Definition: Scanner and digital image resolution is properly called SPI or samples per inch. To scan an image the scanner takes a sampling of portions of the image. The more samples it takes per inch, the closer the scan is to the original image. The higher the resolution, the higher the SPI.
DPI (dots per inch; printer resolution) and PPI (pixels per inch; display resolution) are often used instead of SPI when talking about image resolution although they are actually different measures of resolution.
Also Known As: samples per inch | image resolution | scanner resolution
