| 摘要 |
PURPOSE:To make it possible to accurately measure the shape of a surface to be measured within a short time, by a method wherein spot light is obliquely projected to the surface to be measured and the reflected light from said surface to be measured is received by a light receiving element divided into a plurality of sections and a plurality of the outputs from the divided sections are combined. CONSTITUTION:The spot light 3 obliquely projected to a surface 1 to be measured at an incident angle alpha from a floodlight projector 2 is obliquely reflected from the surface 1 and this reflected light 4 is received by a light receiver 5. This light receiver 5 is constituted of four light receiving elements 7a-7d divided by X- and Y-axis lines intersecting at the center of a light receiving surface 6. Then, if the sum of the outputs of the elements 7a, 7b receiving the reflected light 4 and the sum of the outputs of the elements 7c, 7d receiving said reflected lights 4 are taken out and the difference therebetween is calculated, the calcu lated value is proportional to the angle theta around the X-axis on the surface 1. The X-axis of the elements 7 is present on the optical axis surface constituted of lights 3, 4 but, by arranging the optical axis surface constituted of the lights 3, 4 along the direction of the y-axis of the surface 1, the angle psi around the y-axis of the surface 1 is calculated and, by subtracting the angle psi from the difference between the outputs of the elements 7a, 7c and the outputs of the elements 7b, 7d, the displacement in a z-axis direction is calculated.
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