Software-Based Adjustment of Mobile Autostereoscopic Graphics Using Static Parallax Barriers Martin Paprocki School of Information and Communication Technology, Aalborg University, Denmark mpapro09@student.aau.dk Morten Bak Kristoffersen School of Information and Communication Technology, Aalborg University, Denmark mkr08@student.aau.dk Kim Krog School of Information and Communication Technology, Aalborg University, Denmark kkrog08@student.aau.dk Martin Kraus Department of Architecture, Design and Media Technology, Aalborg University, Denmark martin@create.aau.dk ABSTRACT We show that the autostereoscopic display of stereoscopic images using a static parallax barrier can be improved by adapting the rendering to the angle under which the user is looking at a mobile display; thus, ghosting artifacts and depth reversals can often be avoided even if the user tilts the mobile device. Instead of moving the barrier itself to compensate for a misplacement of the viewing zones in rela- tion to the user, we employ dynamic pixel column shifts to provide a similar compensation in software. This requires a parallax barrier where each section covers two pixel columns at a time instead of one. The proposed method has been im- plemented using OpenGL shaders and a parallax barrier that was designed for a display of exactly half the resolution of the employed display. Technical tests showed a good separa- tion of the left and right images for viewing angles of up to ± 30 ◦ . Preliminary user tests indicate that an improvement in the stereoscopic experience can be achieved. Categories and Subject Descriptors I.3.7 [Three-Dimensional Graphics and Realism]: Vir- tual reality General Terms Algorithms Keywords Autostereoscopy, display, parallax barriers, adaptive inter- face, mobile device, ghosting, context aware interface, GPU Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. AVI ’12, May 21-25, 2012, Capri Island, Italy Copyright c 2012 ACM 978-1-4503-1287-5/12/05... $10.00 1. INTRODUCTION In recent years mobile consumer devices started to adopt autostereoscopic displays. Although autostereoscopic dis- plays with static parallax barriers are a low-cost and com- petitive solution for displaying stereoscopic images, they are quite limited since they have to be viewed from a specific position. Displaying the stereo effect correctly requires the viewer to remain within a relatively narrow viewing angle, as well as maintaining an optimal viewing distance to the autostereoscopic display [12]. If these conditions are not ful- filled, ghosting or reversed stereo depth will deteriorate the stereoscopic effect. The ghosting is caused by leakage from the left eye image to the right eye image and vice versa. The reversed stereo depth occurs if the left image is seen by the right eye and vice versa [11]. In some cases this makes it impossible to obtain the correct stereoscopic effect, e.g., in game applications where the device is tilted as a part of the gameplay. In such a situation, one would from time to time see the correct, a mixed and the reversed stereoscopic image. Presumably, this results in an uncomfortable experience due to the varying depth perception. To overcome some of the limitations of static parallax bar- riers, we present a low-cost software-based improvement of autostereoscopic displays using dynamic pixel column shifts (see Figure 1), which employs static parallax barriers with two pixel columns per section of the barrier (see Figure 2). A test application was implemented demonstrating how an OpenGL application can alter the pixel arrangement based on gyroscope and accelerometer data in order to compensate for varying viewing angles. In the next section, related work is summarized followed by Section 3 describing our method along with an implementation of it. In Section 4, the tech- nical test is discussed and in Section 5, a calibration scene is described and Section 6 reports results of a preliminary user study. Conclusion and future work are presented in Section 7. 2. RELATED WORK Consumer mobile devices with autostereoscopic displays in- clude smartphones [7] and game consoles [8]. In addition, low-cost parallax barriers which can be added to a mobile de-