Capturing Live Audio and Video in Python

In my robotics projects I want to capture live audio and video data in Python. To save you several days, this blog post explains how I go about doing this.

Playing Around with Retinal-Cortex Mappings

Here is a little notebook where I play around with converting images from a polar representation to a Cartesian representation. This is similar to the way our bodies map information from the retina onto the early visual areas. Mapping from the visual field (A) to the thalamus (B) to the cortex (C) These ideas are … Continue reading Playing Around with Retinal-Cortex Mappings →

Understanding Convolution in Tensorflow

This is a quick post intended to help those trying to understand convolution as applied in Tensorflow. There are many good blog posts on the Internet explaining convolution as applied in convolutional neural networks (CNNs), e.g. see this one by Denny Britz. However, understanding the theory in one thing, knowing how to implement it is … Continue reading Understanding Convolution in Tensorflow →

Practical Problems with Natural Language Processing

Recently I've been playing around with the last 15 years of patent publications as a 'big data' source. This includes over 4 million individual documents. Here I thought I'd highlight some problems I faced. I found that a lot of academic papers tend to ignore or otherwise bypass this stuff.

Fixing Errors on Apache-Served Flask Apps

This is just a quick post to remind me of the steps to resolve errors on an Apache-served Flask app. I'm using Anaconda as I'm on Puppy Linux (old PC) and some compilations give me errors. Stuff in square brackets is for you to fill in. Log into remote server (I use ssh keys): ssh -p … Continue reading Fixing Errors on Apache-Served Flask Apps →

Using Alembic to Migrate SQLAlchemy Databases

There are several advantages of using SQLAlchemy as a wrapper for an SQL database. These include stability with large numbers of data records, class/object-oriented approach, plug-and-play underlying databases. However, one under-documented disadvantage is poor change management. If you add a field or table you generally need to regenerate the entire database. This is a pain if … Continue reading Using Alembic to Migrate SQLAlchemy Databases →

Quickpost: Adding a Custom Path to Conda Environment

I have a few Python applications in development in a custom 'projects' directory. I want to be able to run these using 'python -m [appname]'. The easiest way to do this is by adding a .pth file to the site-packages folder of my Python environment (for me '/[userdirpath]/anaconda3/envs/[projectname]/lib/python3.5/site-packages/'). For example, I added a file called 'custom.pth' that … Continue reading Quickpost: Adding a Custom Path to Conda Environment →

Starting a Python Project with Anaconda

It just so happens that on a few systems I have been using Anaconda to allow painless Python coding. For example, on Windows or non-Debian Linux I have struggled to compile packages from source. Anaconda provides a useful wrapper for the main functionality that just works on these operating systems (on my Ubuntu machine or the … Continue reading Starting a Python Project with Anaconda →

Quick Post: Structuring a Python Program

One thing I've found hard about programming in Python is the jump from small scripts or iPython (now Jupyter) notebooks to fully functional programs. Many examples and online tutorials only require a single ".py" file or a series of command line or notebook entries. However, as you get more advanced and start looking at complete Flash applications or … Continue reading Quick Post: Structuring a Python Program →

Quick Post: Recursive Function to Search Multi-Level Dictionary

Many APIs return JSON that is converted into a multilevel dictionary (e.g. EPO OPS). The following code snippet helps find a key (e.g. "id") that is nested within the dictionary. The function is based on this answer. To find more than the first occurrence "return" may be converted to "yield".