DE746035C - Image measuring device for photogrammetric evaluation devices - Google Patents

Description

(RGBl. Π p. 150)

GERMAN EMPIRE

ISSUED JUNE 2, 1944

REICH PATENT OFFICE

PATENT LETTERING

CLASS 42 c GROUP 10

P 78268 IXbJ42c

Robert Zurlinden in La-Tour-de-Peilz, Switzerland,

has been named as the ^ inventor

Photogrammetry G.m.b.H. in Munich image measuring device for photogrammetric evaluation devices

Patented in the German Reich on November 30, 1938 Patent issued December 23, 1043

There are already image measuring devices for phatogrammetric evaluation devices known, in which the image to be measured is fixed, in which, furthermore, the one executing the measuring movement Part of the target device can be displaced in a plane parallel to the image plane is arranged and in which finally attached to this displaceable part by a Projection optics the targeted image point onto a fixed part of the target device is thrown.

In contrast, the invention consists in that the plane of movement of the projection optics Jn such a distance between the Image plane and the fixed part of the target device is arranged that the path, the projection optics during the transition from the aiming of an image point to the aiming of another pixel has to cover a constant fraction of the distance of the targeted pixels below.

The arrangement according to the invention has the advantage of a considerable structural Simplification achieved; it is also achieved that a deflection of the projection beams from their original direction is not required and that · to capture the entire Relatively small movements of the optics in the image area are sufficient. Compared to a known arrangement in which the Optics pivotable about an axis perpendicular to the image plane and closed radially this axis is displaceable, so the advantage is achieved that the mobility of the ' Optics need not correspond to the full dimensions of the image to be measured.

The figure shows an exemplary embodiment of the inventive concept in schematic form Axial section.

In front of the image ^ 4, at the distance b, there is a projection optics O, which projects an image point P onto a screen JT. The latter is located at a distance α from the optics O. The recording is fixed; likewise the screen S, in which there is an index /. The projection optics, however, is in the plane E, which is parallel to

Image or recording plane A runs, movable; The projection optics are driven in a manner known per se by a compound slide system, the innermost slide of which is the carrier of the projection optics and which is moved by a spatial guide. Each point of the image A can therefore be projected onto the screen S by the projection optics 0, depending on its setting. In

In the figure, two further positions of the projection optics 0 when projecting the points P ¹ and P ^{2 are} shown in dashed lines.

The stroke is reduced in the ratio a: ( b + o) , while the image is only reduced in the ratio a: b. If you take z. B. a = b, half the stroke is obtained with the same image size on the screen as on the recording.

The construction of the lens 0 does not cause any difficulties; because you can choose the optical bench so long that the required opening angle is arbitrarily small, z. B. 30 ⁰ . A ground glass screen can be used as a screen or an opaque white screen which, however, does not allow frontal observation. Finally, there is also the possibility of subjectively viewing the image drawn in S. This is supposed to

^{c means} that the designed real image is not captured on a screen, but viewed as in a telescope, but with a steerable eyepiece. In other words, the extensions of the rays that create the designed image are directed back into the observer's eye by prisms and lenses instead of creating them on a diffusely reflecting surface. An optical cardan joint is expediently used, of which the collective lens represents a special case.

Claims (1)

Claim: Image measuring device for photogrammetric evaluation devices, in which the image to be measured is fixed, in which further the part of the target device executing the measurement movement is arranged displaceably in a plane parallel to the image plane and in which the targeted image point onto a fixed part of the Target device is thrown, characterized in that the plane of movement (E) of the projection optics (O) is arranged at such a distance between the image plane (A) and the fixed part (JT) of the target device that the path taken by the projection optics when passing from the aiming of an image point has to cover the aiming of another image point, is a constant fraction of the distance between the targeted image points. To distinguish the subject of the application from the state of the art, the granting procedure the following publications have been considered: German patents .... Xr. 431 003. 644 864. For this purpose ι sheet of drawings Berlin, printed in the Reichsdruckerei.