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这篇文章给大家介绍怎么在iOS中利用摄像头获取环境光感参数,内容非常详细,感兴趣的小伙伴们可以参考借鉴,希望对大家能有所帮助。
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#import "LightSensitiveViewController.h" @import AVFoundation; #import@interface LightSensitiveViewController ()< AVCaptureVideoDataOutputSampleBufferDelegate> @property (nonatomic, strong) AVCaptureSession *session; @end @implementation LightSensitiveViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. self.view.backgroundColor = [UIColor whiteColor]; self.navigationItem.title = @"光感"; [self lightSensitive]; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } #pragma mark- 光感 - (void)lightSensitive { // 1.获取硬件设备 AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; // 2.创建输入流 AVCaptureDeviceInput *input = [[AVCaptureDeviceInput alloc]initWithDevice:device error:nil]; // 3.创建设备输出流 AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init]; [output setSampleBufferDelegate:self queue:dispatch_get_main_queue()]; // AVCaptureSession属性 self.session = [[AVCaptureSession alloc]init]; // 设置为高质量采集率 [self.session setSessionPreset:AVCaptureSessionPresetHigh]; // 添加会话输入和输出 if ([self.session canAddInput:input]) { [self.session addInput:input]; } if ([self.session canAddOutput:output]) { [self.session addOutput:output]; } // 9.启动会话 [self.session startRunning]; } #pragma mark- AVCaptureVideoDataOutputSampleBufferDelegate的方法 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection { CFDictionaryRef metadataDict = CMCopyDictionaryOfAttachments(NULL,sampleBuffer, kCMAttachmentMode_ShouldPropagate); NSDictionary *metadata = [[NSMutableDictionary alloc] initWithDictionary:(__bridge NSDictionary*)metadataDict]; CFRelease(metadataDict); NSDictionary *exifMetadata = [[metadata objectForKey:(NSString *)kCGImagePropertyExifDictionary] mutableCopy]; float brightnessValue = [[exifMetadata objectForKey:(NSString *)kCGImagePropertyExifBrightnessValue] floatValue]; NSLog(@"%f",brightnessValue); // 根据brightnessValue的值来打开和关闭闪光灯 AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; BOOL result = [device hasTorch];// 判断设备是否有闪光灯 if ((brightnessValue < 0) && result) {// 打开闪光灯 [device lockForConfiguration:nil]; [device setTorchMode: AVCaptureTorchModeOn];//开 [device unlockForConfiguration]; }else if((brightnessValue > 0) && result) {// 关闭闪光灯 [device lockForConfiguration:nil]; [device setTorchMode: AVCaptureTorchModeOff];//关 [device unlockForConfiguration]; } } @end
注意点:
首先引入AVFoundation框架和ImageIO/ImageIO.h声明文件
遵循AVCaptureVideoDataOutputSampleBufferDelegate协议
AVCaptureSession对象要定义为属性,确保有对象在一直引用AVCaptureSession对象;否则如果在lightSensitive方法中定义并初始化AVCaptureSession对象,会造成AVCaptureSession对象提前释放, [self.session startRunning];会失效
实现AVCaptureVideoDataOutputSampleBufferDelegate的代理方法,参数brightnessValue就是周围环境的亮度参数了,范围大概在-5~~12之间,参数数值越大,环境越亮
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