A range finder that measures a distance to an object by projecting a signal and receiving it back has a signal projection device for projecting a signal, a first reception device for receiving a reflected signal of the projected signal which is reflected in a range from a near distance to a far distance, and a second reception device for receiving a reflected signal of the projected signal which is reflected from distant objects, in which range finder the distance measurement accuracy is enhanced and no decrease in an overall distance measurement accuracy occurs.
The ranging device performs the active-type ranging, and has a structure in which a photo diode (PD) is provided on the far distance side of position sensitive detector (PSD), and superimposing means is provided for emphasizing a signal current I.sub.F flown from the far distance side electrode by superimposing a signal current obtained by the PD onto a signal current obtained by the PSD. As the superimposing means, an auxiliary PSD (the second PSD) is provided from a predetermined position directing from the near distance side to the far distance side of the original PSD (the first PSD) to the far distance side, and a signal obtained by the second PSD is superimposed on a signal output from the far distance side of the first PSD to emphasize it.
A distance measuring device for a camera has a near infrared light-projecting element for projecting measuring light to be reflected by an object to be photographed. The reflected measuring light is received as a first light beam image at a first position on a surface of a first light-receiving element. The reflected measuring light reflected by the object is also received as a second light beam image at a second position on a surface of a second light-receiving element. A CPU controls the focusing movement of the lens of the camera by computing a distance to the object depending on the first position, compensating the computed distance depending on the second position, and controlling the focusing movement of the lens based on the compensated computed distance. The CPU compares the second position with a predetermined distance value and inhibits the compensation of the computed distance if it is determined that compensation is not necessary.
A position detecting element that enables a position to be detected at high speed and high precision, and a range sensor using the same. The position detecting element is provided with a PIN photodiode array 1 having n segments and a parallel arithmetic processing portion 2 that calculates the segment having maximum intensity by comparing n outputs from the segments of the PIN photodiode array 1. The range sensor includes a light source by which the object to be measured is irradiated by optical beam, a lens that gathers rays of the reflected light from the surface of the object to be measured and the position detecting element mentioned above that detects the position of the light gathered by the lens.
A laser beam profile sensor system for which is capable of accurately determining distances to both close and distant objects, particles, liquid interfaces and the like and of identifying the locations of ice layers on metal surfaces. Basically, the system includes a laser diode for generating a laser beam along a selected path, a receiver spaced from the laser diode for receiving light along a receiver axis, the laser beam and receiver axis intersecting at any desired angle from nearly 0.degree. to nearly 180.degree.. The receiver comprises a linear array of light responsive elements. An optical system is provided for directing light approaching the receiver along the receiver axis to the array. An electronic circuit processes signals from the array elements and produces a display showing the distance to any target lying along the laser beam path that reflects light along the receiver axis.
A distance measuring apparatus includes a first light projecting device for projecting a light to a projection range, and a first light receiving device arranged along a base length direction thereof, for receiving a reflection light of the light projected from the first light projecting device. The first light receiving device has a first position sensor to detect, in accordance with a position of light reception, a distance to an object, the object being located at least within a middle distance. A second light projecting device, provided independent of the first light projecting device, projects a light to substantially the same projection range as the first light projecting device. A second light receiving device, arranged in a direction different from the base length direction of the first light receiving device, receives a reflection light of the light projected from the second light projecting device. The second light receiving device includes (i) a second position sensor to detect, in accordance with a position of light reception, a distance to an object, the object being located at least within a near distance range, and (ii) a third sensor, disposed at a position corresponding to light reception for an object which is located within a far distance range, to detect a distance to the object in the far distance range.
