检测文档中的文本

在文档中检测到的文本周围绘制方框。

深入探索

如需查看包含此代码示例的详细文档，请参阅以下内容：

• 密集文档文本检测教程

代码示例

Python

试用此示例之前，请按照《Vision 快速入门：使用客户端库》中的 Python 设置说明进行操作。 如需了解详情，请参阅 Vision Python API 参考文档。

如需向 Vision 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

import argparse
from enum import Enum

from google.cloud import vision
from PIL import Image, ImageDraw



class FeatureType(Enum):
    PAGE = 1
    BLOCK = 2
    PARA = 3
    WORD = 4
    SYMBOL = 5


def draw_boxes(image, bounds, color):
    """Draws a border around the image using the hints in the vector list.

    Args:
        image: the input image object.
        bounds: list of coordinates for the boxes.
        color: the color of the box.

    Returns:
        An image with colored bounds added.
    """
    draw = ImageDraw.Draw(image)

    for bound in bounds:
        draw.polygon(
            [
                bound.vertices[0].x,
                bound.vertices[0].y,
                bound.vertices[1].x,
                bound.vertices[1].y,
                bound.vertices[2].x,
                bound.vertices[2].y,
                bound.vertices[3].x,
                bound.vertices[3].y,
            ],
            None,
            color,
        )
    return image


def get_document_bounds(image_file, feature):
    """Finds the document bounds given an image and feature type.

    Args:
        image_file: path to the image file.
        feature: feature type to detect.

    Returns:
        List of coordinates for the corresponding feature type.
    """
    client = vision.ImageAnnotatorClient()

    bounds = []

    with open(image_file, "rb") as image_file:
        content = image_file.read()

    image = vision.Image(content=content)

    response = client.document_text_detection(image=image)
    document = response.full_text_annotation

    # Collect specified feature bounds by enumerating all document features
    for page in document.pages:
        for block in page.blocks:
            for paragraph in block.paragraphs:
                for word in paragraph.words:
                    for symbol in word.symbols:
                        if feature == FeatureType.SYMBOL:
                            bounds.append(symbol.bounding_box)

                    if feature == FeatureType.WORD:
                        bounds.append(word.bounding_box)

                if feature == FeatureType.PARA:
                    bounds.append(paragraph.bounding_box)

            if feature == FeatureType.BLOCK:
                bounds.append(block.bounding_box)

    # The list `bounds` contains the coordinates of the bounding boxes.
    return bounds




def render_doc_text(filein, fileout):
    """Outlines document features (blocks, paragraphs and words) given an image.

    Args:
        filein: path to the input image.
        fileout: path to the output image.
    """
    image = Image.open(filein)
    bounds = get_document_bounds(filein, FeatureType.BLOCK)
    draw_boxes(image, bounds, "blue")
    bounds = get_document_bounds(filein, FeatureType.PARA)
    draw_boxes(image, bounds, "red")
    bounds = get_document_bounds(filein, FeatureType.WORD)
    draw_boxes(image, bounds, "yellow")

    if fileout != 0:
        image.save(fileout)
    else:
        image.show()


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("detect_file", help="The image for text detection.")
    parser.add_argument("-out_file", help="Optional output file", default=0)
    args = parser.parse_args()

    render_doc_text(args.detect_file, args.out_file)

后续步骤

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