Abstract: A scanning type radiographic imaging system is disclosed which employs novel means to produce comparable radiation intensity in the object regions being radiographed. Such result is achieved with variable radiation attenuating elements having their attenuation controlled during this scanning process with novel feedback control means. The feedback control is produced with a stationary detection unit having circuit means which generates the electrical control signals.

Abstract: Three-dimensional images are formed from tomographic data collected in a medical diagnostic imaging system. The images include structures of specific interest having voxel densities not confined to a single, exclusive area of the image histogram. A variable threshold dependent on the particular voxel locations is used in extracting the 3-D surface definition in order to eliminate partial volume artifacts in the 3-D image.

Abstract: Objects within a three-dimensional tomographic data set which occupy the same portion of the image histogram are separated prior to three-dimensional surface extraction by applying connectivity first to unwanted objects. The unwanted objects thus identified are modified so that they no longer occupy the same portion of the histogram or are flagged. Next, connectivity is applied to the desired objects using a criterion different from the one used on the unwanted objects.

Abstract: Multiple desired objects within a three-dimensional tomographic data set which occupy the same portion of the image histogram with other unwanted objects are separated with reduced reliance on user interaction by applying connectivity to the unwanted objects and setting the voxels to a new value which removes them from the portion of the histogram. Unwanted objects can be identified by examination of the original two-dimensional slices or after examination of a three-dimensional image to excise objects, whereby the invention functions as an electronic scalpel.

Abstract: Inherent non-uniformities in a gamma camera system are compensated for by reducing the sensitivity for some locations on the detector. The tradeoff between image uniformity improvement and loss of camera sensitivity is maximized. Since the energy correction offsets direct the energy spectra downwards (or the energy window upwards). Scatter rejection is also improved.

Abstract: A correction method and apparatus for Computed Tomography (CT) removes ring and streak artifacts from images by correcting for data contamination by crosstalk errors. Crosstalk coupling between all adjacent detectors can be measured using an off-center phantom to provide X-ray flux having a changing gradient profile from view to view across the detector array of the CT apparatus. Correction factors are found that will remove crosstalk contamination from subsequently measured imaging data.

Abstract: The dynamic range of ultrasound images is extended by providing compensation of errors inherent in the manufacturing process of medical ultrasound phased array probes. Time delay errors are predetermined and stored in a memory associated with each probe. A system then reads the values needed to perform error compensation directly from the particular probe being used.

Abstract: A system for displaying three-dimensional surface structures according to computer graphics methods extracts a surface definition from a tomographic array of data using interpolation of the data for smooth, high resolution images. Interpolation can be performed to a degree where artifact-free images are produced for all viewing orientations. Data-processing capacity and time requirements can be reduced with less interpolation while image quality is maintained for all viewing orientations by inspecting the viewing orientation and appropriately scaling the image.

Abstract: Three-dimensional objects within a tomographic data-base are extracted for viewing by comparing the tomographic data to a predetermined threshold or range defining the object boundaries. A surface extraction method is structured so as to allow for several vector operations, thus adapting the method for implementation using an array processor.

Abstract: A carriage for a machine tool includes ways (16) and (18), a base (14) supporting the ways and a saddle (20) supported by bearings (22) and (24) for movement along the ways to carry a column (26) along the X-axis of the machine tool. The load bearing surface (16a) of way (16) is located at a higher level above machine tool support surface (16a) than the load bearing surface (18a) of way (18). Thrust directed against column (26) in the course of a machining operation is transmitted to saddle (20) through Z-axis ways 40 and way bearings (42), and is transmitted from saddle (20) to thrust bearing surface (16c) of way (16).

Abstract: A numerically controlled automatic tool changing machining center is provided with a rotary driven spindle concentric within which is a spindle bar that may be reciprocated out from or into the spindle by a hydraulic cylinder. Located at the forward end of the spindle bar is a tool receiving socket which is operative to releasably engage the shank of a single toolholder or multiple spindle toolhead transferred to the spindle bar from the machine tool storage magazine by a tool transfer arm. When a large, single toolholder is engaged by the spindle bar, the spindle bar is retracted into the spindle to urge the large single toolholder against the nose of the spindle.

Abstract: A tool measuring apparatus for a machine tool is provided with a plunger (16) mounted to move along an axis (22) to vary the spacing between the end of the plunger and an inductive element (26) of an inductive displacement measuring device (24). Device (24) generates a signal V.sub.y which varies as a function of the spacing between the plunger (16) and device (24). Spindle (14), engaging a tool (12), is moved to a position M located a known distance from inductive element (26). As the spindle is moved to position M, tool (12) engages plunger 16 and moves the plunger to decrease the spacing between the plunger and the element (26) to a value S.sub.3, corresponding to an unknown length d of tool (12). Levels of V.sub.y corresponding to spacing S.sub.3 and to S.sub.2, representing a known nominal value N of tool length, are coupled to a processor 32 and a control 30 to determine tool offset e, i.e., the difference between actual length d and nominal length N.

Abstract: A magazine (10) for a machine tool (not shown) comprises a number of links (12) joined together by pins (14) to form a closed chain (16). A socket (32) is formed in each link for receiving a tool (34) to position the tool center line (36) midway between and in parallel relation with, the axes (40) of the two pins (14) which join the link to adjacent links in the chain (16). A frame (18) supports the chain (16) and received tools (34) for movement along a path of travel to selectively position the tools, the path including sections (26) of little or no curvature, and sections (28, 30) of substantial curvature. To maintain tool movement precisely along the path of travel, and thus prevent contact between tools in adjacent links (12) when the adjacent links travel around a section (28, 30) of substantial curvature, guide bearings (54) are joined to the links and constrained to move along a channel (56) which is in parallel relation with the desired chain path of travel.

Abstract: A rotary shuttle (10) for a machine tool (11) in which no power mechanism is required for moving the pallet (14, 15) with the workpiece off of the shuttle (10) and on to the machine tool worktable (13A) or for withdrawing a pallet (14, 15) with the completed workpiece on it off of the machine tool worktable (13A) and back on to the shuttle (14, 15). A rotatable shuttle (10) is presented with a workpiece support which can also be raised and lowered with pallets (14, 15), which in conjunction with an indexing table (13) moves workpieces between the worktable (13A) and a workpiece support (16, 19). A frame (66) of the shuttle mechanism (10) includes an offset rotatable section (65) which is arranged to extend over a portion (79) of the indexing table (13) with the shuttle mechanism (10) including support arms (16, 19) in conjunction with the offset rotatable section to extend over a portion of the indexing table (13).

Abstract: A gear change mechanism for a machine tool in which shifting forks with sliding gears and constant mesh gearing using clutch and/or brake shifting is eliminated. A shiftable gear mechanism is presented in a gear train for meshing engagement with any one of a plurality of gears for selectively varying the speed of the machine spindle. The shiftable gear mechanism includes a first rotatable shaft and a second shaft connected to a cluster gear positioned to slide and rotate the second shaft in relation to the first shaft. A cylinder apparatus is connected coaxially to the second shaft to slide the second shaft in a reciprocating manner along the first shaft so as to move the cluster gear and vary the gear ratios between the cluster gear and the other gears in the gear train. A bearing assembly is also utilized in conjunction with the second slidable shaft so as to prevent any sliding action between the cluster gear and the shifting mechanism.

Abstract: An apparatus for angularly orienting a machine tool spindle (24) to a keylock position includes a resolver (39) which is directly mounted on a shaft (13) of a spindle drive motor (12), the spindle (24) rotating synchronously with the shaft (13) through a shiftable gear train. Resolver (39) is connected to update a register (45) so that the count shown by the register indicates the angular position of shaft (13) with respect to the spindle head (11) as the shaft rotates. During synchronous rotation, a target (33) revolving with the spindle causes a proximity sensor (32) on the spindle head (11) to generate a pulse when the spindle (24) is in a known orientation relative to the spindle head (11). When a pulse occurs a data processing unit (46) of a numerical control circuit (42) compares the actual count in register (45) with a number of possible count values contained in a data storage table (44).

Abstract: A gib (10) for a machine tool is insertable into a space between a machine tool carriage (42) and the positive way face (40) of a set of machine tool ways (44,96) supporting the carriage (42) for rectilinear movement. The gib (10) includes a body (12) having tapered ends (48) and a planar side surface (46) abutting the positive way face (40). The gib (12) further includes a fixed wedge (16) and a floating wedge (14), each of the wedges (14,16) having a crowned surface (50) in abutting relationship with one of the tapered ends (48) of the body (12), and having planar base surfaces (20,22) abutting a planar surface (38) of the carriage (42). An adjustment screw (28) traverses the body (12) and each of the wedges (14,16), and is rotatable to vary the spacing between the planar side surface (46) of the body (12) and the planar base surfaces (20,22) of the wedges (14,16).

Abstract: A device (10) for measuring the difference in elevation between first and second substantially horizontal surfaces (12a, 12b) includes first and second chambers (10a, 10b) respectively located on the surfaces (12a, 12b). The chambers contain quantities of a fluid such as mercury (116) and are coupled together through a conduit (20) which enables mercury (116) to flow between them as required, so that the mercury levels in the chambers will be in the same horizontal plane. A first device (140a) is mounted at a first distance above the fluid in the first chamber and at a fixed distance above the first surface (12a). Likewise, a second device (140b) is mounted at a second distance above the fluid in the second chamber, and at the same fixed distance above the second surface (12b).

Abstract: In a ball screw transfer drive for a transfer machine, first and second carriages are translated by rotation of a ball screw, the ball screw being actuated by a DC electric or other type of variable speed motor through a ball screw drive train. The first carriage is coupled to the ball screw through a first ball nut which is immovably joined to the first carriage and which has threads in engaging relationship with threads of the ball screw. The second carriage is coupled to the ball screw through a second ball nut which is journaled in bearings attached to the second carriage, threads of the second ball nut likewise being in engaging relationship with the ball screw. A power transmission train is mounted between the ball screw and the second ball nut to rotate the second ball nut during a specified rotation of the ball screw to maintain a pre-specified relationship between the speeds of translation of the first and second carriages during the specified ball screw rotation.

Abstract: A method for rapid acquisition of NMR data utilizes excitation pulses which rotate the longitudinal magnetization through an angle smaller than 90.degree. to create a relatively large transverse magnetization component. A first 180.degree. RF pulse is then applied to create a spin-echo signal, while a second 180.degree. RF pulse is used to rapidly return to equilibrium the residual longitudinal magnetization inverted by the first pulse. The combination of the excitation and the second 180.degree. pulses permits the sequence repetition time to be shortened, thereby reducing the total data collection time. The method is applicable to, for example, two- and three-dimensional embodiments of Fourier transform and multiple-angle projection reconstruction NMR imaging methods.