Abstract: An apparatus for detecting and determining geometric features inside a borehole comprises a body section coupled to and deployable in the borehole by a conveyor, a head section having a first end pivotably coupled to the body section via a joint and a second end having an array of ultrasonic transducers. The array of transducers comprises, for example, a multiplicity of individual actuator elements and a multiplicity of individual sensor elements. An electronic control unit controls the timing of emission of ultrasonic radiation from the actuator elements of the array, receives signals generated by the sensor elements of the array, and controls movement of the head section via an actuator coupled to the joint. A method for reconstructing a geometry and detecting and identifying features in a borehole is also provided.