使用 openCV 捕获图像，无需图像检测 iOS答案

【问题标题】：Capture an image using openCV without image detection iOS使用 openCV 捕获图像，无需图像检测 iOS
【发布时间】：2016-09-15 11:16:36
【问题描述】：

我遇到了一些问题，我已经找到了答案，但没有一个对我有用。

目标：在尝试检测 3 个 QR 码 60 秒后，提供手动捕获图像并将该图像发送到电子邮件的选项。类似于：60 秒过去了 --> UIAlertController 带有一个“确定”按钮，该按钮导致图像捕获视图 --> 用户捕获图像，然后将该图像作为附件添加到电子邮件中，然后他们可以发送

问题：找不到使用https://www.toptal.com/machine-learning/real-time-object-detection-using-mser-in-ios中描述的opencv库捕获图像的方法

我尝试过的事情：

在播放视频时截取屏幕截图（有效，但我正在寻找一种更复杂的方法来做到这一点

(UIImage *)capture {
    UIGraphicsBeginImageContext(self.view.bounds.size);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *imageView = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return imageView;
}

使用 UIImagePickerController（无法让 MFMailComposeViewController 显示。还不断收到“对尚未渲染的视图进行快照会导致空快照。确保您的视图在快照或屏幕更新后的快照之前至少渲染一次。” )

(IBAction)takePhoto:(id)sender {
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.allowsEditing = NO;
    picker.modalPresentationStyle = UIModalPresentationCurrentContext;
    picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    [self presentViewController:picker animated:YES completion:nil];
}

(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
    [self dismissViewControllerAnimated:YES completion:nil];
    [self emailImage:image];
 }

(void)emailImage:(UIImage *)image {
    if ([MFMailComposeViewController canSendMail]) {
        MFMailComposeViewController *mailComposeViewController = [[MFMailComposeViewController alloc] init];
        mailComposeViewController.mailComposeDelegate = self;
        mailComposeViewController.navigationBar.barStyle = UIBarStyleDefault;
        mailComposeViewController.modalPresentationStyle = UIModalPresentationPageSheet;
        NSString *messageBody = @"";
        messageBody = [messageBody stringByAppendingFormat:@"Image Attached"];
        NSArray *recipients = [NSArray arrayWithObjects: @"x@x.com", nil];
        [mailComposeViewController setMessageBody:messageBody isHTML:NO];
        [mailComposeViewController setToRecipients:recipients];

        NSData *data = UIImagePNGRepresentation(image);
        [mailComposeViewController addAttachmentData:data mimeType:@"image/png" fileName:@"Photo"];

        NSString *messageSubject = [NSString stringWithFormat:@"Cannot Scan"];
        [mailComposeViewController setSubject:messageSubject];

        [self presentViewController:mailComposeViewController animated:YES completion:nil];
    }
}
(void)mailComposeController:(MFMailComposeViewController*)controller
  didFinishWithResult:(MFMailComposeResult)result
                error:(NSError*)error {
    NSString *msg1;
    switch (result)
    {
        case MFMailComposeResultCancelled:
            msg1 =@"Sending Mail is cancelled";
            break;
        case MFMailComposeResultSaved:
            msg1=@"Sending Mail is Saved";
            break;
        case MFMailComposeResultSent:
            msg1 =@"Your Mail has been sent successfully. We will be responding shortly with your results.";
            break;
        case MFMailComposeResultFailed:
            msg1 =@"Message sending failed";
            break;
        default:
            msg1 =@"Your Mail is not Sent";
            break;
    }
    UIAlertView *mailResultAlert = [[UIAlertView alloc]initWithFrame:CGRectMake(10, 170, 300, 120)];
    mailResultAlert.message=msg1;
    mailResultAlert.title=@"Message";
    [mailResultAlert addButtonWithTitle:@"OK"];
    [mailResultAlert show];

    dispatch_async(dispatch_get_main_queue(), ^{
        [self dismissViewControllerAnimated:YES completion:nil];
        [self dismissViewControllerAnimated:YES completion:nil];
    }); 
}

有人知道使用 openCV videoCamera 方法手动捕获图像的方法吗？或者如何修复 UIImagePickerController？还是有其他替代解决方案？

谢谢！

【问题讨论】：

标签： ios objective-c iphone image

【解决方案1】：

我发现了 UIImagePickerController 的解决方案。

在 60 秒未检测到 3 个二维码后，会显示 UIAlertController。当按下“OK”按钮时，我执行到另一个视图控制器的 segue。

- (void)tooLong
{
    if ([self.navigationController.visibleViewController isKindOfClass:[UIAlertController class]]) {
        [self.navigationController.visibleViewController dismissViewControllerAnimated:YES completion:nil];
    }
    [self.contourScanner stopScan];
    self.analysisInProgress = NO;
    dispatch_async(dispatch_get_main_queue(), ^{
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:NSLocalizedString(@"Oops", nil)
                                                                   message:NSLocalizedString(@"It looks like we cannot detect your cup. Press 'OK' to take a photo manually. This image will be emailed to us to analyze ourselves.", nil)
                                                            preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *action = [UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil)  style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            [self performSegueWithIdentifier:@"takePhoto" sender:nil];
        }];
    [alert addAction:action];
    [self presentViewController:alert animated:YES completion:nil];
    });
}

然后在那个新的 viewcontroller.m 文件中，我创建了一个全局变量 (@property (strong, nonatomic) UIImagePickerController *picker; )，然后我添加了以下内容以正确拍摄原始图像。

- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];

    if (!self.hasPhotoCaptured) {
        [self takePhoto];
    }
}

- (void)takePhoto {
    self.hasPhotoCaptured = YES;
    self.picker = [[UIImagePickerController alloc] init];
    self.picker.allowsEditing = NO;
    self.picker.modalPresentationStyle = UIModalPresentationCurrentContext;
    self.picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    self.picker.delegate = self;
    self.picker.cameraFlashMode = UIImagePickerControllerCameraFlashModeOff;
    self.picker.cameraDevice = UIImagePickerControllerCameraDeviceRear;

    [self presentViewController:self.picker animated:YES completion:nil];
}

我最初的问题是我没有设置 self.picker.delegate = self;添加后，将调用 OP imagePickerController。

【讨论】：