Face recognition is a biometric identification technology based on face feature information. Face recognition depends on four technologies, namely, face image acquisition and detection, face image preprocessing, face image feature extraction and matching recognition. The fugitive gained 50 kilograms in 9 years, which was discovered by face recognition because there are some features of the face that will not change because of obesity, and the collection of these features is a major technology in face recognition technology. It is basically impossible for fugitives to escape their sins by this means. Unless they have plastic surgery and changed their facial features, they can escape face recognition. Next, let's look at face recognition technology.

1. Face image acquisition and detection of face recognition technology The acquisition technology of face recognition is not to collect a single plane of a face, but to record all face features and their changes in different situations through static images, dynamic images, images at different positions and images with different expressions. These information will be used for identification in the future detection process.

Second, face image preprocessing of face recognition technology Face image preprocessing, that is, accurately calibrate the position and size of the face in the image. In other words, all facial features are filtered out and turned into an information base, not a complete face, but the feature information of a face. In this way, even if some features change, a person's face can be well recognized.

3. Face image feature extraction and matching recognition of face recognition technology The face image feature extraction and matching recognition technology of face recognition technology is the final face recognition link, that is, the information collected by the first two technologies is extracted, analyzed and matched, and the information that can match this face is transferred out of the system library for comparative recognition.