Solid-State Imaging Element Photon Histogram Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional time of flight (ToF) distance measurement methods in electronic devices suffer from decreased accuracy due to noise and disturbances such as background light or instantaneous light emission from external sources, which affect the signal-to-noise ratio and measurement precision.
Innovation Solution
A solid-state imaging element that includes a photon number detection unit, a histogram generation unit, and a distance measurement unit, where the histogram generation unit generates individual histograms for each number of photons and synthesizes them based on variation thresholds, and optionally uses weighted addition or selects the histogram with the minimum standard deviation to suppress noise and disturbances, improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If histograms for respective pixels are synthesized to improve S/N ratio, then signal-to-noise ratio is improved, but measurement accuracy decreases due to noise and disturbance
Solution Approach 1:
The patent segments the histogram data by creating multiple individual histograms for different numbers of photons (0 photons, 1 photon, 2 photons, etc.) rather than synthesizing all pixel histograms into a single combined histogram. This segmentation allows selective processing where only histograms with sufficient signal quality are synthesized, while others are processed individually to avoid noise contamination.
Solution Approach 2:
The patent changes the processing parameter from a uniform synthesis approach to a conditional approach based on the number of detected photons. By setting a threshold value for the number of photons, the system dynamically adjusts whether to perform histogram synthesis or individual histogram processing, optimizing the balance between S/N ratio improvement and measurement accuracy.
2Measurement precision
If all individual histograms are synthesized to improve measurement accuracy, then distance measurement accuracy is improved, but amount of calculation increases
Solution Approach 1:
The patent applies partial synthesis by selectively synthesizing only those individual histograms that meet a predetermined threshold condition (number of photons ≥ threshold). Histograms below the threshold are processed individually without synthesis. This partial action reduces the total calculation amount while still achieving accurate distance measurement for the significant photon events.
Solution Approach 2:
The patent introduces a threshold parameter for the number of photons that controls the degree of histogram synthesis. By adjusting this threshold, the system can optimize the balance between calculation amount and measurement accuracy based on specific application requirements, enabling flexible adaptation to different computational resource constraints.
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 enhances distance measurement accuracy by reducing the influence of noise and disturbances, leading to more precise distance calculations in electronic devices using the ToF method.
Implementation Method 1
a photon number detection unit that detects the number of photons incident on a pixel array unit
Implementation Method 2
a time to a peak of a synthesized histogram is converted into a distance... measuring a distance by irradiating an object with irradiation light from a distance measurement device and obtaining a round-trip time until the irradiation light is reflected and returned
Data Source
AI summary
In a solid-state imaging element that measures a distance, distance measurement accuracy is improved.The solid-state imaging element includes a photon number detection unit, a histogram generation unit, and a distance measurement unit. The photon number detection unit detects the number of photons incident on a pixel array unit over a predetermined number of times and outputs a detection result including the number of photons and a detection timing. The histogram generation unit generates, for each number of photons, a histogram indicating a detection frequency of the number of photons as a frequency for each detection timing, on the basis of the detection result. The distance measurement unit measures a distance to a predetermined object on the basis of the histogram generated.