vqa_iconqa.py

__author__ = 'QingLi'
__version__ = '1.0'

# Interface for accessing the VQA dataset.

# This code is based on the code written by Qing Li for VizWiz Python API available at the following link: 
# (https://github.com/xxx)

# The following functions are defined:
#  VQA        - VQA class that loads VQA annotation file and prepares data structures.
#  getQuesIds - Get question ids that satisfy given filter conditions.
#  getImgIds  - Get image ids that satisfy given filter conditions.
#  loadQA     - Load questions and answers with the specified question ids.
#  showQA     - Display the specified questions and answers.
#  loadRes    - Load result file and create result object.

# Help on each function can be accessed by: "help(COCO.function)"
# example code from https://vizwiz.org/tasks-and-datasets/vqa/ 

import json
import datetime
import copy

class VQA_IconQA:
	def __init__(self, annotation_file=None):
		"""
	   	Constructor of VQA helper class for reading and visualizing questions and answers.
		:param annotation_file (str): location of VQA annotation file
		:return:
		"""
		# load dataset
		self.dataset = {}
		self.imgToQA = {}
		if annotation_file != None:
			print('loading dataset into memory...')
			time_t = datetime.datetime.utcnow()
			dataset = json.load(open(annotation_file, 'r'))
			print(datetime.datetime.utcnow() - time_t)
			self.dataset = dataset
			self.imgToQA = {x['image']:x for x in dataset}

	def getImgs(self):
		return list(self.imgToQA.keys())

	def getAnns(self, imgs=[], ansTypes=[]):
		"""
		Get annotations that satisfy given filter conditions. default skips that filter
		:param  imgs (str array): get annotations for given image names
				ansTypes  (str array)   : get annotations for given answer types
		:return: annotations  (dict array)   : dict array of annotations
		"""
		anns = self.dataset

		imgs = imgs if type(imgs) == list else [imgs]
		if len(imgs) != 0:
			anns = [self.imgToQA[img] for img in imgs]

		ansTypes  = ansTypes  if type(ansTypes)  == list else [ansTypes]
		if len(ansTypes) != 0:
			anns = [ann for ann in anns if ann['answer_type'] in ansTypes]
		return anns

	def showQA(self, anns):
		"""
		Display the specified annotations.
		:param anns (array of object): annotations to display
		:return: None
		"""
		if len(anns) == 0:
			return 0
		for ann in anns:
			print("Question: %s"%ann['question'])
			print("Answer: ")
			print('\n'.join([x['answer'] for x in ann['answers']]))