Skip to content Skip to navigation Skip to collection information

OpenStax_CNX

You are here: Home » Content » Elec 301 - Steganography - What's In Your Picture? » Zeros Hiding Method

Navigation

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

Affiliated with (What does "Affiliated with" mean?)

This content is either by members of the organizations listed or about topics related to the organizations listed. Click each link to see a list of all content affiliated with the organization.
  • Rice University ELEC 301 Projects

    This module is included inLens: Rice University ELEC 301 Project Lens
    By: Rice University ELEC 301As a part of collection: "ELEC 301 Projects Fall 2005"

    Click the "Rice University ELEC 301 Projects" link to see all content affiliated with them.

  • Rice Digital Scholarship

    This module is included in aLens by: Digital Scholarship at Rice UniversityAs a part of collection: "ELEC 301 Projects Fall 2005"

    Click the "Rice Digital Scholarship" link to see all content affiliated with them.

Also in these lenses

  • Lens for Engineering

    This module is included inLens: Lens for Engineering
    By: Sidney BurrusAs a part of collection: "ELEC 301 Projects Fall 2005"

    Click the "Lens for Engineering" link to see all content selected in this lens.

Recently Viewed

This feature requires Javascript to be enabled.
 

Zeros Hiding Method

Module by: Danny Blanco, Elliot Ng, Charlie Ice, Bryan Grandy. E-mail the authors

Summary: This is an overview of our steganographic technique, zeros hiding.

Data Hiding Methods

Zero Hiding

Hiding Information

We arrived at our first data hiding method, which we called “zero hiding,” quite intuitively. If you recall, our compression algorithm removed the least important DCT coefficients. It follows, then, that we could put the bit stream we wish to hide back into these dropped coefficients without changing the image drastically. To do this though, there must be a way to distinguish a zero which resulted from a dropped coefficient and a coefficient that is zero. To do this, we ran the image through a modified compressor that, instead of dropping coefficients below the specified threshold, replaced them with either a plus or minus one, depending on the sign of the coefficient.

Figure 1: The DCT is taken and then each coefficient under the specified threshold (10) will be dropped. These are coefficients are shown in blue in the picture on the right.
Figure 1 (DCT_drop)

Next the hiding algorithm is given a binary data stream and the threshold value. The data stream is then divided up into words. However, the maximum decimal value of the word must be less than the threshold, since values over the threshold signify an important coefficient in the picture. We then increment each word’s decimal value by one to avoid putting in zero valued coefficients, which would otherwise be indistinguishable from zero valued coefficients in the original image. We then go back to the original coefficients matrix and replace the ones with the new value of the data word, maintaining the sign throughout.

Figure 2: The dropped coefficients are replaced with words created from the data stream. The IDCT is then taken, transforming the coefficient matrix back to a picture matrix.
Figure 2 (hiding_zeros)

Data Retrieval

To recover the hidden data the recovery script is given the threshold, and subtracts one from all DCT coefficients blow that threshold and tacks their binary values together, forming the original binary data.

Collection Navigation

Content actions

Download:

Collection as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Module as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Add:

Collection to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks

Module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks