General Electric Company

Analogic Corporation

Thomas W Lambert

Barry F Belanger

James E Blake

Edward W Andrews

Barry N Stone

Norbert Joseph Pelc

Stephen J Riederer

Gary S Keyes

Herbert E Daniels

Robert R Lijewski

Thomas P Liu

Stanley Bernstein

Philip J Griswa

Frank Bernstein

Lucius Stagg

Walter L Robb

An apparatus and method are provided for recording images on photon sensitive recording media (20) which includes a source (12) of image pixel data in digital form having a multiplicity of possible intensity values, a photon generator 16 for exposing the photon sensitive recording media at a fixed intensity level, and a controller (24, 22, 14) for controlling the amount of time of exposure of the recording media in correspondence with the pixel data intensity values from the source. Previously known apparatus either have problems producing clearly distinguishable shades of gray on the recording media or else require much more expensive technology. The most likely applications are the production of hard copy from medical imaging data where clarity and detail are the most important consideration. Other applications may prove feasible with any form of digitizable image data.

Apparatus and method for exposing photosensitive recording media with

An imaging system for generating a color image on film from electronic video image data incorporates feedback control techniques to provide control of film density. The system includes variable gain amplifiers responsive to light intensity output of a film writing device for maintaining the output at a desired set level. In addition, the system includes apparatus and a method for monitoring the density of film images produced by the system and for utilizing the monitored values to modify the system transfer function in a direction to effect a change in the film density towards a desired value.

Color film writing system with closed loop control for electronic images

A system for transferring electronic image data to film which provides correlation or matching between an image as viewed on a video monitor and an image viewed on film. Apparatus is disclosed for measuring image intensity on a video monitor and converting the measured intensity to electronic signals. The image intensity on film under controlled lighting is measured and signals representative of film density provided. The signals obtained by the two measurements are compared and any difference is used to vary a film writing system in a manner to minimize the difference.

Method and apparatus for correlating video and film images produced from

An imaging system for generating a image on film from video image data incorporates feedback control techniques to provide control of film density. The system includes variable gain amplifiers responsive to light intensity output of a film writing device for maintaining the output at a desired set level. In addition, the system includes apparatus and a method for monitoring the density of film images produced by the system and for utilizing the monitored values to modify the system transfer function in a direction to effect a change in the film density towards a desired value.

Film writing system with closed loop control for electronic images

Apparatus for reading out individual X-ray images recorded on a double-emulsion radiographic film or on separate films that were coincident when exposed simultaneously to a polyenergetic or broad X-ray photon energy spectrum beam emergent from a body and where an image corresponding to one obtained with a low energy part of the spectrum is formed on one film and an image corresponding to a higher energy part of the spectrum is formed on the other. One readout apparatus is for the case of two separate films which, after development, are illuminated from the back and optically scanned to derive analog signals representative of the intensities of spatially corresponding picture elements on each film. Another apparatus is for the case where the two images are on opposite sides of a film and are represented by alternate fine image information lines obtained by interposing a grid during the X-ray exposure. Another is for the case where a reflective layer is disposed between the film images during readout. In all cases the films are optically scanned and the resulting analog signals are digitized and variously processed to yield an image representative of that which is different between the two original different energy images.

Film-based dual energy radiography

Apparatus and methods are provided for performing temporal and hybrid subtraction of X-ray images. In one mode, using three memories, a pair of low and high energy X-ray exposures are made before an X-ray contrast medium arrives in a blood vessel to provide mask images. After contrast arrival additional high and low energy exposures are made and the low energy mask is subtracted from the low energy post-contrast images and the high energy mask is subtracted from the high energy post-contrast images and the resulting sequence of low and high energy temporal difference images are stored. The low energy temporal difference images are displayed. If motion artifacts are perceived, hybrid subtraction of low and high energy temporal difference images is undertaken to produce an image data set in which motion artifacts are removed. In an alternate mode, which uses four memories, low and high energy pre-contrast mask images are stored in one pair of memories. Low and high energy live post-contrast images are subtracted from the stored images and the resulting low and high energy temporal difference images are stored in the other pair of memories. These are subtracted to produce hybrid images.

Method and apparatus for X-ray image subtraction

X-ray pulses at two different photon energy levels are produced with an x-ray tube that has an adjustable resistor element in a circuit that connects the anode and filament of the tube to a high voltage supply. Two bias voltage supplies are connected in additive fashion between a control grid element of the tube and its filament to enable control of voltage drop and current through the tube. Switch means are provided to selectively shunt either or both bias voltage supplies in a repeatable order to thereby alter the bias voltage on the control grid and enable producing x-ray pulses having energies corresponding with the voltage drop and current through the tube at a selected bias voltage in accordance with the load line on the anode characteristic curve plot of the tube as determined by the value of the adjustable resistor element.

Multiple voltage x-ray switching system

A composite video signal waveform is fed through a video mixer and to a video monitor for displaying a raster scanned image on its screen. Signals are also fed through the mixer for causing a cursor having distinctive light intensity to be overlayed on the image. Programs for defining multiple cursors are stored in a readable memory. A microprocessor uses the programs for generating cursor parameters for each horizontal raster line and these are stored in a random access memory. A direct memory access controller responds to occurrence of each horizontal sync pulse by loading the cursor parameters for each corresponding raster line into counters which determine the starting point and end point of the cursor in that line or the width of the particular cursor line. During the interval representative of cursor line width, signals are fed through the mixer for altering the brightness intensity of the display. The random access memory is read out on a horizontal line-by-horizontal line basis so as to produce a whole cursor configuration between vertical blanking intervals. Operator interactive controls are provided for moving and angulating cursors.

Cursor generator for use in computerized tomography and other image

Data derived from multiple x-ray views of a body layer is processed in accordance with an image reconstruction algorithm by a central processing unit (CPU) to result in a matrix of digital data corresponding with picture elements (pixels) which are for being displayed on a tv or video monitor. A device for delineating or identifying a region in the displayed picture with a box, irregular trace, or cursor with a bright dotted line uses a trackball to generate data signals corresponding in position with pixels in the matrix. The trackball generated data is processed for producing video picture modulating signals corresponding with the pixels in the matrix to which they positionally relate. The modulating signals are overlayed on the composite video signals from the display controller with a video mixer.

Device for delineating zones in a video image display

In a convolver, analog video waveforms for each horizontal line to a raster scanned video monitor are sampled at regular intervals with a high speed shift register such as a charge coupled device to obtain trains of picture elements (pixels) which are transferred line-after-line to a series of registers to thereby delay the lines by the number of register stages used. As the trains are transferred the pixels are simultaneously supplied to delay elements to delay corresponding pixels in each line by a given amount in reference to the individual pixel which is to be convolved at the instant. The delayed pixel signals existing at the instant are variously processed in summing devices and the result is used to act on the individual pixel to convolve it in accordance with the filter function which is desired.

Analog video convolver for real time two-dimensional image processing

In computed tomography, a computer calculates CT numbers corresponding with the X-ray attenuation by elemental volumes in a body undergoing an X-ray beam scan. Analog signals corresponding with the sequence of CT numbers modulate a raster scanned cathode ray tube to produce a display of the image. Means are provided for controlling the display tube to display elements within a range of CT numbers or gray scale window. New means are provided for causing zones in the image corresponding with picture elements near the selected level or center of the gray scale to blink from gray to white such that when the level is set to correspond with a gray scale level of interest, the blinking zones will have CT numbers corresponding with the level setting. This permits identification of the CT numbers of the zones. The blink mode may be activated while the full image is displayed on the screen and zones of interest may be visualized in the total picture.

CT number identifier in a computed tomography system

X-ray apparatus includes a floor mounted enclosure, a patient supporting table on the enclosure, an X-ray tube casing mounted for angulating in the enclosure, X-ray imaging devices unitarily supported for angulating on a cantilever arm located above the table, and an extensible and contractible and optionally removable link arm for coupling the tube casing and image devices, respectively, to enable their coordinate longitudinal angulation or selectively to enable maintaining the X-ray tube and imaging devices in a fixed vertical relationship.

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Dousman, WI, United States of America

Thomas W Lambert