What is the aliasing/corduroy/moiré artifact?

The aliasing/corduroy/moiré artifact occurs when there is an interaction between the frequency of a grid's lines and the pixel spacing of the imaging system, leading to a distinct interference pattern. This phenomenon often arises in radiographic images where grids are employed to reduce scatter radiation.

When the grid lines’ frequency closely matches that of the pixel grid in the imaging detector, it results in a repeating pattern that can hinder the clarity of the image. This unwanted pattern resembles the appearance of fabric textures, such as corduroy or moiré, which are typically characterized by regular contrasting lines or waves.

Understanding this artifact is crucial for radiologic technologists, as recognition and management of moiré artifacts can greatly improve the quality of the diagnostic images. Proper grid selection and alignment, as well as awareness of pixel density, can help mitigate the occurrence of these artifacts, ensuring clearer and more accurate imaging.