Which factor can help to eliminate moire artifacts?

Moire artifacts are patterns that can appear on radiographic images, often caused by the interaction between the grid used in the imaging process and the digital sampling frequency of the image capture system. These artifacts are particularly noticeable when the frequency of the grid lines and the pixel sampling rate are similar, leading to interference patterns in the image.

Sampling at two times or more the grid frequency helps to minimize moire artifacts because it ensures that the digital sampling rate does not coincide with the grid line frequency. By sampling at a higher rate, you can accurately capture the grid's presence without finding a regular pattern that can cause distracting artifacts. This approach improves the overall quality of the image, as it allows for a better resolution of the actual structures being imaged, avoiding the repetitive patterns that lead to moire effects.

Increasing the exposure time and using lower grid frequencies may not directly address the issue of moire artifacts. While these factors may influence image quality and exposure, they do not sufficiently change the relationship between the grid frequency and the digital sampling. Decreasing the image brightness does not effectively address the root cause of moire artifacts, which is fundamentally about the interaction between grid frequency and sampling. Therefore, selecting a sampling rate that is significantly above the grid frequency is the key