scans

Scans are digital representations produced by sampling real-world objects or scenes using specialized instruments. They are used to preserve, analyze, or transmit information and come in many forms, from flat documents to three-dimensional objects and whole scenes.

Flatbed and sheet-fed scanners capture images of documents and photos. Many include OCR software to extract text. Outputs include PDF, TIFF, and JPEG; resolution ranges from 300 to 1200 dpi for text, higher for archival use. Color depth, bit depth, and dynamic range affect fidelity and shading.

Medical scans convert body structures into images: X-ray, CT, MRI, ultrasound, and PET. They provide cross-sectional or volumetric data, often stored in DICOM. Some modalities use ionizing radiation; others do not. Interpretation relies on radiologists or trained clinicians.

Three-dimensional scanning measures shape and texture with lasers, structured light, or photogrammetry. Outputs include point clouds and meshes and are used in manufacturing, reverse engineering, cultural heritage, and film. Accuracy depends on device, resolution, and scanning geometry.

Other scanning methods include barcode, QR code, and RFID readers that extract encoded data, as well as astronomical and remote-sensing scanners that map large areas.