Three-dimensional shape measurement apparatus

A three-dimensional shape measurement apparatus which directs a laser beam at an object, detects light reflected back from the object, photoelectrically converts the light and subjects it to signal processing to obtain three-dimensional information about the object, comprising:

• a laser light source that generates a laser beam;
• an optical deflector for scanning the laser beam at a predetermined frequency;
• an optical system for projecting the laser beam scanned by the optical deflector at the object;
• two detection slits oriented in a direction parallel to the direction in which light reflected from the object is scanned and facing the object along an optical axis that is perpendicular to the direction of scanning by the optical deflector, said detection slits being mutually displaced by a prescribed distance in the vicinity of a position that is optically conjugate with the object;
• two photosensors for detecting light passing through the respective detection slits;
• signal processing means for cancelling out from the output signal of the photosensors optical reflection characteristic information of the object for acquiring information relating to the shape characteristics of the object in a direction of an optical axis toward the object that is perpendicular to the direction of scanning by the optical deflector.

A three-dimensional shape measurement apparatus which directs a laser beam at an object, detects the light reflected back from the object, photoelectrically converts the light and subjects it to signal processing to obtain three-dimensional information about the object, comprising:

• a laser light source that generates a laser beam;
• an optical system for projecting the laser beam from the laser light source at the object;
• two detection apertures mutually displaced by a prescribed distance in the vicinity of a position that is optically conjugate with the object;
• two photosensors for detecting light reflected from the object passing through the respective detection apertures;
• a divider circuit for dividing the output of one photosensor by that of the other;
• and
• a correction means for correcting prescribed nonlinearity in the output of the divider.

A three-dimensional shape measurement apparatus which directs a laser beam at an eye fundus, detects light reflected back from the eye fundus, photoelectrically converts the light and subjects it to signal processing to obtain three-dimensional information about the eye fundus, comprising:

• a laser light source that generates a laser beam;
• a first optical deflector for scanning the laser beam in one direction at a predetermined frequency;
• a second optical deflector for scanning the laser beam in a direction that is perpendicular to the above said direction at a predetermined frequency;
• an optical system for projecting the laser beam scanned two-dimensionally by the first and second optical deflectors at the eye fundus;
• optical means for scanning light reflected from the eye fundus and guiding it so that scanning is stationary at least with respect to the direction of scanning by the second optical deflector;
• detection means for acquiring information relating to the shape characteristics of the eye fundus in a direction of an optical axis that is perpendicular to the direction of the scanning by the first and second optical deflectors, depending on displacement of the focal point of the light reflected from the eye fundus;
• and
• signal processing means for removing from the output signal of the detection means the influence of the optical reflection characteristics of the eye fundus.