Pulsed Light Imaging Sensor Sensitivity Control
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Solution Overview
Problem
Current imaging techniques face challenges in accurately detecting internal information of objects, particularly in living bodies, due to high-intensity surface reflection components that interfere with the detection of weaker internal dispersion components, leading to low signal-to-noise ratios and reduced spatial resolution.
Innovation Solution
An imaging apparatus that emits first and second pulsed light, with a control circuit adjusting the sensitivity of image sensor pixels to minimize light leakage noise by decreasing sensitivity during surface reflection component incidence and increasing it during internal dispersion component incidence, using a ternary voltage control method to optimize signal charge transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image sensor continuously detects light signals, then the detection capability is maintained, but noise from surface reflection components increases and reduces measurement precision
Solution Approach 1:
The patent applies periodic action by controlling the image sensor to operate in discrete detection periods synchronized with pulsed light emission. The sensor detects light signals only during specific time windows when internal dispersion components are expected to arrive, and remains inactive during periods when surface reflection components dominate. This periodic detection strategy effectively filters out surface reflection noise while capturing the weaker internal dispersion signals, thereby improving measurement precision without continuous operation.
2Measurement precision
If the sensitivity of pixels is increased to detect weak internal dispersion components, then detection capability improves, but light leakage noise from surface reflection components increases
Solution Approach 1:
The patent implements periodic action by enabling the image sensor to alternate between high-sensitivity detection modes and low-sensitivity or inactive states. During detection periods when internal dispersion components are expected, the sensor operates at high sensitivity to capture weak signals. During other periods when surface reflection components are dominant, the sensor reduces sensitivity or remains inactive, preventing light leakage noise from overwhelming the system. This time-varying sensitivity control resolves the contradiction between detecting weak signals and avoiding noise saturation.
Solution Approach 2:
The patent applies preliminary action by predicting the arrival times of internal dispersion components based on the known light propagation characteristics and detecting only during these predetermined time windows. The control circuit is pre-programmed with the expected detection periods, allowing the sensor to be in high-sensitivity mode only when needed. This preliminary planning of detection timing ensures that high sensitivity is applied precisely when internal dispersion components arrive, while avoiding high sensitivity during surface reflection periods, thus preventing light leakage noise.
3Measurement precision
If pulsed light is emitted continuously to maintain detection, then signal availability is improved, but the ability to distinguish internal components from surface reflections deteriorates
Solution Approach 1:
The patent employs periodic action by emitting pulsed light at regular intervals and synchronizing the image sensor's detection windows with the expected arrival times of internal dispersion components. Each pulse generates a detection event, and the system accumulates data across multiple pulses. This periodic emission and detection strategy maintains signal availability while using temporal gating to distinguish internal components from surface reflections, improving signal-to-noise ratio without requiring continuous illumination that would blur temporal distinctions.
Solution Approach 2:
The patent applies continuity of useful action by maintaining a high duty cycle of pulsed light emission and detection, where pulses are emitted frequently enough to provide continuous data flow. Although the light is pulsed rather than continuous, the high repetition rate ensures that detection is ongoing without significant gaps. This maintains signal availability and allows real-time monitoring while preserving the temporal resolution needed to distinguish internal dispersion components from surface reflections through the timing of each pulse-detection cycle.
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 detection accuracy of internal dispersion components by reducing noise from surface reflection components, allowing for higher resolution brain activity measurements without the need for physical contact or spatial separation of light sources and detectors.
Implementation Method 1
a time at which the first pulsed light starts arriving at the pixels after being reflected by the object
Implementation Method 2
an image sensor including pixels
Data Source
AI summary
When a time at which a first pulsed light starts arriving at pixels after being reflected by an object is a first time, a time at which the first pulsed light finishes arriving at the pixels is a second time, and a time at which a second pulsed light starts arriving at the pixels after being reflected by the object is a third time, a control circuit decreases sensitivity of the pixels in first part of a first period from the first time including the second time, to a level lower than the sensitivity of the pixels in at least part of a second period after the first period and up to the third time, and increases the sensitivity of the pixels in second part of the first period, to a level higher than the sensitivity of the pixels in the at least part of the second period.