Abstract: An endoscopic apparatus and method allow for robust autofocusing operation regardless of contrast characteristics of the environment. The endoscopic apparatus and method can focus on a field stop edge and store default information of the apparatus focused on the edge. Later, if the endoscope fails to focus on an internal target object during the course of normal operation, the endoscope recalls the default information from memory to focus the lens on the edge of the field stop. Thus, internal structural objects in front of the endoscopic apparatus are brought into reasonable focus for visualization.

Abstract: An endoscope includes an imaging probe, positioned at the distal end of the elongated member; a pivot mechanism mechanically coupled to the imaging probe; and an actuating assembly extending through the passage of the elongated member and coupled to the pivoting mechanism. The imaging probe includes an objective lens, an imager positioned to receive an image from the objective lens, and a light source for illuminating a target. Upon actuation of the actuating mechanism, the pivot mechanism rotates the imaging probe relative to a point at the distal end of the elongated member.

Abstract: A headspace instrument (10, 70) operates to equilibrate a vapor phase of a headspace sample in a sample loop (40, 74). The sample is equilibrated by flow through the headspace between variable volume chambers (28, 50, 86, 90). The volume of the variable volume chambers are changed in coordinated relation so that a constant total volume is always maintained. An aliquot of the equilibrated sample in the sample loop is delivered to an analytical instrument. The headspace instrument enables delivering a vapor sample from a headspace under conditions which do not disturb the thermodynamic equilibrium between the vapor phase and the non-vapor phase of the sample and avoids having the sampling process impact the results of the analysis. Alternative forms of the headspace instrument enable the conduct of concentration dependent processes and absorption and desorption experiments.

Abstract: A variable-focus variable-magnification optical coupler is provided, for coupling an endoscope to a variety of different cameras having image planes at different positions while maintaining "true-zoom" functioning of the optical coupler. By "true-zoom", it is meant that the focal length of the optical coupler's lens system can be varied without having the image out of focus. That is, once an image is focussed with the optical coupler, the image remains in focus even when the size of the image is changed by a zoom lens of the coupler. In one embodiment, the optical coupler includes an adjustment mechanism which is actuated to move a focus lens and a zoom lens assembly together along the length of the coupler relative to a camera mount. In another embodiment, an adjustment mechanism moves a back focal lens is moved relative to the camera mount to account for the different image plane of the camera.