Minimal Aspect Distortion (MAD) Mosaicing of Long Scenes


Alex Rav-Acha,  Giora Engel,  Shmuel Peleg 

Abstract

Long scenes can be imaged by mosaicing multiple images from cameras scanning the scene. We address the case of a video camera scanning a scene while moving in a long path, e.g. scanning a city street from a driving car, or scanning a terrain from a low flying aircraft.

A robust approach to this task is presented, which is applied successfully to sequences having thousands of frames even when using a hand-held camera. Examples are given on a few challenging sequences. The proposed system consists of two components: (i) Motion and depth computation. (ii) Mosaic rendering.

In the first part a "direct" method is presented for computing motion and dense depth. Robustness of motion computation has been increased by limiting the motion model for the scanning camera. An iterative graph-cuts approach, with planar labels and a flexible similarity measure, allows the computation of a dense depth for the entire sequence.

In the second part a new minimal aspect distortion (MAD) mosaicing uses depth to minimize the geometrical distortions of long panoramic images. In addition to MAD mosaicing, interactive visualization using X-Slits is also demonstrated.

Publications

A. Rav-Acha, G. Engel, and S. Peleg, Minimal Aspect Distortion (MAD) Mosaicing of Long Scenes , IJCV, Vol 78, No. 2-3, July 2008, pp. 187-206.


Demos
(Click on pictures to enlarge or to view the video)


A Street in Jerusalem

 
Input Video

 
MAD Mosaic and Depth (High Resolution)

 
X-Slits Mosaic and Depth Map

 
MAD Mosaic and Depth Map

 
Synthesized Video: X-Slit (1)

 
Synthesized Video: X-Slit (2)

 

Boat Ride in Germany

 


Input Video

 
X-Slits Mosaic and Depth Map

 
Synthesized Video: Virtual Tour using X-slits

 
Synthesized Video: Stereo Panorama

 

Derailed Shinkansen Train

 


Input Video

 
X-Slits Mosaic and Depth Map 

 
Synthesized Video: Stereo Panorama

 
X-Slits Mosaic of Other Side (High Resolution)