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spatial_filtering.py
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204 lines (176 loc) · 7.8 KB
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from PIL import Image
from math import ceil, floor
def image_to_matrix(image: Image) -> list:
image_matrix = []
for line in range(image.width):
image_matrix.append([image.getpixel((line, 0))])
for column in range(1, image.height):
image_matrix[line].append(image.getpixel((line, column)))
return image_matrix
def matrix_to_image(matrix: list) -> Image:
image = Image.new('L', (len(matrix), len(matrix[0])))
for line in range(len(matrix)):
for column in range(len(matrix[line])):
image.putpixel((line, column), matrix[line][column])
return image
def create_empty_matrix(m, n) -> list:
image_matrix = []
for line in range(m):
image_matrix.append([])
for column in range(n):
image_matrix[line].append(0)
return image_matrix
def arithmetic_mean_filter(image: Image, m: int, n: int, modify: bool = False) -> Image:
if not modify:
image = image.copy()
original_image_matrix = image.load()
m1 = floor(m/2)
n1 = floor(n/2)
for line in range(image.width):
for column in range(image.height):
central_pixel = 0
for mask_line in range(-m1, m1+1):
for mask_column in range(-n1, n1+1):
try:
central_pixel += original_image_matrix[line+mask_line, column+mask_column]
except IndexError:
pass
image.putpixel((line, column), central_pixel//(m*n))
return image
def weighted_arithmetic_mean_filter(image: Image, mask: list, modify: bool = False) -> Image:
if not modify:
image = image.copy()
original_image_matrix = image_to_matrix(image)
m1 = floor(len(mask)/2)
n1 = floor(len(mask[0])/2)
sum_mask = 0
for line in range(len(mask)):
for column in range(len(mask[line])):
sum_mask += mask[line][column]
for line in range(image.width):
for column in range(image.height):
central_pixel = 0
for mask_line in range(-m1, m1+1):
for mask_column in range(-n1, n1+1):
try:
central_pixel += original_image_matrix[line+mask_line][column+mask_column] * mask[mask_line+m1][mask_column+n1]
except IndexError:
pass
image.putpixel((line, column), central_pixel//sum_mask)
return image
def median_filter(image: Image, m: int, n: int, modify: bool = False) -> Image:
if not modify:
image = image.copy()
original_image_matrix = image_to_matrix(image)
m1 = floor(m/2)
n1 = floor(n/2)
for line in range(image.width):
for column in range(image.height):
image_pixels = []
for mask_line in range(-m1, m1+1):
for mask_column in range(-n1, n1+1):
try:
image_pixels.append(original_image_matrix[line+mask_line][column+mask_column])
except IndexError:
pass
image_pixels.sort()
image.putpixel((line, column), image_pixels[len(image_pixels)//2])
return image
def apply_linear_filter(image: Image, mask: list) -> list:
original_image_matrix = image_to_matrix(image)
filtered_image_matrix = create_empty_matrix(image.width, image.height)
n1 = floor(len(mask)/2)
m1 = floor(len(mask[0])/2)
for line in range(image.width):
for column in range(image.height):
central_pixel = 0
for mask_line in range(-m1, m1+1):
for mask_column in range(-n1, n1+1):
try:
central_pixel += original_image_matrix[line+mask_line][column+mask_column] *\
mask[mask_column+n1][mask_line+m1]
except IndexError:
pass
if central_pixel > 255:
central_pixel = 255
if central_pixel < -255:
central_pixel = -255
filtered_image_matrix[line][column] = central_pixel
return filtered_image_matrix
def laplacian_filter(image: Image, center_value: int = -8, modify: bool = False, adjusted_laplacian: bool = False) -> Image:
if not modify:
image = image.copy()
if center_value == -8:
laplacian_mask = [[1, 1, 1], [1, -8, 1], [1, 1, 1]]
elif center_value == 8:
laplacian_mask = [[-1, -1, -1], [-1, 8, -1], [-1, -1, -1]]
elif center_value == -4:
laplacian_mask = [[0, 1, 0], [1, -4, 1], [0, 1, 0]]
elif center_value == 4:
laplacian_mask = [[0, -1, 0], [-1, 4, -1], [0, -1, 0]]
else:
return None
laplacian_image = image.copy()
laplacian_image_matrix = apply_linear_filter(image, laplacian_mask)
if adjusted_laplacian:
for line in range(len(laplacian_image_matrix)):
for column in range(len(laplacian_image_matrix[line])):
pixel = laplacian_image_matrix[line][column]
if pixel == 0:
laplacian_image.putpixel((line, column), 127)
elif pixel < 0:
pixel *= -1
if pixel % 2 == 0:
laplacian_image.putpixel((line, column), 127 - pixel // 2)
else:
laplacian_image.putpixel((line, column), 127 - (pixel - 1) // 2)
else:
if pixel % 2 == 0:
laplacian_image.putpixel((line, column), pixel // 2 + 127)
else:
laplacian_image.putpixel((line, column), (pixel - 1) // 2 + 127)
else:
laplacian_image = matrix_to_image(laplacian_image_matrix)
for line in range(image.width):
for column in range(image.height):
if center_value < 0:
image.putpixel((line, column), image.getpixel((line, column)) - laplacian_image_matrix[line][column])
else:
image.putpixel((line, column), image.getpixel((line, column)) + laplacian_image_matrix[line][column])
return image, laplacian_image
def unsharp_masking(image: Image, n: int, m: int, modify: bool = False) -> Image:
if not modify:
image = image.copy()
original_image_matrix = image_to_matrix(image)
blurred_image = arithmetic_mean_filter(image, n, m)
blurred_image_matrix = image_to_matrix(blurred_image)
for line in range(image.width):
for column in range(image.height):
image.putpixel((line, column), original_image_matrix[line][column] +
(original_image_matrix[line][column] - blurred_image_matrix[line][column]))
return image
def high_boost(image: Image, m: int, n: int, k: float, modify: bool = False) -> Image:
if not modify:
image = image.copy()
original_image_matrix = image_to_matrix(image)
blurred_image = arithmetic_mean_filter(image, n, m)
blurred_image_matrix = image_to_matrix(blurred_image)
for line in range(image.width):
for column in range(image.height):
image.putpixel((line, column), original_image_matrix[line][column] + int(k *
(original_image_matrix[line][column] - blurred_image_matrix[line][column])))
return image
def prewitt_border_detection(image: Image, horizontal: bool = True) -> Image:
if horizontal:
prewitt_mask = [[-1, -1, -1], [0, 0, 0], [1, 1, 1]]
else:
prewitt_mask = [[-1, 0, 1], [-1, 0, 1], [-1, 0, 1]]
prewitt_image = apply_linear_filter(image, prewitt_mask)
return matrix_to_image(prewitt_image)
def sobel_border_detection(image: Image, horizontal: bool = True):
if horizontal:
sobel_mask = [[-1, -2, -1], [0, 0, 0], [1, 2, 1]]
else:
sobel_mask = [[-1, 0, 1], [-2, 0, 2], [-1, 0, 1]]
sobel_image = apply_linear_filter(image, sobel_mask)
return matrix_to_image(sobel_image)