Tactile walking surface indicators (TWSIs) were developed to help visually impaired people traveling alone, but TWSIs could be an extra barrier for pedestrians, wheelchair users and baby carriage users without visual impairment. The purpose of this study is to develop TWSIs of the height of bumps less than Japanese Industrial Standard (JIS)-type TWSIs. Especially, the subject of this study is guidance in indoor area for visually impaired people. We investigate the ease of detection and recognition of dot tile patterns which are different from the height (1mm, 2mm), the diameter (20mm, 30mm, 40mm) and the number (64 pieces, 113 pieces) of bumps by white cane. Participants are 12 persons with low vision and 2 totally blind persons. They wear eye mask in the experiment. The result in this study clear that it is possible to detect even the height of 1mm if there are 113 pieces of bumps.