For scenarios of coherent underwater sources at low signal-to-noise ratio (SNR), a novel quaternion-based DOA algorithm without eigendecomposition is proposed using linear vector-hydrophone array. We construct four quaternion models by judiciously arranging the received data to fully utilize statistical information incident signals. To avoid high computational complexity caused eigenvalue decom...

Color in an image is resolved to 3 or 4 color components and 2-Dimages of these components are stored in separate channels. Most of the color image enhancement algorithms are applied channel-by-channel on each image. But such a system of color image processing is not processing the original color. When a color image is represented as a quaternion image, processing is done in original colors. Th...

This paper proposes a new adaptive extended Kalman filter (AEKF) for a class of nonlinear systems perturbed by noise which is not necessarily additive. The proposed filter is adaptive against the uncertainty in the process and measurement noise covariances. This is accomplished by deriving two recursive updating rules for the noise covariances, these rules are easy to implement and reduce the n...

Pose estimation from an arbitrary number of 2-D to 3D feature correspondences is often done by minimising a nonlinear criterion function using one of the minimal representations for the orientation. However, there are many advantages in using unit quaternions to represent the orientation. Unfortunately, a straightforward formulation of the pose estimation problem based on quaternions results in...

Traditionally, the extended Kalman filter (EKF) is a well known approach for general nonlinear data fusion problem. But the unit norm constraint of quaternion vector, which is the most efficient expression of attitude, results in the singularity of error covariance matrix. To overcome this difficulty, the modified extended Kalman filter (MEKF) has been developed by Shuster (1982). In order to i...

This paper is concerned with quaternion-valued functions on the plane and operators which act on such functions. In particular, we investigate the space L(R,H) of square-integrable quaternion-valued functions on the plane and apply the recently developed Clifford-Fourier transform and associated convolution theorem to characterise the closed translation-invariant submodules of L(R,H) and its bo...

Abstract Dynamic movement primitives (DMPs) as a robust and efficient framework has been studied widely for robot learning from demonstration. Classical DMPs mainly focuses on the in Cartesian or joint space, can't properly represent end-effector orientation. In this paper, we present an extended (EDMPs) both space 2-Dimensional (2D) sphere manifold Quaternion-based orientation generalization. ...

Accurate and real-time tracking of the orientation or attitude of rigid bodies has traditional applications in robotics, aerospace, underwater vehicles, human body motion capture, etc. Towards human body motion capture, especially wearable devices, the use of a longer time has always been a challenge for several weeks or several months continuously, so a low-cost chip and a low computational co...

This paper addresses an attitude tracking control design applied to multirotor unmanned aerial vehicles (UAVs) based on ADRC approach. The proposed technique groups the endogenous and exogenous disturbances into a total disturbance, then this is estimated online via extended state observer (ESO). Further, quaternion-based feedback developed, which assisted by feedforward term obtained ESO relie...