Refereed Journal Publications
[1] Koc, B., Arnavut, Z., Kocak, H., “The pseudo-distance technique for parallel lossless compression of color-mapped images,” Computers and Electrical Engineering (CAEE) Journal, Elsevier, Mar.14, 2015.
Data compression is a challenging process with important practical applications. Specialized techniques for lossy and lossless data compression have been the subject of numerous investigations during last several decades. Previously, we studied the use of the pseudo-distance technique (PDT) in lossless compression of color-mapped images and its parallel implementation. In this paper we present a new technique (PDT2) to improve compression gain of PDT. We also present a parallelized implementation of the new technique, which results in substantial gains in compression time while providing the desired compression efficiency. We demonstrate that on non-dithered images PDT2 outperforms PDT by 22.4% and PNG by 29.3%. On dithered images, PDT2 achieves compression gains of 7.1% over PDT and 23.8% over PNG. We also show that the parallel implementation of PDT2, while compromising compression less than 0.3%, achieves near linear speedup and utilization of Intel Hyper-Threading technology on supported systems improves speedup on average 18%. More
[2] Koc, B., Arnavut, Z., Kocak, H., “Lossless compression of dithered images,” Photonics Journal, IEEE, vol.5, no.3, June 2013.
In order to display high-bit resolution images on low-bit resolution displays, bit resolution needs to be reduced. This problem is vital especially for low-cost or small (mobile) devices. To untangle the bit reduction problem, special color quantization algorithms, called dithering, are employed on high-bit resolution images. The dithering process helps to remedy the problem, but it does not help much in terms of storage and transmission of images. To reduce storage needs and lower data transmission, numerous special compression techniques have been proposed in the last several decades. While the well-known compression algorithms, such as gzip, help lower image file sizes, usually, they are not adequate. To improve the compression gain, special compression techniques that take into account structure of image data must be developed. In this paper, we show that, when the pseudo-distance technique (PDT) is used for dithered images, it yields better compression results than GIF and PNG. More
Refereed Conference Publications
[3] Koc, B., Arnavut, Z., Sarkar, D., Kocak, H., “Energy-aware transfer of compressed data on MSP432 family of microcontrollers," 16th International Conference on Clean Energy (ICCE), 2018.
We previously investigated the power consumption of several lossless data compression algorithms on a Texas Instrument (TI) MSP432 microcontroller. In this study, we examine the power consumption of transmission of data between two such microcontrollers using a TI CC3100 Wi-Fi transmission module. Our experimental measurements show that compression algorithms consume very little power compared to the power required to transmit data between the two microcontrollers. For example, while the transmission of an uncompressed 450x450 image used 79,569.0 mW, the compression with move-to-front transformation along with an arithmetic coder (MTF+AC) required 238.8 mW, and the transmission of the compressed image consumed 49,082.2 mW. In conclusion, to minimize energy consumption in sensor networks we recommend the compression of data as much as possible before transmission. More
[4] Koc, B., Arnavut, Z., Sarkar, D., Kocak, H., “Splitting Bits for Lossless Compression of Microarray Images," 14th International Conference on Smart Cities: Improving Quality of Life Using ICT & IoT, 2017.
In an earlier publication we reported on the effectiveness of the Burrows-Wheeler transformation followed by inversion coder (BWIC) in the lossless compression of DNA microarray images where we obtained gains of average 6.5% over generic image compressors. In this work, we propose an enhancement of our previous technique by exploiting the bit distribution of images. Using a simple statistical test, we first decide if it will be gainful to split a 16-bit microarray image into two 8-bit images. In case of splitting, it turns out that the first 8-bit image is highly compressible and we use BWIC to compress it. The second 8-bit image most often contains noise and the bit distribution can become nearly random. We use the Wald-Wolfowitz runs test of randomness to decide whether to compress the second 8-bit image with BWIC or not at all since attempting to compress random data usually results in a larger file size. On select microarray images, by splitting a 16-bit microarray image into 8-bit pieces and selectively compressing the pieces with BWIC, we can achieve upward of 3% compression gain over our previous work. More
[5] Arnavut, Z., Arnavut, M., Koc, B., Kocak, H., “Investigation of Row and Column Permutations for Lossless Compression of Images," High-capacity Optical Networks and Enabling Technologies (HONET-ICT), 2016.
The focus of our present study is on exploring the use of permutation techniques to achieve better compression gains in lossless image compression. As invertible functions, permutations are suitable for use in lossless image compression. In this study, we investigate the problem of determining an optimal permutation of rows or columns of images to improve the standard lossless compression algorithms, such as JPEG. We first recast an optimal permutation as a Hamiltonian circuit problem of an appropriate complete graph. Then we use the Lin-Kernighan heuristic algorithm for the symmetric Traveling Salesman Problem to compute the desired circuit. We include performance results of our proposed algorithm on a set of test images. More
[6] Koc, B., Sarkar, D., Kocak, H., Arnavut, Z., “A study of power consumption on MSP432 family of microcontrollers for lossless data compression,” High-Capacity Optical Networks and Enabling/Emerging Technologies (HONET), pp. 1-5, Dec. 21-23, 2015.
We empirically study power consumptions of two linear transformations and lossless data compression algorithms on a TI MSP432 microcontroller. We developed a custom circuit using a TI INA219 breakout board and an Arduino Uno R3 board and programmed it to record power usage automatically. We validated the accuracy of our measurements with that obtained from TI EnergyTrace software. Our experimental results show that arithmetic coder consumed the least power and required the lowest time for a compression gain of 21.89%. However, when data was preprocessed with the move-to-front transformation and compressed with an arithmetic coder, computation time and energy usage increased only by 21%, while compression gain nearly doubled to 38.39%. More
[7] Preston, C., Arnavut, Z., Koc, B., “Lossless compression of medical images using Burrows-Wheeler transformation with inversion coder,” Engineering in Medicine and Biology Society (EMBC), 2015 37th Annual International Conference of the IEEE, pp.2956-2959, Aug. 25-29, 2015.
Medical imaging is a quickly growing industry where the need for highly efficient lossless compression algorithms is necessary in order to reduce storage space and transmission rates for the large, high resolution, medical images. Due to the fact that medical imagining cannot utilize lossy compression, in the event that vital information may be lost, it is imperative that lossless compression be used. While several authors have investigated lossless compression of medical images, the Burrows-Wheeler Transformation with an Inversion Coder (BWIC) has not been examined. Our investigation shows that BWIC runs in linear time and yields better compression rates than well-known image coders, such as JPEG-LS and JPEG-2000. More
[8] Koc, B., Arnavut, Z., Kocak, H., “Lossless compression of DNA microarray images with inversion coder*,” High-capacity Optical Networks and Enabling Technologies (HONET), pp.186-189, Dec. 15-17, 2014.
DNA Microarray images are used to identify and monitor gene activity, or expression. In a single experiment, a large number of microarray images may be produced. Storage and archiving of these images are an important problem for researchers. Since microarray images can have a wide variety of nearly random patterns with no discernible structures, general entropy coders, e.g. Bzip2, or generic image compressors, e.g. JPEG-LS, do not perform well. In this work, we investigate performance of the inversion coding technique in lossless compression of DNA microarray images. We show that inversion coding outperforms commonly used entropy coders and image compressors. More
[9] Arnavut, Z., Koc, B., Kocak, H., “Scanning paths for lossless compression of pseudo-color images,” Image and Signal Processing Workshop (WNYISPW), 2014 IEEE Western New York, pp.11-14, Nov. 7, 2014.
Pseudo-color images are widely used on World-Wide-Web (WWW) to reduce file storage, RAM, video memory buffer space, and to speed up data transfers. A pseudo-color image consists of indices and indices are stored in a file with raster scan order. The investigations on different scanning patterns in filing of indices showed that further improvements on compression are possible. In this paper, we propose a lossless compression technique based on various scan patterns along with Burrows-Wheeler transformation and inversion rank. We show that proposed technique yields better compression gain than well-known techniques such as GIF, PNG and others on pseudo-color images. More
[10] Koc, B., Arnavut, Z., Kocak, H., “Lossless compression of DNA microarray images with inversion coder,” IEEE, Data Compression Conference (DCC), Mar. 26-28, 2014.
DNA microarray images are used to identify and monitor gene activity, or expression. In this study, we investigate the performance of the inversion coding technique in lossless compression of DNA microarray images. We show that inversion coding outperforms commonly used entropy coders and generic image compressors.More
[11] Koc, B., Arnavut, Z., Kocak, H., “Parallel lossless compression of color-mapped images,” High Capacity Optical Networks and Enabling Technologies (HONET-CNS), 2013 10th International Conference on, pp.131-135, Dec. 11-13, 2013.
The pseudo-distance technique (PDT) in lossless compression of color-mapped images has proved to be effective. We showed previously that by utilizing the PDT along with the Burrows-Wheeler transformation and an entropy coder, we obtained better compression gain than other well-known generic image compressors e.g. Portable Network Graphics (PNG). Most of these techniques have been designed as sequential image compression algorithms. In this paper, we propose a method for the PDT which allows to the parallelization of the PDT and reduces the compression time significantly. More
[12] Koc, B., Arnavut, Z., Kocak, H., “Lossless compression of dithered images with the pseudo-distance technique,” High Capacity Optical Networks and Enabling Technologies (HONET), 2012 9th International Conference on, pp.147-151, Dec. 12-14, 2012.
Despite many advances, still image storage and transfer, particularly in low-cost devices, remain to be important problems. For example, some wireless phone displays do not have the capacity to handle true colors. To remedy this problem, a color quantization (color palette) technique is often applied to images in order to reduce the number of colors. However, to avoid the side effects of the color-quantization, usually a process called dithering is applied to quantized images. Dithering techniques approximate colors which are not available in the palette by utilizing a diffusion technique of colored pixels from within the available palette. In this work, we examine compression of color-quantized images with different dithering techniques and show that the recently introduced modified pseudo-distance technique yields better compression results than the wellknown GIF and PNG techniques. More
[13] Koc, B., Arnavut, Z., “A new context-model for the pseudo-distance technique in lossless compression of color-mapped images,” 2012 SPIE Optics + Photonics, Proc. SPIE 8499, Applications of Digital Image Processing XXXV, Aug. 12-16, 2012.
In this work, we propose a method that utilizes a new context model along with a pseudo-distance technique in compression of color-mapped images. Graphic Interchange Format (GIF) and Portable Network Graphics (PNG) are two of the well-known and frequently used techniques for the compression of color-mapped images. There are several techniques that achieve better compression results than GIF and PNG; however, most of these techniques need two passes on the image data, while others do not run in linear time. The pseudo-distance technique runs in linear time and requires only one pass. We show that using the proposed context model along with the pseudo-distance technique yields better results than both PNG and GIF. More
[14] Koc, B., Arnavut, Z., “A modified pseudo-distance technique for lossless compression on color-mapped images,” IEEE, Data Compression Conference (DCC), Apr. 10-12, 2012.
In this work, we propose a new method, a modified pseudo-distance technique, for color-mapped image compression. There are several techniques that yield better compression results than GIF and PNG; however, some algorithms require two passes on the image data, while some do not run in linear time. Unlike these methods, the pseudo-distance technique requires one pass and runs in linear time. More
[15] Koc, B., Arnavut, Z., “Gradient adjusted predictor with pseudo-distance technique for lossless compression of color-mapped images,” IEEE, Frontiers of Information Technology (FIT), 2011, vol., no., pp.275-280, Dec. 19-21, 2011.
Color-mapped images are widely used in many applications. Unlike most of the color-mapped image compression techniques, which require two passes, the pseudo-distance compression technique requires one pass and runs in linear time. Recently, we showed that when a structured arithmetic coder is used, after a color-mapped image is transformed with a pseudo-distance technique, better compression gains can be achieved over GIF and Huffman coder. In this work, we show that further compression gains are possible when a Gradient Adjusted Predictor is employed along with the pseudo-distance technique. More
[16] Koc, B., Arnavut, Z., “Block-sorting transformations with pseudo-distance technique for lossless compression of color-mapped images,” Image Processing Workshop (WNYIPW), 2011 IEEE Western New York, pp.1-4, Nov 14, 2011. - Best Student Paper Award by IEEE and IS&T in Rochester, NY.
Color-mapped images are widely used in many applications, especially in WWW, and are usually compressed with Graphic Interchange Format (GIF) without any loss. In our recent work, we showed that further compression gains can be achieved for color-mapped images over GIF when a structured arithmetic coder is used along with the pseudo-distance metric, instead of a Huffman coder as suggested by others. In this work, we show that further compression gains are possible when block-sorting transformations are employed along with the pseudo-distance technique. More
[17] Koc, B., Arnavut, Z., “Application of pseudo-distance to lossless coding of color-mapped images,” System of Systems Engineering (SoSE), IEEE, 2011 6th International Conference on, pp.220-224, Jun. 27-30, 2011.
Palette images are widely used in many applications, including WWW which occupies an important role in Cloud Computing. Recently, it has been shown that better compression can be obtained when a Huffman coder is used after a color-mapped image is transformed with a pseudo-distance metric. Unlike most of the color-mapped image compression techniques, which require two passes, the pseudo-distance compression technique requires one pass and runs in linear time. In this work, we show that further compression gains can be achieved for color-mapped images when a structured arithmetic coder is used along with the pseudo-distance metric. More