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Image Demosaicking with Contour Stencils
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Image Demosaicking with Contour Stencils
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Version 20130706 (July 6, 2013)
Pascal Getreuer, getreuer@cmla.ens-cachan.fr, CMLA, ENS Cachan
Please cite IPOL article “Image Demosaicking with Contour Stencils” if you publish results obtained with this software.
This software was written by Pascal Getreuer and is distributed under the terms of the simplified BSD license.
This C source code is a revision of the code accompanying Image Processing On Line (IPOL) article “Image Demosaicking with Contour Stencils” at
http://dx.doi.org/10.5201/ipol.2012.g-dwcs
The original peer-reviewed IPOL version of the code is available from the article page.
Future software releases and updates will be posted at
http://dev.ipol.im/~getreuer/code
Compared to the IPOL version, this revision differs in the following ways:
The compilation is configurable. No libraries are required to compile, but in this case, only BMP images are supported. JPEG, PNG, and TIFF support can be added by compiling with the libaries as summarized in the table:
| Format | Library | Add preprocessor flag |
|---|---|---|
| JPEG | libjpeg | USE_LIBJPEG |
| PNG | libpng | USE_LIBPNG |
| TIFF | libtiff | USE_LIBTIFF |
| BMP | (native) | — |
On Ubuntu and other Debian-based Linux systems, the libraries can be installed by running the following line in a terminal:
sudo apt-get install build-essential libjpeg libjpeg-dev libpng libpng-dev libtiff libtif-dev
On Fedora:
sudo yum install gcc libjpeg libjpeg-devel libpng libpng-devel libtiff libtiff-devel
On Mac OSX, the libraries can be installed with Fink:
sudo fink install libjpeg libpng libtiff
To compile, extract the package, cd into the dmcswl1_20130706 folder, and run make:
tar -xf dmcswl1_20130706.tgz cd dmcswl1_20130706 make -f makefile.gcc
This should produce four executables dmcswl1, dmbilinear, mosaic, and imdiff.
The radius of the contour stencil neighborhood can be specified by changing the RADIUS variable in makefile.gcc. The suggested radius is 2.5. The makefile runs the included program gen_mstencils to generate the file mstencils.c according to the specified radius.
The included makefile will try to use libjpeg, libpng, and libtiff. If linking with these libraries is a problem, they can be disabled by commenting their line at the top of the makefile.
##
# The following three statements determine the build configuration.
# For handling different image formats, the program can be linked with
# the libjpeg, libpng, and libtiff libraries. For each library, set
# the flags needed for linking. To disable use of a library, comment
# its statement. You can disable all three (BMP is always supported).
LDLIBJPEG=-ljpeg
LDLIBPNG=-lpng
LDLIBTIFF=-ltiff
The makefile will automatically set the corresponding preprocessor symbols; only these lines need to be changed. For example, to disable libjpeg and libtiff but to keep libpng support, comment the first and third lines
#LDLIBJPEG=-ljpeg LDLIBPNG=-lpng #LDLIBTIFF=-ltiff
If Doxygen and Graphviz are installed, HTML documentation of the project source code is generated by
doxygen doxygen.conf
The code can be compiled using Microsoft Visual C++ (MSVC). Microsoft Visual Studio Express can be downloaded for free. Since libraries are problematic under Windows, no libraries are used by default and the program will only support BMP images.
These instructions assume familiarity with the MS-DOS Command Prompt. See for example How to use DOS.
The radius of the contour stencil neighborhood can be specified by changing the RADIUS variable in makefile.vc. The suggested radius is 2.5. The makefile runs the included program gen_mstencils.exe to generate the file mstencils.c according to the specified radius.
First, open a command prompt with the visual studio environment by clicking Start Menu → Microsoft Visual Studio → Visual Studio Tools → Visual Studio Command Prompt. (Alternatively, open a regular command prompt and run the vcvarsall.bat.) To compile, use cd to navigate into the dmcswl1_20130706 folder and run nmake:
cd c:\projects\dmcswl1_20130706 nmake -f makefile.vc all
This should produce four executables dmcswl1.exe, dmbilinear.exe, mosaic.exe, and imdiff.exe.
It is possible under Windows to compile the program with libjpeg and libpng to add support for JPEG and PNG images (libtiff should be possible as well, but it is not explored here). To avoid incompatibility problems, the reliable way to compile with a library is to build that library from source using the same compiler.
First, download the libjpeg, libpng, and also the zlib library sources. The zlib library is needed to compile libpng.
Create a folder to contain the libraries, C:\libs for instance. Unzip the library sources into the libs folder so that they are structured as
| libs | ||
| jpeg-8b | ||
| lpng143 | ||
| zlib | ||
This structure will help keep the code organized. Take care to rename the folder for zlib to “zlib” since libpng will look for it. Below are the steps to build each library. If you want JPEG support, build libjpeg. For PNG support, build zlib first and then build libpng.
Building libjpeg
nmake -f makefile.vc libjpeg.libThis should produce libjpeg.lib.
Building zlib
287 #if 0 /* HAVE_UNISTD_H -- this line is updated by ./configure */ 288 # include <sys/types.h> /* for off_t */ 289 # include <unistd.h> /* for SEEK_* and off_t */
vcbuild -upgrade zlib.dsp vcbuild zlib.vcproj "LIB Release|Win32"This should produce a folder “Win32_LIB_Release” containing zlib.lib.
Building libpng
CFLAGS = -nologo -DPNG_NO_MMX_CODE -MT -O2 -W3 -I..\zlib
nmake -f scripts\makefile.vcwin32This should produce libpng.lib.
Once the libraries are built, dmcswl1 can be compiled with JPEG and/or PNG support by adjusting its makefile. Uncomment and edit the lines at the top of dmcswl1_20130706\makefile.vc to reflect the locations of libjpeg, libpng, and zlib:
# # Uncomment and edit the following lines for JPEG support. # LIBJPEG_DIR = "C:/libs/jpeg-8b" LIBJPEG_INCLUDE = -I$(LIBJPEG_DIR) LIBJPEG_LIB = $(LIBJPEG_DIR)/libjpeg.lib # # Uncomment and edit the following lines for PNG support. # ZLIB_DIR = "C:/libs/zlib" ZLIB_INCLUDE = -I$(ZLIB_DIR) ZLIB_LIB = $(ZLIB_DIR)/zlib.lib LIBPNG_DIR = "C:/libs/lpng143" LIBPNG_INCLUDE = -I$(LIBPNG_DIR) LIBPNG_LIB = $(LIBPNG_DIR)/libpng.lib
The makefile will automatically add the corresponding preprocessor symbols based on which libraries are defined. Then from a Visual Studio Command Prompt, compile with
nmake -f makefile.vc all
This should produce dmcswl1.exe, dmbilinear.exe, mosaic.exe, and imdiff.exe with compiled support for JPEG and/or PNG.
Under the approach shown here, libraries are statically linked. The executables do not depend on libjpeg, libpng, or zlib DLL files, so they should still work if transferred to another Windows machine.
A script called “demo” is included to run an example interpolation with the program. There is also an equivalent BAT program for MS-DOS.
| demo | sh script (UNIX) | |
| demo.bat | MS-DOS batch script (Windows) |
To run the demo, open a terminal, navigate to the dmcswl1_20130706 directory, and enter the command ./demo (UNIX) or demo.bat (Windows).
Image credits: the demo test image is by John D. Willson, USGS Amphibian Research and Monitoring Initiative.
The usage syntax for dmcswl1 is
dmcswl1 [options] <input file> <output file>
Program options
| -p <pattern> | CFA pattern |
| -s | Show estimated contours instead of demosaicing. The output is written as an EPS file. |
| -E | Display energy value after each iteration. |
| -a <number> | α, chroma weight (default 1.8) |
| -e <number> | ε, graph weight (default 0.15) |
| -f <number> | σ, graph spatial filtering parameter (default 0.6) |
| -t <number> | convergence tolerance (default 0.001) |
| -m <number> | maximum number of iterations (default 250) |
The option <pattern> specifies the CFA pattern:
| R | G |
| G | B |
| G | R |
| B | G |
| G | B |
| R | G |
| B | G |
| G | R |
For example,
dmcswl1 -p RGGB mosaiced.bmp demosaiced.bmp
Sorry, only BMP/JPEG/PNG/TIFF images are supported.
The program only supports BMP, JPEG, PNG, and TIFF images. If you disabled some of the libraries when compiling, the support for the corresponding formats will be disabled. Regardless of compilation settings, the program always supports Windows Bitmap BMP images.
To use an image that is in an unsupported format, please convert it to a supported format. Images can be conveniently converted using the command line program convert from ImageMagick. Alternatively, an image can be converted by opening the image in an image editor, selecting “Save As...,” and setting “Type” to a supported format.
The usage information is also displayed by dmcswl1 if executed without arguments.
This package includes imdiff, an image difference calculator that compares two images with a specified metric. The usage syntax of imdiff is
imdiff [options] <exact file> <distorted file>
Options:
| -m <metric> | metric to use for comparison, choices are | ||
| max | maximum absolute difference, maxn |An − Bn| | ||
| mse | mean squared error, 1/N sum |An − Bn|2 | ||
| rmse | root mean squared error, (MSE)½ | ||
| psnr | peak signal-to-noise ratio, −10 log10(MSE/2552) | ||
| mssim | mean structural similarity index | ||
| -s | compute metric separately for each channel | ||
| -p <pad> | remove a margin of <pad> pixels before comparison | ||
| -D <number> | D parameter for difference image (explained below) | ||
| -q <number> | quality for saving JPEG images (0 to 100) | ||
Alternatively, a difference image is generated by the syntax
imdiff [-D <number>] <exact file> <distorted file> <output file>
The difference image is computed as Dn = 255/D (An − Bn) + 255/2. Values outside of the range [0,255] are saturated.
The package also includes
Run these programs without arguments for further usage details.
Copyright © 2010–2011, Pascal Getreuer
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This material is based upon work supported by the National Science Foundation under Award No. DMS-1004694. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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