一、圖片變換
0、導(dǎo)入模塊
導(dǎo)入相關(guān)函數(shù)，遇到報(bào)錯(cuò)的話，直接pip install 函數(shù)名。
import numpy as np
import argparse
import cv2
參數(shù)初始化
ap = argparse.ArgumentParser()
ap.add_argument("-i", "--image", required = True,
help = "Path to the image to be scanned")
args = vars(ap.parse_args())
Parameters:
--image images\page.jpg
1、重寫resize函數(shù)
def resize(image, width=None, height=None, inter=cv2.INTER_AREA):
dim = None
(h, w) = image.shape[:2]
if width is None and height is None:
return image
if width is None:
r = height / float(h)
dim = (int(w * r), height)
else:
r = width / float(w)
dim = (width, int(h * r))
resized = cv2.resize(image, dim, interpolation=inter)
return resized
2、預(yù)處理
讀取圖片后進(jìn)行重置大小，并計(jì)算縮放倍數(shù)；進(jìn)行灰度化、高斯濾波以及Canny輪廓提取
image = cv2.imread(args["image"])
ratio = image.shape[0] / 500.0
orig = image.copy()
image = resize(orig, height = 500)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray = cv2.GaussianBlur(gray, (5, 5), 0)
edged = cv2.Canny(gray, 75, 200)
3、邊緣檢測
檢測輪廓并排序，遍歷輪廓。
cnts = cv2.findContours(edged.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)[0]# 輪廓檢測
cnts = sorted(cnts, key = cv2.contourArea, reverse = True)[:5]#保留前5個(gè)輪廓
# 遍歷輪廓
for c in cnts:
# 計(jì)算輪廓近似
peri = cv2.arcLength(c, True)# 計(jì)算輪廓長度，C表示輸入的點(diǎn)集，True表示輪廓是封閉的
#(C表示輸入的點(diǎn)集，epslion判斷點(diǎn)到相對應(yīng)的line segment 的距離的閾值,曲線是否閉合的標(biāo)志位)
approx = cv2.approxPolyDP(c, 0.02 * peri, True)
# 4個(gè)點(diǎn)的時(shí)候就拿出來
if len(approx) == 4:
screenCnt = approx
break
4、透視變換
畫出近似輪廓，透視變換，二值處理
cv2.drawContours(image, [screenCnt], -1, (0, 255, 0), 2)
warped = four_point_transform(orig, screenCnt.reshape(4, 2) * ratio)#透視變換
# 二值處理
warped = cv2.cvtColor(warped, cv2.COLOR_BGR2GRAY)
ref = cv2.threshold(warped, 100, 255, cv2.THRESH_BINARY)[1]
cv2.imwrite('scan.jpg', ref)
二、OCR識別
0、安裝tesseract-ocr
鏈接: 下載
在環(huán)境變量、系統(tǒng)變量的Path里面添加安裝路徑，例如：E:\Program Files (x86)\Tesseract-OCR
tesseract -v#打開命令行，進(jìn)行測試
tesseract XXX.png result#得到結(jié)果
pip install pytesseract#安裝依賴包
打開python安裝路徑里面的python文件，例如C:\ProgramData\Anaconda3\Lib\site-packages\pytesseract\pytesseract.py
將tesseract_cmd 修改為絕對路徑即可，例如：tesseract_cmd = ‘C:/Program Files (x86)/Tesseract-OCR/tesseract.exe'
1、導(dǎo)入模塊
from PIL import Image
import pytesseract
import cv2
import os
2、預(yù)處理
讀取圖片、灰度化、濾波
image = cv2.imread('scan.jpg')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray = cv2.medianBlur(gray, 3)
3、輸出結(jié)果
filename = "{}.png".format(os.getpid())
cv2.imwrite(filename, gray)
text = pytesseract.image_to_string(Image.open(filename))
print(text)
os.remove(filename)
到此這篇關(guān)于Opencv 圖片的OCR識別的實(shí)戰(zhàn)示例的文章就介紹到這了,更多相關(guān)Opencv 圖片的OCR識別內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！
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