Picker International, Inc.

Varian Associates, Inc.

Varian Medical Systems, Inc.

David L Gilblom

Robert P Hunt

Peter S Castro

Jack W Gittings

An x-ray imaging apparatus receives an image-carrying x-ray beam on a flat amorphous silicon imaging panel with a light detector unit disposed behind. The imaging panel is of a multi-layered structure having sequentially a light-blocking layer which is opaque to visible light but transmissive to x-rays, a converting layer of a phosphorescent material for converting x-rays incident thereon into visible light, and a two-dimensional array of photosensitive elements of an amorphous semiconductor material such as amorphous silicon, adapted to undergo a detectable change in electrical characteristic in response to impingement of light. The light detector unit may be a simple light detector for receiving the light emitted from the converting layer and passed through regions between neighboring pairs of the array of photosensitive elements. Since the energy of light thus detected is directly proportional to the total light energy emitted from the converting layer, the output signal from such a light detector unit can be conveniently used for the exposure control of the imaging panel.

X-ray imaging apparatus and method using a flat amorphous silicon

A method and device for selectively displaying a magnified image which permits an operator to appreciate the magnified image in its original context. The device includes a main monitor, a magnifier monitor, associated memories, and a controller. The magnifier monitor is movably mounted with respect to the main monitor. The position of the magnifier monitor in two dimensions represents the approximate center of a region on the main monitor to be magnified. The magnifier monitor is movable in a third dimension, and the position of the magnifier in the third dimension is used to determine the degree of magnification desired.

Video magnifier

A latent image is formed on a stimulable phosphor plate (10) by irradiating the phosphor plate with x-rays from an x-ray source (14). To develop the stimulable phosphor plate, the plate is irradiated with light of a different wavelength from developer light source (32). The light from the developer light source causes the stimulable phosphor plate to give off light of yet another characteristic wavelength. Light from the stimulable phosphor plate is filtered (38) to remove the wavelength of the developer light and focused (42) on a light sensing element (46) of a time delay and integration video camera (34). The stimulable phosphor plate and the video camera are moved relative to each other and the rate of movement is monitored (60). An array control (50) shifts rows of data or charge values along the light sensing element in coordination with movement of the stimulable phosphor plate such that the light emitted by each incremental element of the stimulable phosphor plate is integrated over a full column of detector elements of the light detector array. The time delay and integration video camera produces a video signal indicative of the latent x-ray shadowgraphic image from the stimulable phosphor plate. In one embodiment (FIG. 1), the developer is in a separate unit. In other embodiments, the time delay and integration camera and the stimulable phosphor plate are in a common darkbox such that the latent image is developed immediately and automatically to produce the video image (FIGS. 3, 4, and 5).

Shadowgraphic x-ray imager with TDI camera and photo stimulable phosphor

One or more time delay and integration camera assemblies (A) are mounted in a housing (100) which is rotated by a motor (40, 106) relative to a vertical axis. A tachometer or encoder (44) produces signals whose frequency or voltage varies in accordance with an angular velocity of the camera assemblies about the vertical axis. A clock generator (46) converts the angular velocity signals into clocking signals for controlling movement of vertical lines of data values (20) along an array (14) of light sensitive elements to a shift register (22). In one embodiment, the clock generator includes a divider (82) which converts the angular velocity signal into a voltage, a comparator (84) which compares the first voltage with a second voltage, and a voltage controlled oscillator (88) which oscillates to generate the clocking signal. A second divider (88) defines a feedback loop between the output of the voltage controlled oscillator and the comparator for generating the second voltage. Each line of data from the array update (64) a corresponding line of a panoramic memory (66). The selectable portion (72) of the data from the panoramic memory is retrieved (70) independently of the memory updating. Scan converters (74) convert retrieved portions of the panoramic memory data into appropriate format for display on video monitor (78). In this manner, the panoramic memory is updated as the array rotates and data is independently retrieved from the panoramic memory to form panable displays.

Panoramic time delay and integration video camera system

Mode selection switches (76, 96, 98) selectively interconnect a sensor line shift timing generator (76) with one of three signal sources - (1) a conventional raster scan timing signal from a raster scan sync generator (70), (2) variable speed external timing signals from a tachometer (32), and (3) fixed speed timing signals developed from the horizontal timing signals of the raster scan sync generator. In a time delay and integration mode, the sensor line shift timing generator causes the CCD arrays of an image section (22) and storage section (24) to shift pixel values down the CCD arrays at a rate commensurate with the external timing signal. As a spot of light emanating from a portion of an object moving through an examination region moves along the CCD array, a corresponding pixel charge is shifted through the CCD array at the same speed such that the same pixel charge integrates light from the same spot as it moves the entire length of the CCD array. An output register timing generator (80) generates timing signals for output registers (26 ) such that an output signal is produced that is compatible with EIA-170 television signal standard. In the conventional raster scan mode, the camera works as a conventional video camera. When connected to the variable frequency timing signal, the video picture scrolls down the TV monitor clocked by the tachometer in proportion to the speed of the conveyor. In the calibration mode, the image scrolls down the video screen at a fixed rate.

Multi-mode TDI/raster-scan television camera system

A mode selecting switch (74) selectively interconnects one of an external timing signal from a tachometer (32) and master timing signals from a raster-scan synchronization generator (70) with a sensor line shift timing generator (76). In a time delay and integration mode, the sensor line shift timing generator causes the CCD arrays of an image section (22) and storage section (24) to shift pixel values down the CCD arrays at a rate commensurate with the external timing signal. As a spot of light emanating from a portion of an object moving through an examination region moves along the CCD array, a corresponding pixel charge is shifted through the CCD array at the same speed such that the same pixel charge integrates light from the same spot as it moves the entire length of the CCD array. In a raster-scan mode, the mode selecting switch connects master timing signals from the raster scan sync generator to the sensor line shift timing generator which generates conventional raster-scan timing signals. An output register timing generator (78) generates timing signals under control of an oscillator (80) for output registers (26) such that an output signal is produced that is compatible with EIA-170 television signal standard. Video processing channels (50) and a video synchronization circuit (60) process the output signals to produce a composite video signal.

Dual-mode TDI/raster-scan television camera system

A tachometer (32) monitors the speed of a continuously moving web or article (12). A lens (20) focuses an image of a portion of the web in an examination region (14) on image section (22) of a CCD array. As the web moves, the image moves correspondingly along the image section. A synchronizing circuit (C) adjusts the frequency of the tachometer output signal and uses it in lieu of a fixed frequency oscillator as the master clocking or timing basis for generating clocking pulses for the CCD array. More specifically, the synchronizing circuit generates four phase clocking pulses (.phi.1A-.phi.4A) which shifts lines of CCD data along the image section at the same speed that the image is moving along the CCD section. In this manner, the pixel values integrate light from the same area of the imaged web at each shifted position along the image section. Each line of data from the image section may be shifted at the same rate through an optically light-insensitive storage section (24) and read out serially by shift registers (26) to form a video signal. A quality control analysis circuit (D) monitors the video signal for selected characteristics of the imaged web. Preferably, a record is maintained of the location of flaws and defects noted by the quality analysis circuit.

Growing community of inventors

Los Altos, CA, United States of America

David L Gilblom