基于GPUImage的人脸磨皮、美白、提亮的美颜滤镜
GPUImageBeautifyFilter是一个自定义的美颜滤镜，可以用来处理实时视频流或者是静态图片
主要原理是双边滤波、Canny边缘检测和肤色检测
Sample Code
GPUImageVideoCamera *videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
videoCamera.outputImageOrientation = UIInterfaceOrientationPortrait;
GPUImageView *filterView = [[GPUImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, viewWidth, viewHeight)];
GPUImageBeautifyFilter *beautifyFilter = [[GPUImageBeautifyFilter alloc] init];
[videoCamera addTarget:beautifyFilter];
[beautifyFilter addTarget:filterView];
[videoCamera startCameraCapture];
代码下载地址：https://github.com/YBYHunter/BeautifyFaceAndDetection（感觉好点个Star吧）
