Arrangement detector for plate-shaped object and load port including same

An arrangement detector for plate-shaped objects comprising;

• an imaging means, relatively movable in a substantially perpendicular direction to a plane of the plate-shaped objects, and capable of imaging at least a part of one of the plate-shaped objects along an edge of the one of the plate-shaped objects in an imaging screen, with respect to the plate-shaped objects arranged at predetermined intervals in a container,
• a judgement window setting means for setting a first reference line and a second reference line in a judgement window along a pair of substantially parallel image shading boundary lines, with a width corresponding to a thickness of an edge of a single plate-shaped object, based on a master image corresponding to the edge,
• a shape determination means for determining a shape matching rate by superimposing the judgement window, set by the judgement window setting means, on the image captured by the imaging means, and
• an object judgement means for judging the plate-shaped objects do not exist in the judgement window overlaid on the image captured by the imaging means, in case that the shape matching rate determined by the shape determination means is equal to or less than a predetermined value, wherein
• the first reference line is a continuous straight line in the judgement window, and the second reference line is a collection of discontinuous line segments linearly arranged in the judgement window.