我正尝试在图像中定位矩形,并使用以前训练有素的分类器应用分类器来识别每个数字:
mnist = tf.keras.datasets.mnist
(x_train, y_train), (x_test, y_test) = mnist.load_data()
features = x_train[:8000, :, :]
labels = y_train[:8000]
list_hog_fd = []
for feature in features:
fd = hog(feature.reshape((28, 28)), orientations=9, pixels_per_cell=(14, 14), cells_per_block=(1, 1), visualise=False)
list_hog_fd.append(fd)
hog_features = np.array(list_hog_fd, 'float64')
clf = LinearSVC()
clf.fit(hog_features, labels)
imPath = "/Users/alessandro/Downloads/prova prova(2).jpg"
im = cv2.imread(imPath)
# Convert to grayscale and apply Gaussian filtering
im_gray = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)
im_gray = cv2.GaussianBlur(im_gray, (5, 5), 0)
# Threshold the image
ret, im_th = cv2.threshold(im_gray, 90, 255, cv2.THRESH_BINARY_INV)
# Find contours in the image
ctrs, hier = cv2.findContours(im_th.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
# Get rectangles contains each contour
rects = [cv2.boundingRect(ctr) for ctr in ctrs]
从现在开始,它可以完美地使用我自己的图像,但是每当我启动for循环时,它都会生成空的“ roi”,并返回错误“错误:
OpenCV(4.0.0)/Users/travis/build/skvark/opencv-python/opencv/modules/imgproc/src/resize.cpp:3784:错误:(-215:断言失败)!ssize函数'resize'中的.empty()“
在“ roi = cv2.resize(roi,(28,28),插值= cv2.INTER_AREA)”行。
# For each rectangular region, calculate HOG features and predict
# the digit using Linear SVM.
for rect in rects:
# Draw the rectangles
cv2.rectangle(im, (rect[0], rect[1]), (rect[0] + rect[2], rect[1] + rect[3]), (0, 255, 0), 3)
# Make the rectangular region around the digit
leng = int(rect[3] * 1.6)
pt1 = int(rect[1] + rect[3] // 2 - leng // 2)
pt2 = int(rect[0] + rect[2] // 2 - leng // 2)
roi = im_th[pt1:pt1+leng, pt2:pt2+leng]
# Resize the image
roi = cv2.resize(roi, (28, 28), interpolation=cv2.INTER_AREA)
roi = cv2.dilate(roi, (3, 3))
#Calculate the HOG features
roi_hog_fd = hog(roi, orientations=9, pixels_per_cell=(14, 14), cells_per_block=(1, 1), visualise=False)
nbr = clf.predict(np.array([roi_hog_fd], 'float64'))
cv2.putText(im, str(int(nbr[0])), (rect[0], rect[1]),cv2.FONT_HERSHEY_DUPLEX, 2, (0, 255, 255), 3)
cv2.imshow("Resulting Image with Rectangular ROIs", im)
cv2.waitKey()
如何修复代码?
P.s。供参考,请检查http://hanzratech.in/2015/02/24/handwritten-digit-recognition-using-opencv-sklearn-and-python.html
答案 0 :(得分:0)
在复制代码时会发生这种情况。
解决步骤
1)如果您复制代码,请尝试了解正在发生的事情
2)意识到复制代码不是魔术。它根本不必在任何地方都可以工作
3)如果有错误,请搜索错误并尝试找出错误发生的原因
4)如果您从教程中复制代码后仍然无法使用,请不要在StackOverflow上询问
5)您的问题已经解决
# Make the rectangular region around the digit
leng = int(rect[3] * 1.6)
pt1 = int(rect[1] + rect[3] // 2 - leng // 2)
pt2 = int(rect[0] + rect[2] // 2 - leng // 2)
roi = im_th[pt1:pt1+leng, pt2:pt2+leng]
确定
roi
具有图像尺寸,并且其中包含任何像素。您可以通过简单地打印这样的形状来进行测试
print(im_th.shape)
# Make the rectangular region around the digit
leng = int(rect[3] * 1.6)
pt1 = int(rect[1] + rect[3] // 2 - leng // 2)
pt2 = int(rect[0] + rect[2] // 2 - leng // 2)
roi = im_th[pt1:pt1+leng, pt2:pt2+leng]
print(roi.shape)
您将看到发生了什么