Predictive Focus Value Calculation for Auto-Focus Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional auto-focus processes in image capture devices are slow due to the need to wait for valid frames after lens settlement to calculate focus values, leading to increased latency in determining the optimal lens position for sharp focus.
Innovation Solution
Implementing a predictive auto-focus module that calculates a corrupt focus value from the first frame after lens settlement and predicts a valid focus value, allowing the lens to move to the next position during the second frame, thereby reducing latency by potentially doubling or tripling the speed of the auto-focus process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the auto-focus process waits for valid frames after lens settlement to calculate focus values, then the focus value calculation is accurate, but the auto-focus latency increases significantly
Solution Approach 1:
The patent applies preliminary action by calculating a corrupt focus value from the first frame immediately after lens settlement, before waiting for valid frames. This preliminary calculation uses the corrupt focus value (which includes motion blur) to predict the valid focus value, allowing the system to determine the next lens position in advance rather than waiting for the conventional 2-3 frame delay.
Solution Approach 2:
The patent introduces an intermediary approach by using the corrupt focus value as a mediator to predict the valid focus value. Instead of directly using the valid focus value (which requires waiting), the system uses the corrupt focus value as an intermediate step to estimate what the valid focus value would be, thereby reducing latency while maintaining acceptable accuracy.
2Adaptability or versatility
If the lens moves to each sampled position independently and asynchronously, then the lens positioning is flexible, but the auto-focus process speed is limited by frame validation delays
Solution Approach 1:
The patent applies continuity of useful action by eliminating the idle waiting period between lens movements. Instead of waiting for 2-3 frames to pass before moving to the next lens position, the system continuously performs useful actions by calculating corrupt focus values and predicting valid focus values without interruption, thereby doubling or tripling the auto-focus process speed while maintaining lens positioning flexibility.
3Reliability
If the first valid frame is waited for after lens settlement, then the focus value is reliable, but the time to obtain a valid focus value increases by 2-3 frames
Solution Approach 1:
The patent applies feedback by using the corrupt focus value (obtained from the first frame after lens settlement) to predict the valid focus value. This feedback mechanism allows the system to estimate the reliable focus value without waiting for the conventional 2-3 frame delay, thereby reducing time loss while maintaining focus value reliability through the prediction algorithm.
Data Source
AI summary
Techniques are described for predictive focus value calculation within image capture devices. Image capture devices may include digital still cameras and digital video cameras. The techniques include performing an auto-focus process within an image capture device by predicting a focus value for a scene at a lens position of a lens included in the image capture device based on a corrupt focus value for the lens position calculated from a first frame directly after lens settlement. Therefore, the auto-focus process may determine size and direction of movement for the lens to a next lens position based on the predicted valid focus value, and move the lens to the next lens position during a second frame. In this way, the techniques may move the lens to another lens position during each frame, greatly reducing auto-focus latency by potentially doubling or tripling the speed of the auto-focus process.