Solid-State Image Sensor Internal Trigger Generation
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Solution Overview
Problem
High-speed imaging devices face challenges in detecting movements or changes in objects without using complex optical systems, leading to delayed trigger signal generation and increased production costs, especially when capturing high-speed phenomena like explosions or combustions.
Innovation Solution
A solid-state image sensor with a floating diffusion and source follower amplifier configuration allows for high-speed imaging by storing and reading pixel signals within the sensor, enabling the detection of object changes through frame difference calculations, reducing blurring effects and time delays, and generating trigger signals internally without external sensors or optical systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time image processing is performed on images reproduced from the solid-state image sensor to detect object movement and generate trigger signals, then trigger signal generation is achieved, but the delay time from phenomenon occurrence to trigger signal generation increases due to external frame memory preservation and large computation requirements
Solution Approach 1:
The patent applies preliminary action by performing frame difference calculations between the current frame and previous frame during the imaging process itself, before the imaging operation is discontinued. This allows trigger signal generation to occur with minimal delay, as the comparison data is already prepared and stored in the solid-state image sensor's internal memory rather than requiring post-processing from external frame memory.
Solution Approach 2:
The patent extracts only the necessary pixel signal data required for frame difference calculation directly from the solid-state image sensor's internal storage, rather than preserving and processing complete images in external frame memory. This selective extraction reduces computation requirements and accelerates trigger signal generation while maintaining detection accuracy.
2Measurement precision
If another sensor (contact sensor, position sensor, vibration sensor, or pressure sensor) is used to generate trigger signals, then trigger signal generation is achieved, but the system complexity increases and the sensor cannot be easily placed close to the object in some situations
Solution Approach 1:
The patent applies multi-functionality by enabling the solid-state image sensor to perform both its primary imaging function and the secondary function of generating trigger signals through internal frame difference calculation. This eliminates the need for separate external sensors and reduces system complexity, as the same device that captures images also detects object movement and generates triggering events.
Solution Approach 2:
The patent merges the trigger signal generation function with the imaging function by integrating frame difference calculation capabilities directly into the solid-state image sensor. This combination consolidates multiple functions into a single device, reducing the number of components needed and simplifying the overall system architecture.
3Measurement precision
If light-splitting means (beam splitter or half mirror) is used to separate incident light into plural beams for monitoring and imaging, then trigger signal generation through motion detection is achieved, but the system becomes large and complex, increasing production cost and system size
Solution Approach 1:
The patent replaces the mechanical/optical light-splitting system with an electronic processing approach. Instead of using physical beam splitters or half mirrors to separate light paths for monitoring and imaging, the system uses electronic frame difference calculation on digitally captured images. This substitution eliminates complex optical components while achieving the same motion detection objective.
Solution Approach 2:
The patent uses digital copying of image data within the solid-state sensor to create a virtual monitor channel. By storing and comparing previous frame data with the current frame, the system creates an electronic copy of the imaging function for motion detection purposes, eliminating the need for physical light path duplication through optical splitting components.
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 enables quick and accurate detection of object changes, reducing time delays and production costs by allowing internal trigger signal generation and continuous imaging during sequential reading, effectively capturing high-speed phenomena without the need for complex optical systems.
Implementation Method 1
pixel signals resulting from photoelectric conversion by the photodiode
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A pixel output line (14) is independently provided for each of the pixels arranged in a two-dimensionally array within a pixel area so that pixel signals can be sequentially written in a plurality of memory sections (22) through the pixel output lines (14). When a plurality of frames of pixel signals are held in the memory sections (22), the pixel signals corresponding to two arbitrarily selected frames are read and respectively stored in sample-and-hold circuits (61 and 62), and their difference is obtained. Then, the difference signals corresponding to a predetermined range of the image are integrated, and the integrated value is compared with a threshold. If the integrated value exceeds the threshold, it is presumed that a change in an imaging object has occurred, and a pulse generation circuit (66) generates a trigger signal. By controlling the discontinuation and other imaging actions according to this trigger signal, it is possible to correctly take high-speed images of the situation before or after the occurrence of an objective phenomenon.