{
  "$type": "site.standard.document",
  "description": "In an angle detecting apparatus and projector using range finders, range finding calculations are performed in plural directions using line type passive range finders as a range finding portion. Thus, if one range finding result is an abnormal value, the effects are reduced. The structure is…",
  "path": "/patents/1089220",
  "publishedAt": "2004-03-03T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "G01C3/085",
    "SEIKO PRECISION KK [JP]"
  ],
  "textContent": "In an angle detecting apparatus and projector using range finders, range finding calculations are performed in plural directions using line type passive range finders as a range finding portion. Thus, if one range finding result is an abnormal value, the effects are reduced. The structure is miniaturized. ÄMeans for ResolutionÜ A control circuit 5 calculates four horizontal relative inclination angles between a screen 1 and a projector 2 based on results of range finding calculations of a line type passive range finder 3 doing range finding in five directions, finds their average value, calculates four vertical relative inclination angles between the screen 1 and the projector 2 based on the results of range finding of a line type passive range finder 4 doing range finding in five directions, and finds their average value. A display driving portion 7 adjusts a projection optical system 8 including a condensing lens based on the horizontal and vertical inclination angles calculated by the control circuit 5 and on the distance between range finding calculational regions, thus correcting keystone distortion in the projected image.",
  "title": "Angle detecting apparatus and projector equipped therewith automatically correcting the Keystone distortion"
}