Digital Camera Distortion Correction via Reduced Image Processing

Solution Overview

Problem

Existing image processing methods require multiple interpolation operations to correct trapezoidal distortion in images, leading to increased processing time and image degradation.

Innovation Solution

An image processing apparatus that acquires a reduced image, extracts distortion information, and performs projection transformation using projection parameters to correct trapezoidal distortion, reducing the number of operations and improving processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pixel interpolation is performed twice (in image extraction and projection correction), then distortion correction is achieved, but image degradation increases and processing time increases

Engineering Contradiction:

Improvedistortion correction accuracyVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs distortion correction in advance during the image extraction phase by acquiring a reduced image and computing projection parameters. This preliminary correction eliminates the need for a second interpolation operation during projection correction, thereby reducing processing time while maintaining correction accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the distortion correction process into two independent stages: (1) extracting a reduced image with distortion correction using projection transformation, and (2) using the projection parameters for subsequent processing. This segmentation allows the correction to be performed once during extraction rather than twice during both extraction and projection correction.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If pixel interpolation is performed twice (in image extraction and projection correction), then distortion correction is achieved, but image quality degrades

Engineering Contradiction:

Improvedistortion correction accuracyVSAvoidimage quality

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent performs distortion correction in advance during the image extraction phase by acquiring a reduced image and computing projection parameters. This preliminary correction eliminates the need for a second interpolation operation during projection correction, thereby reducing processing time while maintaining correction accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the distortion correction process into two independent stages: (1) extracting a reduced image with distortion correction using projection transformation, and (2) using the projection parameters for subsequent processing. This segmentation allows the correction to be performed once during extraction rather than twice during both extraction and projection correction.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If distortion correction is performed for each pixel, then correction accuracy is improved, but the number of operations increases and processing time increases

Engineering Contradiction:

Improvecorrection accuracyVSAvoidprocessing efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent uses a reduced image (a copy of the original image at lower resolution) to extract distortion information and compute projection parameters. This copying approach allows distortion correction to be performed on a smaller dataset, reducing the number of operations required while maintaining correction accuracy for the full-resolution image.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent performs distortion correction in advance during the image extraction phase by acquiring a reduced image and computing projection parameters. This preliminary correction eliminates the need for a second interpolation operation during projection correction, thereby reducing processing time while maintaining correction accuracy.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7619663B2Image processing apparatus for correcting distortion of image and image shooting apparatus for correcting distortion of shot image

Publication Date: 2009.11.17 CASIO COMPUTER CO LTD

AI summary

A digital camera acquires the image of an original including an original from a shot image acquired by shooting. The digital camera reduces the image of the original and corrects distortion of the reduced image which is originated from the characteristic of a lens. As the digital camera performs distortion correction on the reduced image, the number of arithmetic operations in distortion correction is reduced, making distortion correction simpler. The digital camera acquires a rectangle defined by the contour of the original, extracts the image of the original to acquire an original image before reduction, and acquires an associated projection-transformed image by affine transformation. The digital camera acquires pixel positions of the original image using an affine parameter, and acquires pixel positions of the image before distortion correction using a relational expression of distortion correction performed on the reduced image.