Imaging Device Dual Accumulator Signal Charge Separation
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Solution Overview
Problem
Conventional imaging devices face challenges in detecting internal information of a target object due to low signal-to-noise ratio and inability to acquire two-dimensional spatial information, particularly when detecting weak biological signals like cerebral blood flow, as most components of detected light are surface-reflected, and existing methods are expensive and limited to one-dimensional information.
Innovation Solution
An imaging device with a first light source emitting pulsed near-infrared light and an image sensor with multiple accumulation units, where the controller manages signal charge accumulation and discharge to separate surface-reflected and internally scattered components, allowing for accurate detection of internally scattered light by eliminating noise from surface-reflected components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging devices detect light from target objects, then internal information can be acquired, but the signal-to-noise ratio is low due to dominant surface-reflected components
Solution Approach 1:
The imaging device segments the detection process into two distinct time periods: a first period for detecting surface-reflected components and a second period for detecting internally scattered components. By temporally separating these detections and using dual accumulators to store respective signal charges, the device can later subtract the surface-reflected signal from the internally scattered signal, effectively eliminating noise and improving the signal-to-noise ratio for internal information detection.
2Measurement precision
If conventional methods use streak cameras for depth information detection, then internal information can be obtained, but the device complexity and cost increase significantly
Solution Approach 1:
The patent uses a standard CMOS or CCD image sensor instead of a specialized streak camera, copying the successful detection approach of conventional imaging devices to a new application. By adding temporal gating control and dual accumulators to a conventional sensor, the device achieves depth-resolved imaging functionality without the high complexity and cost of streak cameras, making the technology more accessible and practical.
3Measurement precision
If conventional imaging devices capture all incident light, then detection sensitivity is maximized, but spatial information resolution is lost
Solution Approach 1:
The patent adds a temporal dimension to the detection process by dividing the detection into two time periods with different accumulation modes. The first accumulator captures spatial information during the first period, while the second accumulator captures spatial information during the second period. This temporal dimensioning allows the device to resolve both surface and internal components while preserving two-dimensional spatial information that would be lost in conventional integrated detection.
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 device achieves high accuracy in detecting biological information like cerebral blood flow with improved signal-to-noise ratio and two-dimensional imaging, reducing unnecessary signal components and enhancing detection precision compared to conventional methods.
Implementation Method 1
each of the pixels including a photoelectric conversion element that, in operation, converts incident light into signal charge
Data Source
AI summary
An imaging device includes a light source, an image sensor, and a controller. Each pixel of the image sensor includes first and second accumulators and a discharger. The controller, while a component of light from the light source reflected by the surface of a target is incident on the image sensor, causes the accumulators to accumulate signal charge not discharged to the discharger, by setting the image sensor so that signal charge is discharged to the discharger, while a component having scattered inside the target is incident on the image sensor, causes the first accumulator to accumulate signal charge by setting the image sensor so that signal charge is not discharged to the discharger and signal charge is accumulated in the first accumulator, and causes the image sensor to generate first and second signals that are respectively based on signal charge accumulated in the first and second accumulators.