Lei Fengnet reported on a feature of the WeChat version of iOS this morning: When you send photos in your friends circle, you can display the location based on the location of the photo. As soon as the news came out, netizens began to try new gameplay.
When uploading a picture in a WeChat circle of friends, click on the location to automatically identify the location of the photo taken
In the past, when we sent a circle of friends, we could display our location information, and now automatically read the location of the photo shoot, so many people think of image recognition technology. In fact, what WeChat has done is not so complicated. Some industry insiders have told us that the new features of Leifeng Networks are based on picture location information (ie, Exif's GPS location information).
What is Exif?Exif (Exchangeable Image File) is an image file format that was originally developed by the Japanese Electronics and Information Technology Association (JEITA) for a set of standards for camera camera manufacturers.
Now, any photo taken by a mobile phone has a set of Exif parameters. In addition to pixel information , Exif also includes various image information such as aperture, shutter, white balance, ISO, focal length, date and time, as well as camera brand and model number. , Color Coding, Sounds recorded while shooting, and GPS Global Positioning System data.
In theory, as long as no special treatment is performed, the Exif information of each picture will remain.
What did WeChat do?The new feature of WeChat this time is likely to call the GPS Global Positioning System data in Exif. These data come from the internal sensors and gyroscopes.
Lei Feng network (search "Lei Feng network" public number attention) in an Exif viewer on the phone photographs tested, the results show that as long as the picture is not compressed, date and time, camera model, pixel and aperture shutter and other information can be Recorded, and the location information requires the user to turn on the GPS to show it.
As shown in the above figure, the location information covered by Exif has longitude, latitude, and altitude, and this set of data corresponds exactly to where Xiao Bian took the photo. It is certain that the new features of WeChat resolve this set of data.
Seeing here, you should know how WeChat accurately identifies the location of the user's uploaded pictures. Is it easier than everyone thinks?