Papers by Massimiliano Agostinelli
Standards play an important role in providing a common set of specifications and allowing inter-o... more Standards play an important role in providing a common set of specifications and allowing inter-operability between devices and systems. Until recently, no standard for high-dynamic-range (HDR) image coding had been adopted by the market, and HDR imaging relies on proprietary and vendor-specific formats which are unsuitable for storage or exchange of such images. To resolve this situation, the JPEG Committee is developing a new coding standard called JPEG XT that is backward compatible to the popular JPEG compression, allowing it to be implemented using standard 8-bit JPEG coding hardware or software. In this paper, we present design principles and technical details of JPEG XT. It is based on a two-layer design, a base layer containing a low-dynamic-range image accessible to legacy implementations, and an extension layer providing the full dynamic range. The paper introduces three of currently defined profiles in JPEG XT, each constraining the common decoder architecture to a subset...
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IEEE Signal Processing Magazine, 2016
I. BACKGROUND A. Motivations H IGH BIT DEPTH data acquisition and manipulation have been largely ... more I. BACKGROUND A. Motivations H IGH BIT DEPTH data acquisition and manipulation have been largely studied at the academic level in the last 15 years and are rapidly attracting interest at the industrial level. An example of the high interest for High Dynamic Range (HDR) imaging is the use of 32-bit floating point data for video and image acquisition and manipulation that allows a variety of visual effects that closely mimic the real world visual experience of the end-user [1] (see Fig. 1 for an illustration). At industrial level, we are witnessing increasing traction towards supporting HDR and Wide Color Gamut (WCG). WCG leverages HDR for each color channel to display a wider range of colors. Consumer cameras are currently available with 14 or 16 bit A/D converter. Rendering devices are also appearing with the capability to display HDR images and video with a peak brightness of up to 4000 nits and to support wide color gamut (ITU-R Rec. BT.2020 [2]) rather than the historical ITU-R Rec. BT.709 [3]. This trend calls for a widely accepted standard for higher bit depth support that can be seamlessly integrated into existing products and applications. While standard formats such as JPEG 2000 [5] and JPEG XR [6] offer support for high bit depth image representations, their adoption requires a non-negligible investment that may not always be affordable in existing imaging ecosystems, and induces a difficult transition, as they are not backwardcompatible with the popular JPEG image format. Instead, most digital camera and mobile phone manufacturers either store images in proprietary RAW formats or, more commonly, offer an HDR mode, which produces a traditional low dynamic range image with improved details. The former solution creates a vendor lock-in problem for consumers, making it difficult to efficiently use images produced by such
Journal of Real-Time Image Processing, 2015
Standards play an important role in providing a common set of specifications and allowing interop... more Standards play an important role in providing a common set of specifications and allowing interoperability between devices and systems. Until recently, no standard for High Dynamic Range (HDR) image coding had been adopted by the market, and HDR imaging relies on proprietary and vendor specific formats which are unsuitable for storage or exchange of such images. To resolve this situation, the JPEG Committee is developing a new coding standard called JPEG XT that is backwards compatible to the popular JPEG compression, allowing it to be implemented using standard 8-bit JPEG coding hardware or software. In this paper, we present design principles and technical details of JPEG XT. It is based on a two-layers design, a base layer containing a Low Dynamic Range (LDR) image accessible to legacy implementations, and an extension layer providing the full dynamic range. The paper introduces three of currently defined profiles in JPEG XT, each constraining the common decoder architecture to a subset of allowable configurations. We assess the coding efficiency of each profile extensively through subjective assessments, using 24 naïve subjects to evaluate 20 images, and objective evaluations, using 106 images with five different tone-mapping operators and at 100 different bit rates. The objective results (based on benchmarking with subjective scores) demonstrate that JPEG XT can encode HDR images at bit rates varying from 1.1 to 1.9 bit/pixel for estimated mean opinion score (MOS) values above
![Research paper thumbnail of JPEG XT: A Compression Standard for HDR and WCG Images [Standards in a Nutshell]](proxy.php?u=https://attachments.academia-assets.com/70834681/thumbnails/1.jpg)
IEEE Signal Processing Magazine, 2016
I. BACKGROUND A. Motivations H IGH BIT DEPTH data acquisition and manipulation have been largely ... more I. BACKGROUND A. Motivations H IGH BIT DEPTH data acquisition and manipulation have been largely studied at the academic level in the last 15 years and are rapidly attracting interest at the industrial level. An example of the high interest for High Dynamic Range (HDR) imaging is the use of 32-bit floating point data for video and image acquisition and manipulation that allows a variety of visual effects that closely mimic the real world visual experience of the end-user [1] (see Fig. 1 for an illustration). At industrial level, we are witnessing increasing traction towards supporting HDR and Wide Color Gamut (WCG). WCG leverages HDR for each color channel to display a wider range of colors. Consumer cameras are currently available with 14 or 16 bit A/D converter. Rendering devices are also appearing with the capability to display HDR images and video with a peak brightness of up to 4000 nits and to support wide color gamut (ITU-R Rec. BT.2020 [2]) rather than the historical ITU-R Rec. BT.709 [3]. This trend calls for a widely accepted standard for higher bit depth support that can be seamlessly integrated into existing products and applications. While standard formats such as JPEG 2000 [5] and JPEG XR [6] offer support for high bit depth image representations, their adoption requires a non-negligible investment that may not always be affordable in existing imaging ecosystems, and induces a difficult transition, as they are not backwardcompatible with the popular JPEG image format. Instead, most digital camera and mobile phone manufacturers either store images in proprietary RAW formats or, more commonly, offer an HDR mode, which produces a traditional low dynamic range image with improved details. The former solution creates a vendor lock-in problem for consumers, making it difficult to efficiently use images produced by such
Visual assessment of HDR video
Electronic Imaging, 2016
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Papers by Massimiliano Agostinelli