Rotation state estimation apparatus, method thereof, and program

A spin state estimation device, wherein an absolute value of w is an integer of 2 or more and u is a unit time, comprising processing circuitry configured to execute operations comprising:

• obtaining a first object image, wherein the first object image represents an image of an object at a certain time point t obtained from an input video of a plurality of frames in time-series;
• obtaining a second object image at a time point t+w·u from the input video;
• creating, based on the first object image, a target estimation image, wherein the target estimation image represents another image of the object at the time point t+w·u by applying a simulated rotation by w unit time according to a hypothesis of spin state to the object in the first object image;
• calculating, for each of a plurality of hypotheses of spin states and a plurality of w, a likelihood of the target estimation image for the second object image;
• and
• estimating a spin state of the object by selecting a specific hypothesis of spin state and a specific w in which the calculated likelihood becomes high from among the plurality of hypotheses of spin states and the plurality of w, wherein the likelihood of the target estimation image becoming high represents a likelihood representing a predetermined condition.