Wavelet Histogram Shifting for Lossless Data Hiding

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Solution Overview

Problem

Existing methods for embedding and extracting data in digital images, such as digital watermarks, face challenges in achieving lossless data hiding and retrieval without visible distortion, especially when dealing with overflow and underflow conditions in integer wavelet transform domains.

Innovation Solution

The use of histogram shifting operations in the wavelet transform domain allows for embedding data by creating a zero-point in the histogram, which guards against overflow and underflow conditions, and enables lossless image reconstruction by modifying the histogram prior to data embedding and embedding parameters within the image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If data is embedded in digital image using traditional methods, then data hiding capability is achieved, but visible distortion artifacts and overflow/underflow conditions occur

Engineering Contradiction:

Improvedata retrieval accuracyVSAvoidvisible distortion artifacts

Core Design Contradiction:

Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the image processing into wavelet transform domains, dividing the image into different frequency sub-bands (LL, LH, HL, HH). Data is embedded specifically in the high-frequency sub-bands (LH, HL, HH) where modifications are less perceptible, while preserving the low-frequency LL sub-band that contains the main image information. This segmentation allows data hiding without visible distortion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies histogram shifting operations that modify the distribution parameters of wavelet coefficients. By creating a zero-point in the histogram and shifting coefficient values, the method embeds data while maintaining the statistical properties of the image. This parameter transformation enables lossless data retrieval without introducing visible artifacts.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If histogram shifting is applied to embed data, then lossless data retrieval is enabled, but additional processing steps and complexity are introduced

Engineering Contradiction:

Improvelossless data retrievalVSAvoidprocessing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary histogram analysis and zero-point creation before data embedding. By pre-processing the wavelet coefficient histogram to create a known zero-point position, the method establishes a reference framework that simplifies the subsequent data embedding and retrieval processes. This preliminary action ensures reliable lossless retrieval without requiring complex real-time processing.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If wavelet transform domain is used for data embedding, then invisibility of watermark is improved, but overflow and underflow conditions create retrieval issues

Engineering Contradiction:

Improvewatermark visibilityVSAvoiddata retrieval reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies histogram shifting to create a zero-point cushion in the wavelet coefficient distribution before embedding data. This zero-point acts as a buffer that prevents overflow and underflow conditions during data embedding operations. By preparing this protective margin in advance, the method ensures reliable data retrieval while maintaining the invisibility of the embedded watermark.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8260065B2Data hiding with wavelet transform histogram shifting

Publication Date: 2012.09.04 NEW JERSEY INSTITUTE OF TECHNOLOGY

AI summary

Embodiments related to data hiding using wavelet transforms and histogram shifting are disclosed.