Device, method, and program for determining parameter indicating shape of ear canal based on layers perpendicular to calculated center line of ear canal
To easily evaluate the performance of an earphone-type device used for otoacoustic authentication at low cost. A generation unit ( 31 ) generates earhole shape data indicating the three-dimensional shape of an individual's ear canal, on the basis of data on the internal structure of an individual's earhole, a center line calculation unit ( 32 ) calculates the center line of the ear canal, on the basis of the ear canal shape data, and a dividing unit ( 33 ) divides the ear canal into a plurality of layers perpendicular to the center line, and calculates, for each of the divided layers, parameters indicating the shape of the ear canal.
1. A parameter determination device comprising:
a memory storing instructions data; and
at least one processor configured to execute the instructions to perform:
generating, based on data regarding an internal structure of an ear hole of an individual, shape of ear hole data indicating a three-dimensional shape of an ear canal of the individual;
calculating a center line of the ear canal based on the shape of ear hole data, by calculating a line connecting respective center points of ellipses approximating two-dimensional shapes of cross sections of the ear canal as the center line of the ear canal;
dividing the ear canal into a plurality of layers perpendicular to the center line; and
calculating a parameter indicating a shape of the ear canal for each of the divided layers.
2. The parameter determination device according to claim 1 , wherein
the at least one processor is configured to execute the instructions to perform:
calculating, as the parameter, a number for identifying each layer obtained by dividing the ear canal and a size of a diameter of a hole relating to a thickness of the ear canal for each layer.
3. A parameter determination method performed by a computer and comprising:
generating, based on data regarding an internal structure of an ear hole of an individual, shape of ear hole data indicating a three-dimensional shape of an ear canal of the individual;
calculating a center line of the ear canal based on the shape of ear hole data, by calculating a line connecting respective center points of ellipses approximating two-dimensional shapes of cross sections of the ear canal as the center line of the ear canal;
dividing the ear canal into a plurality of layers perpendicular to the center line; and
calculating a parameter indicating a shape of the ear canal for each of the divided layers.
4. The parameter determination method according to claim 3 , wherein
calculating the center line of the ear canal comprises:
setting a straight line passing through both ends of the ear canal;
dividing the ear canal into a plurality of layers orthogonal to the straight line passing through both ends of the ear canal, each of the plurality of layers having a predetermined thickness;
approximating a contour of a cross section of the ear canal for each layer with an ellipse; and
connecting respective center points of ellipses of the plurality of layers.
5. A non-transitory recording medium storing a program executable by a computer to perform processing comprising:
generating, based on data regarding an internal structure of an ear hole of an individual, shape of ear hole data indicating a three-dimensional shape of an ear canal of the individual;
calculating a center line of the ear canal based on the shape of ear hole data, by calculating a line connecting respective center points of ellipses approximating two-dimensional shapes of cross sections of the ear canal as the center line of the ear canal;
dividing the ear canal into a plurality of layers perpendicular to the center line;
calculating a parameter indicating a shape of the ear canal for each of the divided layers.
6. The recording medium according to claim 5 , wherein
calculating the center line of the ear canal comprises
setting a straight line passing through both ends of the ear canal;
a step of dividing the ear canal into a plurality of layers orthogonal to the straight line passing through both ends of the ear canal, each of the plurality of layers having a predetermined thickness;
approximating a contour of a cross section of the ear canal for each layer with an ellipse; and
connecting respective center points of ellipses of the plurality of layers.