Particle size distribution measurement method, particle size distribution measurement device, and calculation device

A particle size distribution measurement device configured to measure a particle size distribution of granules having an unknown particle size distribution, the particle size distribution measurement device comprising:

• a calculation device including an image acquisition unit configured to acquire a first CT image of a target sample including the granules, a statistical value calculation unit configured to specify a region of interest by dividing the acquired first CT image into predetermined grids and calculate a first statistical value including a grid statistical value for each of the grids and an overall statistical value of the entire first CT image regarding a CT value, and a measurement unit including a particle size distribution measurement unit configured to measure a particle size distribution of the granules in the target sample based on a second statistical value and the first statistical value, the second statistical value including a grid statistical value and an overall statistical value of a type same as the grid statistical value and the overall statistical value included in the first statistical value in a second CT image of a standard sample including granules having a known particle size;
• and
• an X-ray CT device.