Equipment factors affecting identification of water level with echo for the blind.

Blind people adopt their remaining intact senses to perceive the world for tasks such as determining the water level in a bowl. Pouring water into a bowl generates water sounds and echoes reflected in the bowl. This research develops a bowl with increased echo (called an echo bowl), and analyzes the accuracy of water levels perceived by visually impaired people using a container or a kettle to pour water into a common bowl or an echo bowl. The analysis of factors of pouring and filled equipment indicates that the container has a significantly lower water level error than the kettle when pouring water. The water level error with different combinations of equipment is smallest when pouring water from the container to the echo bowl, and largest when pouring water from the kettle to the common bowl. This work also analyzes the sound of pouring water from the equipment by a simple linear regression analysis, and uses it to interpret the results of the pouring experiment.