Motion Detection Circuit Using Image Signal Processing
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Solution Overview
Problem
Conventional image devices require additional infrared motion sensors to detect moving objects, increasing cost and size, and often result in incorrect activation due to mismatched detection ranges and fields of view between sensors and image sensors.
Innovation Solution
A motion detection method utilizing an extracting circuit, a buffering circuit, and a comparing circuit within the image signal processor to generate representative data from image signals, comparing current and previous images to determine motion detection results, eliminating the need for additional infrared sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an infrared motion sensor is added to detect moving objects, then motion detection capability is improved, but device cost and size increase
Solution Approach 1:
The patent merges the motion detection function with the existing image sensor and image signal processor by adding a motion detection circuit that processes image signals. This eliminates the need for separate infrared motion sensors while maintaining motion detection capability, thereby reducing device cost and size.
Solution Approach 2:
The image sensor and image signal processor are made multi-functional by enabling them to perform both image capture and motion detection. The motion detection circuit utilizes the same image sensor output to generate motion detection results, allowing one component to serve multiple purposes.
2Reliability
If an infrared motion sensor is used for motion detection, then motion detection function is achieved, but detection range mismatches with image sensor field of view
Solution Approach 1:
By merging the motion detection function with the image sensor system, the patent ensures that both motion detection and image capture share the same field of view. The motion detection circuit processes signals from the same image sensor that captures the image, guaranteeing spatial alignment between detection and capture areas.
Data Source
AI summary
A motion detection method includes an extracting circuit generating a first representative data according to a first image in an image signal outputted by an image sensor, a buffering circuit storing the first representative data, the extracting circuit generating a second representative data according to a second image in the image signal, the buffering circuit storing the second representative data and outputting the first representative data to a comparing circuit, and the comparing circuit comparing the first representative data and the second representative data, to generate a motion detection result. When the motion detection result represents “motion”, an image-signal-processing circuit of an image signal processor enters active state to generate output signal. By means of the motion detection method, in an imaging device, the image-signal-processing circuit of the image signal processor can switch between active state and power-off/power-saving state even when there is no additional infrared sensor.