Light Field Image Format (LFIF) is an implementation of a lossy light field image compression method which compresses the light field as a four-dimensional volume to exploit the correlation between adjacent views. The method is based on JPEG baseline encoder. The LFIF library can handle a variety of data and is able to compress a light field as a series of (two or three)-dimensional images or as one four-dimensional image. This project also contains a minimalistic PPM library for reading and writing PPM files and set of tools for light field image compression and decompression. Evaluation of this encoder was performed in the paper (Barina, 2019). The method is described in the paper (Dlabaja, 2019).
The project depends on GCC with C++ 17 implemented. The compilation is organized with the make tool.
To compile the whole project, simply write
make
in its root folder. To compile only part of the project, you can specify which part by writing
make <FOLDER>
where <FOLDER> can be liblfif for LFIF library only, libppm for PPM library only. The tools specifier will compile the whole project because tools depend on it. To compile tools with specific block size, add a parameter BS=<NUMBER> to the make command. A <NUMBER> specifies the size of a block. The default value is 8. Compilation outputs its binaries in bin subfolder of each folder.
The documentation can be generated with Doxygen tool with the command
make doc
The project can be cleaned with make clean.
The tools are able to compress a light field image which exists as a set of ppm images representing individual views. The image files must be sorted in row or column order and the view indices must be part of file names. To compress a light field image, use the compression tool like this:
./tools/bin/lfif{2,3,4}d_compress -i path/to/##/input/###.ppm -o output.lf{2,3,4}d -q <quality>
The # characters can be anywhere in the path and are expanded with sequential numbers. This means that a path ##/file#.ppm will be expanded to files 00/file0.ppm, 00/file1.ppm, ..., 99/file9.ppm. The parameters of the images must be the same. The images must together resemble a square of views.
The <quality> parameters specify a compression quality. The tools consume any floating point number from 1.0 to 100.0. The higher the number, the better the visual quality, but worse compression ratio.
The decompression tool can decompress images compressed with corresponding compression tools. The tools will output the individual views as a set of ppm files with names specified by a mask. To decompress a light filed image, use decompression tools like this:
./tools/bin/lfif{2,3,4}d_decompress -i input.lf{2,3,4}d -o path/to/##/output/###.ppm
The # characters will be expanded in a similar way as with compression tools.
See LICENSE for license and copyright information.
Barina, D.; Chlubna, T.; Solony, M.; aj.: Evaluation of 4D Light Field Compression Methods. In International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG), 2019.
Dlabaja, D.: 4D-DCT Based Light Field Image Compression. In Excel@FIT, 2019.