Abstract: A calibration error correction device for an optical instrument includes a detector operable to detect a position of a focusing lens of an optical instrument along a mechanical path of the focusing lens. A line of sight through an image plane of the optical instrument and the focusing lens at a present position defines an actual viewing direction. The device also includes a memory configured to store viewing direction errors specifying a deviation between a known theoretical viewing direction and the actual viewing direction associated with a plurality of different positions of the focusing lens along the mechanical path and an indicator of at least one value indicative of the actual viewing direction based on the theoretical viewing direction and the viewing direction errors at each of the different positions of the focusing lens along the mechanical path.

Abstract: An electronic leveling apparatus for optically measuring a height difference relative to a leveling staff comprises a telescope, a camera fixed to the telescope, a first actuator for rotating both said telescope and said camera in a horizontal plane about a fixed vertical axis of the apparatus, and a controller. The camera has a depth of focus that is at least twice a depth of focus of the telescope. The controller uses a first output signal from said telescope to output a leveling signal representing a detected height difference. The controller uses a second output signal from said camera to identify a representation of a leveling staff and to control the first actuator based on the identified representation of the leveling staff. Furthermore a method for optically measuring a height difference of an electronic leveling apparatus relative to a leveling staff is provided.

Abstract: A calibration error correction device for an optical instrument includes a detector operable to detect a position of a focusing lens of an optical instrument along a mechanical path of the focusing lens. A line of sight through an image plane of the optical instrument and the focusing lens at a present position defines an actual viewing direction. The device also includes a memory configured to store viewing direction errors specifying a deviation between a known theoretical viewing direction and the actual viewing direction associated with a plurality of different positions of the focusing lens along the mechanical path and an indicator of at least one value indicative of the actual viewing direction based on the theoretical viewing direction and the viewing direction errors at each of the different positions of the focusing lens along the mechanical path.

Abstract: An electronic leveling apparatus for optically measuring a height difference relative to a leveling staff comprises a telescope, a camera fixed to the telescope, a first actuator for rotating both said telescope and said camera in a horizontal plane about a fixed vertical axis of the apparatus, and a controller. The camera has a depth of focus that is at least twice a depth of focus of the telescope. The controller uses a first output signal from said telescope to output a leveling signal representing a detected height difference. The controller uses a second output signal from said camera to identify a representation of a leveling staff and to control the first actuator based on the identified representation of the leveling staff. Furthermore a method for optically measuring a height difference of an electronic leveling apparatus relative to a leveling staff is provided.

Abstract: A method and an arrangement for carrying out an information flow and data flow in a geodetic instrument with image processing is disclosed. For this purpose, the data flow and information flow needed for image processing are distributed to a plurality of function modules which are arranged in the instrument and which comprise function groups and are carried out by means of these function groups. The arrangement includes a plurality of function groups which are arranged in the instrument at locations determined by its construction design. These function groups are composed of a plurality of function modules.

Abstract: The invention relates to an autofocusing method, particularly for telescopes for surveying instruments which are fitted with image sensors that resolve the image signal into individual image elements (pixels), such as CCD lines and/or matrices as well as CMOS image sensors. On the basis of the pixel that is located closest to the optical axis, the local signal amplitude is calculated from the monotonically decreasing or increasing signal all the way to the next local maximum and minimum. In this process, as long as this local signal amplitude is considerably smaller than the maximum signal and the focusing member of the telescope lens is in the focusing position for short focusing distances, this focusing member is shifted in large increments. Depending on the magnitude of the local signal amplitude, the focusing distance is shortened in the area of greater focusing distances in relation to the maximum signal and to the position of the focusing member.

Abstract: The invention relates to an autofocusing method, particularly for telescopes for surveying instruments which are fitted with image sensors that resolve the image signal into individual image elements (pixels), such as CCD lines and/or matrices as well as CMOS image sensors. On the basis of the pixel that is located closest to the optical axis, the local signal amplitude is calculated from the monotonically decreasing or increasing signal all the way to the next local maximum and minimum. In this process, as long as this local signal amplitude is considerably smaller than the maximum signal and the focusing member of the telescope lens is in the focusing position for short focusing distances, this focusing member is shifted in large increments. Depending on the magnitude of the local signal amplitude, the focusing distance is shortened in the area of greater focusing distances in relation to the maximum signal and to the position of the focusing member.

Abstract: A method and an arrangement for carrying out an information flow and data flow in a geodetic instrument with image processing is disclosed. For this purpose, the data flow and information flow needed for image processing are distributed to a plurality of function modules which are arranged in the instrument and which comprise function groups and are carried out by means of these function groups. The arrangement includes a plurality of function groups which are arranged in the instrument at locations determined by its construction design. These function groups are composed of a plurality of function modules.

Abstract: A method for target seeking in geodetic survey measurements comprises the steps of generating at least a first light bundle by a measurement device from a light source arranged therein, the light bundle periodically pivoting back and forth or revolving about the standing axis of the measurement device and fanning out in the vertical plane and being sent to at least one receiver arrangement arranged in at least one target station arranged at a distance from the measurement device.

Abstract: A method is provided for determining edge positions by evaluating digitized electrical signals which are obtained when scanning at least one light-dark structure by means of photoreceivers. The method is characterized in that the regions of four adjacent photoreceivers (i; i+1; i+2; i+3), in the middle of which is located an edge to be determined, are first determined from the signals Y.sub.i, in that the type of edge, light edge, dark edge or dark-light edge or white-black transition or black-white transition is then determined from the signals Y.sub.i, in that a value Mi is formed from the signals of the first two photoreceivers (i; i+1) in such a way that Mi is the extreme of Y.sub.i and Y.sub.i+1 to be expected for the determined type of edge, in that a value Ma is formed from the signals of the two other photoreceivers (i+2; i+3) in such a way that Ma is the extreme of Y.sub.i+2 and Y.sub.

Abstract: An arrangement for measuring angles, particularly for use in theodolites employs light electric detectors to carry out physical measurements. An index mark which is used in the measuring operation is arranged together with at least one reading position of a graduated circle in the object plane of an imaging system. The latter images the reading position of the graduated circle on to a first light electric detector and the index mark on to a second light electric detector. When two reading positions are used to obtain the reading value then the first reading position is imaged on to the second reading position which, together with the index mark, lies in the object plane of the imaging system. The common arrangement of the reading position and the index mark in the object plane of the imaging system eliminates any inaccuracies of the optical components and hence, accidental measuring errors. So it is possible to do without a very complicated light electrical evaluation system.