RU2751986C1 - Space code for recording information inside a transparent object with the ability to read from any direction - Google Patents

Abstract

FIELD: computing.

SUBSTANCE: invention relates to computing. A mark made inside a transparent object, which can be read from any direction and carries recorded information encoded in the mutual arrangement of the mark elements, is characterized by the fact that it is a 3D mark made by treating a transparent object with working optical radiation with the supply of working ultrashort radiation pulses, wherein the mark elements are made along three non-coinciding segments lying in the same plane, where the angle between the randomly chosen first segment and the second segment, counted from the first segment clockwise, lies in the range from 0 to 180 degrees, the angle between the first segment and the third segment, counted from the first segment clockwise, lies in the range from 180 to 360 degrees, the continuation of the third segment beyond the point of intersection with any of the first or second segments lies in the angular sector between the first and second segments, wherein each of the sequences of mark elements along each of the segments is sufficient for complete decoding of the recorded information.

EFFECT: invention ensures mark reading from any direction.

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Description

The present invention relates to optically readable codes containing bit information, recorded in the volume of transparent objects, for example, precious stones, including diamonds and diamonds.

There are various types of machine-readable codes used for recording information, marking and identifying objects, including one-dimensional codes (linear, barcodes), such as Code 39, Code 93, Code 128, Codabar, EAN, ITF, MSI, UPC, Pharmacode, as well as 2D ones like Azteccode, MaxiCode, ShotCode, Ezcode, MicroQRcode, QR Code, DataMatrix, MicroPDF417, PDF417, Codablock-F, BeeTagg.

All of these codes are intended to be applied to the surface of objects, which makes it difficult to apply them in the volume of transparent objects, for example, precious stones, where it is possible to read from different directions (angles). The most technologically advanced of these codes, when reading, admit only rotation by an arbitrary angle relative to the axis perpendicular to the plane of the code, mirror reflection, small deviations of the optical axis of the detector from the perpendicular to the plane of the code. However, in the general case, this is not enough for a full-fledged volumetric marking with the ability to read from an arbitrary direction.

One-dimensional codes (linear, barcodes) can theoretically be read from an arbitrary direction perpendicular to the code axis (the axis along which the code sequence is built, this axis lies in the plane of the code and is perpendicular to the strokes). Thus, when read, they theoretically allow rotation around the specified axis of the code, although they were not originally intended for this. However, it is obvious that when reading from directions close to the indicated axis of the code, the strokes merge with each other and the code cannot be read.

Two-dimensional codes cannot be read from directions close to the plane of the code, because in this case, the code elements are merged with each other.

This prevents the use of these codes for volumetric marking of objects, including precious stones, although volumetric marking is much preferable to surface marking, since the facets of the surface of cut gemstones are oriented in different directions, have very small dimensions and may be inaccessible for marking and detection if a gem inserted into the frame. In addition, surface marks can be destroyed by mechanical and chemical treatments such as polishing, etching. Therefore, it is preferable, especially for expensive stones, to apply a code (mark) under the surface layer in the volume of the stone without changing the outer surface. The creation of two and three-dimensional images in the volume of transparent objects is a promising technology both for information storage purposes and for use in optical technology.

With regard to the marking of precious stones, marks are known that are opaque to optical radiation, created due to the development of a volume of damaged diamond microstructures surrounding natural impurities, or due to the introduction of impurity ions, for example, phosphorus, into the diamond structure, creating detectable defect regions.

There is a known label obtained in diamonds by the method (RU 2357870 C1; WO 2006/092035; US 7284396 B1), and a system for laser marking diamonds, in which it is proposed to engrave authentication codes in the form of labels in the volume of a diamond created by exposure to a controlled sequence of laser pulses in femtosecond range (from a few femtoseconds to 200 picoseconds) with an energy in each laser pulse above the damage threshold of a diamond crystal. In this case, damage was initiated by defects or impurities (nitrogen, hydrogen, sulfur, phosphorus, nickel, boron and others) present in the volume of the material, where the recording laser beam reaches its smallest transverse size and maximum intensity. In this case, the radiation is focused in the volume of the diamond, which leads to the formation of growing defect microstructures, which are opaque to optical radiation, in the places of random distribution of the indicated defects. The marks consist of non-diamond forms of carbon and are formed from several microscopic dot marks with a size of several micrometers (2-5 microns) with a distance between adjacent dot marks of about 50 microns, and the array of dot marks has an area of 250 × 250 microns, and require the use of a special readout for detection. devices. However, at the same time:

- the relative position of points in the label can only determine a certain geometric set of them, for example, the vertices of a virtual triangle based on three points, but not the image of the triangle itself;

- authentication of a stone by the mutual spatial arrangement of point marks in it, created in a rough diamond, cannot be reliable after its cutting, when the position of a part of point marks relative to the edges and among themselves can be changed;

- due to the stochastic location of natural defects in diamond, the creation of tags that have a semantic load, i.e. carrying information is impossible;

- the mark formed in this way may be impossible to detect from another arbitrary direction after cutting the stone, because in some projections, label elements will overlap.

- this method is a way of creating mark elements in a stone, but does not say anything about their mutual arrangement, does not define a specific type of mark - a code that could provide reliable recognition from arbitrary directions.

Known mark obtained in transparent materials by the method (SU 329899 A), in which the latent image was created in transparent diamond plates with a size of 50 × 50 mm and a thickness of 300 μm. A metal mask 50 μm thick was applied to the surface of such a sample, in which the required image was etched by photolithography, after which the sample was bombarded with phosphorus ions. In this case, in addition to the color surface image, an internal image also appeared, and the plates were subjected to subsequent thermal annealing, as a result of which the color image disappeared. The formed image was thermally stable up to 1200 ° C, not destroyed by light, electric and magnetic fields. However, due to the high hardness of the lattice, the depth of penetration of phosphorus ions into the diamond and the depth of placement of the internal image cannot be large; therefore, a thin surface layer containing the mark can be removed by polishing or etching, and an increase in the amount of phosphorus impurities in the diamond and the presence of a visually distinguishable image affects its commercial value.

In addition, such a mark cannot be detected from an arbitrary direction, but only from directions close to perpendicular to the surface.

There is a known label obtained during the synthesis of diamonds by the method of chemical deposition from the gas (vapor) phase by the method (RU 2382122 C1), in which, during the synthesis, at least one doping additive of a chemical element, for example, nitrogen, is introduced into a layer of synthetic diamond material in the form of defective centers emitting radiation with a characteristic wavelength upon excitation. In this case, the doping additive forms a production mark or identification mark in the form of a layer in which, upon appropriate optical excitation, fluorescence appears with peaks at 575 nm and / or 637 nm, which practically instantly disappears when the excitation source is switched off. Recognition (detection) of a production mark or identification mark can be carried out, for example, visually or using special optical instruments. In the general case, it is preferable to recognize the observer directly with the naked eye, since this method allows obtaining spatial information, in particular binocular or depth information.

However, it is well known that the capture of impurities changes depending on the growth sector involved in this process, for example, the {111} growth sector often captures a higher concentration of impurities than the {100} growth sector, which distorts the generated label. In addition, in this method of marking synthetic grown diamonds, additional impurities and defects are introduced into the diamond, which does not improve the quality of the diamond.

In addition, this mark cannot be used to mark natural diamonds or artificial diamonds grown using other technologies.

Since the specified label is a set of layers, it cannot be read from any direction, for example, perpendicular to the specified layers.

There is a known label created using a method for creating an optically permeable image inside a diamond (RU2465377), which consists in creating an image inside a diamond consisting of a given set of optically permeable micron or submicron size elements, which are elongated spindle-shaped clusters of NV centers that fluoresce when exciting irradiation. Images created in diamond crystals from clusters of N-V centers are invisible to the naked eye, in magnifying glasses, as well as any optical and electron microscopes. These clusters (label elements) are created by focused laser radiation, which is introduced into the crystal through a flat polished window.

However, a mark created by this method in an uncut stone, for example, through one polished optical window, will find itself in a faceted stone (after cutting) in a place unknown in advance. In addition, it will have an arbitrary orientation relative to the site through which its detection and recognition will be carried out.

At the same time, this method is a method of creating mark elements in a stone, but does not say anything about their mutual arrangement, does not determine a specific type of mark - a code that could provide reliable recognition from arbitrary directions.

The technical problem of the proposed solution consists in creating a label (code) for recording inside the volume of a transparent object, for reliable reading and recognition of which it is sufficient to observe it from one arbitrary direction (angle).

The technical result is to provide the ability to read the label (code) from any arbitrary direction.

The specified technical result is achieved in a mark applied in the volume of a transparent object, with the ability to read from any arbitrary direction, carrying recorded information encoded in the relative position of the mark elements, characterized in that it is a volumetric mark made by processing a transparent object with working optical radiation with by supplying working ultrashort radiation pulses, while the label elements are made along three non-coinciding segments lying in the same plane, where the angle between an arbitrarily chosen first segment and the second segment, counted from the first segment clockwise, lies in the range from 0 to 180 degrees, the angle between the first segment and the third segment, counted from the first segment clockwise, lies in the range from 180 to 360 degrees, the continuation of the third segment beyond the point of intersection with any of the first or second segments lies in the angular sector between the first and second segments , at however, each of the sequences of mark elements along each of the segments is sufficient for complete decoding of the recorded information.

An additional feature is that the angle between any two segments is at least 10 degrees in modulus,

An additional feature is that some of the elements of the label (code) located along any of the segments are displaced in the direction perpendicular to the corresponding segment.

An additional feature is that the label (code) contains additional elements located in the specified plane, but not lying on the specified segments.

An additional feature is that the sequences of mark (code) elements located along each of the segments, carrying information sufficient for complete decoding of the recorded information, are not identical.

An additional feature is that the recorded information is encoded with a redundancy of more than 4/3, sufficient to restore the recorded information when reading 1/3 of the mark (code), and each of the sequences of mark (code) elements located along each of the segments carries 1/3 redundantly encoded information.

An additional feature is that the location of the mark (code) inside the specified transparent object is chosen so that the distance to another nearest mark (code) placed in the volume of the same transparent object is greater than the depth of field when reading the mark (code).

The essence of the claimed invention lies in the implementation of the elements of the label (code) along three directions so that when observing the label (code) from any angle, it is possible to distinguish elements located along at least one of the indicated directions, and this will be sufficient for complete decoding, and essential to achieve the specified technical result is precisely the choice of angles between the indicated three directions and the redundancy of the information contained in the label (code).

The claimed invention is illustrated by Figures 1 to 9, where:

Fig. 1 - elements of the mark (code), located along three non-coinciding segments.

Fig. 2 - single element of the label (pixel)

Fig. 3 - the simplest bit sequence

Fig. 4 is an example of a mark (code), in which the angles between all three directions are equal and equal to 120 degrees each.

Fig. 5 is an example of execution of a mark (code) in which condition 1 is not fulfilled.

Fig. 6 is an example of execution of a mark (code), in which condition 2 is not fulfilled.

Fig. 7 is an example of execution of a mark (code), in which condition 3 is not fulfilled.

Fig. 8 is an example of execution of a mark (code), in which condition 4 is not fulfilled.

Fig. 9 - combining an arbitrary number of marks (codes) into a periodic structure.

The elements of the label (code) are located along three non-coinciding segments 1,2,3 (Fig. 1) lying in the same XY plane, and the location of the segments simultaneously satisfies the following conditions:

1.if an arbitrarily selected segment 1 is taken as the origin of angular coordinates, then the angle α between segment 1 and segment 2, counted from segment 1 clockwise, lies in the range from 10 to 180 degrees,

2.the angle β between segment 1 and segment 3, counted from segment 1 clockwise, lies in the range from 180 to 350 degrees,

3.the continuation of 4 of the segment 3 beyond the point of intersection of the straight lines lies in the corner sector between the segments 1 and 2,

4. each of the sequences of mark (code) elements located along each of the segments 1, 2, 3, carries information sufficient for complete decoding of the recorded information encoded in the mark (code).

In this case, an additional condition is that the angle between any two segments is at least 10 degrees in modulus.

A unit label element (pixel) 5 (Fig. 2), in the general case, has an elongated spindle-shaped shape. In a particular case, it can have a shape close to a sphere, but this does not change the principle of constructing a label.

The unit elements are lined up along each of the segments 1, 2, and 3, the information is encoded in the mutual arrangement of the elements of the label (code), for example, in the form of a bit sequence 6 (Fig. 3), where the unit element of the label (code) corresponds to one, and his absence at a given position is zero. Figure 3 shows the simplest bit sequence, consisting of 30 ones, corresponds to the number 2 ^ 30-1.

An example of a label (code) is shown in Fig. 4. The simplest case is depicted in which the angles between all three directions are equal and equal to 120 degrees each. It is easy to see that such a choice of angles satisfies the conditions listed above. In this example, along each direction, the same elementary bit sequences are applied, consisting of ones (Fig. 3), however, in the general case, these bit sequences are not necessarily the same. This configuration of the mark (code) allows you to decode (read) it from an arbitrary angle A, B, C, or D, and in each case, sections 6,7, 8, or 9, respectively, can be decoded.

A similar mark (code) is applied by processing a transparent object with working optical radiation focused in the focal region, with the supply of working ultrashort radiation pulses, ensuring the formation of a single element of the mark (code) in the specified focal region, and repeating these steps to form a bit sequence carrying the encoded information about the object. Also, applying a mark (code) is possible in a manner similar to this one, i.e. from one direction using focused laser radiation with an optical axis perpendicular to the XY plane.

On the example of Fig. 4, it is obvious that for a given arrangement of branches, at least one of them can be recognized from any angle, including from any intermediate angles located between A, B, C, and D.

Let us show that if the arrangement of the branches does not satisfy at least one of the above conditions "1" - "4", then there are angles from which recognition is impossible.

Let the condition "1" be not satisfied, i.e. the angle α between the segment 1 and the segment 2, counted from the segment 1 clockwise, is 200 degrees, while the conditions "2" - "5" are fulfilled, FIG. 5. It can be seen that from the perspective E none of the branches can be fully read.

Let the condition "2" be not satisfied, i.e. the angle β between the segment 1 and the segment 3, counted from the segment 1 clockwise, is 160 degrees (Fig. 6). It can be seen that none of the branches can be fully read from the angle F.

Let the condition "3" not be fulfilled, i.e. continuation 4 of segment 3 beyond the point of intersection of straight lines lies outside the corner sector between segments 1 and 2, while other conditions are fulfilled (Fig. 7). It can be seen that none of the branches can be fully read from the perspective G.

Let the condition "4" be not satisfied, i.e. at least one of the sequences of mark (code) elements located along the segments 1, 2, 3 does not contain information sufficient for complete decoding of the recorded information encoded in the mark (code). Obviously, in this case, there is a direction (angle) from which only a branch that does not carry the entire recorded information can be recognized, thus the recorded information cannot be completely decoded.

Suppose that the first additional condition is not satisfied, i.e. the angle between segments, for example 1 and 2, is 5 degrees, while other conditions are met (Fig. 8). It can be seen that the label (code) cannot be read from the perspective H.

Considering the above examples, it is easy to see that the minimum angle between the branches is determined by the transverse dimension of the unit mark (code) element, as well as the distance between adjacent elements, and theoretically can be less than 10 degrees (as shown, if the first additional condition is not met). However, in practice, the recognition of marks (codes) with angles between branches (segments) less than 10 degrees is difficult to implement due to the fact that the segments in most of them are superimposed on one another (Fig. 8).

In addition, individual elements of the mark (code) can be offset relative to the main plane of the mark (code) XY. It is easy to see that such an offset does not interfere with reading from the above angles.

It is essential that for complete decoding of the recorded information contained in the label (code), it is sufficient to decode at least one of the three sequences (branches) located along the segments 1, 2, and 3. In this case, the indicated sequences themselves do not have to be the same. From the examples below, it is clear that the identity of these sequences is not necessary for the implementation of the label (code).

For example, in one of the implementations of the label (code), the complete information of the label (code) is subjected to error-correcting Reed-Solomon coding with redundancy of more than 4/3, sufficient to restore the complete information when reading only 1/3 of the label (code). The received encoded information is written sequentially in three branches. In this case, the branches are not identical, however, to decode all the recorded information, it is sufficient to read any one of them.

In an alternative implementation of the label (code), each of the three indicated sequences (branches) carries the complete information of the label (code), and is essentially a collection of the label (code) that carries the same information, but encoded using different algorithms (using different keys). In this case, the branches carry the same information, but are not identical.

In an alternative implementation of the label (code), these sequences are identical.

In this case, for practical applications, the most preferable is the implementation using Reed-Solomon coding, since it allows you to restore all encoded information in case of loss of any part of the tag (code), in the amount not exceeding 2/3 of the entire tag (code).

It is also possible to combine an arbitrary number of these marks into a periodic or quasiperiodic structure (Fig. 9), as well as to create such honeycomb structures in several layers in the volume of a transparent object. Then, when dividing (cutting) the marked object into several parts, each of them will contain a code (label), read from any angle.

In this case, the distance between similar fragments of the structure 10 and 11 (period T1 in Fig. 9) is selected so that it is greater than the depth of field (depth of field, depth of field), which is provided by the tag (code) reader. If, upon detection from a certain angle, the indicated fragments 10 and 11 appear on the same optical axis (one below the other), they do not merge in the image, since cannot simultaneously fall into the focus of the optical system.

To simplify the search for the label (code) inside the volume of the object, additional markers 12 (Fig. 9) located in the plane of the label (code) can be used.

Individual elements of the spatial mark (code) can be displaced in the direction perpendicular to the corresponding segment. This allows additional information to be encoded using the same number of tag (code) elements.

Claims (7)

1. A mark made in the volume of a transparent object, with the ability to read from any arbitrary direction, carrying recorded information encoded in the relative position of the mark elements, characterized in that it is a volumetric mark made by processing a transparent object with working optical radiation with the supply of working ultrashort radiation pulses, while the label elements are made along three non-coincident segments lying in the same plane, where the angle between an arbitrarily selected first segment and the second segment, counted from the first segment clockwise, lies in the range from 0 to 180 degrees, the angle between the first segment and the third segment, counted from the first segment clockwise, lies in the range from 180 to 360 degrees, the continuation of the third segment beyond the point of intersection with any of the first or second segments lies in the angular sector between the first and second segment, with each from sequences of elements Marks along each of the segments are sufficient for complete decoding of the recorded information. 2. A label according to claim 1, characterized in that the angle between any two segments is at least 10 degrees in modulus. 3. A label according to claim 1 or 2, characterized in that part of the label elements located along any of the segments is displaced in a direction perpendicular to the corresponding segment. 4. A label according to claim 1, or 2, or 3, characterized in that it contains additional elements located in the specified plane, but not lying on the specified segments. 5. A tag according to claim 1, or 2, or 3, or 4, characterized in that the sequences of tag elements located along each of the segments, carrying information sufficient for complete decoding of the recorded information, are not identical. 6. The label according to claim 1, or 2, or 3, or 4, or 5, characterized in that the recorded information is encoded with a redundancy of more than 4/3, sufficient to restore the recorded information when reading 1/3 of the code, and each of the sequences elements of the label, located along each of the segments, carries 1/3 of the redundantly encoded information. 7. A label for recording information in the volume of a transparent object according to claim 1, or 2, or 3, or 4, or 5, or 6, characterized in that its location inside the specified transparent object is chosen so that the distance to another nearest label placed in the volume of the same transparent object had more depth of field when reading the mark.

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