Method and evaluation device for evaluating projection data of an object being examined

An evaluation device for evaluation of projection data of an object being examined, the evaluation device being configured such that

• projection data of an object being examined are provided which are determined along a trajectory in a multiplicity of projection positions relative to a co-ordinate origin;
• a respective trajectory function is determined for the projection positions for each of a multiplicity of positions from a reconstruction region of dimension n by:
• establishing an offset, which corresponds to a value of a scalar product between one of the positions and one of the projection positions, and a direction vector at the co-ordinate origin;
• establishing a hyperplane of dimension n−1 which extends perpendicular to the direction vector and has the offset to the co-ordinate origin;
• establishing a number of intersection points where the hyperplane intersects with the trajectory;
• establishing a derivative vector of the trajectory according to its trajectory path and calculating the derivative vector in the projection position;
• establishing an absolute value of a scalar product between the derivative vector and the position and dividing the absolute value by the number;
• the trajectory functions in a frequency domain of dimension n are transformed relative to the positions;
• the projection data are evaluated by means of the transformed trajectory functions with respect to at least one property of the object.

A test facility for determination and evaluation of projection data of an object being examined, the test facility comprising:

• projection source for radiation of an object being examined from a multiplicity of projection positions lying on a trajectory;
• a detector to determine projection data of the object;
• and
• an evaluation device for evaluation of projection data of an objected being examined, the evaluation device being configured such that:
• projection data of an object being examined are provided which are determined along a trajectory in a multiplicity of projection positions relative to a co-ordinate origin;
• a respective trajectory function is determined for the projection positions for each of a multiplicity of positions from a reconstruction region of dimension n by:
• establishing an offset, which corresponds to a value of a scalar product between one of the positions and one of the projection positions, and a direction vector at the co-ordinate origin;
• establishing a hyperplane of dimension n−1 which extends perpendicular to the direction vector and has the offset to the co-ordinate origin;
• establishing a number of intersection points where the hyperplane intersects with the trajectory;
• establishing a derivative vector of the trajectory according to its trajectory path and calculating the derivative vector in the projection position;
• establishing an absolute value of a scalar product between the derivative vector and the position and dividing the absolute value by the number:
• the trajectory functions in a frequency domain of dimension n are transformed relative to the positions:
• the projection data are evaluated by means of the transformed trajectory functions with respect to at least one property of the object.

A computer program product, comprising program sections which are uploaded on to a computer to perform a method for evaluation of projection data of an object being examined, the method comprising the steps of:

• providing projection data of an object being examined which are determined along a trajectory in a multiplicity of projection positions relative to a co-ordinate origin;
• determining a respective trajectory function for the projection positions, for each of a multiplicity of positions from a reconstruction region of dimension n by:
• establishing an offset, which corresponds to a value of a scalar product between one of the positions and one of the projection positions, and a direction vector at the co-ordinate origin;
• establishing a hyperplane of dimension n−1 which extends perpendicular to the direction vector and the hyperplane has the offset to the co-ordinate origin;
• establishing a number of intersection points where the hyperplane intersects with the trajectory;
• establishing a derivative vector of the trajectory according to its trajectory path and calculating the derivative vector in the projection position;
• establishing an absolute value of a scalar product between the derivative vector and the position and dividing the absolute value by the number of intersection points;
• transforming the trajectory functions into a frequency domain of dimension n relative to the positions;
• evaluating the projection data by means of the transformed trajectory functions with respect to at least one property of the object.