EP0277066A1 - Process for taking cuts from a work piece, depending on the characteristics of said work piece - Google Patents

Abstract

Taking cuts from a workpiece (1) especially in the form of a sheet, by means of a tool guided by a data processing system, according to a programme for taking cuts which may depend on some special features of the said workpiece or on instructions associated with the said workpiece, the said data processing system controlling and being connected to a camera, especially a video camera, responsible for exploring the said workpiece (1), the process providing, before the said exploration, for some of the said special features or instructions to be marked directly on the said workpiece by an operator with the aid of a marking means, in the form of distinctive signs (2, 3, 4, 5, 6) which can be detected by the said camera and can be interpreted as being constraints or suggestions for cutting out to be taken into account in the said programme for taking cuts. The said means of marking is fluorescent and, during its exploration by the said camera, the said workpiece is illuminated by a source of ultraviolet light and is placed before a fluorescent background and the speed of exploration of the said camera can be adjusted as a function of the required sensitivity, for example from 10 to 40 images per second, that is a frequency of exploration of 10 to 40 Hz, preferably approximately 25 Hz. Applications to the development of programmes for taking cuts in an interactive manner, with the aid of a control screen (10) connected to a data processing system. <IMAGE>

Description

The present invention relates to a method of cutting an object, in particular in the form of a sheet, by means of a tool controlled by a computer system, according to a cutting program which may depend on certain characteristics of said object.

When cutting an object, for example an animal skin, with a tool controlled by a computer system, it is necessary to define a cutting program beforehand, and this program must take into account certain peculiarities of the skin to be cut , such as its shape and its orientation with respect to said tool, but also of its possible defects. To cut parts from animal skin according to predetermined shapes, one can manually place on this skin templates having these shapes and ask a computer to read the positions of these templates relative to that of the skin, and to keep them in memory for cutting. In this case, a trained operator is able to place the templates, taking into account the presence of possible faults. The templates can also be placed interactively, using a computer terminal screen comprising an input accessory such as a keyboard associated with a digitizing table and a screen which would display an image of the skin and of the templates, but most of the faults would then not appear on the screen because of the sensitivity of the cameras existing at the present time, and these faults could therefore not be taken into account when defining a cutting program.

The object of the present invention is to propose a method of cutting parts into an object, in particular in the form of a sheet, by means of a tool controlled by a computer system, according to a cutting program which may depend on certain peculiarities of said object, in particular of its defects, without it being necessary to manually place templates to the shapes of these parts, that is to say to define the cutting program, directly on said object.

According to the present invention, a method of cutting an object in particular in the form of a sheet, by means of a tool controlled by a computer system, according to a cutting program which may depend on certain particularities of said object, said computer system controlling and being connected to a camera responsible for exploring said object, provides that, before said exploration, some of said features are marked directly on said object by an operator, using a marking means, under the form of distinctive signs, coded or not, detectable by said camera, and interpretable as being cutting constraints to be taken into account in said cutting program.

According to a characteristic of the present invention, said marking means is fluorescent and said object is illuminated by an ultra-violet light source during its exploration by said camera, so as not to limit the invention to certain colors of objects. Advantageously, said object is placed in front of a fluorescent background during its exploration by said camera.

According to another characteristic of the invention, the speed of exploration of the camera is adjustable as a function of the required sensitivity, then fixed for a given exploration. This exploration speed must be sufficiently low for said signs to be detectable by said camera, for example in the range of approximately 10 to 40 images per second, ie an exploration frequency of approximately 10 to 40 Hz, and preferably of 25 Hz, when said marking means is fluorescent and said object is illuminated by an ultra-violet light source.

According to yet another characteristic of the invention, the distinctive signs include a fluorescent chalk marking to indicate a particular area of the object, and, pasted on said object in the vicinity of said particular area, a patch or a arrangement of fluorescent tablets characteristic of said particular zone which can thus be identified by the shape, size and arrangement of said tablets.

According to one embodiment of the invention, said computer system has cutting instructions in memory, and said signs are coded and interpretable by said computer system as being cutting constraints to be combined with said cutting instructions to define said cutting program. cutting. One of said cutting instructions can for example be the order to cut from said object as many pieces of predetermined shapes as possible without some of them being cut from parts of said object corresponding to some of said features, in particular defects of said object. In the case of faults, certain parts can be cut from parts of said object having certain faults, and certain faults can be admissible in one part of a part but not in another part of this same part.

According to another embodiment of the invention, said computer system shows on a control screen images of the object on which its outline and said distinctive signs are visible and interpretable by an operator as being cutting constraints to define a cutting program interactively using input accessories from said computer system.

Other characteristics and advantages of the present invention will appear better on reading the following description given by way of nonlimiting examples of the possible embodiments of the invention, with reference to the attached drawings, and which will make it clear how the invention can be realized.

• - la figure 1 est une vue de dessus d'une peau d'animal marquée selon le procédé de la presente invention
• - la figure 2 représente un affichage d'écran utilisé pour mettre en oeuvre le procédé de la présente invention
• - les figures 3a à 3d représentent des exemples de signes distinctifs pour le marquage d'objets selon l'invention , et,
• la figure 4 représente un autre exemple de signesm distinctifs selon l'invention.

In the drawings:

• - Figure 1 is a top view of an animal skin marked according to the method of the present invention
• - Figure 2 shows a screen display used to implement the method of the present invention
• FIGS. 3a to 3d show examples of distinctive signs for marking objects according to the invention, and,
• FIG. 4 represents another example of distinctive signs according to the invention.

In the example which will now be described, it is a question of cutting parts from an animal skin containing defects which a video camera cannot detect or recognize without prior marking.

In FIG. 1, an animal skin 1 has defects not shown but marked directly on the skin by means of fluorescent chalk with distinctive signs 2, 3, 4, 5, 6. We will see below that according to the In the form of these signs, "cosmetic" type defects 2, 3, 4 or structural type 5, 6 are recognized. Cosmetic type defects are understood here as appearance defects.

Certain defects are admissible on certain parts of certain parts. This is particularly the case for cosmetic type defects when said object is animal skin. These faults are generally not admissible, for example on the visible part of a shoe upper, but may be admissible on other parts of this part, for example the "assembly", or on other parts. Structural type faults are generally, but not necessarily, to be avoided on all parts.

When the marking of faults has been carried out manually by a specialist, the skin is spread on a table. A video camera is placed above this table, to explore the skin, in order to read its contours and the signs worn on it in order to allow the development of a cutting program taking into account the shape of the skin, as well as the presence of said faults, or other additional instructions.

Advantageously, and according to the invention, the table on which the skin is spread is itself fluorescent, which allows the camera to read the contours of the skin in the same way as said signs. By contour is meant here both the outer contour of the skin and the contours of any holes.

In the case of this example, the camera is a linear type video camera which is fixed above the table, and the table moves below the camera. This arrangement is preferable to that which consists in moving the camera above the table, to limit the problems due to vibrations. In addition, it is preferable to work with a linear type camera to obtain a better definition of the image.

The exploration speed is adjustable according to the required sensitivity, then fixed for a given exploration. In practice, it is convenient to work with exploration speeds which are multiples of twice the frequency of the sector, for example 100,200,300 Hz, etc. for a supply frequency by the sector of 50 Hz, but in certain cases, the sensitivity required for exploration requires lower exploration speeds, for example between 10 and 40 Hz. Thus, good results have been obtained in terms of signal / noise ratio with an exploration frequency of 25 Hz for detecting fluorescent marks illuminated by a source. of ultraviolet light. If one seeks to obtain a resolution of 1 mm², an exploration frequency of 25 Hz corresponds for this example to a speed of movement of the table of 25 mm / s, or 1.5 m / min. An animal skin three meters long can thus be explored in 2 minutes.

In Figure 2, there is shown the display of an interactive placement control screen for the development of a cutting program. The screen 10, connected to a computer system itself connected to said camera, is divided into three parts 11, 12, and 13. The first part 11 is a dialog area reserved for displaying alphanumeric instructions on the screen. attention of the operator, which operator having a keyboard and a digitizing table or an input accessory of the "mouse" type, known per se to those skilled in the art, also connected to said audit computer system. The second part 12 of the screen 10 displays shapes of parts to be cut out from the skin 1, an image of said skin 1 being displayed in the third part 13 of the screen.

Thanks to the fluorescent marking, to the ultra-violet lighting and to the adjustment of the exploration speed here at 25 Hz, according to the invention, the signs 2, 3, 4, 5, 6 of FIG. 1 corresponding to the faults have have been analyzed and interpreted by the computer system, and appear on the screen, either in their original form or in another form, after coding by the computer system, which allows the operator to take these faults into account to define the cutting program. In the case of FIG. 2, said signs appear on the interactive placement screen in their original form. To define this cutting program, the operator moves templates 21, 22, 23, 24, 25, 26 appearing in said second part 12 of the screen 10 using the keyboard and / or the digitizing table or the mouse. These templates are the shapes and dimensions of the parts to be cut in the skin 1, to the scale of the display. The computer program loaded into said computer system of course makes it possible to rotate said templates, in order to best place them on the image of the skin 1. This mode of definition of said cutting program corresponds to the so-called interactive mode.

In this embodiment of the invention, the operator himself assesses whether such or such defect is admissible on such or such piece to be cut, or on part of a piece to be cut. The operator recognizes the types of defect, cosmetic or structural, "punctual" or linear, depending on the shape of the sign that appears on the screen. Figures 3a to 3d give examples of distinctive signs which can be used by said specialist to mark said defects.

Thus, we can agree on the following code:
. a point defect of structural type for the sign of FIG. 3a;
. a cosmetic cosmetic point fault for the sign of Figure 3b;
. a linear structural type defect for the sign of Figure 3c;
. a linear cosmetic defect for the sign of Figure 3d.

Marking can also be carried out as follows: once the defects are surrounded or underlined directly on the skin with fluorescent chalk, a fluorescent tablet or an arrangement of fluorescent tablets characteristic of a type of defect is glued in the vicinity of the defect, on the skin. This is illustrated in FIG. 4, which represents what can be seen on the screen, that is to say the chalk marking 30 of the defect and the pellets 31a, 31b, 31c, the diameters and the arrangement in equilateral triangle of given side are characteristic of the type of defect.

In another embodiment of the invention, said computer program itself defines said cutting program, starting from the instruction to cut as many parts as possible on animal skin, shape, orientation and the skin defects once marked by a specialist as indicated above being detected for said computer system by said camera, then read and interpreted by said computer system, which can then take them into account in the definition of said cutting program.

All kinds of constraints or indications can thus be transmitted to the computer system, or to the operator, not only to prohibit certain choices in the development of the cutting program, but also to suggest others. It is thus possible to limit the computing time of the computer system, or the duration of reflection of the operator, thanks to the signs carried on the object to be cut by the specialist. Indeed, if we return to the case where one of said cutting instructions given to the computer system is the order to cut from animal skin the greatest possible number of pieces of predetermined shapes without some of them being cut in parts of the skin corresponding to defects, the calculation time can be greatly reduced if the specialist responsible for marking the skin has signs corresponding, for example, to preferential or even mandatory cuts and / or orientations of certain parts in certain areas of the skin.

It goes without saying that the present invention is not limited to the examples described above. On the contrary, many technical equivalents may appear to those skilled in the art without departing from the scope of the invention. One could for example use the fluorescent marking illuminated by an ultra-violet light source associated with the adjustment of the speed or frequency of exploration of the camera when machining three-dimensional objects.

Claims (9)

1. Method for cutting an object (1), in particular in the form of a sheet, by means of a tool controlled by a computer system, according to a cutting program which may depend on certain peculiarities of said object, said computer system controlling and being connected to a camera, in particular a video, responsible for carrying out an exploration of said object (1), characterized in that, before said exploration, some of said features are marked directly on said object by an operator, at the using fluorescent marking means, in the form of distinctive signs (2, 3, 4, 5, 6) detectable by said camera, and interpretable as being cutting constraints to be taken into account in said cutting program, said object being illuminated by an ultra-violet light source during its exploration by said camera, the exploration speed of said camera being adjustable as a function of the required sensitivity. 2. Method for cutting an object (1), in particular in the form of a sheet, by means of a tool controlled by a computer system, according to a cutting program which may depend on certain instructions associated with said object, said computer system controlling and being connected to a camera, in particular a video, responsible for carrying out an exploration of said object (1), characterized in that, before said exploration, some of said instructions are carried directly on said object by an operator, at the using fluorescent marking means, in the form of distinctive signs detectable by said camera, and interpretable as being constraints or cutting suggestions to be taken into account in said cutting program, said object being illuminated by a source of ultra-violet light during its exploration by said camera, the exploration speed of said camera being adjustable as a function of the required sensitivity. 3. Method according to any one of the preceding claims, characterized in that the range of speed of exploration of said camera is substantially from 10 to 40 images per second, ie an exploration frequency of 10 to 40 Hz, preferably about 25 Hz. 4. Method according to any one of the preceding claims, characterized in that said object is an animal skin (1) and that some of said distinctive signs (2, 3, 4, 5, 6) correspond to defects of said skin (1). 5. Method according to claim 4, characterized in that different distinctive signs (2, 3, 4, 5, 6) are used for defects of different natures, said different signs being differentiable by said computer system. 6. Method according to one of the preceding claims, characterized in that said distinctive signs include a fluorescent chalk marking to indicate a particular area of the object, and, glued on said object in the vicinity of said particular area , a tablet or an arrangement of fluorescent tablets characteristic of said particular zone. 7. Method according to claim 6, characterized in that said particular zone of the object is identified by the shape, size and arrangement of said pellets. 8. Method according to any one of the preceding claims, characterized in that said computer system already has cutting instructions in memory, and in that said distinctive signs can be interpreted by said computer system as being constraints or cutting suggestions. that it can combine with said instructions to define itself said cutting program. 9. Method according to any one of claims 1 to 7, characterized in that said computer system shows on a control screen (10) at least one image of the object (1) on which said distinctive signs (2, 3, 4, 5, 6) are visible and interpretable by an operator as being constraints or cutting suggestions to define a cutting program interactively by means of input accessories of said computer system.

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