Slides for optical 3D capture of real objects

Abstract

Object holder for the optical 3D detection of real objects, characterized in that a collet 7 or a functionally equivalent clamping device is present, which receives the object 1 either directly, by means of a needle carrier 2 or by means of a functionally equivalent carrier element and is in turn connected to a target mark holder 11 and mark carriers 12, 13 attached thereto in such a way that the target marks 14 attached to the mark carriers ensure a fixed dimensional reference to the object 1 during the object recording.

Description

[0001] The invention relates to an arrangement for mounting real objects, which enables their optical capture from all sides, preferably for the purpose of a complete 3D reconstruction. The objects considered here are, in particular, small biological specimens, such as those of insects, which are fixed to a needle-shaped support.

[0002] Imaging / photogrammetric or triangulation techniques are primarily used for the recording. Other optical techniques are also employed. In these techniques, the object is placed or placed on a slide so that it can be optically captured from different perspectives.

[0003] Most known arrangements, in which the object is placed or laid on a flat horizontal slide for the purpose of 3D reconstruction and driven by a motor, have the disadvantage that the slide obscures at least the surface of the object to be captured during the acquisition process, making it impossible to capture it without changing its position. This significantly complicates not only the acquisition process but also the subsequent data processing.

[0004] Other known devices use a slide made of slender points, allowing for very small footprints and minimal shadowing during image acquisition. However, they can only securely fix sufficiently large and dimensionally stable objects, and handling requires considerable sensitivity.

[0005] Glass plates are also widely used as object slides, but they lead to blurring, discoloration, double reflections and birefringence, and thus to inaccuracies and texture disturbances in the 3D model.

[0006] In order to reduce the algorithmic effort, it is generally common practice to introduce geometrically uniquely coded targets with a known spatial position into the object space and to move and image them together with the object.

[0007] The technical problem underlying the invention is to create a suitable mount for the all-round, distortion-free, and color-neutral optical detection of small objects, typically attached to needle-like supports, which is provided with suitable targets for subsequent 3D reconstruction. This should ensure fast, reliable, and reproducible positioning of such objects with high dimensional accuracy.

[0008] The problem is solved by the invention characterized in the main claim. Advantageous embodiments are specified in the further claims.

[0009] For clarity, the following description and the accompanying drawings refer to the preferred use of the invention for holding macroscopically small biological specimens, e.g., with dimensions between a few millimeters and a few centimeters, without thereby limiting its generality. Likewise, the invention is also suitable for any other type of object that can be mounted in the manner described.

[0010] A needle holder is a tool that is firmly attached to the object and serves to grasp or clamp it. Typical needle holders include pins on which specimens are impaled. However, the objects can also be grasped and clamped without such a tool if their specific shape allows it.

[0011] It is preferably assumed that the subject matter of the invention is used together with a recording device to which it is attached in such a way that, in this configuration, a relative movement can be carried out between the specimen slide and the camera in order to obtain different recording positions and perspectives. Such devices consist, for example, of a rotary drive to which the specimen slide is attached, so that the object is rotated into specific positions within a horizontal plane during recording, and of a vertically arranged semicircular movement path on which the camera is moved to its recording positions at different heights and angles of inclination. Such recording devices have a common center of rotation for the object and camera movement, in which the object to be recorded is to be located.

[0012] The drawings show: Fig. 1 an overall arrangement in accordance with the invention, Fig. 2 the crown 3 of Fig. 1 in enlarged view, Fig. 3 an alternative design of the target mark holder with pyramid-shaped mark carriers, Fig. 4 a group of exemplary target marks in an embodiment according to the invention.

[0013] The position numbers indicate: 1 object 2 needle carriers 3 crowns after Fig. 2 4 telescopic rods 5 clamping ring 6 Quick release plate 7 Collet 8 Retaining ring 9 Locking screw 10th pillar 11 target mark holders 12 upper brand carriers 13 lower brand carriers 14 round target 15 Target sector

[0014] The device according to the invention described below in a preferred embodiment consists accordingly Fig. 1 and Fig. 2 out - a column 10, in the middle of which is located the collet 7 or a functionally comparable three- or multi-jaw chuck and on the outside of which the target mark holder 11 is height-adjustable via a retaining ring 8 and clamped by means of a locking screw 9, - a telescopic rod 4, the column 10 of which is adjustable in height after loosening the clamping ring 5, - a quick-release plate 6, which serves for quick connection to the holding device in which the slide is used.

[0015] The upright position shown is a preferred but not necessary case.

[0016] The collet 7 is designed to be as slim as possible and as shown in Fig. 2 is preferably designed in a conical shape so that it does not obscure the object even when the camera is positioned steeply from below.

[0017] The marker carriers 12 and 13 carry on each of their flat body surfaces a target mark 14 with individual circular coding 15 according to the examples in Fig. 4. To ensure uniqueness, each code appears only once on the entire slide. To prevent distracting reflections, the targets are coated with a very thin, matte layer.

[0018] The marker carriers are firmly connected to the ring-shaped target holder 11 and thus also to the object carrier via the retaining ring 8, so that all dimensional references between the object and the targets remain constant throughout the entire image acquisition. For the geometric shape of the marker carriers, in addition to the Fig. 2 cubes shown also pyramids according to Fig. 3 or other forms may be beneficial.

[0019] In order to cover the object as little as possible during image recording, the target mark holder 11 is as shown in Fig.2 shown as a dimensionally stable basket construction with a thin support ring and thin support struts.

[0020] The following is a functional description of the invention based on its typical handling: Insect specimens are usually mounted on pins for collection and display in entomological display cases. Apart from the puncture site, which results in localized damage to the specimen, this allows for unrestricted viewing from all angles. Experience has shown that the clamping and adhesive forces on the pins are sufficient to safely transmit weight and typical acceleration forces. A similar procedure can be applied to comparable biological or other specimens. Once attached to such pin supports, they should not be removed to prevent further damage or alteration.

[0021] According to the invention, the specimen slide is attached to the mounting device using the quick-action clamping plate 6, and the needle carrier 2 with the specimen 1 mounted on it is clamped into the collet 7. If the specimen itself already has a shape suitable for clamping, it can of course also be clamped directly. The collet enables a universal and fast clamping process for a variable diameter range of the needle carriers used or the specimen. Interchangeable inserts of various sizes and shapes are provided for additional size ranges.

[0022] The collet 7 is then adjusted by adjusting the height of the column 10 using the clamping ring 5 on the telescopic rod 4 so that the object center is at the height of the center of rotation of the holding device. After loosening the locking screw 9, the height of the target mark holder 11 can now also be adjusted so that its ring is also at the height of the center of rotation. The upper mark carriers 12 can then be better captured by the camera when the camera is located above the center of rotation, while the lower mark carriers 13 are more clearly visible when the camera is positioned below the center of rotation.

[0023] Furthermore, the quick-release plate 6 serves to enable the subject matter of the invention to be exchanged quickly and precisely for other provided object carriers on the holding device.

Claims

[1] Object holder for the optical 3D capture of real objects, characterized by that a collet 7 or a functionally equivalent clamping device is present, which receives the object 1 either directly, by means of a needle carrier 2 or by means of a functionally equivalent carrier element and is in turn connected to a target mark holder 11 and mark carriers 12, 13 fastened thereto in such a way that the target marks 14 attached to the mark carriers ensure a fixed dimensional reference to the object 1 during the object recordings. [2] Object holder according to claim 1, characterized by that the collet 7 is connected to a telescopic rod 4 in such a way that the height of the clamped object 1 can be adjusted. [3] Object holder according to claim 1, characterized by that the target mark holder 11 is attached to the telescopic rod 4 by means of a movable retaining ring 8 and is thus adjustable in height. [4] Object holder according to claim 1, characterized bythat it is connected to a quick-release plate 6. [5] Object holder according to claim 1, characterized by that the mark carriers 12 and 13 have a cubic shape. [6] Object holder according to claim 1, characterized by that the mark carriers 12 and 13 have the shape of a truncated pyramid. [7] Object holder according to claim 1, characterized by that the target marks 14 have a circular sector coding 13.

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