densitetsmodulation

Densitetsmodulation, or density modulation, is a general term for techniques that deliberately vary the density of a material, a medium, or a signal in order to influence how it interacts with probing waves, light, or measurement systems. The modulation can be spatial, temporal, or spectral and is achieved by changing composition, layering, porosity, thickness, or by controlling how a sensing or imaging system samples and processes information.

In medical and industrial imaging, density modulation is often used to optimize image quality and reduce exposure. In computed tomography (CT), for example, dose or exposure modulation adjusts the X-ray tube current during rotation to compensate for differing attenuation along the body, aiming for consistent image noise while minimizing radiation dose. Similar ideas appear in radiography and non-destructive testing, where varying material density or contrast agents can enhance visibility of features with different densities.

In materials science and manufacturing, density modulation describes the deliberate variation of density within a structure, such as graded-porosity materials or lattice-structured metamaterials. These density gradients tailor mechanical, thermal, or acoustic properties for specific applications, including lightweight design, impact resistance, or wave control.

In display, printing, and imaging, density modulation underpins tone reproduction methods like halftoning, where a continuous image is represented by spatial variations in ink or pixel density. The approach relies on accurate control of density to produce the desired brightness and contrast.

Common considerations include calibration, potential artifacts at sharp density transitions, and the need for specialized hardware or algorithms to implement and interpret the modulation effectively. See also density, attenuation, and dose modulation.