This paper presents an adaptive image-based visual servoing (IBVS) integrated with adaptive sliding mode control for a vision-based operation of a quadrotor unmanned aerial vehicle (UAV). For a seamless integration with underactuated quadrotor dynamics, roll and pitch channels are decoupled from the other channels using virtual features. This allows a simple and accurate algorithm for estimating depth information and successful application of the proposed guidance and control algorithm. By employing an adaptive gain in the IBVS control method, the chance of image feature loss is reduced, and performance and stability of the vision-guided UAV control system are improved. The overall setup allows image features to be placed at the desired position in the image plane of a camera mounted on the quadrotor UAV. Stability of the IBVS system with the controller is proved using Lyapunov stability analysis. Performance of the overall approach is validated by numerical simulation, vision integrated hardware-inthe-loop simulation, and experiments. The results confirm that the target image is successfully placed at the desired position of the image plane and the quadrotor state variables are properly regulated, showing robustness in the presence of sensor noise, parametric uncertainty, and vibration from motors.input gain vector E r = diagonal matrix with entry of [1, 1, 1, 0, 0, 1] E 4 , E 5 = 0; 0; 0; 1; 0; 0 T and 0; 0; 0; 0; 1; 0 T e = task function for the image-based visual servo control e z = unit vector in the vertical upward direction in inertial coordinate frame F gr = ground effect force, N F i = thrust force of the ith rotor, N f = focal length of camera, pixel f ex = external disturbance vector g = gravity, m=s 2 H _ x = Gaussian radial basis kernel function vector J p = image Jacobian matrix associated to image point p J x , J y , J z = moment of inertia, kg m 2 k , k = proportional gains for velocity references in roll and pitch channels L = Lyapunov function L c , L s = length of the marker defined in camera frame, and image frame, respectively l = length of the bar from the center of the quadrotor to each rotor, m m = mass of the quadrotor, kg N = number of neurons in the neural networks system P i , p i = ith image feature defined in camera frame, and image frame, respectively P r i , p r i = ith image feature defined in imaginary camera frame in the roll-and pitchcompensated camera frame, and image frame, respectively P s i = ith image feature defined in imaginary camera frame in the rotated offset translation compensated camera frame P v i , p v i = ith image feature defined in camera frame, and image frame, respectively R I B = coordinate transformation matrix from body frame to inertial frame R1; , R2; = rotation matrices for and , respectively S = sliding surface in system control design T = translational velocity, m=s u 1 , u 2 , u 3 , u 4 = quadrotor control inputs for altitude, roll, pitch, and yaw W, W ad = diagonal weighting matrix and adaptive weighting matrix for visual servoing w i , w adi = ele...