Imaging Device Clock Frequency Control for Power Reduction
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Solution Overview
Problem
Monitoring camera systems face high power consumption and require expensive, high-capacity memory for storing imaging data, as they continuously capture images without efficiently detecting changes in uneventful environments.
Innovation Solution
An imaging device with a circuit configuration that lowers clock frequency when no change is detected between frames, using oxide semiconductor transistors and a comparison circuit to determine frame differences, allowing for reduced power consumption and memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous imaging is performed to monitor uneventful environments, then monitoring reliability is improved, but power consumption increases
Solution Approach 1:
The imaging device performs imaging at different frame rates based on whether image changes are detected. When no changes are detected, imaging is performed at a lower frame rate (e.g., 1 frame per second), and when changes are detected, imaging switches to a higher frame rate (e.g., 30 frames per second). This periodic adjustment of operation intensity resolves the contradiction by maintaining monitoring reliability through continuous imaging while reducing power consumption during stable periods.
Solution Approach 2:
The device dynamically adjusts its operating state based on real-time conditions. A comparison circuit continuously monitors image changes between frames and dynamically switches between two operational modes: a low-power mode for stable environments and a high-performance mode for changing environments. This dynamic adaptation allows the system to maintain reliability while optimizing power consumption according to actual monitoring needs.
2Quantity of substance
If high-capacity memory is used to store imaging data, then data storage capacity is improved, but device cost increases
Solution Approach 1:
The patent extracts only the essential imaging data that contains meaningful information. By using a comparison circuit to detect image changes, the system identifies and extracts only those frames that contain new information, discarding redundant duplicate frames. This extraction approach reduces the total data volume requiring storage, allowing the use of lower-capacity, less expensive memory devices while still maintaining effective monitoring capabilities.
3Speed
If clock frequency is maintained at high level for continuous imaging, then imaging speed is improved, but power consumption increases
Solution Approach 1:
The clock frequency is adjusted periodically based on monitoring conditions. During periods when no image changes are detected, the clock frequency is reduced to a lower level (e.g., 1/30th of the original frequency), and when changes are detected, the frequency returns to the higher level. This periodic modulation of clock frequency maintains imaging speed capability while significantly reducing average power consumption during stable monitoring periods.
Data Source
AI summary
An imaging device with low power consumption. The imaging device includes a plurality of pixels arranged in a matrix, a first circuit, a second circuit, a third circuit, and a fourth circuit. The first circuit has a function of converting an analog signal into a digital signal. The second circuit has a function of detecting a difference between image data of a first frame and image data of a second frame. The third circuit has a function of controlling the frequency of a clock signal. The fourth circuit has a function of generating clock signals of a plurality of frequencies.