captcha_dataset: Captcha dataset
In decryptr/captcha: Solve Text on Image Computer Vision Challenges

captcha_dataset

R Documentation

Captcha dataset

Description

This object implements a dataset using the torch::dataset() framework. It loads all the images in torch tensors, as well as the labels.

Usage

captcha_dataset(
  root,
  transform_image = captcha::captcha_transform_image,
  transform_label = captcha::captcha_transform_label,
  augmentation = NULL
)

Arguments

`root`	(string): root directory where the files are stored
`transform_image`	(callable, optional): A function/transform that takes in an file path and returns an torch tensor prepared to feed the model. By default, uses the `captcha_transform_image()` function.
`transform_label`	(callable, optional): A function/transform that takes in the file paths and transform them. By default, uses the `captcha_transform_label()` function.
`augmentation`	(function, optional) If not `NULL`, applies a function to augment data with randomized preprocessing layers. This is an object of class `dataset_generator` created using `torch::dataset()` function. It has a `initialize()` method that takes a directory containing the input images, then assigns all the information in-memory with the array data structure for the response variable. It also has a `.getitem()` method that correctly extracts one observation of the dataset in this data structure, and a `.length()` method that correctly calculates the number of Captchas of the dataset. The function calculates the vocabulary based on the identified values in the dataset.

Examples


if (torch::torch_is_installed()) {
  annotated_folder <- system.file(
    "examples/annotated_captcha",
    package = "captcha"
  )
  suppressMessages({
    ds <- captcha_dataset(annotated_folder)
  })
  # gets the first item (the only item in the example)
  # returns a list with x and y torch tensors.
  ds$.getitem(1)
}

decryptr/captcha documentation built on April 15, 2023, 12:42 a.m.