1. A method for operating an x-ray diagnostic device, comprising: creating a subtraction angiography sequence comprising a plurality of low resolution x-ray images containing a moving structure of an object under diagnosis; registering the x-ray images one with another by a transformation; and computing a high resolution image based on the registered x-ray images, wherein the registering comprises: selecting a preferred image from the x-ray images as a reference image, defining the transformation T i as T i = ( 1 0 0 k y , i 1 0 0 0 1 ) · ( 1 k x , i 0 0 1 0 0 0 1 ) · ( s x , i 0 0 0 s y , i 0 0 0 1 ) · ( cos ⁡ ( α i ) - sin ⁡ ( α i ) 0 sin ⁡ ( α i ) cos ⁡ ( α i ) 0 0 0 1 ) · ( 1 0 x i 0 1 y i 0 0 1 ) wherein α i is an angle of rotation, x i and y i is a translation within an image plane, s x,i and s y,i is a scaling in x and y direction, and k x,i and k y,i is a shear in x and y direction, and determining a parameter that map each image of the x-ray images onto the reference image with minimal error based on the transformation.