de.hhn.android.licenseplatedecoder.decoder.LPSegmenter.java Source code

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Here is the source code for de.hhn.android.licenseplatedecoder.decoder.LPSegmenter.java

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package de.hhn.android.licenseplatedecoder.decoder;

import java.util.ArrayList;

import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;

import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.util.Log;

import com.googlecode.tesseract.android.TessBaseAPI;

/*
 ** CLASS NAME: 
 **     LPSegmenter
 **
 ** DESCRIPTION:
 **   This class represents the JNI wrapper for the implemented C++ license plate segmenter
 **
 **
 ** DEVELOPED BY:
 **   Mario Orozco Borrego (MOB)
 **
 ** SUPERVISED BY:
 **     Prof. Dr.-Ing. Permantier, Gerald
 **
 **      
 ** NOTES:
 **   
 **
 */

@SuppressLint("SdCardPath")
public class LPSegmenter {

    private long nativeInputAddr;
    private int countryCode;
    private String result;
    private TessBaseAPI baseApi;

    /**
     * Returns the result of the decoding
     * @return the result
     */
    public String getResult() {
        return this.result;
    }

    /**
     * Returns the dataset to be used and whitelist by the ocr engine, depending on the country code
     * @param countryCode input country code
     * @return the dataset in position 0 and whitelist in position 1
     */
    public String[] getDatasetAndWhiteList(int countryCode) {
        String[] result = new String[2]; // 0: dataset, 1: whitelist
        if (countryCode == 1) { // Germany
            result[0] = "de";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 2) { // Austria
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 3) { // Switzerland
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 4) { // France
            result[0] = "eng";
            result[1] = "0123456789";
        } else if (countryCode == 5) { // Chech Republic
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 6) { // Poland
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 7) { // Great Britain
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 8) { // Italy
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 9) { // Ireland
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 10) { // Slovakia
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else if (countryCode == 11) { // Turkey
            result[0] = "eng";
            result[1] = "0123456789";
        } else if (countryCode == 12) { // Russia
            result[0] = "eng";
            result[1] = "0123456789";
        } else if (countryCode == 13) { // Romania
            result[0] = "eng";
            result[1] = "ABCDEFGHIJKLMNOPRSTUVWXYZ";
        } else
            return null;

        return result;
    }

    /**
     * Constructor
     * @param inputImageAddr input image pointer address
     * @param countryCode input country code
     */
    public LPSegmenter(long inputImageAddr, int countryCode) {
        this.nativeInputAddr = inputImageAddr;
        this.countryCode = countryCode;
        Log.d("Segmenter", "Country Code: " + countryCode);

        /** OCR ENGINE INIT */
        this.baseApi = new TessBaseAPI();
        // INITIALIZATION DEPENDING OF THE COUNTRY CODE
        String languageDataset;
        String whitelist = null;
        String[] datasetWhitelist = getDatasetAndWhiteList(countryCode);
        languageDataset = datasetWhitelist[0];
        whitelist = datasetWhitelist[1];

        this.baseApi.init("/sdcard/", languageDataset); // myDir + "/tessdata/eng.traineddata" must be present
        this.baseApi.setPageSegMode(TessBaseAPI.PageSegMode.PSM_SINGLE_CHAR);
        this.baseApi.setVariable("tessedit_char_whitelist", whitelist);

        ArrayList<Mat> segChars = getCharacters();

        StringBuffer strb = new StringBuffer();
        for (Mat elem : segChars) {
            Imgproc.cvtColor(elem, elem, Imgproc.COLOR_BGR2GRAY);

            Bitmap pass = Bitmap.createBitmap(elem.cols(), elem.rows(), Bitmap.Config.ARGB_8888);
            Utils.matToBitmap(elem, pass, true);

            baseApi.setImage(pass);
            String recognizedText = baseApi.getUTF8Text(); // Log or otherwise display this string...
            strb.append(recognizedText);
            baseApi.clear();
            pass.recycle();
        }
        this.result = strb.toString();
        baseApi.end();
        baseApi = null;
        segChars = null;
    }

    /**
     * Native method which carries out the algorithm
     * @return
     */
    private native long[] process();

    /**
     * Gets the characters from the input image calling process method
     * @return the list of cropped images
     */
    private ArrayList<Mat> getCharacters() {
        ArrayList<Mat> result = new ArrayList<Mat>();
        long[] address = this.process();
        if (address == null)
            return new ArrayList<Mat>();
        for (long elem : address) {
            result.add(new Mat(elem));
        }
        return result;
    }

}