Correction for polychromatic X-ray distortion in CT images
Apparatus and method for enhancing radiographs
Method of selecting a preferred difference image
X-ray image subtracting system Patent #: 4355331
ApplicationNo. 06/280055 filed on 06/30/1981
US Classes:382/130, Producing difference image (e.g., angiography)378/98.12, With image subtraction or addition382/254, IMAGE ENHANCEMENT OR RESTORATION382/294Registering or aligning multiple images to one another
ExaminersPrimary: Krass, Errol A.
Attorney, Agent or Firm
International ClassesG06T 5/50 (20060101)
H04N 5/32 (20060101)
G06T 1/20 (20060101)
AbstractThe method and apparatus furnish difference images from a video signal which contains a sequence of images that are obtained from a patient under examination. First a first of the images contained in the video signal is recorded in a first storage device. Thereby a so-called primary mask is formed. Then, a subsequent second of the images contained in the video signal is recorded in a second storage device. Subsequently, a third of these images is recorded in a third storage device. From here on, images contained in the video signal following the third image are recorded alternatingly in the second and the third storage device. At a certain point of time, a signal for starting data acquisition is provided. Simultaneously or thereafter, a so-called secondary mask is selected. The secondary mask is an image completely recorded in the second or third storage device shortly prior to the generation of the data acquisition signal. This secondary mask is subtracted from those images contained in the video signal which appear after the data acquisition signal has been generated. Thereby the afore-mentioned difference images are formed for display.