Endoscopic Sensor Synchronization via Feedback Control
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Solution Overview
Problem
Endoscopes with CMOS image sensors face challenges in maintaining a stable clock signal due to manufacturing and environmental fluctuations, and lack methods to synchronize multiple sensors with an external clock or each other, leading to artifacts in 3D image capture.
Innovation Solution
The endoscopic arrangement includes control electronics that detect and adjust the sensor clock, frame rate, and image phase of each image sensor to synchronize them with a reference clock, using supply voltage regulation and configuration data transmission via the image data interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an autonomous CMOS oscillator is used in the image sensor, then the sensor can operate independently without external clock lines, but the sensor clock becomes unstable and strongly influenced by manufacturing fluctuations and operating conditions
Solution Approach 1:
The patent implements a feedback mechanism where the sensor transmits its generated clock signal or frame rate information to the control electronics, which then detect deviations from the reference clock and send adjustment commands back to the sensor. This closed-loop feedback system allows the autonomous sensor to maintain synchronization despite manufacturing variations and environmental conditions.
Solution Approach 2:
The patent adjusts the sensor clock frequency by changing operational parameters, specifically by modifying the supply voltage or transmitting configuration data that alters the oscillator characteristics. This allows dynamic adjustment of the clock frequency to match the reference clock despite initial manufacturing tolerances and temperature variations.
2Adaptability or versatility
If multiple image sensors operate autonomously with independent clocks, then each sensor can function independently, but the sensors cannot be synchronized with each other or with an external clock, leading to artifacts in 3D image capture
Solution Approach 1:
The control electronics detect the sensor clock or frame rate transmitted by each sensor and compare it with the reference clock and other sensors. Based on this feedback, the control electronics generate adjustment commands to synchronize all sensors, eliminating timing discrepancies that would cause artifacts in 3D imaging while maintaining autonomous operation.
Solution Approach 2:
The patent uses the existing image data interface for multiple purposes: transmitting image data, transmitting clock/frame rate information for detection, and sending configuration commands for adjustment. This multi-functional use of the data interface enables synchronization without requiring additional dedicated communication channels.
3Reliability
If additional clock lines and sensor contacts are added to achieve stable clocking, then clock stability improves, but the device complexity and number of required connections increase
Solution Approach 1:
The patent makes the existing data interface multi-functional by using it to transmit both image data and clock/frame rate information. The control electronics extract timing information from the transmitted data stream, eliminating the need for separate clock lines and reducing the number of required sensor contacts while maintaining synchronization.
Solution Approach 2:
The patent uses the transmitted image data or embedded synchronization signals as an intermediary carrier to convey timing information. Instead of direct clock line connections, the clock frequency and phase information is embedded in or transmitted alongside the image data, allowing the control electronics to detect and adjust sensor timing without additional physical connections.
Data Source
AI summary
The endoscopic arrangement (10) is provided with a plurality of image sensors (11), a distal end (10a) and a proximal end (10b). Each of the image sensors is arranged to generate a proper sensor clock, which can be influenced by control electronics at the proximal end of the endoscope arrangement so that such sensor, or a plurality of such sensors, can be operated synchronously with each other or synchronously with a clock set externally. The control electronics is provided with mechanism for detecting the sensor clock and/or the sensor frame rate and/or the sensor image phase and adjusting the detected information to a reference clock.