Image dynamic range enhancement

Özyürek, Serkan
In this thesis, image dynamic range enhancement methods are studied in order to solve the problem of representing high dynamic range scenes with low dynamic range images. For this purpose, two main image dynamic range enhancement methods, which are high dynamic range imaging and exposure fusion, are studied. More detailed analysis of exposure fusion algorithms are carried out because the whole enhancement process in the exposure fusion is performed in low dynamic range, and they do not need any prior information about input images. In order to evaluate the performances of exposure fusion algorithms, both objective and subjective quality metrics are used. Moreover, the correlation between the objective quality metrics and subjective ratings is studied in the experiments.


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...
Directional coding of backward compatible high dynamic range (HDR) image coding residues
Feyiz, Kutan; Kamışlı, Fatih; Department of Electrical and Electronics Engineering (2018)
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 ...
Alignment of uncalibrated images for multi-view classification
Arık, Sercan Ömer; Vural, Elif; Frossard, Pascal (2011-12-29)
Efficient solutions for the classification of multi-view images can be built on graph-based algorithms when little information is known about the scene or cameras. Such methods typically require a pairwise similarity measure between images, where a common choice is the Euclidean distance. However, the accuracy of the Euclidean distance as a similarity measure is restricted to cases where images are captured from nearby viewpoints. In settings with large transformations and viewpoint changes, alignment of im...
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
S. Özyürek, “Image dynamic range enhancement,” M.S. - Master of Science, Middle East Technical University, 2011.