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

问题描述

我正在尝试使用来自 Google Cloud Vision API 的现在支持的 PDF/TIFF 文档文本检测.使用他们的示例代码，我可以提交 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 文件仅包含符号"的边界框和文本，即每个单词中的每个字符.这使得 JSON 对象非常笨拙且非常难以使用.我希望能够获得LINES"、PARAGRAPHS"和BLOCKS"的文本和边界框，但我似乎无法通过 AsyncAnnotateFileRequest()代码>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:
{}'.format(
        annotation.text))

推荐答案

不幸的是，在使用 DOCUMENT_TEXT_DETECTION 类型时，您只能获得每页的全文或单个符号.不过，将符号中的段落和行放在一起并不太难，这样的事情应该可行(从您的示例中扩展):

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 上的 Google Vision API OCR 获取行和段落，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！