I am trying to do Laplacian sharpening on the moon image with using this algorithm :
I am converting this image:
But I don't know why I am getting image like this:
Here is my code:
import numpy as np
def readRawFile(name,row_size,column_size):
imgFile = open(name,'rb')
img = np.fromfile(imgFile, dtype = np.uint8, count = row_size * column_size)
img = np.reshape(img,(-1,row_size))
imgFile.close()
return img
img = readRawFile("ass-3/moon464x528.raw", 464, 528)
width = img.shape[0]
height = img.shape[1]
img_pad = np.pad(img, ((1, 1), (1, 1)), 'edge')
w = np.array([1,1.2,1])
t1 = np.array([[0,-1,0],[-1,4,-1],[0,-1,0]])
edge_img = np.zeros((width, height))
edge_pad = np.pad(edge_img, ((1, 1), (1, 1)), 'constant')
for i in range(1,width-1):
for j in range(1,height-1):
edge_pad[i, j]=abs(np.sum((img_pad[i:i + 3, j:j + 3] * t1)*w))
if edge_pad[i, j] < 0:
edge_pad[i, j] = 0
out_img = img-edge_pad[1:edge_pad.shape[0]-1,1:edge_pad.shape[1]-1]
out_img.astype('int8').tofile("ass-3/moon-1.raw")
Can anyone help me please?
There are few issues I was able to identify:
abs
, and remove the if edge_pad[i, j] < 0
...img_pad[i:i + 3, j:j + 3]
is not centered around [i, j]
, replace it with:img_pad[i-1:i+2, j-1:j+2]
.w
in the formula is supposed to be a negative scalar.w = np.array([1, 1.2, 1])
with w = -1.2
.t1
and edge_pad
is np.float64
, and the type of img
is np.uint8
.img - edge_pad[1:edge_pad.shape[0] - 1, 1:edge_pad.shape[1] - 1]
is np.float64
.np.uint8
:out_img = np.clip(out_img, 0, 255).astype(np.uint8)
.I can't see any issues regarding .raw
format.
I replaced the input and output with PNG image format, and used OpenCV for reading and writing the images.
The usage of OpenCV is just for the example - you don't need to use OpenCV.
Here is a "complete" code sample:
import numpy as np
import cv2
#def readRawFile(name, row_size, column_size):
# imgFile = open(name, 'rb')
# img = np.fromfile(imgFile, dtype=np.uint8, count=row_size * column_size)
# img = np.reshape(img, (-1, row_size))
# imgFile.close()
# return img
#img = readRawFile("ass-3/moon464x528.raw", 464, 528)
img = cv2.imread('moon.png', cv2.IMREAD_GRAYSCALE) # Read input image as grayscale.
width = img.shape[0] # The first index is the height (the names are swapped)
height = img.shape[1]
img_pad = np.pad(img, ((1, 1), (1, 1)), 'edge')
#w = np.array([1, 1.2, 1])
w = -1.2 # I think w in the formula is supposed to be a negative a scalar
t1 = np.array([[0, -1, 0], [-1, 4, -1], [0, -1, 0]])
edge_img = np.zeros((width, height))
edge_pad = np.pad(edge_img, ((1, 1), (1, 1)), 'constant')
for i in range(1, width - 1):
for j in range(1, height - 1):
#edge_pad[i, j] = abs(np.sum((img_pad[i:i + 3, j:j + 3] * t1) * w))
# Edge is allowed to be negative.
edge_pad[i, j] = np.sum(img_pad[i-1:i+2, j-1:j+2] * t1) * w
#if edge_pad[i, j] < 0:
# edge_pad[i, j] = 0
# img tyep is uint8 and edge_pad is float64, the result is float64
out_img = img - edge_pad[1:edge_pad.shape[0] - 1, 1:edge_pad.shape[1] - 1]
out_img = np.clip(out_img, 0, 255).astype(np.uint8) # Clip range to [0, 255] and cast to uint8
#out_img.astype('int8').tofile("ass-3/moon-1.raw")
cv2.imwrite('out_img.png', out_img) # Save out_img as PNG image file
# Show the input and the output images for testing
cv2.imshow('img', img)
cv2.imshow('edge_pad', (edge_pad-edge_pad.min())/(edge_pad.max() - edge_pad.min()))
cv2.imshow('out_img', out_img)
cv2.waitKey()
cv2.destroyAllWindows()
Results: