Inspection and identification of cylindrical or conical shaped objects presents a unique challenge for a machine vision system. Due to the circular nature of the objects it is difficult to image the whole object using traditional area cameras and image capture methods. This work describes a unique technique to acquire a 2D image of the entire surface circumference of a cylindrical/conical shaped object. The specific application of this method is the identification of large caliber ammunition rounds in the field as they are transported between or within vehicles. The proposed method utilizes a line scan camera in combination with high speed image acquisition and processing hardware to acquire images from multiple cameras and generate a single, geometrically accurate, surface image. The primary steps involved are the capture of multiple images as the ammunition moves by on the conveyor followed by warping to correct for the distortion induced by the curved projectile surface. The individual images are then tiled together to form one 2D image of the complete circumference. Once this image has been formed an automatic identification algorithm begins the feature extraction and classification process.
Engineers at Oak Ridge National Laboratory have been investigating the feasibility of computer-controlled docking in resupply missions, sponsored by the U.S. Army. The goal of this program is to autonomously dock an articulating robotic boom with a special receiving port. A video camera mounted on the boom provides video images of the docking prot to an image processing computer that calculates the position and orientation (pose) of the target relative to the camera. The control system can then move the boom into docking position. This paper describes a method of uniquely identifying and segmenting the receiving port from its background in a sequence of video images. An array of light- emitting diodes was installed to mark the vertices of the port. The markers have a fixed geometric pattern and are modulated at a fixed frequency. An asynchronous demodulation technique to segment flashing markers from an image of the port was developed and tested under laboratory conditions. The technique acquires a sequence of images and digitally processes them in the time domain to suppress all image features except the flashing markers. Pixels that vary at frequencies within the filter bandwidth are passed unattenuated, while variations outside the passband are suppressed. The image coordinates of the segmented markers are computed and then used to calculate the pose of the receiving port. The technique has been robust and reliable in a laboratory demonstration of autodocking.
New developments in 2-D, wide-bandwidth HgCdTe (MCT) and GaAs quantum-well infrared photodetectors (QWIP) coupled with monolithic microwave integrated circuit (MMIC) technology are now making focal plane array coherent infrared (IR) cameras viable. Unlike conventional IR cameras which provide only thermal data about a scene or target, a coherent camera based on optical heterodyne interferometry will also provide spectral and range information. Each pixel of the camera, consisting of a single photo-sensitive heterodyne mixer followed by an intermediate frequency amplifier and illuminated by a separate local oscillator beam, constitutes a complete optical heterodyne receiver. Applications of coherent IR cameras are numerous and include target surveillance, range detection, chemical plume evolution, monitoring stack plume emissions, and wind shear detection.
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