Abstract: A method and apparatus for automatically estimating a correction to be made to an image deformed with respect to a sequence of images. The method includes detecting of information pixels in the images; calculation of a region of interest located in a binary mapping image made from the images; for each image, search in the image, for the position of a mobile region that maximizes a similarity criterion to the region; and the estimated correction to be made to the image is compared with each image being the affine transformation of the mobile region moving from its found position at which similarity criterion is maximized to the region. The correction is only applied if the balance is equal to the improvement to the similarity criterion in the region of interest and the deterioration of the similarity criterion outside the region of interest is positive.

Abstract: A first method for processing of a radiological image to be used as a mask image in subtracted angiography wherein processing for reduction of noise present in the mask image adapted to preserve the aspect of the noise in the mask image. A second method for processing of a sequence of subtracted images (Jn) obtained by subtraction of a mask image from each of the images in a sequence of images (In) acquired during angiography of blood vessels in an area of interest (104) of a patient (200), wherein processing for reduction of noise present in the subtracted images (Jn) adapted to preserve the aspect of vessels (80) in the subtracted images. A radiography apparatus for implementing a method according to one and/or the other of the first and second methods.

Abstract: A process and radiography device for aiding vascular navigation suitable for an area of interest wherein a series of successive images In of the region of interest is acquired by a image recording. From the series of images In thus acquired a determination is made of a first mask presenting background structures and blood vessels of the region of interest, and a second mask presenting the only background structures. An image IL is acquired exhibiting at least one instrument introduced into one of the vessels of the region of interest. An image Iv is determined for visualizing by combination of the first and second masks and the image. The image to be visualized thus determined is displayed.

Abstract: A method and apparatus for determining a magnification factor in a radiography device of the type comprising an X-ray source and means for acquiring images placed facing the source, the source and the means for acquiring images being mounted so as to rotate about at least one axis with respect to a support on which an object to be X-rayed is intended to be positioned. The method and the apparatus implementing the method comprises: acquiring at least two images corresponding to two different angular positions of the source and of the recording means with respect to the support; identifying on these images projections of at least one point of the X-rayed object; and determining the magnification factor of at least one of the images, first, as a function of the angular displacement of the source and of the recording means between the acquisitions of the images in question and, secondly, as a function of the positions on these images of the identified projections.

Abstract: A method of cardiac radiological examination for coronarography comprises the steps of: a) introducing contrast medium simultaneously in the left coronary artery and in the right coronary artery from the aortic root and, in parallel, b) acquiring a sequence of dynamic images of the propagation of the contrast medium in the left and right coronary arteries with a displacement of the image plane, during the acquisition of said images, along a determined trajectory (E28). The contrast medium can be introduced in a cyclic manner during the acquisition of dynamic images, each cycle of introduction corresponding to a phase of closure of the aortic valve in the cardiac rhythm. 3D and 4D images with optimal efficiency can be obtained in the use of contrast medium. An injection device for producing the above cycles is synchronized with the introduction of the contrast medium.

Abstract: A method and apparatus for monitoring cardiac activity starting from a series of images of the heart made by X-rays. Attenuation of the X-rays is sampled on an area subject to repetitive thickenings of at least one wall of the heart, and a repetitive attenuation signal is interpreted as a signal representative of the heart activity.

Abstract: A method and device for calibrating images acquired by radiography comprising an X-ray source, an image acquisition, a support placed between the source and the image acquisition, on which support an object to be X-rayed is intended to be positioned. A region of interest, in which the object is likely to be found, is determined between the support and the image acquisition, the center of gravity of this region is determined and at least one calibration factor of the image or images is determined as a function of the position thus determined.

Abstract: A method for compressing an intensity dynamic range of an input image to a reduced intensity dynamic range of an image display device includes defining a plurality of units of the input image, determining a local mean estimate of an intensity of each of the plurality of units of the input image, generating a contrast modification processing value for each local mean estimate, and generating an output intensity value, for each local mean estimate, by using only the generated contrast modification processing value and an input intensity value.

Abstract: An element is dissolved displayed having a periodic structure, such as a stent, images of which are acquired by means of a radiography machine of the type comprising an X-ray source and an image detector and an image display placed opposite the source.

Abstract: A method and apparatus for improving angiographic images to be used with a radiography device comprising an X-ray source, a device for recording an image and an object positioned so as to present a region of interest to be imaged. The method comprises a) acquisition of a series of successive images of the region of interest; b) determination of a map image from the series of images; c) determination of a set of parameters characterizing a Gaussian distribution function that models the distribution of the grey levels of the map image; d) determination of a brightness and/or contrast improvement function; and e) application of the improvement function to the series of images in a subtractive mode.

Abstract: A method and apparatus are provided for performing a contrast-based dynamic range management (C-DRM) algorithm. The apparatus comprises an C-DRM processor that performs the C-DRM algorithm of the invention in order to compress an image input to the C-DRM processor down to a desired gray scale range for observation on a display. The C-DRM processor decouples adjustment of image mean values (low frequency) and image contrast values (high frequency), and manages mean and contrast separately. The use of separate mean and contrast modification functions improve on other known compression techniques by providing a more deterministic behavior and reduced complexity, allowing, for example, independent management of negative and positive contrasts. The C-DRM processor can also automatically adapt to the dynamic range of an input image so that the input image thereby applying the minimal compression needed to display the image.

Abstract: A method for management of dynamic range of a radiological image by processing an acquired image by subjecting context components as well as components of the details of the image to contrast expansion factors whose value depends on a signal of the context image, at the position of the concerned pixels. A signal in terms of gray levels or in terms of acquired doses is converted into a radiological thicknesses signal carry out the processing. At the end of the processing, the dynamic range of the processed image is reset so that it corresponds to that of a radiology apparatus, especially by compression. If desired, the factors are modified as a function of a choice made by the user.

Abstract: The method comprises a histogram of the radiographed image, i.e., a real histogram, a mathematical model of the image chain and the object obtained by calibration. The mathematical model of the image chain and the object and a set of parameters of acquisition, of the detector, of the positioner and of the object are used to determine two values of gray level, gray min and gray max, delimiting a useful zone and the part below gray min and the part above gray max are suppressed in the real histogram, i.e., a limited histogram. A set of rules is applied to the limited histogram in order to determine the level of brightness (WL) and the contrast (WW) is obtained from the brightness and possibly from one or more parameters selected by the user or fixed a priori.

Abstract: A process for reconstructing a tridimensional image of an object moving with a substantially cyclic motion, for example the vessels of the human heart, in which, for an acquisition duration extending over several cycles of the movement of the object, an acquisitio of a plurality of initial digital radiographic images is performed using a snapshot apparatus rotating around the object. Initial images having the same temporal occurrence in the course of each cycle are selected respectively in successive cycles so as to form a group of images which is associated with this same temporal occurrence. Several different groups of initial images corresponding respectively to several different temporal occurrences are formed. An intermediate tridimensional representation of the object is reconstructed on the basis of each group of initial images and of an iterative image reconstruction algorithm.

Abstract: A method of compensation for the thickness of an organ in an X-ray machine of the type comprising an X-ray source and a detector of the beam of X-rays after it has passed through the organ, the detector being capable of converting the X-ray beam into a digital electronic signal, in which, from a digitized image, an image of the radiologic thicknesses of an organ traversed by the X-ray beam is calculated, a thickness threshold is defined, from this there is derived an algebraic compensation image to bring the pixels of a level below or above the threshold back to the value of the threshold, and the thickness image and a proportion of the compensation image are summed up, to obtain a compensated thickness image.

Abstract: A method of compensation for the thickness of an organ in an X-ray machine of the type comprising an X-ray source and a means of detection of the beam of X-rays after it has passed through the said organ, the detection means being capable of converting the X-ray beam into a digital electronic signal, in which, from a digitized image, an image of the radiologic thicknesses of an organ traversed by the X-ray beam is calculated, a thickness threshold is defined, from this there is derived an algebraic compensation image to bring the pixels of a level below or above the said threshold back to the value of the threshold, and the thickness image and a proportion of the compensation image are summed up, to obtain a compensated thickness image.

Abstract: Several acquisitions of digital radiographic images of an element of interest are made, by using a moving camera rotating around the element of interest in a plane parallel to the plane of a section, a matching stage is carried out in which projected elements are located in all the acquired images, corresponding respectively to the projections of the element of interest in those acquired images. The width of each projected element is determined and the section of the element of interest is reconstructed from the different widths determined.

Abstract: A method of cardiac radiological examination for coronarography comprises the steps of:

Abstract: A method for compressing an intensity dynamic range of an input image to a reduced intensity dynamic range of an image display device includes defining a plurality of units of the input image, determining a local mean estimate of an intensity of each of the plurality of units of the input image, generating a contrast modification processing value for each local mean estimate, and generating an output intensity value, for each local mean estimate, by using only the generated contrast modification processing value and an input intensity value.

Abstract: Method and apparatus for the management of the dynamics of a digitized radiological image of the type comprising a radiation source and a means of detection of the radiation source after it has crossed an object of interest, the means of detection capable of converting the radiation source into a digital electronic signal, including means for defining an intensity threshold from a so-called digitized input image, means for deducing therefrom an algebraic compensation image to raise the pixels of level below the threshold, and means for adding the input image and the compensation image, in order to obtain a compensated image which preserves the differences and the real relations between internal structures of the object of interest. The method and apparatus is useful in X-ray radiological imaging of internal organs of the human body.