Abstract: An apparatus and method is disclosed for facilitating calibration of a dual energy digital radiography system having a focused multi-element detector assembly. The apparatus includes two sets of calibration elements, each set made of a different basis material. Each calibration element defines a segment of an annulus and is positionable between the system source and detector such that the center defined by the annulus is substantially coincident with the focal spot of the source. Within individual sets, the thicknesses of the respective member elements differ one from another in accordance with a binary progression. Each of the calibration elements is positioned and sized such that it intercepts and attenuates all radiation which ultimately falls upon the detector.

Abstract: An artifact inducing image acquisition mapping system and technique is described for use in connection with digital imaging. A gray scale mapping technique is employed to indicate to an operator the brightness function of each pixel of an image. Where the brightness function is less than 95% of saturation, the image is displayed normally. Where the brightness function is at least equal to the saturation full scale value, that portion of the image is displayed in total black. Where the brightness function is between 95% and 100% of saturation full scale value, the image portion is displayed as mixed dark and light, i.e., a speckled region. An alternate embodiment simply displays saturated regions to total black.

Abstract: A fan beam of radiation (12) is projected on first and second detector arrays (18, 20). The detector arrays and fan beam are swept across a phantom (D). Fine wires (82) in the phantom each cast shadows over fractions of a plurality of the detectors during the sweep. Phantom images (44, 46) are generated from the first and second detector arrays with corresponding pixels of each image corresponding to the same path between a radiation source (10) and corresponding detectors in the arrays. A linear interpolation (50) interpolates the pixels of one of the images to shift their effective spatial position. A transform means (52) transforms the linear interpolated and second phantom image into at least one composite image (54). The linear interpolation is iteratively adjusted (C) to minimize phase change artifacts in corresponding pixels of the composite image. After the appropriate interpolation for each detector or group of detectors has been determined, the appropriate linear interpolations are stored (72).

Abstract: A system and method is disclosed for utilizing image pixel value information generated by a digital radiographic system for quantifying the amount of calcium in a particular object of interest within a subject, wherein the subject also contains additional quantities of calcium located at positions such that the additional calcium interfers with the acquisition of data describing the object of interest. A cursor configured as a parallelogram is described and pixel values are summed along lines parallel to the sides of the parallelogram. A profile is generated from these summations. A portion of the profile corresponding to pixel lines not intersecting the object of interest is used to estimate the contribution of background and other calcium to the profile as a whole, and this estimated value is subtracted from the total profile. Integration of the remainder of the profile provides a scalar value corresponding to the amount of calcium in the object of interest.

Abstract: A radiographic scanner (A) generates a high energy image representation which is stored in a high energy image matrix (V) and a low energy image representation which is stored in a low energy image memory (U). A pair of filter functions selecting circuits (C) select a first or soft tissue specific filter function and second or bone specific filter function, respectively. The soft tissue filter function selecting circuit selects and adjusts the soft tissue filter function in accordance with the pixel value of the low energy image representation for each corresponding pair of pixel values. Convolvers (44, 46) convolve pixel values from the high and low energy image representations with the selected and adjusted filter functions. A soft tissue transform function (48) transforms the filtered high and low energy image representations into a soft tissue or other material specific image representation (42).

Abstract: A method and apparatus for calibrating the detector gain of a dual energy digital radiography system is provided. A basis material calibration object is scanned to create low and high energy pixel data. A regression is performed on the pixel data to derive at least one high energy calibration vector and at least one low energy calibration vector. The calibration vectors are transformed into high and low energy gain functions represented by a Taylor series expansion. An examination object is scanned to create low and high energy image data. The image data is combined with the gain function to create corrected low and high energy image data.