Abstract: The stereotaxic images being digitized, a target pixel in a target region of interest is selected, a target window of chosen dimensional characteristics and containing the said target region of interest is generated around the selected target pixel, a set of pixels is determined in a second image, according to a predetermined selection criterion, a second window, of the same dimensional characteristics as the said target window, is generated around each selected pixel, a correlation processing between the grey-scale levels of the pixels of each second window and the grey-scale levels of the pixels of the target window is carried out so as to obtain a correlation value for each second window, and the region of interest homologous to the target region of interest is identified on the basis of the analysis of the set of correlation values thus obtained, so as to minimize the risks of matching error between the homologous regions of interest.

Abstract: Removable digital X-ray imaging device intended for mammography, comprising X-ray detectors placed on one edge of the device upon imaging. The device contains box for protecting the X-ray detectors by separating the X-ray detectors from the edge of the device, the device being in rest position.

Abstract: System for locating cassettes for producing digital images, in a radiography apparatus of the type comprising an X-ray source, means for data processing, a support for the cassette in an active position and a storage space for the cassette in the inactive position. The cassette comprises means for detecting the insertion of the cassette into the support and means for detecting the identification of the cassette.

Abstract: Cassette device for producing images, for a radiography apparatus of the type comprising a means for receiving mobile cassettes. The cassette comprises a casing of substantially parallelepipedal shape surrounding a means for producing images. The device comprises a means which forms a handle and is arranged on a small face of the casing The means which forms a handle is provided with a stop surface for insertion of the cassette into the reception means of the radiography apparatus.

Abstract: A process is disclosed which involves automatic position-finding for a point of interest of an object that exhibits high contrast as compared with surrounding tissues, the process being carried out by means of a stereotactic photographic device that includes a digital image acquisition system. The process includes a number of steps for each image belonging to the pair of stereotactic images. An initial analysis of a histogram of the image pixels are made, and a subsequent determination is made of a threshold corresponding to the difference between the high contrast objects and the surrounding tissues. A subsequent determination is made of the threshold of the image, in order to obtain a binary image incorporating two gray levels. This is followed by the filtering of the threshold determined image in the preceding step, based on morphological criteria of the object in which the point of interest is located. This operation is designed to obtain a segmented projection of the object of interest.

Abstract: A mammograph is disclosed which includes: a positioning device defining a rotation axis, the positioning device including: an arm .beta..sub.2 ; breast support plate connected to the arm .beta..sub.2 ; a movement device connected to the arm .beta..sub.2 ; and a digital detector connected to the movement device, the digital detector having a detection surface defining a plane .pi.; an arm .beta..sub.1 pivotally connected to the positioning device for pivotally rotating said arm .beta..sub.1 around said rotation axis, the arm .beta..sub.1 having an end; and an X-ray tube movably attached to the end of the arm .beta..sub.1, the X-ray tube defining a beam axis .delta. and being pivotable about the rotation axis so as to move in a first direction that is orthogonal with the rotation axis and direct an X-ray beam, emitted by the X-ray tube, along the beam axis .delta.. Pivoting the X-ray tube within an angle .+-..alpha. causes the movement device to move the digital detector laterally within the plane .pi.

Abstract: The calibration method consists in measuring the efficiency D of a detector cell placed behind the object as a function of various phantom thicknesses E.sub.p and various X-ray tube supply voltages V.sub.m. These measurements enable an analytic model D=f(V.sub.m, E.sub.p) to be determined describing the resulting curves. The inverse function of this analytic model can be used for calculating thickness E.sub.p as a function of the measured efficiency D and the known supply voltage V.sub.m.

Abstract: The invention relates to radiology systems and, more particularly in such systems, to a method that enables the effect of non-reciprocity of the radiographic film to be determined. This effect of non-reciprocity is expressed by coefficients CNRD(d.sub.i) which are a function of the photon dose rate (d.sub.i) on the film, the coefficients CNRD(d.sub.i) being obtained from the coefficients CNRT(t.sub.i) and the determination of the reference lumination L.sub.ref received by the film.

Abstract: The disclosure concerns radiology instruments that include an X-ray source, a receiver of the film or film-screen type, a detection cell and means to compute the yield at the cell. The method consists of performing measurements of the yield at instants t.sub.1, t.sub.2, . . . t.sub.3 during the exposure, so as to determine the lumination or luminous exposure (the quantity of the light received multiplied by the exposure time) on the film and then computing the lumination remaining to be acquired to obtain the chosen optical density on the film.

Abstract: The invention concerns radiology systems and, more particularly, in such systems, to a method to determine and calibrate the lumination (namely the quantity of light received multiplied by the exposure time) received by the radiographic film in order to obtain a given blackening of the film. This method consists in carrying out a certain number of calibrations of the radiology system, and then in making a sensitogram of the type of film used. Then, a radiographic shot is taken with an object of a known thickness E.sub.o and, to obtain a reference optical density DO.sub.refo, the optical density DO.sub.m of the shot obtained is measured and compared with DO.sub.refo on the sensitogram to determine L.sub.ref.