What does a barcode reader utilize to gather information?

A barcode reader uses a pattern of lines and spaces to gather information encoded in a barcode. The barcode consists of various widths of black bars and white spaces, which represent numeric and alphanumeric data. When the barcode reader scans the barcode, it analyzes the arrangement of these bars and spaces, converting the visual patterns into digital data that can be read by a system.

This method leverages light reflection: the black bars absorb light, while the white spaces reflect it, allowing the reader to detect the varying widths of the bars and spaces. The decoder then translates these variations into a format that can be processed. This is crucial for applications such as inventory management, point-of-sale systems, and supply chain tracking.

The other options, while related to different technologies, do not pertain to how barcode readers specifically operate. For instance, color variations refer to color-coded systems rather than the essential black-and-white pattern; ultrasonic waves are used in specific proximity sensing applications, and magnetic fields are utilized in different encoding methods like magnetic stripe readers or RFID, rather than traditional barcode scanning.