DE2723324B2 - Device for fixing measurement images on an image carrier in a photogrammetric device - Google Patents

Description

- A clamping lever (6), which by a clamping screw (4) on a first, on the frame (1) of the Bearing (7) arranged on the image carrier and on a second bearing (8) that fixes the measurement image is supported;

- A support point (5) which rests on a flat reference surface (12) fixed to the device, the distance (e) between the support point (5) and the first bearing (7) and the distance (Q between the first and second bearing ( 7,8) 2> have a ratio given by the equation

e η - 1

is defined, where n 'is the refractive index of the material of the layer carrier (9).

2. Device according to claim 1, characterized y marked, characterized in that the cover plates point is arranged (5) on the clamping screw (4).

3. Apparatus according to claim 1, characterized in that the support point (5) on the Clamping lever (6) is arranged.

4. Device according to one of the preceding claims, characterized in that the ratio between the distance (e) from the support point (5) to the first bearing (7) and the distance (f) from the first to the second bearing (7,8) is constant . 4 ^r >

5. Device according to one of the preceding claims, characterized in that the ratio between the distance (e) from the support point (5) to the first bearing (7) and the distance (f) from the first to the second bearing (7,8) is variable , v> so that the refractive indices of different materials are taken into account.

The invention relates to a device for securing measurement images on an image carrier in one photogrammetric device, the image carrier being reversible and the thickness of the transparent measuring m> plates is variable.

In the known photogrammetric devices, photographic recordings on plates or on films are used as the measurement images as a starting point for the measurement evaluation. h ^r >

The plane of the measurement image is at a constant distance from the lens which scans the measurement image. With different Thickness of the substrate, which is located between the measurement image and the scanning optics, the optical path length changes, so that the scanning optics must always be refocused. The operator is very often not able to adjust the scanning optics free of image parallax. aside from that Focusable scanning optics are expensive and complicated to manufacture.

The invention aims to eliminate this disadvantage. This is done in principle by the fact that at different substrate thicknesses the optical path length is kept constant. This can result in focusable optics can be dispensed with.

The invention is characterized in that to keep the optical path length constant between the Measurement image plane and the lens scanning the measurement image jamming at three points of the Image carrier is provided, the required clamping device containing the following components:

- A clamping lever, which by a clamping screw on a first, on the frame of the picture carrier arranged bearing and is supported on a second bearing which fixes the measurement image;

- a support point that rests on a flat reference surface that is fixed to the device, the distance e between the support point and the first bearing and the distance / between the first and second layer: have a relationship that by the equation

cn ' - I

is defined, where n 'is the refractive index of the material of the layer support.

Embodiments of the invention are explained in more detail with reference to the drawing. Show it

Fig. 1, 2 and 3 different design variants the invention.

According to FIG. 1, the clamping device is arranged at one point on the frame 1 of the image carrier. This clamping device consists of the first bearing 7, the clamping lever 6, which is mounted in the first and second bearings 7, 8. The clamping lever is pressed against the two bearings 7, 8 by the clamping screw 4. The image carrier is arranged with its lower support point 2 on the flat reference surface 12 which is fixed to the device. In reality, three such support points 2 are provided for the entire * image carrier. The image carrier contains a transparent image carrier plate 3, which in the embodiment of FIG. 1 is provided with line marks on the surface 10. The scanning optics 11 is represented by a lens. These scanning optics are firmly focused on the flat image carrier surface 10. The scanning lens 11 is arranged at a distance h + a + k from the surface 10 of the transparent image carrier plate 3. If the entire image carrier is now turned for any reason, the support point 5 comes to rest on the flat reference surface 12 which is fixed to the device. In this case, the distance between the scanning optics 11 and the surface 10 of the transparent image carrier plate 3 is h + b. Here is the condition

satisfies that b = a +. Here, π is the refractive index

the transparent image carrier plate 3. This shows that in both cases the optical path length between the scanning optics 11 and the surface 10 of the

transparent image carrier 3 is the same as the scanning optics 11 therefore no longer has to be focused differently for the one case than for the second case after the Turn of the image carrier.

In FIG. 2, a transparent layer carrier 9 is arranged on the surface 10 of the transparent image carrier plate 3. The photographic layer of the carrier 9 is in contact with the surface 10 of the image carrier plate 3. The clamping screw 4 is tightened. In the exemplary embodiment in FIG. 2, the support point 5 rests on the flat reference surface 12 that is fixed to the device. The distance between the scanning optics 11 and the surface 10 of the transparent image carrier plate 3 is in this case h + c + d. The thickness t / of the layer carrier 9 can be of any desired size. For the special case d = 0 , the embodiment of FIG. 1 has already been described. In the exemplary embodiment of FIG. 2, the optical path length is constant, so that the scanning optics 11 do not have to be focused for different thicknesses d. This is due to the fact that the ratio of the lever lengths e and / of the clamping lever: 6 is defined by the following equation:

In this equation, n ′ is the refractive index of the material of the layer support 9.

Another embodiment is shown in FIG shown, which differs from the previous embodiments in that the support point 5 is attached to the clamping lever 6. The other components have the same reference numbers as in Embodiments of FIG. 1 and 2. They are therefore used in connection with FIG. 3 no longer any closer described.

Claims (1)

15th 20th Patent claims: I. Device for attaching measurement images on an image carrier in a photogrammetric Device in which the image carrier is reversible and the thickness of the transparent measuring plates is variable, characterized in that to keep the optical path length constant between the Measurement image plane (10) and the measurement image from scanning lens (11) a jam on three Points of the image carrier is provided, the required clamping device following components contains: