Image Interpolation Edge Sharpness and Overshoot Control

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Solution Overview

Problem

Conventional image interpolation methods, such as bilinear and bicubic interpolation, suffer from image blurring and block effects due to lack of high-frequency data, and bicubic interpolation results in overshoot phenomena at image edges, especially as the enlargement factor increases.

Innovation Solution

A processing method that detects edges and determines edge directions in an image, interpolates contour pixels, identifies extreme points based on brightness trends, and calculates an interpolation adjust value to differentiate between transition and non-transition areas, allowing for adaptive interpolation techniques like bilateral or bilinear interpolation to enhance edge sharpness without overshoot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If bilinear interpolation method is used, then computation speed is fast, but image blurring and block effects occur due to lack of high frequency data

Engineering Contradiction:
Improvecomputation speedVSAvoidimage quality
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent applies different interpolation strategies to different regions of the image based on edge detection results. For non-edge areas, simple bilinear interpolation is used to maintain speed, while for edge areas, a more sophisticated approach involving contour interpolation and adjustment values is applied to preserve image quality and avoid blurring.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If bicubic interpolation method is used, then edge sharpness is improved, but overshoot phenomenon occurs at image edges

Engineering Contradiction:
Improveedge sharpnessVSAvoidovershoot phenomenon
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an adjustment value that modifies the bicubic interpolation result based on the relationship between the destination pixel and extreme points on the contour. By calculating this adjustment value and applying it to the interpolated result, the method reduces the overshoot phenomenon while maintaining edge sharpness, effectively controlling the interpolation parameters to avoid harmful artifacts.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If bicubic interpolation is used with higher enlargement factor, then edge sharpness increases, but difference from optical enlargement becomes apparent

Engineering Contradiction:
Improveedge sharpnessVSAvoidnaturalness of enlargement
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses edge detection to identify edge areas and then applies a feedback mechanism where the adjustment value is calculated based on the destination pixel's position relative to extreme points on the contour. This feedback loop allows the method to adaptively control the interpolation strength, maintaining natural optical enlargement effects while preserving edge sharpness even at higher enlargement factors.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS8693783B2Processing method for image interpolation
Publication Date: 2014.04.08 ALTEK CORP
  • US8693783B2 patent drawing
  • US8693783B2 patent drawing
  • US8693783B2 patent drawing

AI summary

A processing method for image interpolation is provided. In the method, a contour containing a destination pixel and a plurality of contour pixels is produced and detected by using an edge detection method for a selected area in an original image. Next, two extreme points are identified from the contour pixels by judging the changing trend of brightness value of the contour pixels on the contour. Then using the changing trend and two extreme points determines whether the destination pixel is located at a transition area or a non-transition area. If the destination pixel is located at the non-transition area, an interpolation adjust value is calculated according to the brightness values of the two extreme points and the brightness value of the destination pixel. An interpolation result of the destination pixel is obtained by performing the interpolation on the selected area according to the interpolation adjust value.