Vibration reliability calculation apparatus, vibration reliability calculation method, and computer readable recording medium

1. A vibration reliability calculation apparatus comprising:

a memory storing instructions; and

at least one hardware processor configured to execute the instructions to implement:

an image acquisition unit configured to acquire time-series images of an object that are output by an image capturing apparatus; and

a reliability calculation unit configured to calculate, for a vibration waveform of the object that is derived from a result of comparing one image and another image that constitute the acquired time-series images, a reliability level indicating a reliability of the vibration waveform,

wherein, in a case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, the reliability calculation unit derives a surface displacement component a of measurement target region that occurs due to deformation of the surface of the object, from the displacement distribution on the surface of the object, and calculates the reliability level, based on the derived surface displacement component, and

wherein, in the case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, the reliability calculation unit is further configured to calculate an average value of absolute values of a surface displacement vector constituting the surface displacement component of the measurement target region, and to calculate the reliability level based on the calculated average value.

2. The vibration reliability calculation apparatus according to claim 1 , wherein, in a case where the vibration waveform of the object is derived based on a movement amount of a specific region within each image that is obtained by comparing one image and another image that constitute the time-series images, the reliability calculation unit calculates the reliability level, based on a similarity between the specific region in the one image and the specific region in the other image.

3. The vibration reliability calculation apparatus according to claim 2 , wherein, in a case where the movement amount of the specific region is obtained from a first similarity correlation function in a direction parallel to a shooting surface of the object and a second similarity correlation function in a normal direction of the shooting surface of the object, the reliability calculation unit calculates the reliability level, based on the first similarity correlation function and the second similarity correlation function, by weighting the first similarity correlation function more than the second similarity correlation function.

4. A vibration reliability calculation method implemented by a computer, the vibration reliability calculation method comprising:

an acquiring of time-series images of an object that are output by an image capturing apparatus; and

a calculating, for a vibration waveform of the object that is derived from a result of comparing one image and another image that constitute the acquired time-series images, of a reliability level indicating a reliability of the vibration waveform,

wherein, in a case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, in the calculating, a surface displacement component that occurs due to deformation of the surface of the object is derived from the displacement distribution on the surface of the object, and the reliability level is calculated, based on the derived surface displacement component, and

wherein, in the case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, the calculating further comprises calculating an average value of absolute values of a surface displacement vector constituting the surface displacement component of the measurement target region, and calculating the reliability level based on the calculated average value.

5. The vibration reliability calculation method according to claim 4 , wherein, in a case where the vibration waveform of the object is derived based on a movement amount of a specific region within each image that is obtained by comparing one image and another image that constitute the time-series images, in the calculating, the reliability level is calculated, based on a similarity between the specific region in the one image and the specific region in the other image.

6. The vibration reliability calculation method according to claim 5 , wherein, in a case where the movement amount of the specific region is obtained from a first similarity correlation function in a direction parallel to a shooting surface of the object and a second similarity correlation function in a normal direction of the shooting surface of the object, in the calculating, the reliability level is calculated, based on the first similarity correlation function and the second similarity correlation function, by weighting the first similarity correlation function more than the second similarity correlation function.

7. A non-transitory computer readable recording medium that includes a program recorded thereon, the program including instructions configured to cause a computer to carry out:

an acquiring of time-series images of an object that are output by an image capturing apparatus; and

a calculating, for a vibration waveform of the object that is derived from a result of comparing one image and another image that constitute the acquired time-series images, of a reliability level indicating a reliability of the vibration waveform,

wherein, in a case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, in the calculating, a surface displacement component that occurs due to deformation of the surface of the object is derived from the displacement distribution on the surface of the object, and the reliability level is calculated, based on the derived surface displacement component, and

wherein, in the case where the vibration waveform of the object is calculated using a displacement distribution on a surface of the object that is derived from the time-series images, the calculating further comprises calculating an average value of absolute values of a surface displacement vector constituting the surface displacement component of the measurement target region, and calculating the reliability level based on the calculated average value.

8. The non-transitory computer readable recording medium according to claim 7 , wherein, in a case where the vibration waveform of the object is derived based on a movement amount of a specific region within each image that is obtained by comparing one image and another image that constitute the time-series images, in the calculating, the reliability level is calculated, based on a similarity between the specific region in the one image and the specific region in the other image.

9. The non-transitory computer readable recording medium according to claim 8 , wherein, in a case where the movement amount of the specific region is obtained from a first similarity correlation function in a direction parallel to a shooting surface of the object and a second similarity correlation function in a normal direction of the shooting surface of the object, in the calculating, the reliability level is calculated, based on the first similarity correlation function and the second similarity correlation function, by weighting the first similarity correlation function more than the second similarity correlation function.