Patent ID: 7209543

Claim:
Automatic exposure method for use in a diagnostic imaging apparatus in which an object to be imaged is positioned in an imaging area, a radiation source is used to produce radiation for use in the imaging process, radiation containing image information is detected by an image data receiving means and at least one imaging parameter is controlled during exposure on the basis of a signal detected by an at least one exposure detector, wherein the method comprises at least the following actions: modeling the radiation spectrum obtained from the radiation source of the imaging apparatus as a function of said at least one operating parameters and production of radiation quanta, in a case where the imaging apparatus has components that lie between the radiation source and the image data receiving means, modeling in respect of attenuation of radiation at least one of said components of the imaging apparatus that lie between the radiation source and the image data receiving means, and in a case where the imaging apparatus has components that lie between the radiation source and the exposure detector, modeling at least one of said components that lie between the radiation source and the exposure detector with respect to attenuation of radiation; modeling darkening of the image being detected by the image data receiving means as a function of radiation incident on the image data receiving means, determining thickness of the object to be imaged within the imaging area in the direction of a radiation beam emitted from said radiation source, beginning the exposure, measuring a signal obtained from an exposure detector and determining the object density by comparing the signal to the modeled attenuation of radiation, and on the basis of the aforesaid modelings, the determined object thickness, and the determined object density, determining at least one value of the at least one imaging parameter required to achieve a desired degree of darkening of the image and adjusting the at least one imaging parameter accordingly.