CIDetector是用来分析CIImage，得到CIFeature。用来识别特定特征图片的类，主要可用来识别人脸、
属性和方法介绍
识别类型
//人脸
CORE_IMAGE_EXPORT NSString* const CIDetectorTypeFace NS_AVAILABLE(10_7, 5_0);
//矩形
CORE_IMAGE_EXPORT NSString* const CIDetectorTypeRectangle NS_AVAILABLE(10_10, 8_0);
//二维码
CORE_IMAGE_EXPORT NSString* const CIDetectorTypeQRCode NS_AVAILABLE(10_10, 8_0);
//文本
CORE_IMAGE_EXPORT NSString* const CIDetectorTypeText
使用方法 ：
作为type参数
// Types to be used for +[CIDetector detectorOfType:context:options:]
CIDetector *faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:param];
参数设置
不同参数具有不同识别效果，参数通过字典进行设置
精度设置
//key
CORE_IMAGE_EXPORT NSString* const CIDetectorAccuracy NS_AVAILABLE(10_7, 5_0);
//value
//精度低，速度快
CORE_IMAGE_EXPORT NSString* const CIDetectorAccuracyLow NS_AVAILABLE(10_7, 5_0);
//精度高，速度慢
CORE_IMAGE_EXPORT NSString* const CIDetectorAccuracyHigh NS_AVAILABLE(10_7, 5_0);
特征追踪
//key 用于视频中的特征追踪 value为@YES @NO
CORE_IMAGE_EXPORT NSString* const CIDetectorTracking NS_AVAILABLE(10_8, 6_0);
特征识别尺寸
//key 最小的特征识别尺寸 value为0.0 ~ 1.0 (NSnumber)
CORE_IMAGE_EXPORT NSString* const CIDetectorMinFeatureSize NS_AVAILABLE(10_8, 6_0);
//key 最大的特征识别尺寸 value为1 ~ 256 (NSnumber)
CORE_IMAGE_EXPORT NSString* const CIDetectorMaxFeatureCount NS_AVAILABLE(10_12, 10_0);
使用方法：
//使用方法 作为Options参数传入
// Options that can be used with +[CIDetector detectorOfType:context:options:]
NSDictionary *options = @{CIDetectorAccuracy:CIDetectorAccuracyHigh};
CIDetector * faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:options];
具体特征识别
// 角度个数 value为1，3，5，7，9，11 (NSnumber)之一
CORE_IMAGE_EXPORT NSString* const CIDetectorNumberOfAngles NS_AVAILABLE(10_11, 9_0);
// 图片方向 value为1 ~ 8(NSnumber)之一
CORE_IMAGE_EXPORT NSString *const CIDetectorImageOrientation NS_AVAILABLE(10_8, 5_0);
//识别眨眼 value为@YES,@NO
CORE_IMAGE_EXPORT NSString *const CIDetectorEyeBlink NS_AVAILABLE(10_9, 7_0);
//识别微笑 value为@YES,@NO
CORE_IMAGE_EXPORT NSString *const CIDetectorSmile NS_AVAILABLE(10_9, 7_0);
//焦距 value为float (NSNumber)
CORE_IMAGE_EXPORT NSString* const CIDetectorFocalLength NS_AVAILABLE(10_10, 8_0);
//矩形宽高比 value为float (NSNumber)
CORE_IMAGE_EXPORT NSString* const CIDetectorAspectRatio NS_AVAILABLE(10_10, 8_0);
//识别子特征 value为@YES,@NO
CORE_IMAGE_EXPORT NSString* const CIDetectorReturnSubFeatures __OSX_AVAILABLE_STARTING(__MAC_10_11, __IPHONE_9_0);
使用方法：
//作为Options参数传入
// Options that can be used with -[CIDetector featuresInImage:options:]
NSDictionary *options = @{CIDetectorSmile: [NSNumber numberWithBool:true], CIDetectorEyeBlink:[NSNumber numberWithBool:true]};
NSArray *detectResult = [faceDetector featuresInImage:cImage options:options];
具体使用
人脸识别
可以识别多人，区分人与动物的脸，判断人脸是否在笑和眨眼，但是不能做到区分人的脸，不能做面部解锁等功能。
CIImage *cImage = [CIImage imageWithCGImage:image.CGImage];
//设置人脸识别精度
NSDictionary *options = [NSDictionary dictionaryWithObject:
CIDetectorAccuracyHigh forKey:CIDetectorAccuracy];
//创建人脸探测器
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil options:options];
//获取人脸识别
NSArray *detectResult = [detector featuresInImage:cImage];
UIView * resultView = [[UIView alloc] initWithFrame:_imageView.frame];
[self.view addSubview:resultView];
//分析人脸识别数据
for (CIFaceFeature * faceFeature in detectResult) {
UIView *faceView = [[UIView alloc] initWithFrame:faceFeature.bounds];
faceView.layer.borderColor = [UIColor redColor].CGColor;
faceView.layer.borderWidth = 1;
[resultView addSubview:faceView];
if (faceFeature.hasLeftEyePosition) {
UIView * leftEyeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 5)];
[leftEyeView setCenter:faceFeature.leftEyePosition];
leftEyeView.layer.borderWidth = 1;
leftEyeView.layer.borderColor = [UIColor redColor].CGColor;
[resultView addSubview:leftEyeView];
}
if (faceFeature.hasRightEyePosition) {
UIView * rightEyeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 5)];
[rightEyeView setCenter:faceFeature.rightEyePosition];
rightEyeView.layer.borderWidth = 1;
rightEyeView.layer.borderColor = [UIColor redColor].CGColor;
[resultView addSubview:rightEyeView];
}
if (faceFeature.hasMouthPosition) {
UIView * mouthView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 5)];
[mouthView setCenter:faceFeature.mouthPosition];
mouthView.layer.borderWidth = 1;
mouthView.layer.borderColor = [UIColor redColor].CGColor;
[resultView addSubview:mouthView];
}
//具体特征识别
if (faceFeature.hasSmile) {
NSLog(@"再笑");
}
if (faceFeature.leftEyeClosed) {
NSLog(@"左眼闭了");
}
if (faceFeature.rightEyeClosed) {
NSLog(@"右眼闭了");
}
}
[resultView setTransform:CGAffineTransformMakeScale(1, -1)];
}
人脸识别
二维码识别
CIDetector *qrCodeDetector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{CIDetectorAccuracy:CIDetectorAccuracyHigh}];
NSData *imageData = UIImagePNGRepresentation(_qrImage);
CIImage *ciImage = [CIImage imageWithData:imageData];
NSArray *features = [qrCodeDetector featuresInImage:ciImage];
CIQRCodeFeature *feature = [features objectAtIndex:0];
NSString *scannedResult = feature.messageString;
NSLog(@"%@",scannedResult);
二维码识别
注意事项
坐标位置
CI坐标系是以左下角为原点的，和我们以往UIkit中左上角为原点是不一样的，所以最后的view添加这个段代码
[resultView setTransform:CGAffineTransformMakeScale(1, -1)];
有时候我们使用图片，imageview和image的图片不一样大，默认照片的图片像素很高，我们要将获取的位置进行调整。将坐标乘以以下系数。
#define ConvertX (self.imageView.frame.size.width) / _image.size.width
#define ConvertY (self.imageView.frame.size.height) / _image.size.height
我们也可以在一开始进行特征识别时，将图片缩放至imageview的大小（但是图片识别能力会下降）
float xfactor = self.imageView.bounds.size.width/image.size.width;
float yfactor = self.imageView.bounds.size.height/image.size.height;
cImage = [cImage imageByApplyingTransform:CGAffineTransformMakeScale(xfactor, yfactor)];
使用方法
设置精度的方法和设置具体特征方法不要写在同一个字典中，两个设置的方法是不一样的
//设置高精度人脸识别器
NSDictionary *param = [NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy];
CIDetector *faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:param];
//设置微笑和闭眼识别器
NSDictionary *options = @{CIDetectorSmile: [NSNumber numberWithBool:true], CIDetectorEyeBlink:[NSNumber numberWithBool:true]};
NSArray *detectResult = [faceDetector featuresInImage:cImage options:options];
Demo
Demo地址:人脸识别和二维码扫描