Python 图像扩充之旋转、平移、缩放、裁剪

Python 图像扩充之旋转、平移、缩放、裁剪

旋转

def rotate_img(img, degrees):

'''

旋转图片

:param img: 原始图片

:param degrees: 旋转角度

:return:

'''

height, width = img.shape[:2]

# 旋转后的尺寸

heightNew = int(width * fabs(sin(radians(degrees))) + height * fabs(cos(radians(degrees))))

widthNew = int(height * fabs(sin(radians(degrees))) + width * fabs(cos(radians(degrees))))

# 这里的第一个参数为旋转中心，第二个为旋转角度，第三个为旋转后的缩放因子

# 可以通过设置旋转中心，缩放因子，以及窗口大小来防止旋转后超出边界的问题

matRotation = cv2.getRotationMatrix2D((width / 2, height / 2), degrees, 1)

matRotation[0, 2] += (widthNew - width) / 2

matRotation[1, 2] += (heightNew - height) / 2

resultImg = cv2.warpAffine(img, matRotation, (widthNew, heightNew), borderValue=(255, 255, 255))

return resultImg

if __name__ == '__main__':

img = cv2.imread('D:/test/rabbit.jpg')

resultImg = rotate_img(img, 45)

cv2.imshow('origin', img)

cv2.imshow('result', resultImg)

cv2.waitKey(0)

cv2.destroyAllWindows()

原图：

旋转后：

平移

def pan_img(img, x, y):

'''

图片平移

:param img: 原始图片

:param x: 横向移动像素值

:param y: 纵向移动像素值

:return:

'''

M = np.float32([[1, 0, x], [0, 1, y]])

resultImg = cv2.warpAffine(img, M, (img.shape[1], img.shape[0]))

return resultImg

if __name__ == '__main__':

img = cv2.imread('D:/test/rabbit.jpg')

resultImg = tools.pan_img(img, -50, -50)

cv2.imshow('origin', img)

cv2.imshow('result', resultImg)

cv2.waitKey(0)

cv2.destroyAllWindows()

平移后：

缩放

def resize_proportion(img, h_zoom, w_zoom):

'''

缩放

:param img: 原始图片

:param h_zoom: 纵向比例

:param w_zoom: 横向比例

:return:

'''

height, width = img.shape[:2]

resultImg = cv2.resize(img, (int(width * w_zoom), int(height * h_zoom)))

return resultImg

if __name__ == '__main__':

img = cv2.imread('D:/test/rabbit.jpg')

resultImg = tools.resize_proportion(img, 1, 0.5)

cv2.imshow('origin', img)

cv2.imshow('result', resultImg)

cv2.waitKey(0)

cv2.destroyAllWindows()

缩放后：

裁剪

def cropped_center(img, x1, y1, x2, y2):

'''

裁剪

:param img: 原始图片

:param x1: 左边界

:param y1: 上边界

:param x2: 右边界

:param y2: 下边界

:return:

'''

resultImg = img[y1:y2, x1:x2]

return resultImg

if __name__ == '__main__':

img = cv2.imread('D:/test/rabbit.jpg')

resultImg = tools.cropped_center(img, 20, 20, 400, 400)

cv2.imshow('origin', img)

cv2.imshow('result', resultImg)

cv2.waitKey(0)

cv2.destroyAllWindows()

裁剪后：

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