Featurize images using a small, contained pre-trained deep learning network

• Free software: BSD license

This is the prototype for image features engineering. Supports Python 2.7, 3.4, 3.5, 3.6, and 3.7

pic2vec is a python package that performs automated feature extraction for image data. It supports feature engineering on new image data, and allows traditional machine learning algorithms (such as tree-based algorithms) to train on image data.

pic2vec works on image data represented as either:

1. A directory of image files.
2. As URL pointers contained in a CSV.
3. Or as a directory of images with a CSV containing pointers to the image files.

If no CSV is provided with the directory, it automatically generates a CSV to store the features with the appropriate images.

Each row of the CSV represents a different image, and image rows can also have columns containing other data about the images as well. Each image's featurized representation will be appended as a series of new columns at the end of the appropriate image row.

The goal of this project was to make the featurizer as easy to use and hard to break as possible. If working properly, it should be resistant to badly-formatted data, such as missing rows or columns in the csv, image mismatches between a CSV and an image directory, and invalid image formats.

However, for the featurizer to function optimally, it prefers certain constraints:

• The CSV should have no missing columns or rows, and there should be full overlap between images in the CSV and the image directory

• If checking predictions on a separate test set (such as on Kaggle), the filesystem needs to sort filepaths consistently with the sorting of the test set labels. The order in the CSV (whether generated automatically or passed in) will be considered the canonical order for the feature vectors.

The featurizer can only process .png, .jpeg, or .bmp image files. Any other images will be left out of the featurization by being represented by zero vectors in the image batch.

The following Python code shows a typical usage of pic2vec:

from pic2vec import ImageFeaturizer

image_column_name = 'images'
my_csv = 'path/to/data.csv'
my_image_directory = 'path/to/image/directory/'

my_featurizer = ImageFeaturizer(model='xception', depth=2, autosample=True)

featurized_df = my_featurizer.featurize(image_column_name, csv_path=my_csv,
                                        image_path=my_image_directory)

To get started, see the following example:

1. Cats vs. Dogs: Dataset from combined directory + CSV

Examples coming soon: 2. Hot Dog, Not Hot Dog: Dataset from a CSV with URLs and no image directory

See the Installation Guide for details.

If you run into trouble installing Keras or Tensorflow as a dependency, read the Keras installation guide and Tensorflow installation guide for details about installing Keras/Tensorflow on your machine.

pic2vec generates a flat CSV which is ready for supervised modeling, if the data has been labelled with a variable that can be used as a target. The images are transformed into a set of regular columns containing numeric data. Additionally, if unlabelled, it can be used for unsupervised learning (such as anomaly detection).

To run the unit tests with pytest, run

py.test tests

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.