Improved LUT-Based Image Warping for Video Cameras

Image warping is usually used to perform real-time geometry transformation for video cameras. Several existing look-up table (LUT)-based algorithms achieve real-time performance, but the size of LUT is large and it has to be stored into off-chip memory. To reduce latency and bandwidth requirements due to using off-chip memory, this paper proposes an improved LUT (ILUT) scheme which compresses the LUT small enough that it can be stored in on-chip memory. Firstly, a one-stop transformation is adopted instead of several stages of on-line calculation. Then, the memory size of LUT is reduced by utilizing the similarity of neighbor coordinates and the symmetric characteristic of some image warping. Moreover, an elaborate pipeline hardware structure, cooperating with a novel 25-point interpolation algorithm, is proposed to accelerate the system and save further usage of memory. The proposed system is implemented by a field-programmable gate array-based platform. Two different examples show that the proposed ILUT achieves a real-time performance with small memory usage and low system requirements.

[1]  George Wolberg,et al.  Digital image warping , 1990 .

[2]  Jian-Jun Fang,et al.  A method to reduce number of division operations for perspective texture warping , 2000, 2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353).

[3]  Jordi Gonzàlez,et al.  Importance of detection for video surveillance applications , 2008 .

[4]  Terrance E. Boult,et al.  Separable image warping with spatial lookup tables , 1989, SIGGRAPH '89.

[5]  Bingwei He,et al.  Camera calibration with lens distortion and from vanishing points , 2009 .

[6]  Martin Humenberger,et al.  FPGA-BASED RECTIFICATION AND LENS UNDISTORTION FOR A REAL-TIME EMBEDDED STEREO VISION SENSOR , 2008 .

[7]  Helder Araujo,et al.  Low-cost method for the estimation of the shape of quadric mirrors and calibration of catadioptric cameras , 2007 .

[8]  Yongmin Kim,et al.  Generalized image warping using enhanced lookup tables , 1998, Int. J. Imaging Syst. Technol..

[9]  Jeff Beck,et al.  A dual-conversion-gain video sensor with dewarping and overlay on a single chip , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[10]  Gyeonghwan Kim,et al.  FPGA-based fast image warping with data-parallelization schemes , 2008, IEEE Transactions on Consumer Electronics.

[11]  Arie E. Kaufman,et al.  Forward image mapping , 1999, Proceedings Visualization '99 (Cat. No.99CB37067).

[12]  Frans J. Peters,et al.  Algorithms for division free perspective correct rendering , 2000, Workshop on Graphics Hardware.

[13]  Gang Cheng,et al.  Real-Time FPGA-Based Panoramic Unrolling of High-Resolution Catadioptric Omnidirectional Images , 2009, 2009 International Conference on Measuring Technology and Mechatronics Automation.

[14]  Jong-Wha Chong,et al.  Low-cost implementation of bird's-eye view system for camera-on-vehicle , 2010, 2010 Digest of Technical Papers International Conference on Consumer Electronics (ICCE).

[15]  Robert L. Nagel,et al.  Function-based design process for an intelligent ground vehicle vision system , 2010, J. Electronic Imaging.

[16]  Donald G. Bailey,et al.  A novel approach to real-time bilinear interpolation , 2004, Proceedings. DELTA 2004. Second IEEE International Workshop on Electronic Design, Test and Applications.

[17]  H. Hongo,et al.  A Practical Calibration Method for Top View Image Generation , 2008, 2008 Digest of Technical Papers - International Conference on Consumer Electronics.