使用 Amazon Textract 检测文档文本

要检测文档中的文本，请使用DetectDocumentText操作，然后将文档文件作为输入传递。DetectDocumentText返回 JSON 结构，其中包含检测到的文本的行和单词、文档中文本的位置以及检测到的文本之间的关系。有关更多信息，请参阅 检测文本。

您可以提供输入文档作为图像字节数组 (base64 编码的图像字节) 或 Amazon S3 对象。在此过程中，您将图像文件上传到您的 S3 存储桶并指定文件名称。

检测文档中的文本 (API)

1. 如果您尚未执行以下操作，请：

   1. 使用创建或更新 IAM 用户AmazonTextractFullAccess和AmazonS3ReadOnlyAccess权限。有关更多信息，请参阅 第 1 步：设置 AWS 账户并创建 IAM 用户。

   2. 安装和配置 AWS CLI 和 AWS 开发工具包。有关更多信息，请参阅 第 2 步：设置AWS CLI和AWS软件开发工具包。

2. 将文档上传到 S3 存储桶。

   有关说明，请参阅将对象上传到 Amazon S3中的Amazon Simple Service 用户指南.

3. 使用以下示例调用 DetectDocumentText 操作。

   Java

   以下示例代码在检测到的文本行周围显示文档和框。

   在函数main，替换的值bucket和document将包含您在步骤 2 中使用的 Amazon S3 存储桶名称和文档的名称。

   //Calls DetectDocumentText.
   //Loads document from S3 bucket. Displays the document and bounding boxes around detected lines/words of text.
   package com.amazonaws.samples;
   
   import java.awt.*;
   import java.awt.image.BufferedImage;
   import java.util.List;
   import javax.imageio.ImageIO;
   import javax.swing.*;
   import com.amazonaws.services.s3.AmazonS3;
   import com.amazonaws.services.s3.AmazonS3ClientBuilder;
   import com.amazonaws.services.s3.model.S3ObjectInputStream;
   import com.amazonaws.client.builder.AwsClientBuilder.EndpointConfiguration;
   import com.amazonaws.services.textract.AmazonTextract;
   import com.amazonaws.services.textract.AmazonTextractClientBuilder;
   import com.amazonaws.services.textract.model.Block;
   import com.amazonaws.services.textract.model.BoundingBox;
   import com.amazonaws.services.textract.model.DetectDocumentTextRequest;
   import com.amazonaws.services.textract.model.DetectDocumentTextResult;
   import com.amazonaws.services.textract.model.Document;
   import com.amazonaws.services.textract.model.S3Object;
   import com.amazonaws.services.textract.model.Point;
   import com.amazonaws.services.textract.model.Relationship;
   
   public class DocumentText extends JPanel {
   
       private static final long serialVersionUID = 1L;
   
       BufferedImage image;
       DetectDocumentTextResult result;
   
       public DocumentText(DetectDocumentTextResult documentResult, BufferedImage bufImage) throws Exception {
           super();
           
           result = documentResult; // Results of text detection.
           image = bufImage; // The image containing the document.
   
       }
   
       // Draws the image and text bounding box.
       public void paintComponent(Graphics g) {
   
           int height = image.getHeight(this);
           int width = image.getWidth(this);
   
           Graphics2D g2d = (Graphics2D) g; // Create a Java2D version of g.
   
           // Draw the image.
           g2d.drawImage(image, 0, 0, image.getWidth(this) , image.getHeight(this), this);
   
           // Iterate through blocks and display polygons around lines of detected text.
           List<Block> blocks = result.getBlocks();
           for (Block block : blocks) {
               DisplayBlockInfo(block);
               if ((block.getBlockType()).equals("LINE")) {
                   ShowPolygon(height, width, block.getGeometry().getPolygon(), g2d);
                   /*
                     ShowBoundingBox(height, width, block.getGeometry().getBoundingBox(), g2d);
                    */
               } else { // its a word, so just show vertical lines.
                   ShowPolygonVerticals(height, width, block.getGeometry().getPolygon(), g2d);
               }
           }
       }
   
       // Show bounding box at supplied location.
       private void ShowBoundingBox(int imageHeight, int imageWidth, BoundingBox box, Graphics2D g2d) {
   
           float left = imageWidth * box.getLeft();
           float top = imageHeight * box.getTop();
   
           // Display bounding box.
           g2d.setColor(new Color(0, 212, 0));
           g2d.drawRect(Math.round(left), Math.round(top),
                   Math.round(imageWidth * box.getWidth()), Math.round(imageHeight * box.getHeight()));
   
       }
   
       // Shows polygon at supplied location
       private void ShowPolygon(int imageHeight, int imageWidth, List<Point> points, Graphics2D g2d) {
   
           g2d.setColor(new Color(0, 0, 0));
           Polygon polygon = new Polygon();
   
           // Construct polygon and display
           for (Point point : points) {
               polygon.addPoint((Math.round(point.getX() * imageWidth)),
                       Math.round(point.getY() * imageHeight));
           }
           g2d.drawPolygon(polygon);
       }
   
       // Draws only the vertical lines in the supplied polygon.
       private void ShowPolygonVerticals(int imageHeight, int imageWidth, List<Point> points, Graphics2D g2d) {
   
           g2d.setColor(new Color(0, 212, 0));
           Object[] parry = points.toArray();
           g2d.setStroke(new BasicStroke(2));
   
           g2d.drawLine(Math.round(((Point) parry[0]).getX() * imageWidth),
                   Math.round(((Point) parry[0]).getY() * imageHeight), Math.round(((Point) parry[3]).getX() * imageWidth),
                   Math.round(((Point) parry[3]).getY() * imageHeight));
   
           g2d.setColor(new Color(255, 0, 0));
           g2d.drawLine(Math.round(((Point) parry[1]).getX() * imageWidth),
                   Math.round(((Point) parry[1]).getY() * imageHeight), Math.round(((Point) parry[2]).getX() * imageWidth),
                   Math.round(((Point) parry[2]).getY() * imageHeight));
   
       }
       //Displays information from a block returned by text detection and text analysis
       private void DisplayBlockInfo(Block block) {
           System.out.println("Block Id : " + block.getId());
           if (block.getText()!=null)
               System.out.println("    Detected text: " + block.getText());
           System.out.println("    Type: " + block.getBlockType());
           
           if (block.getBlockType().equals("PAGE") !=true) {
               System.out.println("    Confidence: " + block.getConfidence().toString());
           }
           if(block.getBlockType().equals("CELL"))
           {
               System.out.println("    Cell information:");
               System.out.println("        Column: " + block.getColumnIndex());
               System.out.println("        Row: " + block.getRowIndex());
               System.out.println("        Column span: " + block.getColumnSpan());
               System.out.println("        Row span: " + block.getRowSpan());
   
           }
           
           System.out.println("    Relationships");
           List<Relationship> relationships=block.getRelationships();
           if(relationships!=null) {
               for (Relationship relationship : relationships) {
                   System.out.println("        Type: " + relationship.getType());
                   System.out.println("        IDs: " + relationship.getIds().toString());
               }
           } else {
               System.out.println("        No related Blocks");
           }
   
           System.out.println("    Geometry");
           System.out.println("        Bounding Box: " + block.getGeometry().getBoundingBox().toString());
           System.out.println("        Polygon: " + block.getGeometry().getPolygon().toString());
           
           List<String> entityTypes = block.getEntityTypes();
           
           System.out.println("    Entity Types");
           if(entityTypes!=null) {
               for (String entityType : entityTypes) {
                   System.out.println("        Entity Type: " + entityType);
               }
           } else {
               System.out.println("        No entity type");
           }
           if(block.getPage()!=null)
               System.out.println("    Page: " + block.getPage());            
           System.out.println();
       }
   
       public static void main(String arg[]) throws Exception {
           
           // The S3 bucket and document
           String document = "";
           String bucket = "";
   
           
           AmazonS3 s3client = AmazonS3ClientBuilder.standard()
                   .withEndpointConfiguration( 
                           new EndpointConfiguration("https://s3.amazonaws.com","us-east-1"))
                   .build();
           
                  
           // Get the document from S3
           com.amazonaws.services.s3.model.S3Object s3object = s3client.getObject(bucket, document);
           S3ObjectInputStream inputStream = s3object.getObjectContent();
           BufferedImage image = ImageIO.read(inputStream);
   
           // Call DetectDocumentText
           EndpointConfiguration endpoint = new EndpointConfiguration(
                   "https://textract.us-east-1.amazonaws.com", "us-east-1");
           AmazonTextract client = AmazonTextractClientBuilder.standard()
                   .withEndpointConfiguration(endpoint).build();
   
   
           DetectDocumentTextRequest request = new DetectDocumentTextRequest()
               .withDocument(new Document().withS3Object(new S3Object().withName(document).withBucket(bucket)));
   
           DetectDocumentTextResult result = client.detectDocumentText(request);
           
           // Create frame and panel.
           JFrame frame = new JFrame("RotateImage");
           frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
           DocumentText panel = new DocumentText(result, image);
           panel.setPreferredSize(new Dimension(image.getWidth() , image.getHeight() ));
           frame.setContentPane(panel);
           frame.pack();
           frame.setVisible(true);
   
       }
   }
   

   AWS CLI

   此 AWS CLI 命令显示 detect-document-text CLI 操作的 JSON 输出。

   替换的值Bucket和Name将包含您在步骤 2 中使用的 Amazon S3 存储桶名称和文档的名称。

   aws textract detect-document-text \
    --document '{"S3Object":{"Bucket":"bucket","Name":"document"}}'

   Python

   以下示例代码显示检测到的文本行周围的文档和框。

   在函数main，替换的值bucket和document将包含您在步骤 2 中使用的 Amazon S3 存储桶名称和文档的名称。

   #Detects text in a document stored in an S3 bucket. Display polygon box around text and angled text 
   import boto3
   import io
   from io import BytesIO
   import sys
   
   import psutil
   import time
   
   import math
   from PIL import Image, ImageDraw, ImageFont
   
   
   # Displays information about a block returned by text detection and text analysis
   def DisplayBlockInformation(block):
       print('Id: {}'.format(block['Id']))
       if 'Text' in block:
           print('    Detected: ' + block['Text'])
       print('    Type: ' + block['BlockType'])
      
       if 'Confidence' in block:
           print('    Confidence: ' + "{:.2f}".format(block['Confidence']) + "%")
   
       if block['BlockType'] == 'CELL':
           print("    Cell information")
           print("        Column: " + str(block['ColumnIndex']))
           print("        Row: " + str(block['RowIndex']))
           print("        ColumnSpan: " + str(block['ColumnSpan']))
           print("        RowSpan: " + str(block['RowSpan']))    
       
       if 'Relationships' in block:
           print('    Relationships: {}'.format(block['Relationships']))
       print('    Geometry: ')
       print('        Bounding Box: {}'.format(block['Geometry']['BoundingBox']))
       print('        Polygon: {}'.format(block['Geometry']['Polygon']))
       
       if block['BlockType'] == "KEY_VALUE_SET":
           print ('    Entity Type: ' + block['EntityTypes'][0])
       if 'Page' in block:
           print('Page: ' + block['Page'])
       print()
   
   def process_text_detection(bucket, document):
   
       
       #Get the document from S3
       s3_connection = boto3.resource('s3')
                             
       s3_object = s3_connection.Object(bucket,document)
       s3_response = s3_object.get()
   
       stream = io.BytesIO(s3_response['Body'].read())
       image=Image.open(stream)
   
      
       # Detect text in the document
       
       client = boto3.client('textract')
       #process using image bytes                      
       #image_binary = stream.getvalue()
       #response = client.detect_document_text(Document={'Bytes': image_binary})
   
       #process using S3 object
       response = client.detect_document_text(
           Document={'S3Object': {'Bucket': bucket, 'Name': document}})
   
       #Get the text blocks
       blocks=response['Blocks']
       width, height =image.size  
       draw = ImageDraw.Draw(image)  
       print ('Detected Document Text')
      
       # Create image showing bounding box/polygon the detected lines/text
       for block in blocks:
               print('Type: ' + block['BlockType'])
               if block['BlockType'] != 'PAGE':
                   print('Detected: ' + block['Text'])
                   print('Confidence: ' + "{:.2f}".format(block['Confidence']) + "%")
   
               print('Id: {}'.format(block['Id']))
               if 'Relationships' in block:
                   print('Relationships: {}'.format(block['Relationships']))
               print('Bounding Box: {}'.format(block['Geometry']['BoundingBox']))
               print('Polygon: {}'.format(block['Geometry']['Polygon']))
               print()
               draw=ImageDraw.Draw(image)
               # Draw WORD - Green -  start of word, red - end of word
               if block['BlockType'] == "WORD":
                   draw.line([(width * block['Geometry']['Polygon'][0]['X'],
                   height * block['Geometry']['Polygon'][0]['Y']),
                   (width * block['Geometry']['Polygon'][3]['X'],
                   height * block['Geometry']['Polygon'][3]['Y'])],fill='green',
                   width=2)
               
                   draw.line([(width * block['Geometry']['Polygon'][1]['X'],
                   height * block['Geometry']['Polygon'][1]['Y']),
                   (width * block['Geometry']['Polygon'][2]['X'],
                   height * block['Geometry']['Polygon'][2]['Y'])],
                   fill='red',
                   width=2)    
   
                    
               # Draw box around entire LINE  
               if block['BlockType'] == "LINE":
                   points=[]
   
                   for polygon in block['Geometry']['Polygon']:
                       points.append((width * polygon['X'], height * polygon['Y']))
   
                   draw.polygon((points), outline='black')    
     
                   # Uncomment to draw bounding box
                   #box=block['Geometry']['BoundingBox']                    
                   #left = width * box['Left']
                   #top = height * box['Top']           
                   #draw.rectangle([left,top, left + (width * box['Width']), top +(height * box['Height'])],outline='black') 
   
   
       # Display the image
       image.show()
       # display image for 10 seconds
   
       
       return len(blocks)
   
   def main():
   
       bucket = ''
       document = ''
       block_count=process_text_detection(bucket,document)
       print("Blocks detected: " + str(block_count))
       
   if __name__ == "__main__":
       main()
   
   

   Node.js

   以下 Node.js 示例代码显示了检测到的文本行周围的文档和框，将结果的图像输出到运行代码的目录中。它利用image-size和images软件包。

   在函数main，替换的值bucket和document将包含您在步骤 2 中使用的 Amazon S3 存储桶名称和文档的名称。替换的值regionConfig使用您的账户所在地区的名称。

   async function main(){
   
   // Import AWS
   const AWS = require("aws-sdk")
   // Use Image-Size to get 
   const sizeOf = require('image-size');
   // Image tool to draw buffers
   const images = require("images");
   
   // Create a canvas and get the context
   const { createCanvas } = require('canvas')
   const canvas = createCanvas(200, 200)
   const ctx = canvas.getContext('2d')
   
   // Set variables
   const bucket = 'bucket-name' // the s3 bucket name
   const photo  = 'image-name' // the name of file
   const regionConfig = 'region'
   
   // Set region if needed
   AWS.config.update({region:regionConfig});
   
   // Connect to Textract
   const client = new AWS.Textract();
   // Connect to S3 to display image
   const s3 = new AWS.S3();
   
   // Define paramaters
   const params = {
     Document: {
       S3Object: {
         Bucket: bucket,
         Name: photo
       },
     },
   }
   
   // Function to display image
   async function getImage(){
     const imageData =  s3.getObject(
       {
           Bucket: bucket,
           Key: photo
         }
       
     ).promise();
     return imageData;
   }
   
   // get image
   var imageData = await getImage()
   
   // Get the height, width of the image
   const dimensions = sizeOf(imageData.Body)
   const width = dimensions.width
   const height = dimensions.height
   console.log(imageData.Body)
   console.log(width, height)
   
   canvas.width = width;
   canvas.height = height;
   
   try{
     // Call API and log response
     const res = await client.detectDocumentText(params).promise();
     var image = images(imageData.Body).size(width, height)
     //console.log the type of block, text, text type, and confidence
     res.Blocks.forEach(block => {
       console.log(`Block Type: ${block.BlockType}`),
       console.log(`Text: ${block.Text}`)
       console.log(`TextType: ${block.TextType}`)
       console.log(`Confidence: ${block.Confidence}`)
   
       // Draw box around detected text using polygons
       ctx.strokeStyle = 'rgba(0,0,0,0.5)';
       ctx.beginPath();
       block.Geometry.Polygon.forEach(({X, Y}) =>
       ctx.lineTo(width * X - 10, height * Y - 10)
       );
       ctx.closePath();
       ctx.stroke();
       console.log("-----")
     }) 
   
     // render image
     var buffer = canvas.toBuffer("image/png");
     image.draw(images(buffer), 10, 10)
     image.save("output-image.jpg");
     
   } catch (err){
   console.error(err);}
   
   }
   
   main()

4. 运行示例。Python 和 Java 示例显示了文档图像。每行检测到的文本都有一个黑框。绿色垂直线是检测到的单词的开头。红色垂直线是检测到的单词的末尾。这些区域有：AWS CLI示例仅显示的 JSON 输出DetectDocumentTextoperation.