BE1017990A3 - Method for making engraving from digital picture, involves staple-converting picture with variable color intensity in line pattern, determining smooth contours of lines from pattern, and performing milling of zones within contours - Google Patents

Abstract

The method involves staple-converting a digital picture (1) with variable color intensity in a line pattern (2). Smooth contours (3) of lines are determined from the line pattern, where thickness of the lines is proportional to intensity of the picture with variable color intensity. Milling of zones (4) within the contours is performed by a milling machine, where colors of engraving are depend on materials selected for the zones.

Description

METHOD FOR MAKING AN ENGRAVING AND ENGRAVING MADE ACCORDING TO SUCH A METHOD

The invention relates to a method for making an engraving on the basis of an illustration with variable color intensity. This invention also relates to an engraving made by such a method.

There are already several methods for making engravings based on illustrations with variable color intensity.

In the first place engravings can be made manually. Here, an engraver will cut out an image with the aid of a burin in, for example, a metal base. For example, with a copper engraving in a copper plate a line pattern is cut out. Analogously, a steel engraving can be obtained by cutting a line pattern from sheet steel. Such copper or steel engravings were often used as a printing plate. Steel engravings often served to print stamps and banknotes. It is also known to provide jewelery and art objects with inscriptions. When making such engravings, an engraver is often inspired by illustrations with a variable color intensity.

However, it takes a great deal of practice for a person skilled in the art to be able to convert an illustration with a variable color intensity into an engravable line pattern that produces a recognizable image in comparison with the illustration. This manual engraving based on an illustration with variable color intensity is also an extremely labor-intensive method of converting a sketch or drawing into an engraving.

Laser engraving was used to automate the making of an engraving based on an illustration with variable color intensity. With this technique, dots from a dot pattern are burned into a substrate with a laser beam. This substrate can, for example, consist of several layers, whereby, for example, the top layer is burned away in these dots. In addition, the substrate can for instance be made of a plastic, which discolours into these dots when the laser beam is burned in. The dot pattern can for instance be derived by software from an illustration with variable color intensity, wherein a laser machine is then controlled by software to burn this dot pattern in the aforementioned substrate.

However, this laser engraving requires expensive laser equipment. Moreover, it is not self-evident to obtain a recognizable image in comparison with the illustration. The contrast and recognisability of the result of this laser engraving is, in fact, strongly dependent on the material. The recognisability of the result is often complicated by the fact that the engraving depth is rather limited and depends on the interaction between the laser beam and the chosen substrate. Chemical additives often have to be added to improve the recognisability of the result.

The object of this invention is to provide a method for making an engraving based on an illustration with variable color intensity, which does not have the above-mentioned disadvantages.

This object of the invention is achieved by providing a method for making an engraving based on an illustration with variable color intensity, said method comprising the following steps: - Step 1 converting the illustration with variable color intensity into a line pattern ; - Step 2 determining smooth contours of the lines from the line pattern; - Step 3 using a milling machine to mill from a surface the zones that lie within these contours or the zones that lie outside these contours to arrive at the engraving.

This method is much less labor-intensive than the conventional classical engraving methods that require manual work.

With this method, the contrast and recognisability of an image obtained is also much less material dependent than with laser engraving. This is because engraving depth is not so limited with milling as with laser engraving. Because this engraving depth is not so limited, images with larger contrasts can also be obtained than with laser engraving. A greater variety of materials such as substrate can also be used to achieve a recognizable result.

To obtain an engraving via milling, one could in principle also mill points such as with laser engraving. However, this is practically unworkable because it takes a very long time and the advantage of saving time is lost due to reduced labor intensity. However, by converting the variable color intensity illustration according to this method into easily millable zones, a recognizable image can be obtained in a particularly advantageous manner with the aid of milling.

In a preferred method according to the present invention, the line pattern comprises, or the line pattern is completely composed of, one or more sets of substantially parallel lines.

Parallel lines provide guidance for converting an illustration with variable color intensity into millable zones. They also ensure that the engraving can be milled even faster. Even when these lines have a variable thickness and are interrupted here and there, because their thickness becomes equal to 0, such an engraving can still be milled particularly quickly.

For example, the lines of a particularly preferred method according to the present invention may have a variable thickness, the thickness of a line at each point of this line being a function of the color intensity of the illustration at that point. Here, the thickness of a line at any point in a specific method can be proportional to the color intensity of the variable color intensity illustration.

Preferably, the spacing between the lines of a set of substantially parallel lines according to the present invention is equal.

Even more preferentially, the lines then have a variable thickness, the thickness of a line at each point being at least 0 and at most the spacing between two adjacent parallel lines.

In a most preferred method according to the present invention, the thickness of a line at a point is then 0 when the color intensity of the variable color intensity illustration at this point is a first extremum of this variable color intensity and the thickness of a line at a point is the spacing between two adjacent parallel lines when the color intensity of the variable color intensity illustration at this point is a second extremum of this variable color intensity.

With such a method, an illustration with variable color intensity can be converted into a line pattern in a particularly easily reproducible manner. Moreover, this line pattern will always lend itself particularly well to determining zones within or outside of which a milling machine must be milled in order to arrive at an engraving with a recognizable image compared to the illustration. With a smaller distance between parallel lines, a recognizable image with a photo-realistic effect can be obtained in this way. Through optical illusion, an observer will no longer perceive such lines as lines, but as an image with variable color intensity. With black and white lines, an observer will have the illusion of seeing gray levels. With a greater distance between these parallel lines, a more abstracted form of the illustration is obtained, whereby an image can nevertheless be particularly well recognizable.

Preferably, the lines of a set of substantially parallel lines according to the present invention are angled with respect to the horizontal direction of the illustration. This angle can hereby be chosen judiciously in function of the illustration to be processed and its recognizability. Such an angle can, for example, enhance or weaken the dynamism of an image. With an image of running animals, this angle can be selected, for example, according to the direction of movement of these animals, whereby the movement is enhanced. Analogously, for example, on the basis of an image of a sea, with the aid of previously horizontal lines you can support the calm of this sea, while lines at a certain angle can support the turbulence of this sea.

In a further specific method for making an engraving on the basis of a variable color intensity illustration according to the present invention, step 1 comprises the following sub-steps: - Step 1 a. Converting a variable color intensity illustration into a greyscale illustration, wherein the intensity of the gray value at each point is proportional to the color intensity of the variable color intensity illustration at that point; b. converting the grayscale illustration into a line pattern.

This specific method is especially recommended when the variable color intensity illustration does not consist of gray values and when, when converting this illustration to a line pattern, the function is between the color intensity at a certain point and the line thickness that is assumed for a line which runs through that point is considerably simplified with a transformation from a function of color intensity to a function of gray values.

Step 1 and / or step 2 according to the present invention are preferably carried out using software. In addition, step 3 is preferably carried out with a CNC-controlled milling machine.

In this way the method according to the invention can be fully automated, whereby a highly reproducible and recognizable engraving is obtained in an extremely smooth manner.

In such an at least partially automated method, the various steps according to the present invention are preferably carried out in the following specific manner: - Step 1 the illustration with variable color intensity is converted into the line pattern by means of an image processing program; - Step 2 the smooth contours of the lines from the line pattern are determined with the aid of a CAM (Computer Aided Manufacturing) program;

- Step 3 The CNC controlled milling machine is using the CAM

program from step 2 controlled.

In particular, the variable color intensity illustration in a method according to the present invention is a standard digital photograph.

The substrate from which the said zones are milled in order to arrive at the engraving, preferably comprises a first layer of a first color and a second layer of a second color. In a specific case, this second layer can be a cover layer that is applied to the first layer. The choice of this substrate is further discussed in the detailed description below.

The object of this invention is furthermore also achieved with the aid of an engraving made with the aid of a method according to the present invention.

This invention will now be further elucidated on the basis of the following detailed description of a preferred embodiment of a method for making an engraving on the basis of an illustration with variable color intensity according to the present invention. The purpose of this description is only to provide clarifying examples and to indicate further advantages and details of this embodiment, and thus can in no way be interpreted as a limitation of the scope of the invention or of the patent rights claimed in the claims.

In this detailed description reference is made to the accompanying drawings by reference numerals, Figure 1 schematically showing the various steps of this preferred method according to the invention; Figures 2 to 5 show some line patterns obtained from the same illustration with variable color intensity, according to step 1 of the preferred method, with different setting parameters in this step 1 of this preferred method; Figure 6 shows the smooth contours of the line pattern of Figure 2, which are determined with step 2 of this preferred method; Figure 7 shows the zones within the smooth contours of Figure 6 in black; figure 8 the zones outside the smooth contours of figure 6 are shown in black.

Figure 1 shows the various steps for making an engraving on the basis of an illustration (1) with variable color intensity according to the specific preferred embodiment of the present invention described herein.

In the first step, an illustration (1) with variable color intensity is converted into a line pattern (2). If this illustration (1) does not consist of gray values, according to this embodiment it is first converted into a gray value illustration (1), the intensity of the gray value at each point being proportional to the color intensity of the variable color intensity illustration (1) at that point.

According to this preferred embodiment, the line pattern (2) which is further formed from the gray-value illustration (1) during step 1 is made up of one or more sets of substantially parallel lines (2a, 2b).

For the sake of clarity, the obtained lines (2a, 2b) are in each case black parallel lines (2a, 2b) on a white background. However, the color of these lines (2a, 2b) has no importance for this method.

These lines (2a, 2b) have a variable thickness (d), the thickness (d) of a line (2a, 2b) in each point of this line (2a, 2b) being a function of the gray value of the illustration (1) ) at that point. This thickness (d) is furthermore at each point of the line (2a, 2b) a minimum of 0 and a maximum of the distance (s) between two adjacent parallel lines (2a, 2b). The lines (2a, 2b) of a set of substantially parallel lines (2a, 2b) here have an equal spacing (s). In this embodiment, the thickness (d) of a line (2a, 2b) at a point equal to 0 is taken if the gray value of the illustration (1) at this point is equal to white. The thickness (d) of a line (2a, 2b) is taken at a point equal to the distance (s) between two adjacent parallel lines (2a, 2b) if the gray value of the illustration (1) in this point is equal to black. The lines (2a, 2b) of a set of substantially parallel lines (2a, 2b) are furthermore at an angle (a) with respect to the horizontal direction (H) of the illustration (1).

In this first step of this preferred method according to the present invention, the illustration (1) with gray values is converted into the line pattern (2) with the aid of an image processing program. A digital photo is used as illustration (1) with variable color intensity and possibly converted into an illustration (1) with gray values. To convert this grayscale illustration (1) into a line pattern (2), various setting parameters can be set in this image processing program. A first setting parameter is the number of sets of essentially parallel lines (2a, 2b) from which this line pattern (2) must be constructed. A second setting parameter is the spacing (s) for each set of substantially parallel lines (2a, 2b). A third setting parameter is the angle (a) at which a set of substantially parallel lines (2a, 2b) with respect to the horizontal direction (H) of the illustration (1) are placed. This intermediate distance (s) and this angle (a) can be taken differently for different sets of essentially parallel lines (2a, 2b).

Different line patterns (2) obtained with this image processing program on the basis of this first step on the basis of an illustration (1) with variable color intensity are shown in Figure 2. The illustration (1) with variable color intensity was not shown here. This illustration (1) is a digital photo of a surfer at sea.

To arrive at the line pattern (2) from Figure 2, one set of substantially parallel lines (2a) was selected. The distance (s) for this set of essentially parallel lines (2a) was chosen to be relatively small. As a result, the obtained line pattern (2) provides a fairly photorealistic reproduction of the original illustration (1). The closer an observer is to this line pattern (2), the more clearly he sees that this line pattern (2) is made up of lines. The farther an observer from this line pattern (2) stands, the more he gets the impression of perceiving gray values. By observing this optical illusion of gray values, one obtains the photorealistic effect. 135 ° was chosen as the angle (a) for the line pattern (2) shown in Figure 2. This enhances the dynamic effect of the surfer in motion on the waves of the sea.

To obtain the line pattern (2) from Figure 3, one set of essentially parallel lines (2a) was also selected. The distance (s) for this set of essentially parallel lines (2a) was chosen to be relatively large compared to the distance (s) to arrive at the line pattern of Figure 2. This results in a more abstracted image of the original illustration (1), in which one can clearly recognize the surfer on the waves of the sea. In this way it is even easier to mill an engraving based on an illustration (1) with variable color intensity. Again the angle (a) was chosen to be 135 °.

To obtain the line pattern (2) from Fig. 4, one set of substantially parallel lines (2a) was selected, the spacing (s) was taken relatively large, and the angle (a) was set to 0 °. By setting this angle (a) to 0 °, you inhibit the movement of the surfer on the waves of the sea and you obtain a more static reproduction of the original illustration (1).

To obtain the line pattern (2) from Figure 5, two sets of substantially parallel lines (2a, 2b) were selected, the distance (s) for both sets of mainly parallel lines (2a, 2b) was taken slightly smaller than for the line pattern (2) from Figure 4 and the angle (a) for the first set of substantially parallel lines (2a) was taken to be 0 °, while the angle (a) for the second set of substantially parallel lines (2b) was taken to be 90 ° taken. The vertical lines (2b) slow down the movement of the surfer even further. However, thanks to an additional collection of essentially parallel lines (2b), a more detailed reproduction of the original illustration (1) is obtained.

In the second step of this preferred method for making an engraving on the basis of an illustration (1) with variable color intensity, which is also schematically shown in Figure 1, the flowing contours (3) of the lines (2a, 2b) are determined ) of the line pattern (2) obtained in the first step. Figure 6 depicted such smooth contours (3), which were obtained in accordance with step 2 of this invention on the basis of the line pattern (2) shown in Figure 2.

To determine these smooth contours (3), the line pattern (2) from Figure 2 was vectorized in a CAM program. These smooth contours (3) form the smooth edges of the black lines (2a) from the line pattern (2) of Figure 2.

Then, as schematically shown in Figure 1, in a third and final step of this preferred method for making an engraving based on an illustration (1), with the aid of a milling machine, the zones (4) that are formed from a substrate are within these contours (3) or the zones (5) that are outside of these contours (3) are milled.

The zones (4) that lie within the contours (3) of Figure 6 were shown in black in Figure 7. The zones (5) that lie outside the contours (3) of figure 6 were shown in black in figure 8.

To mill these zones (4) within the contours (3) or zones (5) outside the contours (3) from a substrate, the CAM program generates, with which these contours (3) were determined from the line pattern (2) in step 2, now the control program for a CNC-controlled milling machine. The user of this CAM program can select whether the CNC controlled milling machine should either mill the zones (4) within the contours (3) or the zones (5) outside the contours (3). The user also indicates which cutters he has at his disposal and how deep the ground must be milled.

Different materials can be used as substrate. This substrate preferably consists of sheet material, but it can equally well be, for example, cylindrical, with a control program adapted for this purpose being controlled a CNC-controlled milling machine.

The substrate can for instance comprise a first layer of base material of a first color and a second layer of a second color. This second layer can also consist of base material, but it can just as well be a cover layer which is applied on top of this first layer. The base material may be, for example, a wooden solid core plate or a plastic plate, etc. A top layer may be used, for example, a paint layer or a coating, etc.

In this way different combinations of materials are conceivable for making an engraving according to this method. We give a few examples of substrates that are certainly not exhaustive: - a base material from a ferrous material, to which a surface color has been applied by means of, for example, painting or another surface treatment; - a plastic plate of several layers, wherein each layer has a different color or different characteristics; - a transparent base plate on which an opaque coating has been applied; - a laminated wooden core board; - a painted wooden panel.

When the substrate is composed of a first layer in a first color and a second layer of a second color, the engraving obtained after milling in the area inside (4) or outside (5) will contour (3), inside (4) the contours (3) have the first color, while outside (5) the contours (3) will have the second color, or vice versa. The colors of the engraving here only depend on the materials chosen for the substrate. In principle, such an engraving can therefore be realized in any color combination.

However, the substrate for such an engraving could also be made of monochrome colors and may also be formed of a homogeneous material. Thanks to the light and shadow effects, a similar image can be obtained after milling as an image formed from the two colors. This is because milling results in deeper zones (4 or 5) that cause the light and shadow effects.

For milling, a combination of ordinary milling and conical milling can be used. These conical cutters have a conical part, the top not necessarily being pointed. Using this conical portion on the cutter, the line thickness of the engraving varies with the depth at each point.

The finer the tip of the cutter, the finer the engraving can become. Before milling, the top layer of the chosen material is visible in the first machine in the milling machine. If this material comprises an underlayer in a second color, if the depth is sufficiently deep, this underlayer will be made visible in the second color. With a conical cutter, when the milling depth is small, a thin milled line will arise, whereby a thin line in the second color becomes visible. When the milling depth is greater, a wider milled line is created, whereby a wider line becomes visible in the second color, at the expense of the first color.

In this way, in step 3, by choosing the substrate, the cutters to be handled and the milling depth, one still has a great influence on the end result of the engraving to be made and an infinite variety of engravings can be obtained quickly and in a well reproducible manner. be based on an illustration (1) with variable color intensity.

Claims (16)

Method for making an engraving on the basis of an illustration (1) with variable color intensity, characterized in that this method comprises the following steps: - Step 1 converting the illustration (1) with variable color intensity into a line pattern ( 2); - Step 2 determining smooth contours (3) of the lines (2a, 2b) from the line pattern (2); - Step 3 milling the zones (4) within these contours (3) or the zones (4) outside these contours (3) with the aid of a milling machine to arrive at the engraving. Method according to claim 1, characterized in that the line pattern (2) is made up of one or more sets of substantially parallel lines (2a, 2b). Method according to claim 1 or 2, characterized in that the lines (2a, 2b) have a variable thickness (d), the thickness (d) of a line (2a, 2b) being a function in each point of this line of the color intensity of the illustration (1) at that point. Method according to claim 3, characterized in that the thickness (d) of a line (2a, 2b) in each point of this line (2a, 2b) is proportional to the color intensity of the variable color intensity illustration (1). Method according to claim 2, 3 or 4, characterized in that the spacing (s) between the lines (2a, 2b) of a set of substantially parallel lines (2a, 2b) is the same. Method according to claim 5, characterized in that the lines (2a, 2b) have a variable thickness (d), wherein the thickness (d) of a line (2a, 2b) in each point is at least O and at most the intermediate distance (s) between two adjacent parallel lines (2a, 2b). Method according to claim 3 or 4 and 6, characterized in that the thickness (d) of a line (2a, 2b) in a point is 0 when the color intensity of the variable color intensity illustration (1) is a first in this point extremum of this variable is color intensity and the thickness (d) of a line (2a, 2b) at a point is the distance (s) between two adjacent parallel lines (2a, 2b) when the color intensity of the variable illustration illustration (1) color intensity at this point is a second extremum of this variable color intensity. Method according to one of claims 2 to 7, characterized in that the lines (2a, 2b) of a set of substantially parallel lines (2a, 2b) are angled (a) with respect to the horizontal direction (H ) of the illustration (1). Method according to one of the preceding claims, characterized in that step 1 comprises the following sub-steps: - Step 1 a. Converting an illustration (1) with variable color intensity into an illustration (1) with grayscale, wherein the intensity ( 1) of the gray value at each point is proportional to the color intensity of the illustration (1) with variable color intensity at that point; b. converting the illustration (1) with grayscale into a line pattern (2). Method according to one of the preceding claims, characterized in that step 1 and / or step 2 are performed by software. Method according to one of the preceding claims, characterized in that step 3 is performed with a CNC-controlled milling machine. Method according to claims 10 and 11, characterized in that in: - Step 1, the illustration (1) with variable color intensity is converted into the line pattern (2) by means of an image processing program; - Step 2 the smooth contours (3) of the lines (2a, 2b) from the line pattern (2) are determined with the aid of a CAM program; - Step 3 the CNC controlled milling machine is controlled with the help of the CAM program from step 2. A method according to any one of the preceding claims, characterized in that the illustrative variable color intensity is a standard digital photo. A method according to any one of the preceding claims, characterized in that the substrate comprises a first layer of a first color and a second layer of a second color. Method according to step 14, characterized in that the second layer is a cover layer applied to the first layer. 16. Engraving, characterized in that it is produced with the aid of a method according to one of claims 1 to 15.