2017 年 17 巻 3 号 p. 191-197
This study proposes an in-situ method to extract the outer surface shape of deforming thermoplastic materials during combustion. The proposed method consists of backlight photography of the burning sample which enables extraction of its shadowgraph and following filtered back-projection. Ultraviolet LED is chosen as backlight source based on a preliminary test, which shows the intensity is relatively larger than that of chemiluminescence from flame. An optical system was developed, in which the object was rotatable while the backlight and the camera were fixed. First, a draft test without burning was conducted to confirm the validity of the proposed method. A test with a burning sample was then conducted to check the applicability to extraction of the outer surface shape of the deforming object during combustion. The accuracy of the current system was evaluated for both non-burning and burning tests. The cross-sectional area obtained from the reconstructed image was compared with that obtained from design dimension of sample and that measured by a laser displacement sensor. Several points to be improved are discussed based on the results.
