1. A robot identification system, comprising: a robot having a rotatable arm; a camera imaging the robot; an angle detector detecting a rotation angle of the arm; a model generator that generates a robot model representing a form of the robot on the basis of the rotation angle detected by the angle detector; and an image processor comparing an image captured by the camera with the robot model generated by the model generator and thereby identifying a robot image representing the robot in the image captured by the camera, wherein the robot includes a first robot having a first rotatable arm, and a second robot having a second rotatable arm, the angle detector includes a first angle detector detecting a first rotation angle of the first rotatable arm of the first robot, and a second angle detector detecting a second rotation angle of the second rotatable arm of the second robot, the model generator generates a first robot model representing the form of the first robot on the basis of the first rotation angle detected by the first angle detector, and a second robot model representing the form of the second robot on the basis of the second rotation angle detected by the second angle detector, and the image processor compares the image captured by the camera with the first robot model and the second robot model generated by the model generator, to identify a first robot image representing the first robot and a second robot image representing the second robot in the image captured by the camera.