Visual artifacts on the sample optimized images

[victordomingos]

I noticed that two of the sample optimized images shown in the Readme file have noticeable visual artifacts, that in my opinion shouldn't be present. Please take a look at this screenshot of a detail from p1_opti_by_pkikani.jpeg:

And this one from m2_opti_by_pkikani.jpg:

Notice that dust-like scattered pixels? I am not sure what is causing them, but unless the optimized images are meant to be used in very low resolution, it may be a problem.

[prashant-kikani]

Yes. I also have noticed that. I don't know why that's happening.. Its not like it appears in every image.
I tried to optimize these images in a online optimizer. There its working fine with no change in resolution & size decreased.

They are occuring in full dark / full white parts. May be median smoothing can be done to lower the effect of this noice. As median noice is an effective way to remove S&P noice.

[tuanhm11299]

I have a question, why when I return self like in the code:
`def init_leaf(self, value, freq):
return self(value, freq, None, None)

    def init_node(self,left_child,right_child):
        freq = left_child.freq + right_child.freq
        return self(None,freq,left_child,right_child)` 

The problem says:
self is not callable
Is it will cause error or nothing ? This is the first time i use Python so i dunno is it make error or not.

[victordomingos]

@tuanhm11299 in the last line you are returning the result of the call to a callable under the name self. Maybe it does not make sense.

Let’s see. In object oriented Python, it’s a common practice to use self in a method as a reference to the object itself (the class instance). From the code you posted, we are not able to tell what class does self refer to, and what arguments does its __init__() method expect. Can you please provide more details on your code and what you’re trying to to?

[tuanhm11299]

well I'm making node of huffman tree and I want to init leaf and node, so can be another way to return self ?

[victordomingos]

Not sure if I am understanding correctly.but if you intend to return the object corresponding to the current class instance, you may just use return self.

[tuanhm11299]

Oh i see, maybe new versions of Python have no return like my code :D

[victordomingos]

I am not sure that defining a a class inside another class is very “pythonic”. What I would expect is something like defining a new class that inherits from the previous one.

Concerning the return statement, you may do something like return __Node(.....), which will allow you to generate a new instance of that class on return. Is that what you meant?

[tuanhm11299]

Yeah that's what I meant, sir. :D