如何使用 Tesseract 从该图像中获取文本？

Question

目前我正在使用下面的代码从图像中获取文本并且它工作正常，但它不适用于这两张图像，似乎 tesseract 无法扫描这些类型的图像。请告诉我如何修复它

https://i.ibb.co/zNkbhKG/Untitled1.jpg

https://i.ibb.co/XVbjc3s/Untitled3.jpg

def read_screen():
        spinner = Halo(text='Reading screen', spinner='bouncingBar')
        spinner.start()
        screenshot_file="Screens/to_ocr.png"
        screen_grab(screenshot_file)

        #prepare argparse
        ap = argparse.ArgumentParser(description='HQ_Bot')
        ap.add_argument("-i", "--image", required=False,default=screenshot_file,help="path to input image to be OCR'd")
        ap.add_argument("-p", "--preprocess", type=str, default="thresh", help="type of preprocessing to be done")
        args = vars(ap.parse_args())

        # load the image 
        image = cv2.imread(args["image"])
        gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

        if args["preprocess"] == "thresh":
                gray = cv2.threshold(gray, 177, 177,
                        cv2.THRESH_BINARY | cv2.THRESH_OTSU)[1]
        elif args["preprocess"] == "blur":
                gray = cv2.medianBlur(gray, 3)

        # store grayscale image as a temp file to apply OCR
        filename = "Screens/{}.png".format(os.getpid())
        cv2.imwrite(filename, gray)

        # load the image as a PIL/Pillow image, apply OCR, and then delete the temporary file
        pytesseract.pytesseract.tesseract_cmd = 'C:\Program Files\Tesseract-OCR\tesseract.exe'
        #ENG
        #text = pytesseract.image_to_string(Image.open(filename))

        #VIET
        text = pytesseract.image_to_string(Image.open(filename), lang='vie')

        os.remove(filename)
        os.remove(screenshot_file)

        # show the output images

        '''cv2.imshow("Image", image)
        cv2.imshow("Output", gray)
        os.remove(screenshot_file)
        if cv2.waitKey(0):
                cv2.destroyAllWindows()
        print(text)
        '''
        spinner.succeed()
        spinner.stop()
        return text

Answer 1

您应该尝试不同的 psm 模式，而不是像这样的默认模式：

target = pytesseract.image_to_string(im,config='--psm 4',lang='vie')

来自文档的练习：

Page segmentation modes:
  0    Orientation and script detection (OSD) only.
  1    Automatic page segmentation with OSD.
  2    Automatic page segmentation, but no OSD, or OCR.
  3    Fully automatic page segmentation, but no OSD. (Default)
  4    Assume a single column of text of variable sizes.
  5    Assume a single uniform block of vertically aligned text.
  6    Assume a single uniform block of text.
  7    Treat the image as a single text line.
  8    Treat the image as a single word.
  9    Treat the image as a single word in a circle.
 10    Treat the image as a single character.
 11    Sparse text. Find as much text as possible in no particular order.
 12    Sparse text with OSD.
 13    Raw line. Treat the image as a single text line,
                        bypassing hacks that are Tesseract-specific.

例如，对于 /Untitled3.jpg，您可以尝试 --psm 4，如果失败，您可以对两者都尝试 --psm 11。

根据您的 tesseract 版本，您还可以尝试不同的 oem 模式：

Use --oem 1 for LSTM, --oem 0 for Legacy Tesseract. Please note that Legacy Tesseract models are only included in traineddata files from tessdata repo.

编辑

此外，如您的图像所示，有两种语言，因此如果您希望使用 lang 参数，您需要手动将图像分成两部分，以免混淆 tesseract 引擎并使用不同的 lang 值为了他们。

编辑 2

下面是 Unitiled3 的完整工作示例。我注意到你对阈值的使用不当。您应该将 maxval 设置为大于阈值的值。就像在我的示例中一样，我将 thresh 设置为 177，但将 maxval 设置为 255，因此 177 以上的所有内容都将为黑色。我什至不需要做任何二值化。

import cv2
import pytesseract
from cv2.cv2 import imread, cvtColor, COLOR_BGR2GRAY, threshold, THRESH_BINARY

image = imread("./Untitled3.jpg")
image = cvtColor(image,COLOR_BGR2GRAY)
_,image = threshold(image,177,255,THRESH_BINARY)
cv2.namedWindow("TEST")
cv2.imshow("TEST",image)
cv2.waitKey()
text = pytesseract.image_to_string(image, lang='eng')
print(text)

输出：

New York, New York

Salzburg, Austria

Hollywood, California

如何使用 Tesseract 从该图像中获取文本？

How can I get text from this image with Tesseract?

python

tesseract