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Recent advances in light field technologies is fostering the research and development of novel imaging applications. Such applications perform processing of the light field information to create new visual effects such as, for example, refocusing, perspective change, colour adjustment. Light field imaging is very data intensive compared with usual digital photographic imaging, and novel compression algorithms are needed for addressing the problem of light field storage and transmission. Raw digital light field images exhibit low spatial correlation if compared to regular images and hence the performance in terms of rate-distortion of current state-of-the-art image encoders can be superseded by devising novel image compression architectures.

In [21], a quality metric for light field content is designed. A light field image is a sampling of the intensity and direction information of the light rays crossing the main lens of a digital light field camera. The light field information captured by a camera must be processed in order to render images of the scene to the final user at a given focal plane or viewpoint. In the area of light field imaging, efficient representation, processing, compression and quality evaluation techniques and methodologies are currently under research in order to foster the development of novel industrial, entertainment or scientific applications. This paper focuses on the problem of evaluating the quality of experience when viewing rendered decompressed light field images. A processing chain for coding and decoding a light field image is first defined as reference model. Then, a novel metric for quality evaluation of the rendered views is proposed. This metric measures the variation of structural similarity on a set of viewpoints extracted from the light field. Subjective evaluation is performed and the correlation between objective metrics and the subjective results is reported and discussed. The proposed objective quality metric resulted in a nearly strong correlation with the subjective assessment results.

In [20], an architecture for lossy compression of unfocused light field images is proposed. Raw light fields are preprocessed by demosaicing, devignetting and slicing of the raw lenslet array image. The slices are then compressed with the JPEG 2000 image coding standard. The performance of the proposed method is compared against direct application of JPEG 2000 compression on the 4D light field. The experimental analysis has been conducted under a set of different compression ratios and the obtained results show that the proposed method outperforms direct application of the reference architecture.

An analysis of raw light field image compression of sliced lenslet array is presented in [19] The distortion introduced by compression is measured in terms of peaks signal-to-noise ratio and the structural similarity index. The obtained results are finally discussed.

An algorithm for lossy compression of unfocused light field images is proposed in [18]. The raw light field is preprocessed by demosaicing, devignetting and slicing of the raw lenset array image. The slices are then rearranged in tiles and compressed by the standard JPEG 2000 encoder. The experimental analysis compares the performance of the proposed method against the direct compression with JPEG 2000, and JPEG XR, in terms of BD-PSNR gain and bit rate reduction. Obtained results show that the proposed method outperforms direct application of the reference state of the art image encoders.

Current methodologies for the generation of 3D point cloud from real world scenes rely upon a set of 2D images capturing the scene from several points of view. Novel plenoptic cameras sample the light field crossing the main camera lens creating a light field image. The information available in a plenoptic image must be processed in order to render a view or create the depth map of the scene. A method for the reconstruction of 3D models is proposed in [17]. The reconstruction of the model is obtained from a single image shot. Exploiting the properties of plenoptic images, a point cloud is generated and compared with a point cloud of the same object but generated with a different plenoptic camera.

An efficient coding scheme based on low-complexity preprocessing of the raw light field image, is proposed in [16]. It produces a pseudo-temporal sequence of frames (i.e., pseudo-video) for standard compression using HEVC. The proposed scheme also aims at contributing for defining a benchmark for compression of light field images using standard video codecs.

In [15], a framework aiming at ensuring user control over his data while minimizing the user intervention needed for enabling the control functionalities is proposed. (XPLORE)

In [14], a performance study of HEVC-compatible coding of Lytro-Illum light fields using different data formats for standard coding is presented. The results show that relative performance is not consistent across all coding configurations, raising new research questions regarding standard coding of Lytro-Illum light fields using HEVC. Most importantly, the proposed data formats greatly increase HEVC performance. (XPLORE)

In [13], an algorithm for the compression of light field images a.k.a. plenoptic images is proposed. The micro images composing a plenoptic image are processed by an adaptive prediction tool, aiming at reducing data correlation before entropy coding takes place. The algorithm is compared with state-of-the-art image compression algorithms, namely, JPEG 2000 and JPEG XR. Obtained results demonstrate that the proposed algorithm improves the coding efficiency.  (BIBTEX (XPLORE)

In [12], a no-reference method for image blockiness estimation in the spatial domain is presented. Based on the Sobel operator, a low computational complexity algorithm is proposed for measuring blockiness distortion. Simulation results show that the blockiness estimation obtained by the proposed algorithm is comparable with algorithms demanding higher computational complexity. (Block distortion metric algorithm and code).

In [11], a smart phone application aiming at reducing both cellular network load and file downloading time by leveraging network resource sharing. Groups of neighboring devices are formed depending on geographical position and battery consumption. WWAN and WLAN are then shared under an altruistic cooperative scenario for an increased user experience when accessing multimedia content.

In [10], a comparison between the JPEG XR and JPEG 2000 as tools for re-encoding JPEG images taken by smart phone camera is presented. Experimental tests on image data set are performed in order to collect numerical evidence of the distortion introduced by the re-encoding process.

In [9], a client-server architecture enabling network resource sharing for image download applications is proposed. Experimental analysis is based on subjective evaluation where user compares direct access to images with the proposed cooperative access. Results show that downloading time can be drastically reduced for an increased user experience.

In [8], a two-stage identification method for signals in the white spaces, using combined energy detection and feature detection. The band of interest is divided by means of the Discrete Wavelet Packet Transformation (DWPT) in sub-bands where the signal power is calculated. Modulation classifiers taking into account the statistical parameters of the signal in the wavelet domain are used as features for identifying the modulation schemes, in this case specifically for the DVB-T broadcast standard. Finally, a signal transmission architecture based on Motion JPEG XR has been implemented in order to explore and evaluate a practical application of indoor signal distribution over white-spaces.

In [7,(PDF)], an interactive high resolution image viewing architecture for mobile devices based on JPEG XR. Display resolution, resolution scalability, image tiling are investigated in order to optimize the coding parameters with the objective to improve the user experience. Experimental tests are performed on a set of large images and comparisons against accessing the images without parameter optimization are reported.

In [6], a comparison between ISO/IEC image coding standards JPEG, JPEG 2000 and JPEG XR is presented. The main objective is to evaluate the performances of the recently standardized JPEG XR in transmissions over channel affected by errors.

In [5], an algorithm for error recovery in JPEG XR images is presented. The algorithm enables the decoder to realign itself to the right bitstream position and to correctly decode the most part of the image while adding very little computational overhead.

In [4], an technique combining fractals theory and wavelet decomposition to achieve spatial zoom and slow motion replay of HD digital color video sequences is presented.

In [3], a method for browsing large JPEG XR compressed images over the Internet is presented. Region of interest specified by the user are progressively downloaded and displayed with an approach aiming to minimize the transferred information between the request and the image presentation. Experimental analysis show that the proposed method is an effective way for browsing large JPEG XR coded images.

In [2]  a server-client remote-control application for sharing a Scanning Electron Microscope between laboratories is proposed. Obtained results show that all the main requirements indicated in the introduction as possible application fields have been successfully satisfied. In particular, the developed
application gives the possibility to carry out remote video analyses and microscope remote controlling for educational goals.

In [1], luminance masking, Contrast Sensitivity Function (CSF) and temporal masking are taken into account with fast in-service algorithms for a novel no-reference quality index which uses an effective HVS model. The proposed index is able to assess blockiness distortion with a fast image domain measure.

REFERENCES

 

 

[22] Cristian Perra, W. Song, A. Liotta, “Effects of light field subsampling on the quality of experience in refocusing applications”, International Conference on Quality of Multimedia Experience (QoMEX), Santa Margherita di Pula, Italy, 2018, ISBN: 978-1-5386-2605-4 (DOI)

[21] Cristian Perra, “Assessing the quality of experience in viewing rendered decompressed light field,” Multimedia Tools and Applications, 2018,  ISSN: 13807501, DOI: 10.1007/s11042-018-5615-3

[20] C. Perra, D.D. Giusto, “Light Field Compression on Sliced Lenslet Array”, International Journal of Internet Technology and Secured Transactions, 2017, ISSN: 1748-5703

[19]  C. Perra, D.D. Giusto, “Raw Light Field Image Compression of Sliced Lenslet Array”, IEEE International Symposium on Broadband Multimedia Systems and Broadcasting , Cagliari, Italy, 2017.

[18] C. Perra, D. Giusto, “JPEG 2000 Compression of Unfocused Light Field Images Based on Lenslet Array Slicing”, IEEE International Conference on Consumer Electronics (ICCE), Las Vegas, USA, 2017.

[17] C. Perra, F. Murgia, D. Giusto, “An analysis of 3D point cloud reconstruction from light field images,” IEEE International Conference on Image Processing Theory, Tools and Applications (IPTA), Oulu, Finland, 2016.

[16] C. Perra, P. Assuncao, “High efficiency coding of light field images based on tiling and pseudo-temporal data arrangement,” IEEE International Conference on Multimedia and Expo, Seattle, USA, July 2016.  (PDF)

[15] C. Perra, “A framework for user control over media data based on a trusted point,”  IEEE International Conference on Consumer Electronics (ICCE), 2015. (XPLORE)

[14] A. Vieira, H. Duarte, C. Perra, L. Tavora, P. Assuncao, “Data formats for high efficiency coding of Lytro-Illum light fields”, in International Conference on Image Processing Theory, Tools and Applications (IPTA), 2015. (XPLORE)

[13] C. Perra, “Lossless plenoptic image compression using adaptive block differential prediction,” IEEE International Conference on acoustics, speech, and signal processing, 2015. (BIBTEX (XPLORE)

[12] C. Perra, “A Low Computational Complexity Blockiness Estimation based on Spatial Analysis,” IEEE 22nd Telecommunications Forum (Telfor), 2014, ISBN: 978-1-4799-6190-0. (Block distortion metric algorithm and code).

[11] C. Perra, “Wireless Cooperative Access for Next Generation Mobility Applications,” IEEE 21st Telecommunications forum (TELFOR), 2013.

keywords – Cooperative Access, Network Cooperation, Mobility Applications, Network rosource sharing, JPEG, JPEGXR, JPEG XR

[10] C. Perra, “Re-encoding JPEG images for smart phone applications,” IEEE 21st Telecommunications forum (TELFOR), 2013

keywords – Digital Photography, JPEG, JPEGXR, JPEG XR, Image Coding, Re-encoding, Transcoding, Smart Phone Applications

[9] C. Perra, “Wireless cooperative access to images,” 9th IEEE International Wireless Communications and Mobile Computing Conference, 2013.

keywords – Mobile Device Cooperation, Image Transmission, Image Coding, Digital Photography, JPEG, JPEGXR, JPEG XR, Smartphone applications

[8] M. Fadda, M. Murroni, C. Perra, V. Popescu, “TV White Spaces Exploitation for Multimedia Signal Distribution,”  Signal Processing: Image Communication, 2012.

[7] B. Saba, C. Perra, D.D. Giusto, “Interactive image viewing in mobile devices based on JPEG XR,” Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2012. (PDF)

[6] B. Saba, C. Perra, D.D. Giusto, “Image transmission over error-prone channels”, IEEE 19th Telecommunications forum (TELFOR), 2011.

[5] C. Perra,  P.A. Pes, D.D. Giusto, “High-Frequency Error Recovery In JPEG XR Coded Images”, IEEE International Conference on Image Processing (ICIP), 2011.

[4] M. Murroni, C. Perra, D.D. Giusto, “Slow Motion and Zoom in HD Digital Videos using Fractals”, International Journal of Digital Multimedia Broadcasting, 2009.

[3] C. Perra, D.D. Giusto, “An image browsing application based on JPEG XR,”  International Workshop on Content-Based Multimedia Indexing (CBMI), 2008.

[2] F. Mighela, C. Perra, “Remote Control  for  Microscopy  Applications,” IEEE Instrumentation and Measurement Technology Conference (IMTC), 2006.

[1] F. Massidda, D.D. Giusto, C. Perra, “No reference video quality estimation based on human visual system for 2.5/3G devices,” Proceedings of SPIE – The International Society for Optical Engineering, 2005.

ABSTRACTS

Cristian Perra, “Assessing the quality of experience in viewing rendered decompressed light field,” Multimedia Tools and Applications, 2018,  ISSN: 13807501, DOI: 10.1007/s11042-018-5615-3

Abstract —A light field image is a sampling of the intensity and direction information of the light rays crossing the main lens of a digital light field camera. The light field information captured by a camera must be processed in order to render images of the scene to the final user at a given focal plane or viewpoint. In the area of light field imaging, efficient representation, processing, compression and quality evaluation techniques and methodologies are currently under research in order to foster the development of novel industrial, entertainment or scientific applications. This paper focuses on the problem of evaluating the quality of experience when viewing rendered decompressed light field images. A processing chain for coding and decoding a light field image is first defined as reference model. Then, a novel metric for quality evaluation of the rendered views is proposed. This metric measures the variation of structural similarity on a set of viewpoints extracted from the light field. Subjective evaluation is performed and the correlation between objective metrics and the subjective results is reported and discussed. The proposed objective quality metric resulted in a nearly strong correlation with the subjective assessment results.

[16] C. Perra, P. Assuncao, “High efficiency coding of light field images based on tiling and pseudo-temporal data arrangement”, IEEE International Conference on Multimedia and Expo, Seattle, USA, July 2016.  (PDF)

Abstract —Digital light fields are obtained by sampling of huge number of light rays, capturing the colour intensity of a whole visual scene from different view angles. The large amount of data that is necessary to represent a light field requires highly efficient compression methods to store and exchange such type of signals. This paper presents a light field coding scheme based on a low-complexity preprocessing approach that generates a pseudo-video sequence suitable for standard compression using HEVC. The efficiency of the proposed scheme is evaluated using a data set of twelve light field images and low-delay B HEVC coding configuration. The R-D performance obtained by the proposed scheme is consistently better than JPEG, revealing significantly higher gains, particularly for higher compression ratios.

[15]  C. Perra, “A framework for user control over media data based on a trusted point,”  IEEE International Conference on Consumer Electronics (ICCE), 2015.  (XPLORE)

Abstract —The rapid evolution of media services has having a strong impact on the way users process and share their data. At the same time, users are becoming every day more aware of the risks that might arise while exchanging or processing video data through the net. The need for frameworks enabling processing and sharing of the content under user control is becoming a very important issue since adequate level of security and privacy must be provided to the final users. After reviewing the state of the art in the area of media processing and sharing under user control, this paper presents a framework aiming at ensuring user control over his data while minimizing the user intervention needed for enabling the control functionalities.

[14] A. Vieira, H. Duarte, C. Perra, L. Tavora, P. Assuncao, “Data formats for high efficiency coding of Lytro-Illum light fields”, in International Conference on Image Processing Theory, Tools and Applications (IPTA), 2015.  (XPLORE)

Abstract —Light fields captured by the Lytro-Illum camera are the first to appear in the consumer market, capable of providing refocused pictures at acceptable spatial resolution and quality. Since this is partially due to sampling of a huge number of light rays, efficient compression methods are required to store and exchange light field data. This paper presents a performance study of HEVC-compatible coding of Lytro-Illum light fields using different data formats for standard coding. The efficiency of 5 different light field data formats are evaluated using a data set of 12 light field images and the standard HEVC coding configurations of Still-Image Profile, All-Intra, Low Delay B and P and Random Access. Unexpectedly, the results show that relative performance is not consistent across all coding configurations, raising new research questions regarding standard coding of Lytro-Illum light fields using HEVC. Most importantly, the proposed data formats greatly increase HEVC performance.

[13] C. Perra, “Lossless plenoptic image compression using adaptive block differential prediction,” IEEE International Conference on acoustics, speech, and signal processing, 2015.

Abstract —Plenoptic images are obtained from the projection of the light crossing a matrix of microlens arrays which replicates the scene from different direction into a camera device sensor. Plenoptic images have a different structure with respect to regular digital images, and novel algorithms for data compression are currently under research. This paper proposes an algorithm for the compression of plenoptic images. The micro images composing a plenoptic image are processed by an adaptive prediction tool, aiming at reducing data correlation before entropy coding takes place. The algorithm is compared with state-of-the-art image compression algorithms, namely, JPEG 2000 and JPEG XR. Obtained results demonstrate that the proposed algorithm improves the coding efficiency.

[12] C. Perra, “A Low Computational Complexity Blockiness Estimation based on Spatial Analysis,” IEEE 22nd Telecommunications Forum (Telfor), 2014, ISBN: 978-1-4799-6190-0. (Block distortion metric algorithm and code).

Abstract —Measuring blockiness distortion in images and video is fundamental in the field of image and video quality assessment. A no-reference method for image blockiness estimation in the spatial domain is presented in this paper. Based on the Sobel operator, a low computational complexity algorithm is proposed for measuring blockiness distortion. Simulation results show that the blockiness estimation obtained by the proposed algorithm is comparable with algorithms demanding higher computational complexity.

Keywords — No-reference, Blockiness, Sobel, Image quality, Distortion.

[11] C.Perra, “Wireless Cooperative Access for Next Generation Mobility Applications,” IEEE 21st Telecommunications forum (TELFOR), 2013.

Abstract —This paper presents a smart phone application aiming at reducing both cellular network load and file downloading time by leveraging network resource sharing. Groups of neighboring devices are formed depending on geographical position and battery consumption. WWAN and WLAN are then shared under an altruistic cooperative scenario for an increased user experience when accessing multimedia content.

Keywords —Cooperative access, Network cooperation.

Research Areas: Cooperative Access, Network Cooperation, Mobility Applications, Network rosource sharing, JPEG, JPEGXR, JPEG XR

[10] C. Perra, “Re-encoding JPEG images for smart phone applications,” IEEE 21st Telecommunications forum (TELFOR), 2013.

Abstract — Capturing, storing and browsing images from smart phones is a task performed by any user every day. ISO/IEC JPEG is the commonly used standard for lossy compression of digital images. During the more than twenty years from JPEG standardization, novel image coding algorithms have been developed providing superior compression capabilities. In particular, the recent JPEG XR, providing high compression ratios and low computational complexity is an interesting candidate for the development of novel applications for smart phones. In this paper, a comparison between the JPEG XR and JPEG 2000 as tools for re-encoding JPEG images taken by smart phone camera is presented. Experimental tests on image data set are performed in order to collect numerical evidence of the distortion introduced by the re-encoding process.

Keywords —Digital photography, JPEG XR, image coding.

Research Areas: Digital Photography, JPEG, JPEGXR, JPEG XR, Image Coding, Re-encoding, Transcoding, Smart Phone Applications

[9] C. Perra, “Wireless cooperative access to images,” 9th IEEE International Wireless Communications and Mobile Computing Conference, 2013.

Abstract —User expectations while accessing visual content from mobile devices are often neglected for reasons that are mainly related to the time varying nature of overlay networks. Fast spreading of smart phone devices is fostering novel applications enabling cooperative access to multimedia resources exploiting cooperation between devices by sharing network resources. This paper focuses on accessing remote images from smart phone devices in a cooperative scenario. A client-server architecture enabling network resource sharing for image download applications is proposed. Experimental analysis is based on subjective evaluation where user compares direct access to images with the proposed cooperative access. Results show that downloading time can be drastically reduced for an increased user experience.

Keywords — mobile device cooperation, image transmission

Research Areas: Mobile Device Cooperation, Image Transmission, Image Coding, Digital Photography, JPEG, JPEGXR, JPEG XR, Smartphone applications

[8] M. Fadda, M. Murroni, C. Perra, V. Popescu, “TV White Spaces Exploitation for Multimedia Signal Distribution,”  Signal Processing: Image Communication, 2012.

Abstract — The new spectrum regulation policies for dynamic spectrum access, especially those concerning the use of the white spaces in the Digital Terrestrial Television (DTT) bands, arise the need for fast and reliable signal identification and classification methods. In this paper we present a two-stage identification method for signals in the white spaces, using combined energy detection and feature detection. The band of interest is divided by means of the Discrete Wavelet Packet Transformation (DWPT) in sub-bands where the signal power is calculated. Modulation classifiers taking into account the statistical parameters of the signal in the wavelet domain are used as features for identifying the modulation schemes, in this case specifically for the DVB-T broadcast standard. Finally, a signal transmission architecture based on Motion JPEG XR has been implemented in order to explore and evaluate a practical application of indoor signal distribution over white-spaces.

Keywords — signal processing for transmission, dynamic spectrum access, TV whites paces, spectrum sensing

[7] B. Saba, C. Perra, D.D. Giusto, “Interactive image viewing in mobile devices based on JPEG XR,” Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2012.

Abstract — Services for high definition image browsing on mobile devices require a careful design since the user experience is heavily depending on the network bandwidth, processing delay, display resolution, image quality. Modern applications require coding technologies providing tools for resolution and quality scalability, for accessing spatial regions of interest (ROI), for reducing the domain of the coding algorithm decomposing large images into tiles. Some state-of-the-art technologies satisfying these requirements are the JPEG2000 and the JPEG XR. This paper presents the design of an interactive high resolution image viewing architecture for mobile devices based on JPEG XR. Display resolution, resolution scalability, image tiling are investigated in order to optimize the coding parameters with the objective to improve the user experience. Experimental tests are performed on a set of large images and comparisons against accessing the images without parameter optimization are reported.

Keywords — JPEG XR, Interactive Access.

[6] B. Saba, C. Perra, D.D. Giusto, “Image transmission over error-prone channels”, IEEE 19th Telecommunications forum (TELFOR), 2011.

Abstract — This paper deals with the problem of image transmission over error-prone channels. A comparison between ISO/IEC image coding standards JPEG, JPEG 2000 and JPEG XR is presented. The main objective is to evaluate the performances of the recently standardized JPEG XR in transmissions over channel affected by errors.

Keywords — Error channel, image coding, JPEG XR.

[5] C. Perra,  P.A. Pes, D.D. Giusto, “High-Frequency Error Recovery In JPEG XR Coded Images”, IEEE International Conference on Image Processing (ICIP), 2011.

Abstract — Image data compressed with JPEG XR when transmitted over error-prone channels is severely distorted. In fact, due to the adaptive coding strategies used by the codec, even a single bit error causes a mismatch in the alignment of the reading position from the bitstream, leading to completely different images at the decoder side. We propose an extension to the JPEG XR algorithm, consisting in an error recovery process enabling the decoder to realign itself to the right bitstream position and to correctly decode the most part of the image. We have performed several experiments using different encoder parameter and different error probabilities while image distortion is measured by PSNR objective metric. The simplicity of the proposed algorithm adds very little computational overhead and seems very promising as confirmed by objective image quality results in experimental tests.

Keywords — Error recovery, Image coding, JPEG XR

[4] M. Murroni, C. Perra, D.D. Giusto, “Slow Motion and Zoom in HD Digital Videos using Fractals”, International Journal of Digital Multimedia Broadcasting, 2009.

Abstract —Slow motion replay and spatial zooming are special effects used in digital video rendering. At present, most techniques to perform digital spatial zoom and slow motion are based on interpolation for both enlarging the size of the original pictures and generating additional intermediate frames. Mainly, interpolation is done either by linear or cubic spline functions or by motion estimation/compensation which both can be applied pixel by pixel, or by partitioning frames into blocks. Purpose of this paper is to present an alternative technique combining fractals theory and wavelet decomposition to achieve spatial zoom and slow motion replay of HD digital color video sequences. Fast scene change detection, active scene detection, wavelet subband analysis and color fractal coding based on Earth Mover’s Distance (EMD) measure are used to reduce computational load and to improve visual quality. Experiments show that the proposed scheme achieves better results in terms of overall visual quality compared to the state‐of‐the art techniques.

Keywords — Video Rendering, HDTV, fractals, wavelets

[3] C. Perra, D.D. Giusto, “An image browsing application based on JPEG XR,”  International Workshop on Content-Based Multimedia Indexing (CBMI), 2008.

Abstract — A method for browsing large compressed images over the Internet is presented. Images are compressed using a very recent coded file format, referred to as JPEG XR, designed primarily for storage of continuous-tone photographic images and currently at the beginning of the ISO/IEC standardization process. In the proposed method, region of interest specified by the user are progressively downloaded and displayed with an approach aiming to minimize the transferred information between the request and the image presentation. Experimental analysis show that the proposed method is an effective way for browsing large JPEG XR coded images.

Keywords —JPEG XR, JPEG2000, Image Browsing

[2] F. Mighela, C. Perra, “Remote Control  for  Microscopy  Applications,” IEEE Instrumentation and Measurement Technology Conference (IMTC), 2006.

Abstract — The sharing of resources and instruments between research laboratories is becoming a widespread policy, in particular as a consequence of the rapid development of ICT technologies. The paper proposes a remote-control application for sharing a Scanning Electron Microscope between laboratories.

[1] F. Massidda, D.D. Giusto, C. Perra, “No reference video quality estimation based on human visual system for 2.5/3G devices,” Proceedings of SPIE – The International Society for Optical Engineering, 2005.

Abstract — 2.5/3G devices should achieve satisfactory QoS, overcoming mobile standards drawbacks. In-service/blind quality monitoring is essential in order to improve perceptual quality according to Human Visual System. Several techniques have been proposed for image/video quality assessment. A novel no-reference quality index which uses an effective HVS model is proposed. Luminance masking, Contrast Sensitivity Function and temporal masking are taken into account with fast in-service algorithms. The proposed index is able to assess blockiness distortion with a fast image domain measure. Compression/post-processing blurring effects are measured with a standard approach. Moving artifacts distortion is evaluated taking into account standard deviation with respect to a natural image statistical model. Several distortion effects, in wireless noisy channels with low video-streaming/playback bit rates (e.g. edge busyness and image persistence) are evaluated. A multi-level pooling algorithm (block, temporal-window, frame, and sequence levels) is used. Validation tests have been developed in order to assess index performance and computational complexity. The final measure provides human-like threshold-effect and high correlation with subjective data. Low complexity algorithms can be derived for real-time, HVS-based, QoS management for low-power consumer devices. Different distortion effects (e.g. ringing and jerkiness) can be easily included.

Additional information:

Subject: Light field; Plenoptic; Sub-aperture; Lenslet array; 3D Point Cloud; Coding; Compression; Transmission; HEVC; JPEG2000; PSNR; SSIM; Objective quality evaluation; Subjective quality evaluation.

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Performance analysis of JPEG Pleno light field coding2019Perra, C.; Astola, Pekka; da Silva, Eduardo A. B.; Khanmohammad, Hesam; Schelkens, Peter; Tabus, ...Ioan
JPEG Pleno: providing representation interoperability for holographic applications and devices2019Schelkens, Peter; Ebrahimi, Touradj; Gilles, Antonin; Gioia, Patrick; Oh, Kwan-Jung; Pereira, Fer...nando; Perra, Cristian; Pinheiro, Antonio M. G.ETRI JOURNAL
Short-long term anomaly detection in wireless sensor networks based on machine learning and multi-parameterized edit distance2019Cauteruccio, F.; Fortino, G.; Guerrieri, A.; Liotta, A.; Mocanu, D. C.; Perra, C.; Terracina, G.;... Torres Vega, M.INFORMATION FUSION
A framework for view progressive coding of light field2018Perra, C.; Giusto, D.Institute of Electrical and Electronics Engineers Inc.
Leveraging OTT and ISP Cooperation to Enhance End to End QoS by Exchanging Valuable Resources2018Scarlato, Michele; Ortiz, Jordi; Perra, Cristian; Skarmeta, AntonioIEEE Computer Society
Effects of light field subsampling on the quality of experience in refocusing applications2018Perra, C.; Song, W.; Liotta, A.Institute of Electrical and Electronics Engineers Inc.
An Analysis of HEVC Compression for Light Field Image Refocusing Applications2018Perra, C.; Giusto, Daniele
Light field compression on sliced lenslet array2018Perra, Cristian; Giusto, DanieleINTERNATIONAL JOURNAL OF INTERNET TECHNOLOGY AND SECURED TRANSACTIONS
A Review of Predictive Quality of Experience Management in Video Streaming Services2018Torres Vega, Maria; Perra, Cristian; De Turck, Filip; Liotta, AntonioIEEE TRANSACTIONS ON BROADCASTING
Resilience of Video Streaming Services to Network Impairments2018Torres Vega, Maria; Perra, Cristian; Liotta, AntonioIEEE TRANSACTIONS ON BROADCASTING
Assessing the quality of experience in viewing rendered decompressed light fields2018PERRA, CRISTIANMULTIMEDIA TOOLS AND APPLICATIONS
Next generation architecture for real time multimedia applications2017Scarlato, Michele; Perra, CristianInstitute of Electrical and Electronics Engineers Inc.
JPEG 2000 compression of unfocused light field images based on lenslet array slicing2017Perra, Cristian; Giusto, DanieleInstitute of Electrical and Electronics Engineers Inc.
Effect of Lossy Networks on Stereoscopic 3D-Video Streams2017Torres Vega, Maria; Perra, Cristian; Mocanu, Decebal Constantin; Liotta, Antonio
Raw light field image compression of sliced lenslet array2017Perra, Cristian; Giusto, DanieleIEEE (Institute of Electrical and Electronics Engineers)
Light field coding based on flexible view ordering for unfocused plenoptic camera images2017Perra, CristianINTERNATIONAL JOURNAL OF APPLIED ENGINEERING RESEARCH
High efficiency coding of light field images based on tiling and pseudo-temporal data arrangement2016Perra, Cristian; Assuncao, Pedro
3D reconstruction from plenoptic image2016Murgia, Francesca; Giusto, Daniele; Perra, CristianIEEE (Institute of Electrical and Electronics Engineers)
An analysis of 3D point cloud reconstruction from light field images2016Perra C; Murgia F; Giusto D
3D point cloud reconstruction from single plenoptic image2016Murgia, F.; Perra, C.; Giusto, D.TELFOR JOURNAL
Lossless plenoptic image compression using adaptive block differential prediction2015Perra, CristianInstitute of Electrical and Electronics Engineers
Data Formats for High Efficiency Coding of Lytro-Illum Light Fields2015Vieira, A; Duarte, H; Perra, Cristian; Tavora, L; Assuncao, P.
A Framework for User Control Over Media Data Based on a Trusted Point2015PERRA C
Unfocused plenoptic camera calibration2014Murgia F; Fernandez S B; Giusto D D; Perra C
Comparing Gamma and Weibull as Frame Size Distributions for High Efficient Video Coding2014Perra, CristianELEKTRONIKA IR ELEKTROTECHNIKA
A Low Computational Complexity Blockiness Estimation based on Spatial Analysis2014Perra C
Next Generation Mobility Applications: A Wireless Cooperative Access Architecture2014Perra CTELFOR JOURNAL
On the coding of plenoptic raw images2014Perra C
Wireless Cooperative Access for Next Generation Mobility Applications2013PERRA C
Wireless cooperative access to images2013Perra C
Re-encoding JPEG images for smart phone applications2013PERRA C
TV white spaces exploitation for multimedia signal distribution2012Fadda M; Murroni M; Perra C; Popescu VSIGNAL PROCESSING-IMAGE COMMUNICATION
Interactive image viewing in mobile devices based on JPEG XR2012Saba B.; Perra C.; Giusto DLECTURE NOTES OF THE INSTITUTE FOR COMPUTER SCIENCES, SOCIAL INFORMATICS AND TELECOMMUNICATIONS ENGINEERINGSpringer
   
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