Stereo imaging

Abstract: A vehicular stereoscopic imaging system provides a calculation of a distance between one or more sensors on a vehicle and a light source or object in a target scene remote from the vehicle. The imaging system may be useful in a headlamp dimmer control system, such that the headlamps, are modulated between their low and high beams in response to the calculated distance and intensities and/or colors of the light sources sensed by the sensors. The stereoscopic imaging system determines the distance to the object by comparing similarly classified signals received by each of two imaging array sensors in order to determine a relative position of an image representing the light source on each sensor. The distance to the object or light source may then be calculated as a function of the respective positions on the sensors, the focal lengths of focusing optics associated with each sensor and a predetermined separation distance between the axes of the two sensors. An associated accessory, such as a display, headlamps, windshield wipers, a warning indicator or signaling device and/or the brake system of the vehicle may be adjusted or activated in response to an output of the imaging system.

Abstract: A system and method for recognizing gestures. The method comprises obtaining image data and determining a hand pose estimation. A frontal view of a hand is then produced. The hand is then isolated the background. The resulting image is then classified as a type of gesture. In one embodiment, determining a hand pose estimation comprises performing background subtraction and computing a hand pose estimation based on an arm orientation determination. In another embodiment, a frontal view of a hand is then produced by performing perspective unwarping and scaling. The system that implements the method may be a personal computer with a stereo camera coupled thereto.

Abstract: The present disclosure relates to a method and apparatus for localizing an object in space, such as a gallstone in a human, using stereo imaging and ultrasound imaging. The localization system is described in connection with a dry table shock wave lithotripter, and uses a conventional ultrasound imaging system but wherein the ultrasound transducer has been modified to enable its location in space to be readily determined automatically. This is accomplished by providing a hood fixed to this transducer, the hood having a plurality of reference points which may be in the form of light sources such as LEDs. This hood is imaged by head and foot video cameras. By calibrating the cameras with respect to a reference point, calibrating the focal point of the shock wave system with respect to the reference point, and knowing the relationship of the hood to the ultrasound transducer, the position of the stone with respect to the reference point can be determined by ultrasound imaging of the stone, along with suitable storage of the ultrasound and camera images, digitizing and processing of these images. Given this information, the patient with the stone can be suitably moved so as to position the stone at the focal point of the shock wave generating system.

Abstract: Plants constantly adapt their leaf orientation in response to fluctuations in the environment, to maintain radiation use efficiency in the face of varying intensity and incidence direction of sunlight. Various methods exist for measuring structural canopy parameters such as leaf angle distribution. However, direct methods tend to be labour-intensive, while indirect methods usually give statistical information on stand level rather than on individual leaves. We present an area-based, binocular stereo system composed of commercially available components that allows three-dimensional reconstruction of small- to medium-sized canopies on the level of single leaves under field conditions. Spatial orientation of single leaves is computed with automated processes using modern, well-established stereo matching and segmentation techniques, which were adapted for the properties of plant canopies, providing high spatial and temporal resolution (angle measurements with an accuracy of approx. +/-5 degrees and a maximum sampling rate of three frames per second). The applicability of our approach is demonstrated in three case studies: (1) the dihedral leaflet angle of an individual soybean was tracked to monitor nocturnal and daytime leaf movement showing different frequencies and amplitudes; (2) drought stress was diagnosed in soybean by quantifying changes in the zenith leaflet angle distribution; and (3) the diurnal course of the zenith leaf angle distribution of a closed soybean canopy was measured.