light from an unintended area, the amount of signal electric charges as an amount of intended electric charges produced in response to light from the intended area, thereby generating spatial information.