Imaging Device Subject Tracking with Dynamic Feedback Gain
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Solution Overview
Problem
Existing imaging systems face challenges in accurately tracking moving subjects, particularly with telephoto lenses, due to image blurring caused by hand shake and detection delays, which affect the precision of subject positioning within the image frame.
Innovation Solution
An imaging device equipped with a subject detecting unit, motion vector acquiring unit, and moving unit that compares the subject image's position with a target position, using motion vectors and correction vectors to adjust the image's position within the frame, thereby reducing movement and improving tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback gain is set to be large to enhance subject trackability, then subject tracking performance is improved, but tracking oscillates depending on photographing conditions
Solution Approach 1:
The patent applies dynamics by making the feedback gain variable rather than fixed. The gain is dynamically adjusted based on detection accuracy and subject movement characteristics. When detection accuracy is high, a larger gain is used to improve tracking responsiveness. When detection accuracy is low or subject movement is rapid, the gain is reduced to prevent oscillation. This dynamic adjustment resolves the contradiction between trackability and stability.
Solution Approach 2:
The patent changes the feedback gain parameter adaptively based on detection conditions. The control unit adjusts the gain value according to detection accuracy metrics and subject movement speed. This parameter change allows the system to optimize tracking performance under different conditions while avoiding oscillation, effectively resolving the contradiction between high trackability and tracking stability.
2Stability of the object's composition
If feedback gain is set to be small to avoid oscillation, then tracking stability is improved, but subject trackability degrades and subject is likely to be missed
Solution Approach 1:
The system dynamically adjusts feedback gain based on real-time detection conditions. When detection accuracy is high and subject movement is slow, a larger gain is applied to maintain subject trackability. When detection accuracy drops or subject moves rapidly, the gain is reduced to maintain stability. This dynamic approach prevents the need to use a consistently small gain, thereby maintaining both stability and trackability.
Solution Approach 2:
The feedback gain parameter is changed adaptively based on detection accuracy and subject movement characteristics. This allows the system to use larger gains when conditions permit (improving trackability) and smaller gains when conditions require it (maintaining stability), resolving the contradiction between these two requirements.
3Extent of automation
If subject detection is performed by analyzing captured image, then detection function is achieved, but detection delay with respect to real time necessarily occurs
Solution Approach 1:
The patent applies preliminary action by performing subject detection on a previous frame while simultaneously acquiring the current frame. The detection result from the previous frame is used to generate prediction information for the current frame, allowing the system to compensate for detection delay. This approach maintains automated detection functionality while reducing the effective delay by using predictive compensation.
Solution Approach 2:
The system uses prediction information generated from previous detection results to cushion against detection delay. By preparing prediction data in advance and using it to compensate for the delay in real-time detection, the system maintains accurate subject tracking despite the inherent delay in image analysis-based detection.
4Measurement precision
If telephoto lens is used to capture moving subject, then subject magnification is improved, but image blurring due to hand shake increases
Solution Approach 1:
The patent applies feedback by using subject tracking information to generate correction vectors that compensate for hand shake. The control unit continuously monitors subject position and adjusts the imaging range or subject position detection to counteract blurring effects. This feedback mechanism allows the system to maintain subject magnification while reducing image blurring caused by hand shake through active compensation.
Solution Approach 2:
The patent replaces mechanical stabilization (physical camera stabilization) with electronic/image processing-based stabilization. By using subject tracking and prediction to generate correction vectors and adjust imaging parameters, the system achieves blurring reduction without requiring mechanical stabilization components, thereby maintaining subject magnification while reducing hand shake effects.
Data Source
AI summary
An imaging device includes a subject detecting unit configured to detect a subject image from a captured image captured by an imaging element; a motion vector acquiring unit configured to acquire a motion vector of the subject image detected by the subject detecting unit, by comparing image signals in different frames acquired by the imaging element; a comparison unit configured to acquire a comparison result, by comparing a position of the subject image detected by the subject detecting unit with a predetermined position; and a moving unit configured to reduce movement of the position of the subject image in the imaging range, by moving the subject image on the basis of the motion vector and the comparison result.