Version 4 - Nov 2021

by Tina Nikoukhah [email protected] and Jérémy Anger [email protected] and Rafael Grompone von Gioi [email protected]

ZERO is an implementation of the JPEG grid detector applied to forgery detection in images described in the paper:

 "JPEG Grid Detection based on the Number of DCT Zeros and its
 Application to Automatic and Localized Forgery Detection" by Tina
 Nikoukhah, Jérémy Anger, Thibaud Ehret, Miguel Colom, Jean-Michel
 Morel and Rafael Grompone von Gioi.

PDF

IPOL

• src/main.c: Main code.

• src/zero.{c,h}: ZERO functions for the libzero library.

• README.txt: this file.

• LICENSE: GNU AFFERO GENERAL PUBLIC LICENSE Version 3.

• Makefile: Compilation instructions.

• src/iio.{c,h}: iio code and header.

• create_votemap.py: Creates a colored vote map.

python create_votemap.py votes.png

• merge_zero.py: Creates a final visual result which merges the two forgery masks.

python merge_zero.py mask_f.png mask_m.png luminance.png

• zero.py: Python binding to run the code.

python zero.py <image_file>

• *.{png,jpg}: Test images.

The compiling instruction is just

    make

or if you want the code to be parallel

   make openmp

from the directory where the source codes and the Makefile are located.

To compile the library to use the python binding do

    make libzero

To create the compressed version of the image, use imagemagick

    convert -quality 99% <image> <image_compressed.jpg>

To verify a correct compilation you can apply the algorithm to the test images. This can be done by executing:

    make test

This should print the following message:

test on roma.png
----------------
./zero roma.png roma99.jpg
No overall JPEG grid found.

No suspicious traces found in the image with the performed analysis.

test on pelican.png
-------------------
./zero pelican.png pelican99.jpg
main grid found: #6 (6,0) log(nfa) = -6373.72

The most meaningful JPEG grid origin is not (0,0).
This may indicate that the image has been cropped.

test on tampered1.png
---------------------
./zero tampered1.png tampered1_99.jpg
No overall JPEG grid found.

A meaningful grid was found here:
bounding box: 104 94 to 153 159 [50x66] grid: #0 (0,0) log(nfa) = -25.8163

Suspicious traces found in the image.
This may be caused by image manipulations such as resampling,
copy-paste, splicing.  Please examine the deviant meaningful region
to make your own opinion about a potential forgery.

test on tampered2.png
---------------------
./zero tampered2.png tampered2_99.jpg
main grid found: #6 (6,0) log(nfa) = -6188.44

A meaningful grid different from the main one was found here:
bounding box: 330 68 to 401 111 [72x44] grid: #34 (2,4) log(nfa) = -39.2402

The most meaningful JPEG grid origin is not (0,0).
This may indicate that the image has been cropped.

Suspicious traces found in the image.
This may be caused by image manipulations such as resampling,
copy-paste, splicing.  Please examine the deviant meaningful region
to make your own opinion about a potential forgery.

Copyright (c) 2018-2021 Tina Nikoukhah [email protected] Copyright (c) 2018-2021 Jérémy Anger [email protected] Copyright (c) 2018-2021 Rafael Grompone von Gioi [email protected]

ZERO is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

ZERO is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.

I would be grateful to receive any comment, especially about errors, bugs, or strange results.