1. An image processing apparatus comprising: a holding unit that holds, for each event which may occur in an image, a type of an object to be determined whether or not to come in contact with another object in a physical space, wherein the holding unit is configured to hold in advance, for each event, an object type which is preset in advance as a type of an object to be determined whether or not to come in contact with another object in the physical space; a unit that sequentially acquires an image of each frame output from an image sensing device; a first detection unit that detects, before performing an object detection on an image of interest, an event which occurs in the image of interest; a specifying unit that specifies, from object types each of which is held in advance in the holding unit and is preset in advance as a type of an object to be determined whether or not to come in contact with another object in the physical space, the object type which corresponds to the event detected by the first detection unit; a second detection unit that detects an object of the object type specified by the specifying unit from the image of interest; and a determination unit that determines whether objects detected by the second detection unit come in contact with each other in the physical space, wherein the first detection unit detects a first event, and the specifying unit specifies, from the holding unit, a first object type and a second object type as the object types which correspond to the first event, and the determination unit: sets an image, among the images of the frames, in which a distance between respective detection positions, in the image, of a first object corresponding to the first object type and a second object corresponding to the second object type is equal to or less than a threshold, as a target image, and determines that the first object and the second object come in contact with each other in the physical space, if a magnitude of acceleration, in the target image, of the first object is greater than or equal to a threshold, and an angle formed by a vector representing the acceleration and a vector representing velocity, in the target image, of the second object is less than a threshold.