数字图像与机器视觉--基于python+opencv识别硬币和细胞数量以及条形码检测

数字图像与机器视觉--基于python+opencv识别硬币和细胞数量以及条形码检测

一、用奇异值分解（SVD）对一张图片进行特征值提取（降维）处理

奇异值分解(Singular Value Decomposition，以下简称SVD)是在机器学习领域广泛应用的算法，它不光可以用于降维算法中的特征分解，还可以用于推荐系统，以及自然语言处理等领域。

具体代码如下

import numpy as np
import os
from PIL import Image
import matplotlib.pyplot as plt
import matplotlib as mpl
from pprint import pprint


def restore1(sigma, u, v, K):  # 奇异值、左特征向量、右特征向量
    m = len(u)
    n = len(v[0])
    a = np.zeros((m, n))
    for k in range(K):
        uk = u[:, k].reshape(m, 1)
        vk = v[k].reshape(1, n)
        a += sigma[k] * np.dot(uk, vk)
    a[a < 0] = 0
    a[a > 255] = 255
    # a = a.clip(0, 255)
    return np.rint(a).astype(\'uint8\')


def restore2(sigma, u, v, K):  # 奇异值、左特征向量、右特征向量
    m = len(u)
    n = len(v[0])
    a = np.zeros((m, n))
    for k in range(K+1):
        for i in range(m):
            a[i] += sigma[k] * u[i][k] * v[k]
    a[a < 0] = 0
    a[a > 255] = 255
    return np.rint(a).astype(\'uint8\')


if __name__ == "__main__":
    A = Image.open("C:/Users/86199/Pictures/lena/lena.jpg", \'r\')
    print(A)
    output_path = r\'./SVD_Output\'
    if not os.path.exists(output_path):
        os.mkdir(output_path)
    a = np.array(A)
    print(a.shape)
    K = 50
    u_r, sigma_r, v_r = np.linalg.svd(a[:, :, 0])
    u_g, sigma_g, v_g = np.linalg.svd(a[:, :, 1])
    u_b, sigma_b, v_b = np.linalg.svd(a[:, :, 2])
    plt.figure(figsize=(11, 9), facecolor=\'w\')
    mpl.rcParams[\'font.sans-serif\'] = [\'simHei\']
    mpl.rcParams[\'axes.unicode_minus\'] = False
    for k in range(1, K+1):
        print(k)
        R = restore1(sigma_r, u_r, v_r, k)
        G = restore1(sigma_g, u_g, v_g, k)
        B = restore1(sigma_b, u_b, v_b, k)
        I = np.stack((R, G, B), axis=2)
        Image.fromarray(I).save(\'%s\\svd_%d.png\' % (output_path, k))
        if k <= 12:
            plt.subplot(3, 4, k)
            plt.imshow(I)
            plt.axis(\'off\')
            plt.title(\'奇异值个数：%d\' % k)
    plt.suptitle(\'SVD与图像分解\', fontsize=20)
    plt.tight_layout()
    # plt.subplots_adjust(top=0.9)
    plt.show()

运行代码：

可以直观地发现当奇异值越少，图片越模糊，查看文件信息也可以看到图片大小依次变大。

二、采用图像的开闭运算，检测出2个样本图像中硬币、细胞的个数

操作起来十分简单，步骤分别为

读取图片–>转为灰度图片–>二值化–>腐蚀–>膨胀–>找中心点–>标识–>显示

在中途可能腐蚀膨胀多次效果更好，具体代码如下

这里我用到的原图是以下两张

import cv2
import numpy as np

def stackImages(scale, imgArray):
    """
        将多张图像压入同一个窗口显示
        :param scale:float类型，输出图像显示百分比，控制缩放比例，0.5=图像分辨率缩小一半
        :param imgArray:元组嵌套列表，需要排列的图像矩阵
        :return:输出图像
    """
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range(0, rows):
            for y in range(0, cols):
                if imgArray[x][y].shape[:2] == imgArray[0][0].shape[:2]:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (0, 0), None, scale, scale)
                else:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]),
                                                None, scale, scale)
                if len(imgArray[x][y].shape) == 2: imgArray[x][y] = cv2.cvtColor(imgArray[x][y], cv2.COLOR_GRAY2BGR)
        imageBlank = np.zeros((height, width, 3), np.uint8)
        hor = [imageBlank] * rows
        hor_con = [imageBlank] * rows
        for x in range(0, rows):
            hor[x] = np.hstack(imgArray[x])
        ver = np.vstack(hor)
    else:
        for x in range(0, rows):
            if imgArray[x].shape[:2] == imgArray[0].shape[:2]:
                imgArray[x] = cv2.resize(imgArray[x], (0, 0), None, scale, scale)
            else:
                imgArray[x] = cv2.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None, scale, scale)
            if len(imgArray[x].shape) == 2: imgArray[x] = cv2.cvtColor(imgArray[x], cv2.COLOR_GRAY2BGR)
        hor = np.hstack(imgArray)
        ver = hor
    return ver


#读取图片
src = cv2.imread("cell.png")
img = src.copy()

#灰度
img_1 = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

#二值化
ret, img_2 = cv2.threshold(img_1, 127, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)

#腐蚀
kernel = np.ones((20, 20), int)
img_3 = cv2.erode(img_2, kernel, iterations=1)

#膨胀
kernel = np.ones((3, 3), int)
img_4 = cv2.dilate(img_3, kernel, iterations=1)

#找到硬币中心
contours, hierarchy = cv2.findContours(img_4, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)[-2:]

#标识硬币
cv2.drawContours(img, contours, -1, (0, 0, 255), 5)

#显示图片
cv2.putText(img, "count:{}".format(len(contours)), (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
cv2.putText(src, "src", (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
cv2.putText(img_1, "gray", (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
cv2.putText(img_2, "thresh", (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
cv2.putText(img_3, "erode", (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
cv2.putText(img_4, "dilate", (0, 30), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (255, 0, 0), 3)
imgStack = stackImages(1, ([src, img_1, img_2], [img_3, img_4, img]))
cv2.imshow("imgStack", imgStack)
cv2.waitKey(0)

# -*- coding: utf-8 -*-
"""
Created on Fri Dec 10 15:07:39 2021

@author: 13774
"""

#导入相关包
import cv2
import numpy as np
import os
#定义文件路径
cell_file="coin.png"
coin_file="cell.png"
cell_read=cv2.imread(cell_file)
coin_read=cv2.imread(coin_file)
cell_gauss=cv2.GaussianBlur(cell_read,(5,5),0)#高斯降噪
cell_gray=cv2.cvtColor(cell_gauss,cv2.COLOR_BGR2GRAY)#灰度化
cell_att=cell_gray

for j in range(3,342):
    low=int(sum(cell_gray[j]))
    high=int(sum(cell_gray[335]))
    add=(high-low)/len(cell_read[3])
    for i in range(len(cell_read[3])):
        if int(cell_att[j][i])+add>255:
             cell_att[j][i]=255
        else :
            cell_att[j][i]+=add


thre,cell_bw=cv2.threshold(cell_att,170,255,cv2.THRESH_BINARY_INV)#二值化
#闭运算，填充空洞
#构造一个全1的5*5的矩阵
kernel=np.ones((3,3),int)#设置形态学操作卷积的大小
cell_close=cv2.morphologyEx(cell_bw,cv2.MORPH_CLOSE,kernel)

#开运算
#构造一个全1的5*5的矩阵
kernel=np.ones((20,20),int)#设置形态学操作卷积的大小
cell_open=cv2.morphologyEx(cell_close,cv2.MORPH_OPEN,kernel)
#腐蚀运算
#构造一个全1的5*5的矩阵

#腐蚀运算
#构造一个全1的5*5的矩阵
kernel=np.ones((20,20),int)#设置形态学操作卷积的大小
cell_corr=cv2.erode(cell_open,kernel,iterations=1)

kernel=np.ones((11,11),int)#设置形态学操作卷积的大小
cell_open=cv2.morphologyEx(cell_corr,cv2.MORPH_OPEN,kernel)


cell_count,hir=cv2.findContours(cell_open,cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)
#检测所有轮廓，所有轮廓建立一个等级树结构。
print(len(cell_count))
cell_read=cv2.imread(cell_file)
result = cv2.drawContours(cell_read, cell_count, -1 ,(0, 255, 0), 1)
cv2.imshow(\'I\',result)
cv2.waitKey(0)

三、采用图像梯度、开闭、轮廓运算等，对图片中的条形码进行定位提取；再调用条码库获得条码字符。

这里使用的图片是

具体代码如下

import cv2
import numpy as np
import imutils
from pyzbar import pyzbar
def stackImages(scale, imgArray):
    """
        将多张图像压入同一个窗口显示
        :param scale:float类型，输出图像显示百分比，控制缩放比例，0.5=图像分辨率缩小一半
        :param imgArray:元组嵌套列表，需要排列的图像矩阵
        :return:输出图像
    """
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range(0, rows):
            for y in range(0, cols):
                if imgArray[x][y].shape[:2] == imgArray[0][0].shape[:2]:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (0, 0), None, scale, scale)
                else:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]),
                                                None, scale, scale)
                if len(imgArray[x][y].shape) == 2: imgArray[x][y] = cv2.cvtColor(imgArray[x][y], cv2.COLOR_GRAY2BGR)
        imageBlank = np.zeros((height, width, 3), np.uint8)
        hor = [imageBlank] * rows
        hor_con = [imageBlank] * rows
        for x in range(0, rows):
            hor[x] = np.hstack(imgArray[x])
        ver = np.vstack(hor)
    else:
        for x in range(0, rows):
            if imgArray[x].shape[:2] == imgArray[0].shape[:2]:
                imgArray[x] = cv2.resize(imgArray[x], (0, 0), None, scale, scale)
            else:
                imgArray[x] = cv2.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None, scale, scale)
            if len(imgArray[x].shape) == 2: imgArray[x] = cv2.cvtColor(imgArray[x], cv2.COLOR_GRAY2BGR)
        hor = np.hstack(imgArray)
        ver = hor
    return ver


#读取图片
src = cv2.imread("C:/Users/86199/Pictures/computer/tm.png")
img = src.copy()

#灰度
img_1 = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

#高斯滤波
img_2 = cv2.GaussianBlur(img_1, (5, 5), 1)


#Sobel算子
sobel_x = cv2.Sobel(img_2, cv2.CV_64F, 1, 0, ksize=3)
sobel_y = cv2.Sobel(img_2, cv2.CV_64F, 0, 1, ksize=3)
sobel_x = cv2.convertScaleAbs(sobel_x)
sobel_y = cv2.convertScaleAbs(sobel_y)
img_3 = cv2.addWeighted(sobel_x, 0.5, sobel_y, 0.5, 0)

#均值方波
img_4 = cv2.blur(img_3, (5, 5))

#二值化
ret, img_5 = cv2.threshold(img_4, 127, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)

#闭运算
kernel = np.ones((18, 18), int)
img_6 = cv2.morphologyEx(img_5, cv2.MORPH_CLOSE, kernel)

#开运算
kernel = np.ones((100,100), int)
img_7 = cv2.morphologyEx(img_6, cv2.MORPH_OPEN, kernel)

#绘制条形码区域
contours = cv2.findContours(img_7, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
contours = imutils.grab_contours(contours)
c = sorted(contours, key = cv2.contourArea, reverse = True)[0]
rect = cv2.minAreaRect(c)
box = cv2.cv.BoxPoints(rect) if imutils.is_cv2() else cv2.boxPoints(rect)
box = np.int0(box)
cv2.drawContours(img, [box], -1, (0,255,0), 6)

#显示图片信息
cv2.putText(img, "results", (30, 30), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_1, "gray", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_2, "GaussianBlur",(40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_3, "Sobel", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_4, "blur", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_5, "threshold", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_6, "close", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)
cv2.putText(img_7, "open", (40, 40), cv2.FONT_HERSHEY_SIMPLEX, 2.0, (255, 0, 0), 3)

#输出条形码
barcodes = pyzbar.decode(src)
for barcode in barcodes:
    barcodeData = barcode.data.decode("utf-8")
    cv2.putText(img, barcodeData, (50, 70), cv2.FONT_HERSHEY_SIMPLEX, 1.0, (0, 255, 0), 3)

#显示所有图片
imgStack = stackImages(0.5, ([img_1, img_2,img_3,img_4],[img_5,img_6,img_7,img]))
cv2.imshow("imgStack", imgStack)
cv2.waitKey(0)

四、参考资料

Opencv：10个步骤检测出图片中条形码

https://blog.csdn.net/junseven164/article/details/121711581?spm=1001.2014.3001.5501