Now some websites have launched new login methods. Users no longer need to enter a user name and password. As long as they take a photo with the camera, the computer can know which user you are through your face. How did this happen?
It's easy for everyone to distinguish you, me and him by facial appearance. However, scientists do not know exactly how the brain works when we recognize human faces, but this has not stopped the computer from becoming a "facial stylist".
The computer has no talent to distinguish different faces. It only has the ability to deal with a large amount of data. Therefore, in the eyes of the computer, the photos of both handsome men and beautiful women are just a pile of numbers. The color value of each point on the photo is stored in the computer program in the form of numbers, and all tasks are realized by calculating these data.
The first thing the computer should do is to use a "face template" to move and calculate up, down, left and right in the picture data. According to the calculation results, lock out the position and size of the face in the picture, catch the face part in the picture, and adjust the size to the standard state. After finding the face, the next step is to judge whose face it is. In order to recognize human faces, the computer will establish a database that stores the photos of everyone when they log in for the first time. The computer needs to compare the face it is looking at with thousands of faces in the database. In order to make face comparison the most critical step, researchers have thought a lot of ideas.
One way is to find the position of eyes, nose and mouth on each face. Although humans can see it at a glance, computers need to be calculated by certain methods. Then, by measuring the size information such as the distance between the two eyes and the size of the nose, we can compare whether the photo matches the facial information of a person in the database.
There is also a more accurate "feature face" method. We can see that Li Lei looks like Li Lei and Han Mei looks like Han Mei. They must be identified by some features on their faces, but sometimes they can't tell what they are. The computer can give full play to its advantage of "good arithmetic", synthesize a large number of face data in the database for calculation, and calculate dozens of "characteristic faces", and then each real face can be composed of these characteristic faces in proportion, just as a cocktail can be mixed with several different wines, as long as the "blending proportion" of each characteristic face contained in the two faces is very close, It can be judged that it belongs to the same person.
Of course, there will be times when the computer can't recognize the human face. The person in the photo is wearing a mask or sunglasses. There is only half of the face in the photo, or the light in the photo is too dark or too bright, which may lead to the failure of the face recognition system. Scientists still have a lot of work to do in order to improve the "eyesight" of the computer.