2016 年 33 巻 3 号 p. 57-62
Dysfunctions of mastication and swallowing are caused by the growth in the mixed dentition period, postoperative symptoms in surgical procedures, missing tooth/teeth, simply aging, etc. There is a dietary report on the reduction of food intake due to prolonged chewing. Therefore, we tried to develop a noncontact chewing cycle analyzer, which works on tablet PCs. After a face area is captured, the top far-left pixel was tracked to measure the whole-face transition and two pixels at the captured mouth angle were picked up to measure the optical flow method. The mouth movement in the period of food intake, mastication and swallowing, was recorded. The movement showed kinds of wave forms, which sometimes contained irregular forms. But the compensation using the whole-face movement clearly showed the repeated mastication. Due to the limitation of the calculation loading in tablet PCs, the range of practically measurable fps was 8 to 9 in the maximum 30. We reduced the size of captured image and the number of pixels for the optical flow analysis, and chose the effective edge-extraction filter for the faster calculation. The data captured at 8 fps were enough to record wave forms of the mouth movement. Such non-contact chewing cycle analyzer is of value to evaluate the mastication dysfunction and recovery.