A study of the impact of light fields watermarking on the perceived quality of the refocused data

Abstract

Securing multimedia data from undesired manipulation is a widely investigated topic in the state of the art. A large number of techniques has been developed for protecting images, videos, and also audio from malicious attacks. Nowadays new imaging systems pose new challenges from the data protection point of view. In particular, plenoptic cameras allow to record multiple views of a scene by using a single camera in a single shot, thus avoiding the problems related to calibration and camera synchronization. In this contribution, a novel embedding scheme tuned to light fields is presented. The watermark is inserted in the horizontal and vertical detail subbands of the first level of the Haar wavelet transform. The aim of this work is twofold: the design of a water-marking system that does not affect the depth map estimation procedure and therefore the refocusing procedure and the 3D scene reconstruction. On the other hand, the impact of light field data modification with respect to the perceived quality has been investigated. Experimental tests, both objective and subjective, have been carried out for assessing the performances of the proposed algorithm

Angularly continuous light‐field format: Concept, implementation, and evaluation

“…Coding will play a significant role in the delivery of future light‐field multimedia, which will need to balance between the extent of data reduction and the possible changes in visual quality. Results of scientific effort can already be observed in the works of Viola et al and Paudyal et al Other works of Viola et al address subjective test methodology, which was also investigated by Darukumalli et al A different work of Paudyal et al demonstrates the importance of light‐field content and displays system selection for subjective tests on perceived quality, consider watermarking, and present a light‐field dataset captured by a Lytro camera. A database particularly created for QoE studies on the perceived quality of light‐field visualization was also presented by Murgia et al…”

Um Esquema para Inserção de Marcas D'Água em Imagens de Light Field

“…para compressão [8] e proteção de propriedade intelectual [9]. Com relação a estaúltima, têm sido documentadas na literatura proposições de técnicas de marca d'água para light fields no domínio de wavelets [10] e da 2D-DCT [9], por exemplo. Porém, a representação mais natural de um light field parece ser por meio de uma estrutura 4-dimensional, com duas dimensões para o plano das vistas e outras duas para o plano espacial da imagem.…”

Comparison of Interactive Subjective Methodologies for Light Field Quality Evaluation

“…Several studies have been devoted to subjective quality evaluation of LF contents. Paudyal et al investigate the impact of watermarking on visual quality of LF contents, and especially the relationship between watermark strength and visual quality, using Absolute Category Rating (ACR) [1]. Darukumalli et al examine the quality of experience associated to LF displays in relation to zooming levels and regions of interest, using ACR and Degradation Category Rating (DCR) [2].…”