Commissariat a L'energie Atomique

Bernard Thevenin

Francis Glasser

Michel Tararine

Corinne Mestais

Jean-Luc Martin

Monique Marcaud

Digital radiography device protected against risk of electrocution

A method and a device for taking digital images in which the exposure time of the object to X or .gamma. rays is controlled and optimized in a way that produces, with each taking of an image, a non-saturated image and minimizes the dose of radiation necessary to produce this image. The device includes at least one image sensor having measurement pixels and pixels. The measurement pixels measure a current representative of a dose of radiation received by the object, and the image pixels are used to form the digital image. The dose of radiation measured by the measurement pixels is compared to a guide-line value, and when this dose measurement reaches the guide-line value the collection of the electrical charge by the image pixels is stopped. The stopping of the collection of the electrical charges is performed without stopping the radiation emission.

Method and device for the taking of digital images with control and

A nuclear detection process and an apparatus therefore, including base potential correction and corresponding apparatus in which the base potential is measured by establishing a histogram of the values of the detected pulses and the value of the abscissa of the first peak of the histogram is determined and is subtracted from the values of the detected pulses.

Nuclear detection process with base potential correction and

The coordinates X and Y of the location of a scintillation crystal excited by nuclear radiation are determined as a function of the signals X.sup.+, X.sup.-, Y.sup.+, Y.sup.- produced conventionally by an electronic circuit associated with the scintillation crystal. The signals X.sup.+, X.sup.-, Y.sub.+ and Y.sup.- are digitized and the digital coordinate X (respectively Y) is obtained as the product of a first digital data item X.sup.+ -X.sup.- (respectively Y.sup.+ -Y.sup.-) and a second digital data item inversely proportional to the energy of the nuclear radiation received. To prevent beats in the value of the coordinates X and Y, which leads to a moire phenomenon in the radiation image, a random element is introduced into the calculation, for example by adding p random bits to the first digital data item.

Process for locating nuclear radiation with reduction of moire phenomenon

A multiple interpolation process for image correction involves the precalculation of interpolation contributions relative to all the possible locations of the points of an elementary mesh. The positions of these locations are determined as a function of an interpolation fineness to be obtained. It is shown that this precalculation can be obtained without significantly enlarging the memory of an apparatus used. In addition, the performance speed permits the 'in flight' definition of images and the display of weakly defined images in highly defined images.

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St Egreve, France

Bernard Thevenin