用相機測量物體的大小

Question

我需要做一個方法來測量照片中的物體......我的意思是我可以將物體與卡的大小進行比較以獲得物體的大小，但是我不知道如何比較這...任何想法？

這裏是我正在拍照

- (IBAction)takePicture:(id)sender { 
// Create image picker controller 
UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init]; 

// Set source to the camera 
imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera; 

// Delegate is self 
imagePicker.delegate = self; 

// Allow editing of image ? 
imagePicker.allowsImageEditing = NO; 

// Show image picker 
[self presentModalViewController:imagePicker animated:YES]; 

    } 

     - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo 
    { 
UIAlertView *alert; 

// Unable to save the image 
if (error) 
    alert = [[UIAlertView alloc] initWithTitle:@"Error" 
             message:@"Unable to save image to Photo Album." 
             delegate:self cancelButtonTitle:@"Ok" 
          otherButtonTitles:nil]; 
else // All is well 
    alert = [[UIAlertView alloc] initWithTitle:@"Success" 
             message:@"Image saved to Photo Album." 
             delegate:self cancelButtonTitle:@"Ok" 
          otherButtonTitles:nil]; 
[alert show]; 
[alert release]; 
} 

Answer 1

這裏的一些內部監督辦公室網站移植image processing algorithms。如果您可以檢測到圖像的外邊緣和某個參考對象（並且知道它們處於相同的深度），則您應該能夠近似大小。

編輯 - 原來那裏沒有代碼鏈接。 Here's an SO answer about using OpenCV to do edge detection。無論如何，重點是，您需要圖像處理來從照片中提取可測量的特徵。