python
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PyTorch CRNN: Seq2Seq Digits Recognition w/ CTC
This article discusses handwritten character recognition (OCR) in images using sequence-to-sequence (seq2seq) mapping performed by a Convolutional Recurrent Neural Network (CRNN) trained with Connectionist Temporal Classification (CTC) loss. The aforementioned approach is employed in multiple modern OCR engines for handwritten...
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Improving Tesseract 4's OCR Accuracy through Image Preprocessing
In this work I took a look at Tesseract 4’s performance at recognizing characters from a challenging dataset and proposed a minimalistic convolution-based approach for input image preprocessing that can boost the character-level accuracy from 13.4% to 61.6% (+359% relative...
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PyTorch Iterative FGVM: Targeted Adversarial Samples for Traffic-Sign Recognition
Inspired by the progress of driverless cars and by the fact that this subject is not thoroughly discussed I decided to give it a shot at creating smooth targeted adversarial samples that are interpreted as legit traffic signs with a...
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RSA: Encrypt in .NET & Decrypt in Python
So… one of my current projects required the following actions: asymmetrically encrypt a string in .NET using a public key and decrypt it in a python script using a private key. The problem that I’ve encountered was that, apparently, I...
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Avoid a Mistake: Correctly Calculate Multiclass Accuracy
Today I held a short laboratory which tackled different metrics used in evaluating classifiers. One of the tasks required that, given the performances of 2 classifiers as confusion matrices, the students will calculate the accuracy of the 2 models. One...
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Bypassing ASLR and DEP - Getting Shells with pwntools
Today, I’d like to take some time and to present a short trick to bypass both ASLR (Address Space Layout Randomization) and DEP (Data Execution Prevention) in order to obtain a shell in a buffer-overflow vulnerable binary. I’ve seen this...