Instant Auto-Focus Camera Distance Estimation
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Solution Overview
Problem
Existing auto-focus mechanisms in cameras often face a trade-off between accuracy and speed, leading to prolonged start-to-shot times due to the time-consuming process of determining and adjusting the focus position, which negatively impacts user experience.
Innovation Solution
A camera system incorporating an image sensor, movement and/or orientation sensors, a timer, and a control circuit that calculates distances and adjusts the lens position based on movement and orientation data to achieve rapid auto-focus, allowing for quick focus adjustment without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional auto-focus mechanisms (contrast or phase detection) are used, then the focus accuracy can be achieved, but the start-to-shot time becomes too long
Solution Approach 1:
The system performs preliminary distance estimation using passive stereo vision before the actual photo capture is triggered. By calculating the distance to the subject in advance (during the viewfinder or display phase), the lens can be pre-positioned or quickly adjusted when the shutter is pressed, eliminating the need for time-consuming focus search at the moment of capture.
Solution Approach 2:
The patent introduces an intermediary distance estimation mechanism that uses passive stereo vision (comparing images from slightly different angles captured by the sensor array) to infer subject distance. This intermediary measurement allows the system to determine focus position without relying solely on traditional active methods like laser ranging, thus reducing time while maintaining accuracy.
2Loss of time
If laser auto-focus is used to quickly estimate distance, then the start-to-shot time is reduced, but the device complexity and energy consumption increase
Solution Approach 1:
The system uses the camera's existing image sensor array to perform both image capture and distance estimation functions. The same sensor that captures the scene also provides the data needed for stereo vision-based distance calculation, eliminating the need for separate laser ranging hardware and reducing overall device complexity.
Solution Approach 2:
The image sensor array is made multi-functional by using it not only for capturing images but also for performing passive stereo vision calculations to estimate distance. This universal use of the sensor eliminates the need for dedicated laser or ultrasonic distance measurement components, simplifying the device architecture.
3Measurement precision
If contrast auto-focus is used to ensure accurate focus, then the focus precision is maintained, but the convergence speed becomes slow
Solution Approach 1:
The system performs preliminary distance estimation using passive stereo vision before the actual photo capture is triggered. By calculating the distance to the subject in advance (during the viewfinder or display phase), the lens can be pre-positioned or quickly adjusted when the shutter is pressed, eliminating the need for time-consuming focus search at the moment of capture.
Solution Approach 2:
The patent replaces the mechanical iterative search process of contrast auto-focus with a computational approach using passive stereo vision. Instead of mechanically moving the lens back and forth to find the focus point by measuring contrast changes, the system uses image processing algorithms to calculate the optimal focus position based on distance estimation from stereo pairs, significantly speeding up convergence.
Data Source
AI summary
Systems, apparatuses, and methods for implementing an instant auto-focus mechanism with distance estimation are disclosed. A camera includes at least an image sensor, one or more movement and/or orientation sensors, a timer, a lens, and control circuit. The control circuit receives first and second images captured by the image sensor of a given scene. The control circuit calculates a distance between first and second camera locations when the first and second images, respectively, were captured based on the one or more movement and/or orientation sensors and the timer. Next, the control circuit calculates an estimate of a second distance between the camera and an object in the scene based on the distance between camera locations and angles between the camera and the object from the first and second locations. Then, the control circuit causes the lens to be adjusted to bring the object into focus for subsequent images.