Privacy protection of tone-mapped HDR images using false colours

ÇİFTÇİ, Serdar
Akyüz, Ahmet Oğuz
PİNHEİRO, Antonio M. G.
Ebrahimi, Touradj
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 (TMOs) is studied. Two different TMO techniques are tested, a simple TMO based on the Gamma transform and a more complex local TMO. Moreover, two false colour palettes are also tested, and are applied to images that result from both TMOs and also to an LDR image that represents the centre exposure in the image sequence used to create the HDR image. The degree of privacy protection is analysed through both a subjective test using crowdsourcing and an objective test using face recognition algorithms. It is concluded that the application of the two studied false colour palettes reduces the recognition accuracy with respect to both tests.


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 ...
Evaluation of tone mapping and exposure fusion algorithms on HDR videos for face detection and recognition
Çavdarlı, Fehime Betül; Akyüz, Ahmet Oğuz; Department of Computer Engineering (2022-2-08)
High dynamic range (HDR) images have become popular recently especially for video surveillance systems. One of the most important reasons for this is that in areas where there is under or over-exposure, classical low dynamic range (LDR) images are insufficient to capture details, while HDR images have better visual details and contain wide range illumination values. However, since HDR images cannot be viewed on conventional LDR displays, additional processing such as tonemapping and/or fusion are required t...
Image dynamic range enhancement
Özyürek, Serkan; Akar, Gözde; Department of Electrical and Electronics Engineering (2011)
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 inform...
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...
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....
Citation Formats
S. ÇİFTÇİ, A. O. Akyüz, A. M. G. PİNHEİRO, and T. Ebrahimi, “Privacy protection of tone-mapped HDR images using false colours,” IET SIGNAL PROCESSING, pp. 1055–1061, 2017, Accessed: 00, 2020. [Online]. Available: