Computational Out-of-Focus Image Generation Using Multi-Focus Capture
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Solution Overview
Problem
Existing digital image processing technologies make it difficult for users to obtain out-of-focus images, especially with compact digital still cameras, due to the narrow image area and deep focal depth, which requires specialized lenses and can be expensive and difficult to use.
Innovation Solution
A digital image processing apparatus and method that includes a storage unit for reference subject distance information, a zoom information obtaining unit, a notification unit, an image generating unit, and an out-of-focus image generating unit, which allows for the generation of out-of-focus images by combining focused subject and background images, guiding the user to adjust the subject distance for optimal results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long focus lens with shallow focal depth of field is used to obtain out-of-focus images, then the out-of-focus image quality is improved, but the device complexity and cost increase due to requiring separate lens purchase and installation
Solution Approach 1:
The patent creates virtual copies of the subject and background at different focal planes by capturing multiple images at different focus distances, then synthesizes an out-of-focus image by combining these copies. This eliminates the need for physical long focus lenses while achieving the desired optical effect through computational methods.
Solution Approach 2:
The patent replaces the mechanical optical system (physical long focus lens with shallow DOF) with a computational system that captures multiple images at different focus distances and processes them to generate out-of-focus images. This substitution eliminates the need for specialized hardware while achieving the same visual effect.
2Weight of moving object
If a compact digital still camera with narrow imaging area is used, then the device portability is improved, but the focal depth becomes deep making out-of-focus images difficult to obtain
Solution Approach 1:
The patent segments the image into subject region and background region by capturing multiple images at different focus distances. The subject is captured at close focus distance while the background is captured at far focus distance, allowing independent processing of each region to create the desired out-of-focus effect.
Solution Approach 2:
The patent adds a temporal dimension by capturing multiple images at different focus distances over time, then processes these images in the computational domain to create the out-of-focus effect. This transforms the spatial limitation into a temporal solution, allowing the compact camera to achieve effects normally requiring optical complexity.
3Reliability
If multiple images are captured at different focus distances and processed to generate out-of-focus images, then the out-of-focus image quality is improved, but the processing time and computational complexity increase
Solution Approach 1:
The patent performs preliminary actions by capturing multiple images at different focus distances before final processing. These pre-captured images serve as ready-to-use source material that can be quickly processed and combined to generate the out-of-focus image, reducing the overall time required compared to real-time computational methods.
Solution Approach 2:
The patent changes the focus distance parameter across multiple captures to create the necessary image set. By systematically varying this parameter and pre-processing the images, the system optimizes the balance between capture time and processing time, achieving efficient out-of-focus image generation.
Data Source
AI summary
Provided are an image processing method, a digital image processing apparatus, and a recording medium storing the image processing method. The method includes capturing a first image, a second image, and a third image, which are captured with different focuses for the same subject and background; setting a subject portion and a background portion by using the first and second images; and combining the first image for the subject portion and the third image for the background portion with each other to obtain an out-of-focus image.