In this paper, we present a new video database: CVD2014-Camera Video Database. In contrast to previous video databases, this database uses real cameras rather than introducing distortions via post-processing, which results in a complex distortion space in regard to the video acquisition process. CVD2014 contains a total of 234 videos that are recorded using 78 different cameras. Moreover, this database contains the observer-specific quality evaluation scores rather than only providing mean opinion scores. We have also collected open-ended quality descriptions that are provided by the observers. These descriptions were used to define the quality dimensions for the videos in CVD2014. The dimensions included sharpness, graininess, color balance, darkness, and jerkiness. At the end of this paper, a performance study of image and video quality algorithms for predicting the subjective video quality is reported. For this performance study, we proposed a new performance measure that accounts for observer variance. The performance study revealed that there is room for improvement regarding the video quality assessment algorithms. The CVD2014 video database has been made publicly available for the research community. All video sequences and corresponding subjective ratings can be obtained from the CVD2014 project page (http://www.helsinki.fi/psychology/groups/visualcognition/).

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Subjective evaluation is used to identify impairment factors of multimedia quality. The final quality is often formulated via quantitative experiments, but this approach has its constraints, as subject's quality interpretations, experiences and quality evaluation criteria are disregarded. To identify these quality evaluation factors, this study examined qualitatively the criteria participants used to evaluate audiovisual video quality. A semi-structured interview was conducted with 60 participants after a subjective audiovisual quality evaluation experiment. The assessment compared several, relatively low audio-video bitrate ratios with five different television contents on mobile device. In the analysis, methodological triangulation (grounded theory, Bayesian networks and correspondence analysis) was applied to approach the qualitative quality. The results showed that the most important evaluation criteria were the factors of visual quality, contents, factors of audio quality, usefulness -followability and audiovisual interaction. Several relations between the quality factors and the similarities between the contents were identified. As a research methodological recommendation, the focus on content and usage related factors need to be further examined to improve the quality evaluation experiments.

This paper presents a new database, CID2013, to address the issue of using no-reference (NR) image quality assessment algorithms on images with multiple distortions. Current NR algorithms struggle to handle images with many concurrent distortion types, such as real photographic images captured by different digital cameras. The database consists of six image sets; on average, 30 subjects have evaluated 12-14 devices depicting eight different scenes for a total of 79 different cameras, 480 images, and 188 subjects (67% female). The subjective evaluation method was a hybrid absolute category rating-pair comparison developed for the study and presented in this paper. This method utilizes a slideshow of all images within a scene to allow the test images to work as references to each other. In addition to mean opinion score value, the images are also rated using sharpness, graininess, lightness, and color saturation scales. The CID2013 database contains images used in the experiments with the full subjective data plus extensive background information from the subjects. The database is made freely available for the research community.

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We measured the eye movements of participants who watched a 6-minute movie in stereoscopic and non-stereoscopic form. We analyzed four shots of the movie. The results indicate that in a 2D movie viewers tended to look at the actors, as most of the eye movements were clustered there. The significance of the actors started at the beginning of a shot, as the eyes of the viewer focused almost immediately to them. In S3D movie the eye movement patterns were more widely distributed to other targets. For example, complex stereoscopic structures and objects nearer than the actor captured the interest and eye movements of the participants. Also, the tendency to first look at the actors was diminished in the S3D shots. The results suggests that in a S3D movie there are more eye movements which are directed to wider array of objects than in a 2D movie. INTRODUCTIONThe purpose of a moviemaker is to influence the viewers to pay attention to salient events of the script, so that the viewers understand the details, consequences and emotional significance of events 1 . This can be accomplished by utilizing for example shot distance, focus, angle, movement, point of view, scene composition and principles of cutting 1,2 . In a stereoscopic film the effect of these techniques might be different, as the processes of stereoscopic vision affect the way viewers pay attention and understand the scenes. Moviemakers and stereographers know how to utilize the possibilities of stereoscopy, as recent excellent stereoscopic films have shown, but there is less empirical data related to these effects. According to our recent studies the viewers most often mention experiences of reality-likeness, presence, enhanced emotions and richness of structural details when watching a stereoscopic movie 3,4 . Asking the viewers to describe their experiences is the best way to form an understanding of the underlying psychological processes 5-8 , so these results tell us a lot about the experiential added value of stereoscopy. However, there are also processes that are not consciously accessible. These processes might be reflexive, automatic or too quick to enter the consciousness of the viewer. For example, eye movements and the related changes in the focus of attention are only partially guided by conscious intentions of the viewers. As the locations where the eyes stop to collect information determine what parts of the visual environment we notice, measuring the eye movements with stereoscopic film shows, which part of each shot is regarded as informative and important.Eye movements can be divided to two main phases. Firstly, there are fixations when the eye is pointing to a single location of the scene. Secondly, there are saccades when the eyes quickly move the point of regard to another position. Information is acquired during fixations, as during the saccades the information from the eye is mostly suppressed. Experiments suggest that viewers look at the most informative areas of the scene. The definition of informative depends on the task and the cont...

In this study, alternative methods for studying legibility of text while walking with a mobile phone were examined. Normal reading and pseudo-text search were used as visual tasks in four walking conditions. Visual performance and subjective evaluation of task difficulty were used as measures of text legibility. According to the results, visual performance suffers from increasing walking speed, and the effects are greater on reading velocity for pseudo-text search. Subjects also use more homogenous strategies when reading compared to pseudo-text search, and therefore it is concluded that reading is a more useful measure of legibility. Subjective measures are found to be more sensitive to small variations in legibility than objective measures, and give additional information about task demands. Hence, without both objective and subjective measurements important information about legibility in different conditions and with different tasks will be lost.