What type of scanning is not used in biometrics?

Infrared scanning is not typically classified as a biometric method. Biometric technologies focus on the unique physical or behavioral characteristics of individuals for identification and authentication purposes. Retinal scanning, fingerprints, and voice recognition are all established biometric methods that analyze specific traits unique to a person.

Retinal scanning involves analyzing the unique patterns in the retina at the back of the eye, making it a secure and highly accurate biometric method. Fingerprint scanning relies on the distinct patterns of ridges and valleys found in an individual's fingertips, which are unique to each person. Voice recognition analyzes characteristics of an individual's voice, such as pitch and tone, allowing for identification based on vocal attributes.

In contrast, infrared scanning generally refers to the use of infrared light to collect information about objects and surfaces, which may not involve the identification or verification of specific biological traits of individuals. While infrared technology can be useful in various applications, it does not fit the criteria for biometric identification. Thus, this makes it the correct choice as not being used in biometrics.