OCR tutorial step 1 - Process image

Demonstrates how to upload image files to Cloud Storage, and extract and translate text from the images by using the Vision API and Translation API.

Documentation pages that include this code sample

To view the code sample used in context, see the following documentation:

Code sample

Go


package ocr

import (
	"context"
	"fmt"
	"log"
)

// ProcessImage is executed when a file is uploaded to the Cloud Storage bucket you
// created for uploading images. It runs detectText, which processes the image for text.
func ProcessImage(ctx context.Context, event GCSEvent) error {
	if err := setup(ctx); err != nil {
		return fmt.Errorf("ProcessImage: %v", err)
	}
	if event.Bucket == "" {
		return fmt.Errorf("empty file.Bucket")
	}
	if event.Name == "" {
		return fmt.Errorf("empty file.Name")
	}
	if err := detectText(ctx, event.Bucket, event.Name); err != nil {
		return fmt.Errorf("detectText: %v", err)
	}
	log.Printf("File %s processed.", event.Name)
	return nil
}

Java


import com.google.cloud.functions.BackgroundFunction;
import com.google.cloud.functions.Context;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.cloud.translate.v3.DetectLanguageRequest;
import com.google.cloud.translate.v3.DetectLanguageResponse;
import com.google.cloud.translate.v3.LocationName;
import com.google.cloud.translate.v3.TranslationServiceClient;
import com.google.cloud.vision.v1.AnnotateImageRequest;
import com.google.cloud.vision.v1.AnnotateImageResponse;
import com.google.cloud.vision.v1.Feature;
import com.google.cloud.vision.v1.Image;
import com.google.cloud.vision.v1.ImageAnnotatorClient;
import com.google.cloud.vision.v1.ImageSource;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.ProjectTopicName;
import com.google.pubsub.v1.PubsubMessage;
import functions.eventpojos.GcsEvent;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.logging.Level;
import java.util.logging.Logger;

  @Override
  public void accept(GcsEvent gcsEvent, Context context) {

    // Validate parameters
    String bucket = gcsEvent.getBucket();
    if (bucket == null) {
      throw new IllegalArgumentException("Missing bucket parameter");
    }
    String filename = gcsEvent.getName();
    if (filename == null) {
      throw new IllegalArgumentException("Missing name parameter");
    }

    detectText(bucket, filename);
  }
}

Node.js

/**
 * This function is exported by index.js, and is executed when
 * a file is uploaded to the Cloud Storage bucket you created
 * for uploading images.
 *
 * @param {object} event A Google Cloud Storage File object.
 */
exports.processImage = async event => {
  const {bucket, name} = event;

  if (!bucket) {
    throw new Error(
      'Bucket not provided. Make sure you have a "bucket" property in your request'
    );
  }
  if (!name) {
    throw new Error(
      'Filename not provided. Make sure you have a "name" property in your request'
    );
  }

  await detectText(bucket, name);
  console.log(`File ${name} processed.`);
};

Python

def process_image(file, context):
    """Cloud Function triggered by Cloud Storage when a file is changed.
    Args:
        file (dict): Metadata of the changed file, provided by the triggering
                                 Cloud Storage event.
        context (google.cloud.functions.Context): Metadata of triggering event.
    Returns:
        None; the output is written to stdout and Stackdriver Logging
    """
    bucket = validate_message(file, "bucket")
    name = validate_message(file, "name")

    detect_text(bucket, name)

    print("File {} processed.".format(file["name"]))

What's next

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