Multi-Focus Imaging System for Extended Depth of Field

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Solution Overview

Problem

Conventional cameras struggle to capture high-quality images with multiple objects at different depths in focus within a single image, as the depth of field is typically shallow, making it difficult to maintain focus on objects at various distances along the z-axis.

Innovation Solution

A system and method that suggests multiple regions of interest within a scene, allows user selection through touch input, calculates autofocus parameters for each region, and generates a single multi-focus image by capturing and seamlessly integrating multiple images, each with one region in focus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the camera lens is zoomed in to capture detailed images, then the image quality of the main subject is improved, but the depth of field becomes shallower making it difficult to maintain focus on multiple objects at different distances

Engineering Contradiction:
Improveimage qualityVSAvoiddepth of field
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The image capture process is segmented into multiple shots, each focused on a different depth plane. The system identifies multiple regions of interest at different depths and captures separate images for each region, then combines them into a single composite image where all regions are in focus simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The focus distance is dynamically adjusted between multiple capture shots. The autofocus mechanism changes focus positions sequentially to target different depth planes, allowing the camera to capture multiple depth layers that are then merged into a single image with extended depth of field.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the camera attempts to focus on multiple objects at different depths in a single shot, then all objects could potentially be in focus, but the autofocus mechanism can only maintain focus on one depth plane at a time

Engineering Contradiction:
Improvemulti-focus capabilityVSAvoidfocus accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary analysis during a preview mode to identify multiple regions of interest at different depths before actual image capture. This preliminary detection allows the system to plan the focus sequence and capture the necessary number of shots to ensure all regions are properly focused in the final composite image.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the autofocus mechanism to determine when each depth plane is properly focused. After capturing images at different focus positions, the system evaluates the focus quality of each region and adjusts the capture sequence as needed to ensure all regions achieve optimal focus in the final composite image.

Inventive Principle:
Principle #23Feedback

3Length of moving object

If multiple images are captured and combined to create a multi-focus image, then the depth of field is extended to include multiple depth planes, but the image capture time and processing complexity increase

Engineering Contradiction:
Improvedepth of fieldVSAvoidimage capture time
Core Design Contradiction:
Length of moving objectVSLoss of time

Solution Approach 1:

The system captures only the necessary number of images required to cover all identified regions of interest, rather than capturing excessive numbers of images at every possible focus distance. The autofocus mechanism intelligently determines the minimum number of shots needed to achieve proper focus on all target regions, reducing capture time while maintaining multi-focus capability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3127320B1System and method for multi-focus imaging
Publication Date: 2019.10.23 QUALCOMM INC
  • EP3127320B1 patent drawingFigure 1
  • EP3127320B1 patent drawingFigure 2
  • EP3127320B1 patent drawingFigure 3

AI summary

Systems and methods for multi-focus imaging are disclosed. An imaging system may suggest multiple regions of interest to a user based on a preview mode of a scene of interest. The user may select a plurality of the suggested regions of interest for a multi-focus image. The imaging system calculates the autofocus parameters for each of the multiple regions of interest and captures single images of each of the regions of interest when the shutter button of the camera is pressed. The imaging system then generates a multi-focus image from the multiple images.