Android Open Source - esr-scanner Ocr Recognize Async Task

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The source code is released under:

Apache License

Java Source Code

/*
 * Copyright 2011 Robert Theis/*w w  w  . j av a2 s  . com*/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ch.luklanis.esscan;

import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import com.googlecode.leptonica.android.Binarize;
import com.googlecode.leptonica.android.Pix;
import com.googlecode.leptonica.android.ReadFile;
import com.googlecode.tesseract.android.TessBaseAPI;

import java.util.List;

import ch.luklanis.esscan.paymentslip.EsIbanResult;
import ch.luklanis.esscan.paymentslip.EsIbanValidation;
import ch.luklanis.esscan.paymentslip.EsrResult;
import ch.luklanis.esscan.paymentslip.EsrValidation;
import ch.luklanis.esscan.paymentslip.PsResult;
import ch.luklanis.esscan.paymentslip.PsValidation;

/**
 * Class to send OCR requests to the OCR engine in a separate thread and
 * appropriately send a success/failure message.
 */
final class OcrRecognizeAsyncTask extends AsyncTask<String, String, PsValidation> {

    private IBase base;
    private TessBaseAPI baseApi;
    private Bitmap bitmap;
    private OcrResult ocrResult;
    private OcrResultFailure ocrResultFailure;
    private ProgressDialog indeterminateDialog;
    private long start;
    private long end;

    // Constructor for single-shot mode
    OcrRecognizeAsyncTask(IBase base, TessBaseAPI baseApi, ProgressDialog indeterminateDialog,
                          Bitmap bitmap) {
        this.base = base;
        this.baseApi = baseApi;
        this.indeterminateDialog = indeterminateDialog;
        this.bitmap = bitmap;
    }

    // Constructor for continuous recognition mode
    OcrRecognizeAsyncTask(IBase base, TessBaseAPI baseApi, Bitmap bitmap) {
        this.base = base;
        this.baseApi = baseApi;
        this.bitmap = bitmap;
    }

    @Override
    protected PsValidation doInBackground(String... arg0) {
        String textResult = null;
        int[] wordConfidences = null;
        int overallConf = -1;
        start = System.currentTimeMillis();
        end = start;

        Pix thresholdedImage = Binarize.otsuAdaptiveThreshold(ReadFile.readBitmap(bitmap));

        try {
            // Log.i("OcrRecognizeAsyncTask",
            // "converted to bitmap. doing setImage()...");
            baseApi.setImage(thresholdedImage);

            // Log.i("OcrRecognizeAsyncTask", "setImage() completed");
            textResult = baseApi.getUTF8Text();
            // Log.i("OcrRecognizeAsyncTask", "getUTF8Text() completed");
            wordConfidences = baseApi.wordConfidences();
            overallConf = baseApi.meanConfidence();
            end = System.currentTimeMillis();
        } catch (RuntimeException e) {
            Log.e("OcrRecognizeAsyncTask",
                    "Caught RuntimeException in request to Tesseract. Setting state to CONTINUOUS_STOPPED.",
                    e);

            try {
                baseApi.clear();
            } catch (NullPointerException e1) {
                // Continue
            }
            return null;
        }

        // Check for failure to recognize text
        if (textResult == null || textResult.equals("")) {
            ocrResultFailure = new OcrResultFailure(end - start);
            return null;
        }

        // Get bounding boxes for characters and words
        List<Rect> wordBoxes = baseApi.getWords().getBoxRects();
        List<Rect> textlineBoxes = baseApi.getTextlines().getBoxRects();
        List<Rect> regionBoxes = baseApi.getRegions().getBoxRects();

        PsValidation validation = base.getValidation();

        while (validation.validate(textResult)) {
            if (!validation.nextStep()) {
                break;
            }
        }

        if (validation.getCurrentStep() == 1) {
            validation = (validation.getSpokenType()
                    .equals(EsrResult.PS_TYPE_NAME) ? new EsIbanValidation() : new EsrValidation());

            while (validation.validate(textResult)) {
                if (!validation.nextStep()) {
                    break;
                }
            }

            if (validation.getCurrentStep() > 1) {
                Handler handler = base.getHandler();
                Message message = Message.obtain(handler, R.id.es_change_ps_type, validation);
                message.sendToTarget();
            }
        }

        ocrResult = new OcrResult(bitmap,
                textResult,
                wordConfidences,
                overallConf,
                textlineBoxes,
                wordBoxes,
                regionBoxes,
                (end - start));

        return validation;
    }

    @Override
    protected void onPostExecute(PsValidation validation) {
        super.onPostExecute(validation);

        Handler handler = base.getHandler();

        if (validation != null) {
            if (validation.finished() && handler != null) {
                // Send results for single-shot mode recognition.

                String completeCode = validation.getCompleteCode();
                PsResult psResult = validation.getSpokenType()
                        .equals(EsrResult.PS_TYPE_NAME) ? new EsrResult(completeCode) : new EsIbanResult(
                        completeCode);

                Message message = Message.obtain(handler, R.id.es_decode_succeeded, psResult);
                message.sendToTarget();

                if (indeterminateDialog != null) {
                    indeterminateDialog.dismiss();
                }
            } else if (handler != null) {
                // Send results for continuous mode recognition.
                try {
                    // Send the result to CaptureActivityHandler
                    Message message = Message.obtain(handler, R.id.decode_succeeded, ocrResult);
                    message.sendToTarget();
                } catch (NullPointerException e) {
                    // continue
                }
            }
        } else {
            bitmap.recycle();
            try {
                Message message = Message.obtain(handler, R.id.decode_failed, ocrResultFailure);
                message.sendToTarget();
            } catch (NullPointerException e) {
                // continue
            }
        }

        if (baseApi != null) {
            baseApi.clear();
        }
    }
}

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