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import cv2
import numpy as np
import service.edgeDetectionService
def frequency_filter(image, filtered):
fftImg = np.fft.fft2(image) # 对图像进行傅里叶变换
fftImgShift = np.fft.fftshift(fftImg) # 傅里叶变换后坐标移动到图像中心
handle_fftImgShift1 = fftImgShift * filtered # 对傅里叶变换后的图像进行频域变换
handle_fftImgShift2 = np.fft.ifftshift(handle_fftImgShift1)
handle_fftImgShift3 = np.fft.ifft2(handle_fftImgShift2)
handle_fftImgShift4 = np.real(handle_fftImgShift3) # 傅里叶反变换后取频域
return np.uint8(handle_fftImgShift4)
# 低通滤波
def lp_filter(imgs, args):
"""
理想低通滤波
d0: int | 截止频率
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
H = np.empty_like(image, dtype=float)
M, N = image.shape
mid_x = int(M / 2)
mid_y = int(N / 2)
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((y - mid_x) ** 2 + (x - mid_y) ** 2)
if d <= d0:
H[x, y] = 1
return frequency_filter(image, H)
def butterworth_lp_filter(imgs, args):
"""
巴特沃斯低通滤波
d0: int | 截止频率
n: int | 阶数
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
n = int(args['n'])
H = np.empty_like(image, float)
M, N = image.shape
mid_x = int(M / 2)
mid_y = int(N / 2)
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((y - mid_x) ** 2 + (x - mid_y) ** 2)
H[x, y] = 1 / (1 + (d / d0) ** (2 * n))
return frequency_filter(image, H)
def gauss_lp_filter(imgs, args):
"""
高斯低通滤波
d0: int | 截止频率
n: int | 阶数
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
n = int(args['n'])
H = np.empty_like(image, float)
M, N = image.shape
mid_x = M / 2
mid_y = N / 2
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((x - mid_x) ** 2 + (y - mid_y) ** 2)
H[x, y] = np.exp(-d ** n / (2 * d0 ** n))
return frequency_filter(image, H)
# 高通滤波
def hp_filter(imgs, args):
"""
理想高通滤波
d0: int | 截止频率
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
H = np.empty_like(image, dtype=float)
M, N = image.shape
mid_x = int(M / 2)
mid_y = int(N / 2)
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((y - mid_x) ** 2 + (x - mid_y) ** 2)
if d >= d0:
H[x, y] = 1
return frequency_filter(image, H)
def butterworth_hp_filter(imgs, args):
"""
巴特沃斯高通滤波
d0: int | 截止频率
n: int | 阶数
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
n = int(args['n'])
H = np.empty_like(image, float)
M, N = image.shape
mid_x = int(M / 2)
mid_y = int(N / 2)
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((y - mid_x) ** 2 + (x - mid_y) ** 2)
H[x, y] = 1 / (1 + (d0 / d) ** n)
return frequency_filter(image, H)
def gauss_hp_filter(imgs, args):
"""
高斯高通滤波
d0: int | 截止频率
n: int | 阶数
:return: img
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
d0 = int(args['d0'])
n = int(args['n'])
H = np.empty_like(image, float)
M, N = image.shape
mid_x = M / 2
mid_y = N / 2
for x in range(0, M):
for y in range(0, N):
d = np.sqrt((x - mid_x) ** 2 + (y - mid_y) ** 2)
H[x, y] = (1 - np.exp(-d ** n / (2 * d0 ** n)))
return frequency_filter(image, H)
def roberts_grad(imgs, args=None):
"""
Roberts 梯度算子
:return: img
"""
return service.edgeDetectionService.roberts(imgs, args)
def sobel_grad(imgs, args=None):
"""
Sobel 梯度算子
"""
return service.edgeDetectionService.sobel(imgs, args)
def prewitt_grad(imgs, args=None):
"""
Prewitt梯度算子
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
preX = np.array([[1, 0, -1], [1, 0, -1], [1, 0, -1]])
preY = np.array([[1, 1, 1], [0, 0, 0], [-1, -1, -1]])
x = cv2.filter2D(image, cv2.CV_16S, preX)
y = cv2.filter2D(image, cv2.CV_16S, preY)
absX = cv2.convertScaleAbs(x)
absY = cv2.convertScaleAbs(y)
return cv2.addWeighted(absX, 0.5, absY, 0.5, 0)
def laplacian_grad(imgs, args=None):
"""
Laplacian梯度算子
"""
image = cv2.cvtColor(imgs[0], cv2.COLOR_BGR2GRAY)
lap = np.array([[0, -1, 0], [-1, 4, -1], [0, -1, 0]])
return cv2.filter2D(image, ddepth=-1, kernel=lap)