CN111598198B

CN111598198B - Image two-dimensional code generation method and reading method based on LSB information hiding

Info

Publication number: CN111598198B
Application number: CN202010422569.2A
Authority: CN
Inventors: 张健; 何睿清; 余辉龙; 魏峘; 赵静; 包永强; 段宁璨
Original assignee: Nanjing Institute of Technology
Current assignee: Nanjing Institute of Technology
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2024-04-26
Anticipated expiration: 2040-05-18
Also published as: CN111598198A

Abstract

When the two-dimensional code is generated, two-dimensional code information is converted into binary information, a color digital bitmap is selected as a carrier, RGB values of each pixel point are converted into YUV format, the binary information replaces the lowest bit of gray information Y in the YUV format, a new gray image is obtained, Y' UV is restored to RGB information through inverse change, and the new RGB information is restored to a bitmap with the two-dimensional code information. And when the bitmap with the two-dimensional code information is read into a computer, converted into a YUV format, and the lowest bit of the first n values of the Y matrix is read. The binary bits of the two-dimensional code information are substituted for the lowest bits of the gray information of the image, and the visual effect of the original image is not affected because the lowest bits of the gray information are substituted, and the two-dimensional code information is carried. When the two-dimensional code information is read, the two-dimensional code can be recovered only by taking out the lowest bit of the gray level image.

Description

Image two-dimensional code generation method and reading method based on LSB information hiding

Technical Field

The invention belongs to the technical field of two-dimension codes, and particularly relates to an image two-dimension code generation method and a reading method based on LSB information hiding.

Background

The two-dimension code is a graph which is distributed on a plane (two-dimension direction) according to a certain rule by using a certain specific geometric figure and is used for recording data symbol information, the concept of 0 and 1 bit streams which form the internal logic foundation of a computer is skillfully utilized in code programming, a plurality of geometric shapes corresponding to binary are used for representing literal numerical information, and the literal numerical information is automatically read through an image input device or a photoelectric scanning device so as to realize automatic information processing. The traditional two-dimensional code adopts black and white square to represent information, and the two-dimensional code information is blended into an image and is generally simply overlapped, so that the visual effect of the image is affected. Therefore, it is necessary to design an image two-dimensional code that can be hidden.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an image two-dimensional code generation method and a reading method based on LSB information hiding.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

The image two-dimensional code generation method based on LSB information hiding is characterized by comprising the following steps of:

step one: converting the two-dimensional code information into binary information;

Step two: selecting a color digital bitmap as a carrier, and converting RGB values of each pixel point in the carrier into YUV format;

step three: replacing the lowest bit of gray information Y in YUV format with binary information to obtain new gray image;

Step four: the Y' UV is restored into RGB information through inverse change;

step five: and recovering the new RGB information into a bitmap with the two-dimensional code information.

In order to optimize the technical scheme, the specific measures adopted further comprise:

Further, in the second step, YUV and RGB are both 8 bits, and three values of RGB of each pixel point in the carrier are converted into YUV format representation according to the following formula:

Y＝0.299R+0.587G+0.114B

U＝-0.1687R-0.3313G+0.5B+128

V＝0.5R-0.4187G-0.0813B+128

Wherein R, G, B represents three primary color components of the color digital bitmap, Y represents gray information of a pixel point, and U, V represents two color difference information, respectively.

Further, the third step is specifically as follows:

let the carrier pixel be mxn, the gray information of each pixel point be represented by an 8-bit binary number, forming set C:

C＝{x_ij|0≤i＜M,0≤j＜N,x_ij∈{0，1，...，255}}

wherein x _ij represents the gray information of the pixel points in the ith row and the j columns;

Let S be n bits of binary information to be hidden:

s＝{s_i|0≤i＜n,s_i∈{0，1}}

Wherein s _i represents the i-th bit information, N < M×N;

selecting the first n data from C according to the principle of row priority to form a set C':

C′＝{x_k|0≤k＜n,x_k∈{0，1，...，255}}

where x _k represents the selected kth data, x _k is represented by an 8-bit binary representation, each bit number is represented in turn as x _k0,x_k1,x_k2,x_k3,x_k4,x_k5,x_k6,x_k7,

And (3) replacing the lowest bit x _k0 of x _k with s _i to obtain each bit number of x _k′,x_k ', sequentially obtaining s _i,x_k1,x_k2,x_k3,x_k4,x_k5,x_k6,x_k7, and obtaining new gray information Y ' according to x _k ', thereby obtaining a new gray image.

Further, in the fourth step, Y' UV is restored to RGB information by inverse-changing as follows:

R＝Y′+1.402(V-128)

G＝Y′-0.34414(U-128)-0.71414(V-128)

B＝Y′+1.772(U-128)。

In addition, a method for reading the two-dimensional code generated by the image two-dimensional code generation method is also provided, and the method is characterized by comprising the following steps: and reading the bitmap with the two-dimensional code information into a computer, converting the bitmap into a YUV format, reading the lowest bits of the first n values of the Y matrix, and recovering the two-dimensional code information.

The beneficial effects of the invention are as follows: the binary bits of the two-dimensional code information are substituted for the lowest bits of the gray information of the image, and the visual effect of the original image is not affected because the lowest bits of the gray information are substituted, and the two-dimensional code information is carried. When the two-dimensional code information is read, the two-dimensional code can be recovered simply and quickly by taking out the lowest bit of the gray level image.

Drawings

Fig. 1 is a flowchart of image two-dimensional code generation.

Fig. 2 is an image two-dimensional code reading flow chart.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings.

The image two-dimensional code generation method shown in fig. 1 specifically comprises the following steps:

1. The information which needs to be changed into the two-dimensional code is converted into binary by a computer.

2. Any color digital bitmap is searched for as a carrier. Converting the RGB three values of each pixel point into YUV format representation, wherein YUM and RGB are 8 bits:

Y＝0.299R+0.587G+0.114B

U＝-0.1687R-0.3313G+0.5B+128

v=0.5R-0.4187G-0.0813b+128

3. The binary information replaces the least significant bit of Y8 bit information, and the specific process is as follows:

1) Let the image pixels be mxn, the gray information of each pixel point be represented by an 8-bit binary number, forming set C:

C＝{x_ij|0≤i＜M,0≤j＜N,x_ij∈{0，1，...，255}}

S is a message to be hidden by n-bit:

S＝{s_i|0≤i＜n,s_i∈{0，1})

the requirements are: n < m×n.

2) The first n data are chosen from C by row-first principle, C' = { x _k|0≤k＜n,x_k e {0, 1..once., 255 }.

X _k can be represented in an 8-bit binary representation:

x_k0

x_k1

x_k2

x_k3

x_k4

x_k5

x_k6

x_k7

s _i is a one-bit binary. Replace x _k0, the Least Significant Bit (LSB) of x _k.

X _k is changed to x _k':

x_k0

x_k1

x_k2

x_k3

x_k4

x_k5

x_k6

x_k7

a new gray image Y' is obtained.

4. Y' UV was restored to RGB bitmap by inverse change:

R＝Y′+1.402(V-128)

G＝Y′-0.34414(U-128)-0.71414(V-128)

B＝Y′+1.772(U-128)。

5. And recovering the new RGB information into a bitmap with the two-dimensional code information.

As shown in fig. 2, when the two-dimensional code is read, a bitmap with the two-dimensional code information is read into a computer and converted into a YUV format, and the lowest bits of the first n values of the Y matrix are read to recover the two-dimensional code information.

It should be noted that the terms like "upper", "lower", "left", "right", "front", "rear", and the like are also used for descriptive purposes only and are not intended to limit the scope of the invention in which the invention may be practiced, but rather the relative relationship of the terms may be altered or modified without materially altering the teachings of the invention.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the invention without departing from the principles thereof are intended to be within the scope of the invention as set forth in the following claims.

Claims

1. The image two-dimensional code generation method based on LSB information hiding is characterized by comprising the following steps of:

Step two: selecting a color digital bitmap as a carrier, and converting RGB values of each pixel point in the carrier into YUV format; in the second step, YUV and RGB are 8 bits, and three values of RGB of each pixel point in the carrier are converted into YUV format representation according to the following formula:

Y＝0.299R+0.587G+0.114B

U＝-0.1687R-0.3313G+0.5B+128

V＝0.5R-0.4187G-0.0813B+128

wherein R, G, B represents three primary color components of the color digital bitmap, Y represents gray information of pixel points, and U, V represents two color difference information;

Step three: replacing the lowest bit of gray information Y in YUV format with binary information to obtain new gray image Y' UV; the third step is as follows:

C＝{x_ij|0≤i＜M,0≤j＜N,x_ij∈{0,1,…,255}}

Let S be n bits of binary information to be hidden:

S＝{s_i|0≤i＜n,s_i∈{0,1}}

Wherein s _i represents the i-th bit information, N < M×N;

C'＝{x_k|0≤k＜n,x_k∈{0,1,...,255}}

S _i is substituted for the lowest bit x _k0 of x _k to obtain each bit number of x _k',x_k ' which is s _i,x_k1,x_k2,x_k3,x_k4,x_k5,x_k6,x_k7 in sequence, and new gray information Y ' is obtained according to x _k ';

step four: the Y' UV is restored into RGB information through inverse change;

2. The LSB information hiding-based image two-dimensional code generating method according to claim 1, wherein: in the fourth step, Y' UV is restored to RGB information by inverse change as follows:

R＝Y'+1.402(V-128)

G＝Y'-0.34414(U-128)-0.71414(V-128)

B＝Y'+1.772(U-128)。

3. The method for reading a two-dimensional code generated by the image two-dimensional code generation method according to claim 1, comprising the steps of: and reading the bitmap with the two-dimensional code information into a computer, converting the bitmap into a YUV format, reading the lowest bits of the first n values of the Y matrix, and recovering the two-dimensional code information.