Directional coding of backward compatible high dynamic range (HDR) image coding residues

Download

index.pdf

Date

2018

Author

Feyiz, Kutan

Metadata

Show full item record

Item Usage Stats

250
views

230
downloads

High dynamic range (HDR) image and video formats are proposed to overcome limitations of widely accepted standard 8-bit low dynamic range (LDR) image and video representations. The main aim of these formats is to encode the whole luminance range of real world scenes which changes from extreme darkness ( 10 − 6 cd/ m 2 ) to bright sunshine ( 10 8 cd/ m 2 ), and to generate and store such scenes independent from the display technology. To achieve a successful transition from LDR to HDR technology, backward compatible image and video representation formats are proposed so that both LDR and HDR displays can use the same representation to show LDR and HDR versions of the same content. This is typically achieved by including in the representation an LDR base layer, and an HDR enhancement layer that includes a method to predict HDR content from the LDR content in the base layer and possibly residue data to correct the HDR prediction. The main focus of this thesis is to implement a more efficient coding method for backward compatible HDR image coding residues, which are defined as the differences between original HDR images and their predictions from the corresponding base layer LDR images. As the first stage, analyses of similarities between spatial characteristics of backward compatible HDR image coding residues and LDR motion-compensated (MC) prediction residuals, for which directional coding methods were proposed, are performed. These analyses are followed by an implementation of suitable directional transforms which model spatial v characteristics of backward compatible HDR image coding residues more efficiently. Ratedistortion performance of the proposed method for coding of backward compatible HDR image coding residues are evaluated with objective and perceptual quality metrics. Results indicate that the proposed coding method can perform better than the standard coding methods for the coding of backward compatible HDR image coding residues.

Subject Keywords

High dynamic range image, Image compression .

URI

http://etd.lib.metu.edu.tr/upload/12621803/index.pdf
https://hdl.handle.net/11511/27043

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Privacy protection of tone-mapped HDR images using false colours ÇİFTÇİ, Serdar; Akyüz, Ahmet Oğuz; PİNHEİRO, Antonio M. G.; Ebrahimi, Touradj (2017-12-01) High dynamic range (HDR) imaging has been developed for improved visual representation by capturing a wide range of luminance values. Owing to its properties, HDR content might lead to a larger privacy intrusion, requiring new methods for privacy protection. Previously, false colours were proved to be effective for assuring privacy protection for low dynamic range (LDR) images. In this work, the reliability of false colours when used for privacy protection of HDR images represented by tone-mapping operators...
An Evaluation of ghost removal algorithms for exposure fusion Kutlu, Tuğser; Akar, Gözde; Department of Electrical and Electronics Engineering (2015) In high dynamic range imaging (HDR), the goal is to capture a scene with a higher dynamic range than the camera capable of capturing with a single exposure. Similar to HDR, exposure fusion is a process that takes multiple images and combines them to create a single dynamically enhanced image by only keeping the properly exposed elements. When using multiple images, local motion of objects can influence the quality of the final image in such a way that local motion of objects causes a ghost artifact. In this...
Automatic saturation correction for dynamic range management algorithms Artusi, Alessandro; POULİ, Tania; BANTERLE, Francesco; Akyüz, Ahmet Oğuz (2018-04-01) High dynamic range (HDR) images require tone reproduction to match the range of values to the capabilities of a display. For computational reasons and given the absence of fully calibrated imagery, rudimentary color reproduction is often added as a post-processing step rather than integrated into tone reproduction algorithms. In the general case, this currently requires manual parameter tuning, and can be automated only for some global tone reproduction operators by inferring parameters from the tone curve....
Deep joint deinterlacing and denoising for single shot dual-ISO HDR reconstruction Çoğalan, Uğur; Akyüz, Ahmet Oğuz; Department of Computer Engineering (2019) HDR (High Dynamic Range) images have traditionally been obtained by merging multiple exposures each captured with a different exposure time. However, this approach entails longer capture times and necessitates deghosting if the captured scene contains moving objects. With the advent of modern camera sensors that can perform per-pixel exposure modulation, it is now possible to capture all of the required exposures within a single shot. The new challenge then becomes how to best combine different pixels with ...
Ghost Removal in High Dynamic Range Images Khan, Erum Arif; Akyüz, Ahmet Oğuz; Reinhard, Erik (2006-10-11) High dynamic range images may be created by capturing multiple images of a scene with varying exposures. Images created in this manner are prone to ghosting artifacts, which appear if there is movement in the scene at the time of capture. This paper describes a novel approach to removing ghosting artifacts from high dynamic range images, without the need for explicit object detection and motion estimation. Weights are computed iteratively and then applied to pixels to determine their contribution to the fin...

Citation Formats

K. Feyiz, “Directional coding of backward compatible high dynamic range (HDR) image coding residues,” M.S. - Master of Science, Middle East Technical University, 2018.