How to setLanguageHint in Google OCR SDK? - ocr

Question

I am testing few sample code for OCR using Google Cloud Vision API. I observed the APIs can able to detect English language very easily from an Image but in other language like Hindi, the APIs are not able to detect.
MyCode :
public static void detectText(String filePath) throws Exception, IOException {
System.out.println("Detect Text\n");
List<AnnotateImageRequest> requests = new ArrayList<>();
ByteString imgBytes = ByteString.readFrom(new FileInputStream(filePath));
Image img = Image.newBuilder().setContent(imgBytes).build();
Feature feat = Feature.newBuilder().setType(Feature.Type.TEXT_DETECTION).build();
AnnotateImageRequest request = AnnotateImageRequest.newBuilder().addFeatures(feat).setImage(img).build();
requests.add(request);
Credentials myCredentials = ServiceAccountCredentials.fromStream(
new FileInputStream(jsonPath));
ImageAnnotatorSettings imageAnnotatorSettings =
ImageAnnotatorSettings.newBuilder()
.setCredentialsProvider(FixedCredentialsProvider.create(myCredentials))
.build();
try (ImageAnnotatorClient client = ImageAnnotatorClient.create(imageAnnotatorSettings)) {
BatchAnnotateImagesResponse response = client.batchAnnotateImages(requests);
List<AnnotateImageResponse> responses = response.getResponsesList();
for (AnnotateImageResponse res : responses) {
if (res.hasError()) {
System.out.printf("Error: %s\n", res.getError().getMessage());
return;
}
// For full list of available annotations, see http://g.co/cloud/vision/docs
for (EntityAnnotation annotation : res.getTextAnnotationsList()) {
System.out.printf("Text: %s\n", annotation.getDescription());
}
}
}
}
Image :
But the same image, i have tried in Google Drive, all the text from the image is easily detected.
Please let me know, same image how can i use in the code to detect the text?

Answer 1

Use ImageContext class
ImageContext imageContext = ImageContext.newBuilder()
.addLanguageHints("hi")
.build();
and set ImageContext in your AnnotateImageRequest
AnnotateImageRequest request =
AnnotateImageRequest.newBuilder()
.addFeatures(feat)
.setImage(img)
.setImageContext(imageContext)
.build();
Ref : OCR Language Support
Hope this help!

Answer 2

Note: I'm not a Java developer.
Below is the general representation, that matches your need in Python
{
"requests": [
{
"imageContext": {
"languageHints": [
"hi"
]
},
"features": [
{
"type": "TEXT_DETECTION"
}
]
}
]
}
Refer to: https://cloud.google.com/vision/docs/reference/rest/v1/images/annotate#ImageContext