Abstract: The present invention provides a control system for and method of controlling an apparatus of the type for exposing photographic film with image data which control system and method are adapted to compensate for variations in the exposure intensity, while also adjusting for different formats of image data. In one form, control system of the present invention determines the format of the image data, determines an exposure format in response to the format of the image data for producing an image on the film having a predetermined size, and calibrates an intensity for the exposure in response to the determined exposure format.

Abstract: A predetermined gradation of film transmittance levels, e.g. a gray scale, provided by a film exposure system is calibrated so as to consistently create an image on photographic film in accordance with the predetermined gradation of film transmittance levels. A light source is responsive to a drive signal, for generating light so that the exposure of different portions of the film to the light can be varied as a function of the drive signal so as to vary the resulting transmittance level of the portions of the film after the exposed portions of film are developed in order that the image can be formed on the film, and a sensing device senses the transmittance level of a developed portion of film exposed to at least one preselected value of light exposure and generates a transmittance level signal representative of the sensed transmittance level.

Abstract: 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.

Abstract: In a digital fluorography system a television (TV) camera converts X-ray images to analog video signals that are converted to digital pixel words in an analog-to-digital converter (ADC). The sync signals for the TV camera and the sample clock signals for the ADC are derived from a novel resettable crystal controlled sync generator. A phase-locked loop provides an ac reference signal at one-half power line frequency which is equivalent to TV frame rate. The sync generator is reset to start a new frame and an ensuing sequence of crystal controlled horizontal sync pulses only in response to occurrence of ac reference signals so every frame is in registration. A digital video processor (DVP) subtracts a mask image from each image in a sequence of images that are acquired while an X-ray contrast medium is appearing in and disappearing from a blood vessel. The resulting difference images are stored in analog video signal format in an analog video disk recorder.

Abstract: In a digital fluoroscopy system, analog video signals representative of successive x-ray image frames are converted to digital pixel values that are used as addresses, respectively. A digital memory stores at its respective locations a digital value corresponding to the logarithm of an address value so that when a digital pixel value represented by an address is fed from the analog-to-digital converter to the memory the memory will output the logarithm of the pixel value in digital form. Pixel values for successive x-ray images are subtracted in-phase on a pixel-by-pixel basis to produce digital difference pixel signals which are converted to analog video signals for driving a television monitor that displays an image representative of the difference between x-ray images.

Abstract: 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.

Abstract: A toilet tissue dispensing assembly comprising a housing which can fit over the mounting brackets of an existing wall-mounted toilet tissue dispenser and having two opposed, laterally projecting arms, one of the arms having a driving gear assembly powered by a battery-operated motor contained within that arm and a cylindrical core that is received within a roll of toilet tissue and having a driven gear assembly on one of its ends adapted to engage the driving gear in the arm and having a spring-biased pin adapted to engage an opening in the other arm, whereby actuation of the motor will cause the core to be rotated to dispense a desired amount of tissue.