Wide-Angle Image Calibration via Foreground Segmentation

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Solution Overview

Problem

Wide-angle camera images often exhibit significant distortion in corner regions, leading to unnatural appearances of objects like humans and buildings during correction, and existing methods fail to fully eliminate distortions in the background near the foreground.

Innovation Solution

An image calibration method that applies primary lens distortion correction, segments the foreground and background, performs secondary distortion correction using machine learning to align and morph feature pixels, and fills residual empty pixels by extending the background image, ensuring a non-deformed foreground and undistorted background.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If distortion correction is applied to the corner region of the wide-angle image, then the distortion in the corner region is reduced, but objects in the region such as human or building will be looked unnaturally after correction

Engineering Contradiction:
Improvedistortion correction accuracyVSAvoidnatural appearance of objects
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The image is segmented into foreground and background regions. Different correction strategies are applied to each region: the background undergoes geometric transformation to straighten lines, while the foreground objects are preserved with minimal distortion to maintain their natural appearance. This segmentation allows simultaneous optimization of both distortion correction and object naturalness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different quality requirements are applied to different regions of the image. The background region prioritizes geometric accuracy and straight lines, while the foreground region prioritizes preserving the natural appearance of objects. This local quality approach allows each region to be optimized according to its specific requirements without compromising the other.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the background is calibrated to transform distorted lines into straight lines, then the background geometry is improved, but a part of the background close to the foreground still has unnatural distortion

Engineering Contradiction:
Improvebackground geometry accuracyVSAvoiddistortion in background near foreground
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The image is divided into foreground and background segments. The background segmentation allows independent processing of background regions, enabling geometric correction of distant background elements while preserving the appearance of foreground objects. This segmentation prevents the propagation of unnatural distortion from the background to the foreground region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A mask or transition region acts as an intermediary between the foreground and background processing. This intermediary ensures that the geometric transformation applied to the background does not directly affect the foreground objects, allowing smooth transition and preventing unnatural distortion in the boundary region between foreground and background.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If foreground and background are segmented and different corrections are applied, then both regions can be optimized, but the processing complexity increases

Engineering Contradiction:
Improveoverall image calibration qualityVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The image is segmented into foreground and background using automated algorithms that identify object boundaries. This segmentation enables independent optimization of each region with appropriate correction methods, achieving high overall calibration quality. The automation of segmentation reduces the manual processing complexity despite the increased computational steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different correction parameters and transformation models are applied to different regions based on their characteristics. The system dynamically adjusts processing parameters for foreground versus background regions, allowing optimal correction for each while managing complexity through parameterized processing pipelines rather than fixed complex procedures.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12148132B2Image calibration method and image calibration apparatus
Publication Date: 2024.11.19 ALTEK SEMICON
  • US12148132B2 patent drawing
  • US12148132B2 patent drawing
  • US12148132B2 patent drawing

AI summary

An image calibration method applied to a wide-angle image and executed by an image calibration apparatus includes applying primary lens distortion correction for the wide-angle image to generate a corrected image, segmenting an foreground image from the corrected image to generate a background image, applying secondary distortion correction for the foreground image based on the pre-defined object to generate a calibrated foreground image, fusing the background image with the calibrated foreground image to generate a fused image, detecting at least one residual empty pixel not overlapped by the calibrated foreground image within the fused image, and utilizing a machine learning algorithm to fill the at least one residual empty pixel of the fused image by extending the background image to provide an output image. The foreground image contains feature pixels relate to a pre-defined object and the background image has empty pixels corresponding to the foreground image.