An intuitive user interaction method using multi-sensors for pencil drawing filter of NPR rendering in mobile devices

Abstract

The user interface is one of the most important factors to use various functions of mobile device easily. Recently, the importance of the user interface has been increased after Apple emphasized emotional UX(User eXperience) by applying multi-touches to iPhone. Mobile device Manufacturers have tried to apply embedded sensors to apps as user interface. Microphone was applied to execute functions combined with voice recognition and GPS sensor was used to find a location in navigation apps or game apps. Like these services, several sensors have roles of interface between user and device. In this paper, we propose an intuitive user interaction method using multi-sensors in NPR(Non-Photorealistic) rendering. The proposed method renders pencil drawing filter for a given photo image with the direction and strength of line strokes which are applied in vector fields. At this point, the method changes direction of stroke with x-coordinate values and y-coordinate values and control the strength of the stroke with z-coordinate values after catching three coordinate values in real-time from the orientation sensor on a mobile device. The method also adjusts brightness of image by transforming intensity of light from the light sensor. The light sensor updates intensity of light source continuously. If the user brings the mobile device closer to the external light source, the light sensor value will increase and the intensity of brightness becomes stronger. In addition, the user can make an attenuation effect with orientation sensor combined with light sensor for specific scope in a photo image and change the attenuation scope by moving action of his holding mobile device. This is a user interaction method for emotional image processing using sensors in mobile devices. We developed an app which generated pencil drawing filter effect for a photo image. We experimented sensor based emotional user interaction and compared various results of image processing effects using two combinatorial sensors. Finally, this paper proved efficiency through the experimental results and evaluated the effectiveness of the proposed method.