Photon Counting Sensor Timing for Lower Memory Bit Use
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Solution Overview
Problem
The existing photon measurement sensors require a long shutter time for dark measurements, leading to an increase in memory bits and circuit area due to the need for time-based luminance value prediction.
Innovation Solution
A light-receiving apparatus with a counting unit, a setting unit, and an acquiring unit that measures photon incidence, updates time information based on elapsed time, and acquires time information when a counted value reaches a threshold before the exposure period ends, allowing for variable update cycles and reduced memory bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a long shutter time is set for dark measurements using time-based luminance value prediction, then measurement accuracy in dark conditions is improved, but the number of memory bits and circuit area increase
Solution Approach 1:
The patent applies dynamics by making the update cycle of time information variable rather than fixed. The control unit dynamically adjusts the update cycle based on the current count value relative to the threshold value. When the count value is far from the threshold, a longer update cycle is used; when close to the threshold, a shorter update cycle is used. This dynamic adjustment optimizes both measurement accuracy and memory resource utilization.
Solution Approach 2:
The patent changes the parameter of update cycle length based on the relationship between count value and threshold value. By modifying this temporal parameter dynamically, the system achieves accurate photon counting while reducing the number of bits required for time information storage, thereby reducing circuit area without sacrificing measurement precision.
2Measurement precision
If a long shutter time is set for dark measurements, then measurement accuracy in dark conditions is improved, but the number of memory bits increases
Solution Approach 1:
The system dynamically adjusts the update cycle of time information based on the count value. This dynamic approach ensures that time information is updated frequently enough to maintain measurement accuracy while avoiding unnecessary updates that would require more memory bits, thus optimizing the balance between precision and memory usage.
Solution Approach 2:
By changing the update cycle parameter adaptively, the patent reduces the number of bits needed to represent time information while preserving measurement accuracy. The variable update cycle allows the system to use fewer bits in conditions where high temporal resolution is not critical, while maintaining sufficient resolution when needed.
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 reduces the number of bits required for memory and circuit area while maintaining accurate photon measurement, especially in varying illumination conditions.
Implementation Method 1
a photoelectric conversion element that converts incident light into an electric signal by photoelectric conversion
Data Source
AI summary
A light-receiving apparatus (1a) includes a counting unit (11), a setting unit (12), and an acquiring unit (13). The counting unit is configured to measure a detection number of times that represents the number of times incidence of a photon to a light-receiving element has been detected within an exposure period and to output a counted value. The setting unit is configured to set a cycle of updating time information in accordance with an elapsed time during the exposure period. The acquiring unit is configured to acquire the time information indicating a time at which the counted value reaches a threshold before the exposure period elapses.