ppf.angauge 0.1.0

Convert images of analog gauge to readings

README

Ever stared at an old analog gauge - like that dusty water meter in your basement - and wished you could convert its indicators into actionable data?

ppf.angauge (pronounced like "engage") to the rescue: It converts photos of your gauge to digital readings. It handles

• meters with a single indicator showing an analog value (like an ammeter or the gauge in the logo)
• meters having multiple indicators each showing a digit [0, 10) of the actual reading (like the water meter shown below).

Note: It reads indicators (hands rotating in front of dials). It does not read registers (rotating drums with printed digits).

It provides:

• a python package to integrate into your own projects
• a command line tool for quick testing and prototyping

Isn't this very similar to "AI-on-the-edge"? It is. In fact, if you are looking for a firmware to run on an esp32-cam board, you are better off using that project. If you are working on a different platform, if you want the flexibility to integrate with your own (python) code, or if you are reading value-indicators (not digit-indicators), keep reading.

Usage

The command-line tool works as follows:

> read_gauge <config.toml> <image.bmp>
image.bmp, 0.5632

where config.toml is a configuration file specifying location, size, and orientation of the indicators in image.bmp, which we will explain in a second. For more information on command line options, see read_gauge --help.

The following code snippet shows how to do the same in python:

from ppf.angauge import read_config, read_gauge, mle
from matplotlib.pyplot import imread

# read configuration file:
config = read_config('config.toml')

# read image:
img = imread('image.jpg')

# read meter hands from image:
readings = read_gauge(img, config)

# determine most likely meter state given readings:
value, errorbar = mle(readings)