A mobile spherical mosaic system
This paper proposes a new mobile mosaic system using the spherical surface for the panoramic image synthesis. The proposed system consists of image acquisition interface, exposure compensation, local image alignment, spherical projection, and blending. The image acquisition interface guides the users to capture images by displaying a wire frame on the spherical surface. The camera pose and direction are estimated by Gyro sensor and accelerometer. We correct the different brightness levels of images using local means and variances in the overlapped regions. Then, the images are locally realigned since the sensor information has much noise. We implement the successive template matching on the spherical surface, which reduces the sensor errors and misalignment in the 3-D rotational motion. After getting the 3-D rotation information of images, the images are rotated in the virtual 3-D space and projected on the spherical surface. We derive the spherical projection using the radius of virtual mosaic sphere and focal length. Finally, the overlapped multiple images are blended only at the boundaries on the spherical surface. We have implemented the system in the usual tablet PC and mobile phone. According to the various experiments, the proposed spherical mosaic system composes the full environment around the user in real-time.