iphone - 如何使用 iphone 在照片中找到矩形？

Question

我需要从 iPhone 拍摄的照片中识别、旋转和裁剪一个矩形(名片)。我相信这可以通过使用 OpenCV 来完成，但我以前没有使用过。谁能就此提供一些提示？

Answer 1

从 iOS 8 开始，您现在可以使用返回 CIRectangleFeature 的新检测器 CIDetectorTypeRectangle。您可以添加选项:

• 准确度:低/高

• 纵横比:例如，如果您只想查找正方形，则为 1.0

  CIImage *image = // your image
  NSDictionary *options = @{CIDetectorAccuracy: CIDetectorAccuracyHigh, CIDetectorAspectRatio: @(1.0)};
  CIDetector *rectangleDetector = [CIDetector detectorOfType:CIDetectorTypeRectangle context:nil options:options];
  
  NSArray *rectangleFeatures = [rectangleDetector featuresInImage:image];
  
  for (CIRectangleFeature *rectangleFeature in rectangleFeatures) {
      CGPoint topLeft = rectangleFeature.topLeft;
      CGPoint topRight = rectangleFeature.topRight;
      CGPoint bottomLeft = rectangleFeature.bottomLeft;
      CGPoint bottomRight = rectangleFeature.bottomRight;
  }
  

更多信息请参见 WWDC 2014 Advances in Core Image, Session 514.

An example from shinobicontrols.com