TranSign, Android Sign Translator

TranSign, Android Sign Translator

This project shows text extraction from the input image. It is used for road sign texts translations. First, the image is preprocessed using OpenCv functions and than the text from road sign is detected and extracted.

Input

The process

  1. Image preprocessing
    Imgproc.cvtColor(img, img, Imgproc.COLOR_BGR2GRAY);
    Imgproc.GaussianBlur(img, img, new Size(5,5), 0);
    Imgproc.Sobel(img, img, CvType.CV_8U, 1, 0, 3, 1, 0);
    Imgproc.threshold(img, img, 0, 255, Imgproc.THRESH_OTSU+THRESH_BINARY);
    
  2. Contour detection
    List<MatOfPoint> contours;
    Imgproc.findContours(img, contours, new Mat(), Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_NONE);
    
  3. Deleting contours on edges, small contours, wrong ratio contours and wrong histogram contours
  4. Preprocessing before extraction
  5. Extraction
    TessBaseAPI baseApi = new TessBaseAPI();
    baseApi.init(TESSBASE_PATH, DEFAULT_LANGUAGE);
    baseApi.setImage(bm);
    String resultParcial;
    
  6. Translation

Sample

Preprocessing – converting to greyscale, Gaussian blurring, Sobel, binary threshold + Otsu’s, morphological closing

Contour detection and deleting wrong contours

Preprocessing before extraction

Extraction

Translation