Auto-Focus Distance Estimation for Flash and Image Stabilization Control
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Solution Overview
Problem
Lower cost digital cameras, such as those in mobile terminals, face complexity and cost issues in adjusting flash and image stabilization based on scene characteristics, making existing systems impractical for multifunction devices.
Innovation Solution
Implementing an automatic focus system to determine subject distance, which selectively enables image stabilization and flash based on exposure time and distance, allowing for different exposure settings and flash usage within or beyond a maximum flash range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flash and image stabilization are controlled based on scene characteristics and distance, then image quality under varying lighting conditions is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the automatic focus (AF) system's distance measurement capability with the automatic exposure (AE) system's flash control function. The AF system, which already exists for focusing purposes, is repurposed to provide distance information for flash and image stabilization control, eliminating the need for separate sensing systems and reducing overall device complexity while maintaining reliable image quality across varying conditions.
2Measurement precision
If separate sensing systems are added for flash control, then flash operation accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the automatic focus system serve multiple functions: it continues to provide focusing capability while simultaneously providing distance measurement information for flash control and image stabilization. This multi-functional use of the AF system eliminates the need for dedicated separate sensing systems, maintaining measurement precision while reducing device complexity and cost.
Data Source
AI summary
A distance to a subject in a scene is determined using an automatic focus (AF) system of a digital camera. Image stabilization and flash are selectively automatically enabled based on the determined distance to capture an image of the scene. For example, in some embodiments, an exposure time for the scene may be determined using an automatic exposure (AE) system of the digital camera, and selective use of image stabilization and flash may involve, responsive to the determined exposure time exceeding the maximum exposure time, capturing an image of the scene using the determined exposure time with image stabilization if the determined distance exceeds a maximum flash range or capturing an image of the scene using a predetermined exposure time with flash if the determined distance is within the maximum flash range.