ai_utilities

Several useful scripts for use with fast.ai lectures and libraries.

image_download is the primary function. It provides easy download of images from bing, google, baidu, and/or flickr (though the later requires an apikey). It is intended for direct import of images within a python script or Jupyter Notebook.

make-train-valid makes a train-valid directory and randomly copy files from labels_dir to sub- directories. It has largely been replaced by the capabilities within fastai but is still useful.

Installation

• pip install icrawler
• pip install python-magic or pip install python-magic-bin
• git clone https://github.com/prairie-guy/ai_utilities.git

image_download.py

Downloads up to a n_images (typically limited to 100-300) from a specified search engine, including bing, baidu and flickr. The search_text can be different from its label. Images are checked to be valid images and duplicates are eliminated. Images are saved to the directory dataset by defalult. (Based upon the excellent work of: https://github.com/hellock/icrawler)

usage: image_download(search_text:Path, n_images, label:str=None, engine:str='bing', image_dir='dataset', apikey=None)
           where, 'engine'   = ['bing'|'google'|baidu'|'flickr'],
                  'flickr' requires an apikey and
                  'label' can be different from 'search_text'

Example Usage

Download up to 100 images of each class, check each file to be a valid jpeg image, save to directory dataset and create data = ImageDataBunch.from_folder(...). Optionally create an imagenet-type directory structure.

import sys
sys.path.append('your-parent-directory-of-ai_utilities')
from ai_utilities import *
from pathlib import Path
from fastai.vision.all import *

for p in ['dog', 'goat', 'sheep']:
    image_download(p, 100)
path = Path.cwd()/'dataset'    
data = ImageDataLoaders.from_folder(path,valid_pct=0.2, item_tfms=Resize(224))

# Optionally, create an imagenet-type file directory.
make_train_valid(path)
data = ImageDataLoaders.from_folder(path, train='train', valid='valid', item_tfms=Resize(224))

make_train_valid.py

From a directory containing sub-directories, each with a different class of images, make an imagenet-type directory structure. It randomly copies files from labels_dir to sub-directories: train, valid, test. Creates an imagmenet-type directory usable by ImageDataBunch.from_folder(dir,...)

usage: make_train_valid(labels_dir:Path, train:float=.8, valid:float=.2, test:float=0)                           
     positional arguments:
        labels_dir     Contains at least two directories of labels, each containing
                       files of that label
         optional arguments:
                        train=.8  files for training, default=.8
                        valid=.2  files for validation, default=.2
                        test=  0  files for training, default=.0

For example, given a directory:

catsdogs/
         ..cat/[*.jpg]
         ..dog/[*.jpg]

Creates the following directory structure:

catsdogs/
         ..cat/[*.jpg]
         ..dog/[*.jpg]
         ..train/
                 ..cat/[*.jpg]
                 ..dog/[*.jpg]
         ..valid/
                 ..cat/[*.jpg]
                 ..dog/[*.jpg]