Image Capture for Post-Capture Refocusing
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Solution Overview
Problem
Existing camera technologies lack the ability to refocus or manipulate focus after capturing an image, especially when the initial focus is on an unintended object, and they cannot create images with all objects in focus, which limits creative freedom for photographers.
Innovation Solution
A method that estimates a distance map of the scene during preview, captures a set of images focused at principal depths, and processes these images to produce an output image for refocusing or focus manipulation, using a small number of images instead of the entire range of focus positions, thereby reducing storage and processing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plenoptic camera is used to enable refocusing at any point after shooting, then focus manipulation capability is improved, but device complexity and sensor requirements increase significantly
Solution Approach 1:
The patent divides the continuous depth range into discrete depth segments or layers. Instead of capturing the entire light field with complex optics, the system segments the scene into multiple depth planes and captures images at these discrete focal distances. This segmentation allows refocusing capability while using standard camera optics and sensors, significantly reducing device complexity while maintaining focus manipulation versatility.
2Adaptability or versatility
If images are captured at all possible focus positions to enable complete refocusing, then focus manipulation capability is improved, but storage and processing requirements increase
Solution Approach 1:
The patent extracts only the essential depth information needed for refocusing by identifying and capturing images at principal depths only. Instead of storing all possible focus position images, the system extracts the key depth layers that contain the majority of scene information. This extraction approach maintains refocusing capability while dramatically reducing the quantity of images that need to be stored and processed.
3Device complexity
If standard camera optics and sensors are used, then device complexity is reduced, but focus manipulation capability after capture is lost
Solution Approach 1:
The patent performs preliminary depth estimation and principal depth identification during the image capture phase. By pre-processing the scene to identify important depth layers before actual image capture, the system can capture a minimal set of images at critical depths that preserve all necessary information for post-capture refocusing. This preliminary action enables focus manipulation with standard optics by preparing the depth structure in advance.
Data Source
AI summary
A system, method, and computer program product for capturing images for later refocusing. Embodiments estimate a distance map for a scene, determine a number of principal depths, capture a set of images, with each image focused at one of the principal depths, and process captured images to produce an output image. The scene is divided into regions, and the depth map represents region depths corresponding to a particular focus step. Entries having a specific focus step value are placed into a histogram, and depths having the most entries are selected as the principal depths. Embodiments may also identify scene areas having important objects and include different important object depths in the principal depths. Captured images may be selected according to user input, aligned, and then combined using blending functions that favor only scene regions that are focused in particular captured images.