Reid E. Kellogg

New correlation method for measuring texture noise in x-ray screens

A new method to measure the texture (structure) noise produced by x-ray screens has been developed. Different films are exposed with the same screen and are scanned in registration. The numerical correlation of the two sets of pixel data then contains only the texture noise component. This is a powerful technique allowing texture noise to be measured quantitatively in the presence of the quantum noise and film grain noise background. Our results support the generally accepted belief that texture noise is small compared with quantum and film grain noise. There are advantages to visualizing texture noise behavior in Cartesian space (as correlation functions) as well as in frequency space (as noise power spectra). Some examples of structure noise correlations and the corresponding spectra are presented.