Camera Image Fusion Across Focal Lengths for Uniform Focus

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Solution Overview

Problem

Image capture devices with large image sensors and lenses often suffer from a mismatch in ground truth position, leading to non-uniform focus levels across frames, with center regions being in focus while outer regions are out of focus, despite autofocus techniques.

Innovation Solution

The technique involves capturing multiple frames at different focal lengths and combining them using a camera processor to generate a composite frame with both center and outer regions in focus, leveraging image fusion to address the non-uniform focus levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If large image sensors and lenses are used to maximize resolution and image quality, then pixel density and signal-to-noise ratio are improved, but mismatch in ground truth position occurs causing non-uniform focus levels across the frame

Engineering Contradiction:
Improveimage qualityVSAvoidfocus uniformity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The image frame is divided into multiple regions (center region and outer regions) with different focus requirements. Each region is processed separately to achieve optimal focus, then combined into a final composite image with uniform focus across the entire frame.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different focus levels are applied to different regions of the image frame. The center region receives one focus level while outer regions receive adjusted focus levels to compensate for the ground truth position mismatch, ensuring each region has optimal local quality.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If autofocus techniques are applied to center the focus on the subject, then the center region achieves sharp focus, but outer regions become out of focus due to lens characteristics

Engineering Contradiction:
Improvecenter focus sharpnessVSAvoidouter region focus
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The image is segmented into center and outer regions that are focused at different times. Multiple frames are captured with the lens focused on different regions, then the segments are combined to produce a final image with uniform focus across all regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lens focusing operation is performed periodically multiple times, each time focusing on a different region of the frame. This periodic refocusing allows all regions to be captured in focus across multiple frames, which are then combined.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If multiple frames are captured at different focal lengths to achieve uniform focus, then focus uniformity is improved, but the processing complexity and time required increase

Engineering Contradiction:
Improvefocus uniformityVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple frames captured at different focal lengths are merged into a single composite image. The merging process combines the in-focus regions from each frame, achieving uniform focus across the entire image while managing processing complexity through efficient algorithms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of physically moving the lens to different positions for each region, digital copies of frames at different focal lengths are created and processed. This allows multiple focus states to be captured and combined without requiring complex mechanical adjustments during processing.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4078942B1Image fusion
Publication Date: 2025.10.15 QUALCOMM INC
  • EP4078942B1 patent drawingFigure 1
  • EP4078942B1 patent drawingFigure 2
  • EP4078942B1 patent drawingFigure 3

AI summary

In general, techniques are described regarding fusing or combining frames of image data to generate composite frames of image data. Cameras comprising camera processors configured to perform the techniques are also disclosed. A camera processor may capture multiple frames at various focal lengths. The frames of image data may have various regions of the respective frame in focus, whereas other regions of the respective frame may not be in focus, due to particular configurations of lens and sensor combinations used. The camera processor may combine the frames to achieve a single composite frame having both a first region (e.g., a center region) and a second region (e.g., an outer region) in focus.