Updated a bit

assignment2/solution.py

@@ -288,9 +288,11 @@ def two_e():
 # EXCERCISE 3: Image Filtering #
 ################################
 def ex3():
-    three_a()
-    three_b()
-    three_c()
+    #three_a()
+    # three_b()
+    # three_c()
+    #three_d()
+    three_e()
 
 def three_a():
     """
@@ -382,14 +384,84 @@ def three_c():
     axs[3].set(title='Median')
     plt.show()
 
+
+def three_d():
+    """
+    Implement a 2-D version of the median filter. Test it on an image
+    that was corrupted by Gaussian noise and on an image that was corrupted by salt
+    and pepper noise. Compare the results with the Gaussian filter for multiple noise
+    intensities and filter sizes.
+    """
+    lena = uz_image.imread('./data/images/obama.jpg', uz_image.ImageType.float64)
+    lena_grayscale = uz_image.transform_coloured_image_to_grayscale(lena.astype(np.float64))
+    lena_salt_and_pepper = uz_image.sp_noise(lena_grayscale)
+
+    # Depeppered
+    deppepered_lena = uz_image.apply_median_method_2D(lena_salt_and_pepper, 7)
+    # Sharpened
+    kernel = np.array([[-1, -1, -1], 
+                       [-1, 17, -1],
+                       [-1, -1,-1]])
+
+    kernel = kernel * 1./9.
+    sharpened_lena = cv2.filter2D(deppepered_lena, cv2.CV_64F, kernel)
+
+
+    fig, axs = plt.subplots(1, 4)
+    
+    axs[0].imshow(lena_grayscale, cmap='gray')
+    axs[0].set(title='Orginal image')
+    axs[1].imshow(lena_salt_and_pepper, cmap='gray')
+    axs[1].set(title='Salt and Pepper applied')
+    axs[2].imshow(deppepered_lena, cmap='gray')
+    axs[2].set(title='Deppepeerd lena')
+    axs[3].imshow(sharpened_lena, cmap='gray')
+    axs[3].set(title='Sharpened lena')
+    
+    plt.show()
+
+def three_e():
+    """
+    Implement the hybrid image merging that was presented at the lectures. 
+    To do this you will have to implement the Laplacian filter. Filter the images
+    (one with the Gaussian and one with the Laplacian filter) and merge them together
+    (regular or weighted average). You can use images lincoln.jpg and obama.jpg.
+    Hint: To get good results, experiment with different kernel sizes for each operation
+    and different weights when merging images.
+    """
+    obama_image = uz_image.imread_gray('./data/images/obama.jpg', uz_image.ImageType.float64)
+    lincoln_image = uz_image.imread_gray('./data/images/lincoln.jpg', uz_image.ImageType.float64)
+    laplaced_obama = uz_image.filter_laplace(obama_image, 35)
+    gaussed_lincoln = uz_image.gaussfilter2D(lincoln_image, 5)
+
+    merged = uz_image.sum_two_grayscale_images(laplaced_obama, gaussed_lincoln)
+
+    fig, axs = plt.subplots(2, 3)
+    fig.suptitle('Linoln and Obama')
+
+    axs[0, 0].imshow(lincoln_image, cmap='gray')
+    axs[0, 0].set(title='Lincoln')
+    axs[1, 0].imshow(gaussed_lincoln, cmap='gray')
+    axs[1, 0].set(title='Lincoln gauss')
+    axs[0, 1].imshow(obama_image, cmap='gray')
+    axs[0, 1].set(title='Obama')
+    axs[1, 1].imshow(laplaced_obama, cmap='gray')
+    axs[1, 1].set(title='Obama laplace')
+    axs[0, 2].imshow(merged, cmap='gray')
+    axs[0, 2].set(title='Merged')
+    axs[1, 2].set_visible(False)
+
+    plt.show()
+
+
 # ######## #
 # SOLUTION #
 # ######## #
 
 def main():
     #ex1()
-    ex2()
-    #ex3()
+    #ex2()
+    ex3()
 
 if __name__ == '__main__':
     main()

assignment2/uz_framework/image.py

@@ -326,9 +326,18 @@ def get_gaussian_kernel(sigma: float):
 
     return result / np.sum(result)
 
-def gaussfilter2D(imge: Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]], sigma: float):
-    kernel = get_gaussian_kernel(sigma)
-    kernel = cv2.filter2D(kernel, cv2.CV_64F, kernel)
+def gaussfilter2D(image: Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]], sigma: float) -> Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]]:
+    """
+        Accepts: image, sigma  
+        Applies gaussian noise on image
+        returns: filtered_image
+    """
+    filtered_image = image.copy()
+    kernel = np.array(get_gaussian_kernel(sigma))
+    filtered_image = cv2.filter2D(filtered_image, cv2.CV_64F, kernel)
+    filtered_image = cv2.filter2D(filtered_image, cv2.CV_64F, kernel.T)
+    
+    return filtered_image
 
 def simple_median(signal: npt.NDArray[np.float64], width: int):
     signal = signal.copy()
@@ -340,6 +349,44 @@ def simple_median(signal: npt.NDArray[np.float64], width: int):
         signal[middle_element] = np.median(signal[i:i+width])
     return signal
 
+def apply_median_method_2D(image:Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]], width: int):
+    if width % 2 == 0:
+        raise Exception('No u won\'t do that')
+    image = image.copy()
+    W_HALF = int(np.floor(width/2))
+    padded_image = np.pad(image, W_HALF, mode='edge')
+    print(image.shape)
+    IMAGE_HEIGHT = image.shape[0] # y
+    IMAGE_WIDTH = image.shape[1] # x
+
+    for x in range(W_HALF, IMAGE_WIDTH):
+        for y in range(W_HALF, IMAGE_HEIGHT):
+            median_filter = np.zeros(0)
+            STARTX = x - W_HALF
+            STARTY = y - W_HALF
+            for m in range(width):
+                median_filter = np.append(median_filter, padded_image[STARTY + m][STARTX: STARTX + width], axis=0)
+            if image.dtype.type == np.uint8:
+                image[y][x] = int(np.mean(median_filter))
+            else:
+                image[y][x] = np.mean(median_filter)
+    return image
+
+def filter_laplace(image:Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]], sigma: float):
+    # Prepare unit impulse and gauss kernel
+    unit_impulse = np.zeros((1, 2 * int(np.ceil(3*sigma)) + 1))
+    unit_impulse[0][int(np.ceil(unit_impulse.size /2)) - 1]= 1
+    gauss_kernel = get_gaussian_kernel(sigma)
+    assert(len(gauss_kernel) == len(unit_impulse[0]))
+
+    laplacian_filter = unit_impulse - gauss_kernel
+
+    # Now apply laplacian filter
+    applied_by_x = cv2.filter2D(image, -1, laplacian_filter)
+    applied_by_y = cv2.filter2D(applied_by_x, -1, laplacian_filter.T)
+    
+    return applied_by_y
+
 def gauss_noise(I, magnitude=.1):
     # input: image, magnitude of noise
     # output: modified image
@@ -366,4 +413,6 @@ def sp_noise1D(signal, percent=.1):
     signal[np.random.rand(signal.shape[0]) < percent / 2] = 0.4
     return signal
 
-    
+def sum_two_grayscale_images(image_a: Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]], image_b :Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]]) -> Union[npt.NDArray[np.float64], npt.NDArray[np.uint8]]:
+    # Merge image_a and image_b
+    return (image_a + image_b)/ 2