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This paper proposes a modification to standard cryptographic techniques. The key idea is to mitigate side channel attacks by dynamically changing the encryption key with redundant numbers at each encryption step. Side channel attacks currently are a major vulnerability; they exploit the implementation of the cryptosystem rather than attacking the cryptosystem. Side channel attacks have a wide range...
This paper introduces the OpenCV-FFI software package, which exposes datatypes and functions from the OpenCV computer vision library into the Ruby programming language. OpenCV-FFI uses the foreign function interface (FFI) to produce a Ruby API which mirrors the OpenCV C API; further layers of complexity are then built on that core API. Example code and benchmarking results show the effectiveness of...
RANSAC has become an essential tool for the robust estimation of inter-image geometries using point correspondences. Due to its randomized nature, RANSAC becomes inefficient for large numbers of incorrect matches. This paper presents four methods for utilizing prior geometric information when estimating the homography which register a pair of near-nadir aerial images. In this case the initial geometric...
<?Pub Dtl?>A common subexpression elimination algorithm is proposed to minimize the complexity of the multiple constant multiplication operation. The coefficients (constants) of the multiple constant multiplication are represented using the binary signed digit number system. The binary signed digit representations of each coefficient are enumerated using the representation tree. The algorithm...
This paper describes a biologically inspired flight control strategy for unpiloted aerial vehicles (UAVs) using optical flow and depth information. The scene depth map is generated by measurement of optical flow in a uniform grid across the image. Grid regions are each analyzed singularly, each ones depth is estimated by comparing their observed motion with the motion of the craft as measured by the...
Biologically inspired unpiloted aerial vehicle (UAV) flight control typically uses regulation of optical flow magnitude or distribution. These designs were motivated by research undertaken on insects that showed they too used optical flow in their flight. Recent research has suggested that optical flow alone can not sufficiently explain the altitude control behaviour of honeybees and houseflies; those...
Reliable depth estimation is a cornerstone of many autonomous robotic control systems. The Microsoft Kinect is a new, low cost, commodity game controller peripheral that calculates a depth map of the environment with good accuracy and high rate. In this paper we calibrate the Kinect depth and image sensors and then use the depth map to control the altitude of a quadrotor helicopter. This paper presents...
Correlation of images is a common step in image registration algorithms. Therefore it is important that the correlation step be efficient and accurate. This paper introduces the ‘shear average’ method for computing the relative translation between two similar images. We demonstrate that the proposed technique performance is comparable to traditional phase-correlation based techniques, while also being...
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