Table 4: Summary of the literature studies related to environment recognition based on the ANN method. The number of environments analyzed, the average accuracy and the accuracy-related to each environment are reported. (cont.).

Study (Refs.)	# Environments (per study)	Average Accuracy (per study)	Accuracy Boll Impact	Accuracy Metal Impact	Accuracy Wood Impact	Accuracy Plastic Impact	Accuracy Open or Close Door	Accuracy Typing	Accuracy Knocking	Accuracy Phone Ringing	Accuracy Grains Falling	Accuracy Spray	Accuracy Whistle	Accuracy Voice	Accuracy Music
[57]	11	92.41%	100.00%	95.00%	96.50%	100.00%	85.00%	75.00%	90.00%	100.00%	80.00%	95.00%	100.00%	–	–
[63]	4	77.00%	–	–	–	–	–	–	–	–	–	–	–	62.00%	80.00%