无法显示 OCR 的结果

Question

我有这个 mainActivity java 文件，我想显示 OCR 的结果。

错误：创建目录/storage/emulated/0/TesseractSample/tessdata失败，检查Android清单是否具有写入外部存储的权限。
无法将文件复制到 tessdata java.io.FileNotFoundException：/storage/emulated/0/TesseractSample/tessdata/eng.traineddata：打开失败：ENOENT（没有那个文件或目录）

3.Unable 解码流：java.io.FileNotFoundException：/storage/emulated/0/TesseractSample/imgs/ocr.jpg：打开失败：EACCES（权限被拒绝）

数据路径必须包含子文件夹 tessdata！

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Environment;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.googlecode.tesseract.android.TessBaseAPI;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class MainActivity extends Activity {

    private static final String TAG = MainActivity.class.getSimpleName();
    static final int PHOTO_REQUEST_CODE = 1;
    private TessBaseAPI tessBaseApi;
    TextView textView;
    Uri outputFileUri;
    private static final String lang = "eng";
    String result = "empty";

    private static final String DATA_PATH = Environment.getExternalStorageDirectory().toString() + "/TesseractSample/";
    private static final String TESSDATA = "tessdata";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button captureImg = (Button) findViewById(R.id.action_btn);
        if (captureImg != null) {
            captureImg.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    startCameraActivity();
                }
            });
        }
        textView = (TextView) findViewById(R.id.textResult);
    }


    /**
     * to get high resolution image from camera
     */
    private void startCameraActivity() {
        try {
            String IMGS_PATH = Environment.getExternalStorageDirectory().toString() + "/TesseractSample/imgs";
            prepareDirectory(IMGS_PATH);

            String img_path = IMGS_PATH + "/ocr.jpg";

            outputFileUri = Uri.fromFile(new File(img_path));

            final Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);

            if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
                startActivityForResult(takePictureIntent, PHOTO_REQUEST_CODE);
            }
        } catch (Exception e) {
            Log.e(TAG, e.getMessage());
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode,
                                 Intent data) {
        //making photo
        if (requestCode == PHOTO_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
            prepareTesseract();
            startOCR(outputFileUri);
        } else {
            Toast.makeText(this, "ERROR: Image was not obtained.", Toast.LENGTH_SHORT).show();
        }
    }

    /**
     * Prepare directory on external storage
     *
     * @param path
     * @throws Exception
     */
    private void prepareDirectory(String path) {

        File dir = new File(path);
        if (!dir.exists()) {
            if (!dir.mkdirs()) {
                Log.e(TAG, "ERROR: Creation of directory " + path + " failed, check does Android Manifest have permission to write to external storage.");
            }
        } else {
            Log.i(TAG, "Created directory " + path);
        }
    }


    private void prepareTesseract() {
        try {
            prepareDirectory(DATA_PATH + TESSDATA);
        } catch (Exception e) {
            e.printStackTrace();
        }

        copyTessDataFiles(TESSDATA);
    }

    /**
     * Copy tessdata files (located on assets/tessdata) to destination directory
     *
     * @param path - name of directory with .traineddata files
     */
    private void copyTessDataFiles(String path) {
        try {
            String fileList[] = getAssets().list(path);

            for (String fileName : fileList) {

                // open file within the assets folder
                // if it is not already there copy it to the sdcard
                String pathToDataFile = DATA_PATH + path + "/" + fileName;
                if (!(new File(pathToDataFile)).exists()) {

                    InputStream in = getAssets().open(path + "/" + fileName);

                    OutputStream out = new FileOutputStream(pathToDataFile);

                    // Transfer bytes from in to out
                    byte[] buf = new byte[1024];
                    int len;

                    while ((len = in.read(buf)) > 0) {
                        out.write(buf, 0, len);
                    }
                    in.close();
                    out.close();

                    Log.d(TAG, "Copied " + fileName + "to tessdata");
                }
            }
        } catch (IOException e) {
            Log.e(TAG, "Unable to copy files to tessdata " + e.toString());
        }
    }


    /**
     * don't run this code in main thread - it stops UI thread. Create AsyncTask instead.
     * https://developer.android.com/reference/android/os/AsyncTask.html
     *
     * @param imgUri
     */
    private void startOCR(Uri imgUri) {
        try {
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 4; // 1 - means max size. 4 - means maxsize/4 size. Don't use value <4, because you need more memory in the heap to store your data.
            Bitmap bitmap = BitmapFactory.decodeFile(imgUri.getPath(), options);

            result = extractText(bitmap);

            textView.setText(result);

        } catch (Exception e) {
            Log.e(TAG, e.getMessage());
        }
    }


    private String extractText(Bitmap bitmap) {
        try {
            tessBaseApi = new TessBaseAPI();
        } catch (Exception e) {
            Log.e(TAG, e.getMessage());
            if (tessBaseApi == null) {
                Log.e(TAG, "TessBaseAPI is null. TessFactory not returning tess object.");
            }
        }

        tessBaseApi.init(DATA_PATH, lang);

//       //EXTRA SETTINGS
//        //For example if we only want to detect numbers
//        tessBaseApi.setVariable(TessBaseAPI.VAR_CHAR_WHITELIST, "1234567890");
//
//        //blackList Example
//        tessBaseApi.setVariable(TessBaseAPI.VAR_CHAR_BLACKLIST, "!@#$%^&*()_+=-qwertyuiop[]}{POIU" +
//                "YTRWQasdASDfghFGHjklJKLl;L:'\"\|~`xcvXCVbnmBNM,./<>?");

        Log.d(TAG, "Training file loaded");
        tessBaseApi.setImage(bitmap);
        String extractedText = "empty result";
        try {
            extractedText = tessBaseApi.getUTF8Text();
        } catch (Exception e) {
            Log.e(TAG, "Error in recognizing text.");
        }
        tessBaseApi.end();
        return extractedText;
    }
}

Answer 1

如果您的目标是 Android SDK 23 或更高版本，除了在 Android 清单文件中请求权限外，您还必须 request permissions from the user at run time。

或者，您可以通过更改 build.gradle 中的 targetSdkVersion 值来定位 SDK 22 或更低版本。

无法显示 OCR 的结果

Unable to display the results of OCR

java

ocr

android