Light-Based Distance Measurement With Sequential Microcell Windows
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Solution Overview
Problem
Existing distance-measuring devices using single-photon photosensitive microcells, such as SPADs or SNSPDs, suffer from non-linear responses due to dead time and saturation, leading to inaccurate measurements, especially in high-intensity light conditions, requiring large storage and computational resources for histogram processing.
Innovation Solution
A measuring device with a processing group that implements sequential observation time windows, alternating between active and inactive phases of photosensitive microcells to achieve a linear response, allowing for precise distance calculations without histogram storage or complex processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-photon photosensitive microcells are used for distance measurement, then measurement precision is improved, but non-linear response due to dead time causes measurement accuracy to deteriorate under high-intensity light conditions
Solution Approach 1:
The patent applies periodic action by implementing sequential observation time windows where photosensitive microcells are alternately activated and deactivated. This periodic switching prevents continuous exposure to high-intensity light, eliminating saturation effects and dead time non-linearities while maintaining precise distance measurement capability through systematic sampling across multiple cycles.
Solution Approach 2:
The patent implements dynamics by making the activation state of photosensitive microcells time-dependent rather than static. The processing group dynamically controls each microcell's operational state, switching between active and inactive phases based on predetermined time windows, thereby adapting the system's response characteristics to prevent saturation while preserving measurement precision.
2Measurement precision
If histogram processing is used to correct non-linear response, then measurement accuracy is improved, but device complexity and computational resources increase
Solution Approach 1:
The patent applies preliminary action by pre-defining sequential observation time windows and the activation/deactivation schedule for photosensitive microcells before measurement begins. This predetermined temporal structure eliminates the need for post-measurement histogram processing and complex computational corrections, as the linear response is achieved through the initial design of the measurement protocol rather than subsequent data processing.
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 accurate distance measurements with reduced computational and storage needs, overcoming saturation limits and maintaining precision even in intense background noise conditions.
Implementation Method 1
each of which is configured to generate an electrical signal following the impact of at least a single photon on its sensitive surface
Implementation Method 2
emission means for emitting a light radiation in direction of a reference object
Data Source
AI summary
A device for measuring the distance (d) of a reference object (O) includes an emitter for emitting a light radiation (R), a receiver including an area sensitive to the light radiation (R), the sensitive area being provided with one or more photosensitive microcells, and a processing group configured to perform the measurement by implementing a first acquisition step including starting a plurality (n) of consecutive observation time windows (i) while keeping the emitter deactivated, a second acquisition step including starting a plurality (m) of consecutive observation time windows (y) by activating the emitter, and a step of defining the time of flight (ToF) value of the measurement based on processing the detection times acquired in the second acquisition step and the detection times (tbgi) acquired in the first acquisition step.