Merge branch 'master' of https://git.elphel.com/nathaniel/image-compression

compress_start.py

@@ -69,17 +69,19 @@ if __name__ == '__main__':
  
     diff = []
     for ii in range(len(tiff1)):
-        image = Image.open(tiff1[ii])
-        image = np.array(image)[1:,:]
+        image = Image.open(tiff1[ii])    #Open the image and read it as an Image object
+        image = np.array(image)[1:,:]    #Convert to an array, leaving out the first row because the first row is just housekeeping data
         ar1, ar2 = image.shape
        
-        ind1, ind2 = np.random.randint(0,ar1), np.random.randint(0,ar2)
-        surrounding = []
-        for i,j in product(np.arange(-1,2), repeat=2):
-            if i == 0 and j == 0:
+        ind1, ind2 = np.random.randint(0,ar1), np.random.randint(0,ar2) #ind1 randomly selects a row, ind2 randomly selects a column, 
+                                                                        #this is now a random pixel selection within the image
+        
+        surrounding = []                                                #initialize a list to be filled the 8 surrounding pixels
+        for i,j in product(np.arange(-1,2), repeat=2):                  #Iterate through the combinations of surrounding pixel indices
+            if i == 0 and j == 0:                                       #Avoid the target pixel
                 continue
             else:
-                surrounding.append(image[ind1+i, ind1+j])
+                surrounding.append(image[ind1+i, ind1+j])               #Add the other 8 pixels to the list
         diff.append(np.max(surrounding)-np.min(surrounding))