谷歌移动视觉文本 API 示例

Question

我目前正在编写代码，该代码应该能够查看文本图片，然后从基于 Android 的设备的图片中提取文本。我在网上做了一些研究，发现谷歌提供了他们自己的 API，称为“Mobile Vision”（一个包含许多项目的包，即文本识别、面部识别等）。然而，在他们的演示中，他们只演示了实时文本识别。我想知道是否有人可以给我一个使用 Mobile Vision API 对静止图像进行文本识别的示例。欢迎任何帮助。谢谢。

Answer 1

Google Play Services Mobile Vision API 文档描述了如何执行此操作，您可以使用 TextRecognizer 类来检测 Frames 中的文本。获得位图图像后，您可以将其转换为帧并对其进行处理。请参阅下面的示例。

// imageBitmap is the Bitmap image you're trying to process for text
if(imageBitmap != null) {

    TextRecognizer textRecognizer = new TextRecognizer.Builder(this).build();

    if(!textRecognizer.isOperational()) {
        // Note: The first time that an app using a Vision API is installed on a
        // device, GMS will download a native libraries to the device in order to do detection.
        // Usually this completes before the app is run for the first time.  But if that
        // download has not yet completed, then the above call will not detect any text,
        // barcodes, or faces.
        // isOperational() can be used to check if the required native libraries are currently
        // available.  The detectors will automatically become operational once the library
        // downloads complete on device.
        Log.w(LOG_TAG, "Detector dependencies are not yet available.");

        // Check for low storage.  If there is low storage, the native library will not be
        // downloaded, so detection will not become operational.
        IntentFilter lowstorageFilter = new IntentFilter(Intent.ACTION_DEVICE_STORAGE_LOW);
        boolean hasLowStorage = registerReceiver(null, lowstorageFilter) != null;

        if (hasLowStorage) {
            Toast.makeText(this,"Low Storage", Toast.LENGTH_LONG).show();
            Log.w(LOG_TAG, "Low Storage");
        }
    }


    Frame imageFrame = new Frame.Builder()
            .setBitmap(imageBitmap)
            .build();

    SparseArray<TextBlock> textBlocks = textRecognizer.detect(imageFrame);

    for (int i = 0; i < textBlocks.size(); i++) {
        TextBlock textBlock = textBlocks.get(textBlocks.keyAt(i));

        Log.i(LOG_TAG, textBlock.getValue()); 
        // Do something with value
    }
}

您还需要确保在模块的 build.gradle 中包含移动视觉依赖项

dependencies {
    compile 'com.google.android.gms:play-services-vision:9.4.0'
} 

并且还在应用的 Android 清单中包含以下内容

<meta-data
    android:name="com.google.android.gms.vision.DEPENDENCIES"
    android:value="ocr" />