python-3.x - 如何使用 PyTesseract 去除图像噪声以改善结果？

Question

我正在尝试从视频的左上角获取文本“P1”和“P2”。

P1

P2

我拍摄了一个框架并将它们裁剪为以下图像，然后应用此处找到的图像处理：

P1 裁剪

P2 裁剪

使用 pytesseract 从图像中识别文本

虽然它适用于我使用图像编辑器手动编辑的裁剪静止图像，但在使用 cv2 从视频中获取帧时它不起作用。

我不确定这是为什么，但我怀疑它与下图中的黑白背景有关，但我不知道如何在不删除文本的情况下摆脱它。

P1 后期图像处理

这是我的代码

import cv2
import pytesseract
import re
from difflib import SequenceMatcher
def determineWinner(video):
    winnerRect = [(70,95),(146,152)]
    cap = cv2.VideoCapture(video)
    if(cap.isOpened() == False):
        print("No dice")
        return
    fps = cap.get(cv2.CAP_PROP_FPS)
    frames = cap.get(cv2.CAP_PROP_FRAME_COUNT)
    print(fps)
    print(frames)
    desiredSeek = frames - int(fps * 9)
    print(desiredSeek)
    seconds = desiredSeek/fps
    print(seconds)
    minutes = seconds/60
    print(minutes)
    partial = minutes - int(minutes)
    print(partial)
    seconds = partial * 60
    print(seconds)
    print(str(int(minutes)) +":"+ str(seconds))

    cap.set(cv2.CAP_PROP_POS_FRAMES,(desiredSeek))

    ret,img = cap.read()
    winTxt = []
    p1Count = 0
    p2Count = 0

    cv2.namedWindow("",cv2.WINDOW_NORMAL)

    ret,img = cap.read()
    while ret:
        key = cv2.waitKey(1)
        if key == ord('q'):
            break
        if key == ord('e'):
            ret,img = cap.read()
            if ret:
                winROI = img[winnerRect[0][1]:winnerRect[1][1],winnerRect[0][0]:winnerRect[1][0]]
                gray = cv2.cvtColor(winROI, cv2.COLOR_BGR2GRAY)
                blur = cv2.GaussianBlur(gray, (3,3), 0)
                thresh = cv2.threshold(blur, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]

                # Morph open to remove noise and invert image
                kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
                opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=1)
                invert = 255-opening
                invert=cv2.resize(invert,None,fx=2,fy=2)
                wConfig='-l eng --oem 1 --psm 10 -c tessedit_char_whitelist=P12'
                winTxt = pytesseract.image_to_string(invert,config=wConfig)
                cv2.rectangle(img,winnerRect[0],winnerRect[1],(255,0,0),2)
                cv2.imshow("winroi",invert)
                cv2.imshow("",img)
                cv2.resizeWindow("",800,600)
                print(winTxt)
                desiredSeek+=1
                seconds = desiredSeek/fps
                minutes = seconds/60
                partial = minutes - int(minutes)
                seconds = partial * 60
                print(str(int(minutes)) +":"+ str(seconds))
            else:
                break

    cap.release()
    cv2.destroyAllWindows()

标签： python-3.xopencvtextocrpython-tesseract

Answer 1

此代码用作测试脚本。我只提取了包含P1. 要在新图像上应用过滤器，只需擦除预定义的阈值，如下所示：

从：

low_blue, low_green, low_red, upper_blue, upper_green, upper_red = (115, 0, 0, 255, 178, 255)

到：

low_blue, low_green, low_red, upper_blue, upper_green, upper_red = (0, 0, 0, 255, 255, 255)

并开始修改参数，如下所述。确定参数后，按esc退出程序，取控制台显示的参数，粘贴到thresholds元组中。

---

如何使用它：

• 很重要。要使其正常工作，您必须单击鼠标左键选择来自 的窗口cv2.imshow()，在这种情况下Original image或Binary image

• q增加和w减少下蓝色阈值

• a增加和s减少绿色阈值下限
• ... 对于上下颜色 ( BGR) 阈值，依此类推

---

import numpy as np
import cv2

low_blue, low_green, low_red, upper_blue, upper_green, upper_red = (115, 0, 0, 255, 178, 255)

# Get picture
path = "C:\\Users\\asd\\asd\\P1.png"
frame = cv2.imread(path)

while 1:

    lower_color = np.array((low_blue, low_green, low_red))
    upper_color = np.array((upper_blue, upper_green, upper_red))

    # extract binary image with active blue regions
    binary_image = cv2.inRange(frame, lower_color, upper_color)

    cv2.imshow('Original image', binary_image)

    #erode for the little white contour to dissapear
    binary_image = cv2.erode(binary_image, cv2.getStructuringElement(cv2.MORPH_RECT,(3,3)))
    binary_image = cv2.dilate(binary_image, cv2.getStructuringElement(cv2.MORPH_RECT,(3,3)))

    cv2.imshow('Binary image  ', binary_image)

    k = cv2.waitKey(5) & 0xFF
    if k == 27:
        break
    if k == ord('q'):
        low_blue += 1
    if k == ord('w'):
        low_blue -= 1
    if k == ord('a'):
        low_green += 1
    if k == ord('s'):
        low_green -= 1
    if k == ord('z'):
        low_red += 1
    if k == ord('x'):
        low_red -= 1
    if k == ord('e'):
        upper_blue += 1
    if k == ord('r'):
        upper_blue -= 1
    if k == ord('d'):
        upper_green += 1
    if k == ord('f'):
        upper_green -= 1
    if k == ord('c'):
        upper_red += 1
    if k == ord('v'):
        upper_red -= 1

    print("low_blue=", low_blue, "low_green=", low_green, "low_red=",low_red, "upper_blue", upper_blue, "upper_green=",
          upper_green, "upper_red=",upper_red)


cv2.destroyAllWindows()

---

结果

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