Moiréstrukturer

Moiréstrukturer, also known as moiré patterns, are large-scale interference patterns that emerge when two similar, typically fine, patterns are superimposed. These patterns are not present in the individual components but arise from their interaction. The effect is most commonly observed when two grids or screens are slightly misaligned or have different periodicities. The resulting moiré pattern is a new, often much larger, grid or series of lines, curves, or other shapes.

The formation of moiré patterns is a visual phenomenon related to the sampling and aliasing of repetitive patterns. When the spacing or orientation of the superimposed patterns changes, the moiré pattern also changes, becoming larger or smaller, or shifting its appearance. This sensitivity makes moiré patterns useful in certain applications, such as in measuring small displacements or in security printing where a hidden image can be revealed by viewing it through a patterned overlay.

In digital imaging, moiré artifacts can appear when a digital sensor's pixel grid interacts with a finely detailed image or a textured surface. This is particularly common when photographing fabrics with fine repeating patterns, such as certain textiles or screens. These digital moiré patterns are considered an unwanted artifact and can degrade image quality. Techniques exist to mitigate or remove moiré in digital photography and scanning. The term "moiré" itself originates from a type of watered silk fabric, referring to its wavy, lustrous appearance, which is reminiscent of these optical interference patterns.