从PDF的Google Vision API OCR获取线和段落，而不是符号 [英] Get Lines and Paragraphs, not symbols from Google Vision API OCR on PDF

问题描述

我正在尝试使用Google Cloud Vision API现已支持的PDF/TIFF文档文本检测.使用他们的示例代码，我能够提交PDF并接收带有提取文本的JSON对象.我的问题是，保存到GCS的JSON文件仅包含边界框和符号"的文本，即每个单词中的每个字符.这使得JSON对象非常笨拙并且很难使用.我希望能够获得"LINES"，"PARAGRAPHS"和"BLOCKS"的文本和边框，但是我似乎找不到通过AsyncAnnotateFileRequest()方法执行此操作的方法.

I am attempting to use the now supported PDF/TIFF Document Text Detection from the Google Cloud Vision API. Using their example code I am able to submit a PDF and receive back a JSON object with the extracted text. My issue is that the JSON file that is saved to GCS only contains bounding boxes and text for "symbols", i.e. each character in each word. This makes the JSON object quite unwieldy and very difficult to use. I'd like to be able to get the text and bounding boxes for "LINES", "PARAGRAPHS" and "BLOCKS", but I can't seem to find a way to do it via the AsyncAnnotateFileRequest() method.

示例代码如下:

def async_detect_document(gcs_source_uri, gcs_destination_uri):
    """OCR with PDF/TIFF as source files on GCS"""
    # Supported mime_types are: 'application/pdf' and 'image/tiff'
    mime_type = 'application/pdf'

    # How many pages should be grouped into each json output file.
    batch_size = 2

    client = vision.ImageAnnotatorClient()

    feature = vision.types.Feature(
        type=vision.enums.Feature.Type.DOCUMENT_TEXT_DETECTION)

    gcs_source = vision.types.GcsSource(uri=gcs_source_uri)
    input_config = vision.types.InputConfig(
        gcs_source=gcs_source, mime_type=mime_type)

    gcs_destination = vision.types.GcsDestination(uri=gcs_destination_uri)
    output_config = vision.types.OutputConfig(
        gcs_destination=gcs_destination, batch_size=batch_size)

    async_request = vision.types.AsyncAnnotateFileRequest(
        features=[feature], input_config=input_config,
        output_config=output_config)

    operation = client.async_batch_annotate_files(
        requests=[async_request])

    print('Waiting for the operation to finish.')
    operation.result(timeout=180)

    # Once the request has completed and the output has been
    # written to GCS, we can list all the output files.
    storage_client = storage.Client()

    match = re.match(r'gs://([^/]+)/(.+)', gcs_destination_uri)
    bucket_name = match.group(1)
    prefix = match.group(2)

    bucket = storage_client.get_bucket(bucket_name=bucket_name)

    # List objects with the given prefix.
    blob_list = list(bucket.list_blobs(prefix=prefix))
    print('Output files:')
    for blob in blob_list:
        print(blob.name)

    # Process the first output file from GCS.
    # Since we specified batch_size=2, the first response contains
    # the first two pages of the input file.
    output = blob_list[0]

    json_string = output.download_as_string()
    response = json_format.Parse(
        json_string, vision.types.AnnotateFileResponse())

    # The actual response for the first page of the input file.
    first_page_response = response.responses[0]
    annotation = first_page_response.full_text_annotation

    # Here we print the full text from the first page.
    # The response contains more information:
    # annotation/pages/blocks/paragraphs/words/symbols
    # including confidence scores and bounding boxes
    print(u'Full text:\n{}'.format(
        annotation.text))

推荐答案

不幸的是，使用DOCUMENT_TEXT_DETECTION类型时，您只能获取每页的全文或单个符号.不过，将符号中的段落和线条放在一起并不难，像这样的东西应该起作用(从您的示例扩展而来):

Unfortunately when using the DOCUMENT_TEXT_DETECTION type, you can only get the full text per-page, or the individual symbols. It's not too difficult to put together the paragraphs and lines from the symbols though, something like this should work (extending from your example):

breaks = vision.enums.TextAnnotation.DetectedBreak.BreakType
paragraphs = []
lines = []

for page in annotation.pages:
    for block in page.blocks:
        for paragraph in block.paragraphs:
            para = ""
            line = ""
            for word in paragraph.words:
                for symbol in word.symbols:
                    line += symbol.text
                    if symbol.property.detected_break.type == breaks.SPACE:
                        line += ' '
                    if symbol.property.detected_break.type == breaks.EOL_SURE_SPACE:
                        line += ' '
                        lines.append(line)
                        para += line
                        line = ''
                    if symbol.property.detected_break.type == breaks.LINE_BREAK:
                        lines.append(line)
                        para += line
                        line = ''
            paragraphs.append(para)

print(paragraphs)
print(lines)

这篇关于从PDF的Google Vision API OCR获取线和段落，而不是符号的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！