Swift 3 – 如何提高Tesseract的图像质量？
我正在使用Swift 3来构build一个移动应用程序，允许用户拍摄照片并在所得图像上运行Tesseract OCR。
不过，我一直在试图提高扫描的质量，似乎并没有太多的工作。 我已经把照片分成了一个更加“放大”的区域，我想辨认，甚至尝试使它变成黑白。 是否有任何“提升”或优化图像质量/尺寸的策略，使Tesseract可以更好地识别它？ 谢谢！
tesseract.image = // the camera photo here tesseract.recognize() print(tesseract.recognizedText) 我得到这些错误，不知道该怎么做：
Error in pixCreateHeader: depth must be {1, 2, 4, 8, 16, 24, 32} Error in pixCreateNoInit: pixd not made Error in pixCreate: pixd not made Error in pixGetData: pix not defined Error in pixGetWpl: pix not defined 2017-03-11 22:22:30.019717 ProjectName[34247:8754102] Cannot convert image to Pix with bpp = 64 Error in pixSetYRes: pix not defined Error in pixGetDimensions: pix not defined Error in pixGetColormap: pix not defined Error in pixClone: pixs not defined Error in pixGetDepth: pix not defined Error in pixGetWpl: pix not defined Error in pixGetYRes: pix not defined Please call SetImage before attempting recognition.Please call SetImage before attempting recognition.2017-03-11 22:22:30.026605 EOB-Reader[34247:8754102] No recognized text. Check that -[Tesseract setImage:] is passed an image bigger than 0x0.
我一直使用tesseract相当成功地迅速3使用以下内容：
func performImageRecognition(_ image: UIImage) { let tesseract = G8Tesseract(language: "eng") var textFromImage: String? tesseract?.engineMode = .tesseractCubeCombined tesseract?.pageSegmentationMode = .singleBlock tesseract?.image = imageView.image tesseract?.recognize() textFromImage = tesseract?.recognizedText print(textFromImage!) }
我也发现预处理图像也有帮助。 我添加了以下扩展到UIImage
导入UIKit导入CoreImage
extension UIImage { func toGrayScale() -> UIImage { let greyImage = UIImageView() greyImage.image = self let context = CIContext(options: nil) let currentFilter = CIFilter(name: "CIPhotoEffectNoir") currentFilter!.setValue(CIImage(image: greyImage.image!), forKey: kCIInputImageKey) let output = currentFilter!.outputImage let cgimg = context.createCGImage(output!,from: output!.extent) let processedImage = UIImage(cgImage: cgimg!) greyImage.image = processedImage return greyImage.image! } func binarise() -> UIImage { let glContext = EAGLContext(api: .openGLES2)! let ciContext = CIContext(eaglContext: glContext, options: [kCIContextOutputColorSpace : NSNull()]) let filter = CIFilter(name: "CIPhotoEffectMono") filter!.setValue(CIImage(image: self), forKey: "inputImage") let outputImage = filter!.outputImage let cgimg = ciContext.createCGImage(outputImage!, from: (outputImage?.extent)!) return UIImage(cgImage: cgimg!) } func scaleImage() -> UIImage { let maxDimension: CGFloat = 640 var scaledSize = CGSize(width: maxDimension, height: maxDimension) var scaleFactor: CGFloat if self.size.width > self.size.height { scaleFactor = self.size.height / self.size.width scaledSize.width = maxDimension scaledSize.height = scaledSize.width * scaleFactor } else { scaleFactor = self.size.width / self.size.height scaledSize.height = maxDimension scaledSize.width = scaledSize.height * scaleFactor } UIGraphicsBeginImageContext(scaledSize) self.draw(in: CGRect(x: 0, y: 0, width: scaledSize.width, height: scaledSize.height)) let scaledImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return scaledImage! } func orientate(img: UIImage) -> UIImage { if (img.imageOrientation == UIImageOrientation.up) { return img; } UIGraphicsBeginImageContextWithOptions(img.size, false, img.scale) let rect = CGRect(x: 0, y: 0, width: img.size.width, height: img.size.height) img.draw(in: rect) let normalizedImage : UIImage = UIGraphicsGetImageFromCurrentImageContext()! UIGraphicsEndImageContext() return normalizedImage } }
然后在将图像传递给performImageRecognition之前调用它
func processImage() { self.imageView.image! = self.imageView.image!.toGrayScale() self.imageView.image! = self.imageView.image!.binarise() self.imageView.image! = self.imageView.image!.scaleImage() }
希望这可以帮助