HK1059099B - Method and unit for the production of images with high resolution in jacquard fabric - Google Patents

Description

Method and apparatus for producing high-definition images in jacquard fabric

Technical Field

The invention relates to a method for producing high-definition images in a jacquard fabric and to a device for carrying out the method.

Background

EP0692562 describes a method of forming an optical image of a fabric composed of patterned warp and weft threads. In this method, the pattern is recorded by the data processing system and displayed on the display screen, the pattern being scanned in from the original state. Thereafter, by means of CAD, the warp and weft threads forming the fabric are assigned to a weave pattern, defining the weave of the fabric formed therefrom. This is a well-known regular weave such as plain, satin, twill and basket weaves. Subsequently, the warp and weft running pattern is determined in consideration of the specific parameters of the yarn and the fabric parameters. The predetermined pattern of passage of the yarns and the weft is corrected in view of the dynamic characteristics and the pattern of passage of the warp and the weft. This corrected warp/weft threading pattern is displayed by means of an output unit, for example by means of a display screen or a printer. After correction, various colors are assigned to the respective warp and weft.

The disadvantages of this approach are: the color is selected as a function of the color that can be displayed in the output unit, for which purpose a person skilled in the art with experience in weaving is required. The output unit is a display screen or printer that operates on the basis of primary colors (red, green and blue (RGB)) and has an additional color mix. However, it is known that it is not possible to reproduce the image in the fabric exactly in the basic color by means of the weft of the textile. Since the colors that can be displayed by the output unit also comprise mixed colors, it is necessary to provide the yarn with such mixed colors.

DE4438535 discloses a method for jacquard weaving of coloured fabrics. In this method, the image copy to be woven is decomposed by means of a sieving method known from printing technology. In this method, an original is transferred to a computer by scanning and displayed on a display screen, with a large number of color shades. The color is then reduced to a diagrammatical and desired number of colors. Finally, these numbers of colors are decomposed into screen dots of red, yellow and blue, and black and white colors, which have the size of a weaveable dot. After the color decomposition, a weaving program is established by means of computer technology, each screen point corresponding to a weaving point. These weaving points are tied according to the classical jacquard method, that is to say a regular weave with a repeating complete weave (repeat) is used.

The known method has significant disadvantages. In order to carry out this method, a person skilled in the art with weaving experience is absolutely necessary. Specifically, it can be understood that: in the case of weaving copies of color images of the colors yellow, red and blue, color mixing is lacking, that is to say not having all the color shades originally present. In general, to improve the image copy of the weave, corrections are needed. However, such corrections can only be made by those skilled in the art who have experience with weaving. Among the colors decomposed for copying, it is assumed that color mixing occurs in the region between the printed colors during the printing operation. In other words, the printed color dots are not sharply demarcated, but rather the printed colors of adjacent color dots flow locally into another color dot in the edge region. In the known method, the diagram is broken up into screen points, which form weaving points with sharp delimitations. The mixing effect is produced due to the low resolution of the human eye.

Therefore, it is known that: the introduction of jacquard looms has made it possible to produce differently processed (differentiated) patterns, but the production times for more complex patterns are very long and the work to be performed is very complex. The introduction of CAD systems in the field of jacquard weaving has resulted in a considerable simplification of the necessary work, while reducing the possibility of errors in designing and forming the different yarn interlaces for the purpose of obtaining various effects. Nevertheless, CAD systems force workers to perform special additional work on the images in order to form structures on the final fabric that are as similar as possible to the original images to be reproduced on the fabric.

In fact, the work for preparing the images and their corresponding processing, let alone the knitting system to be used later, proceeds as follows:

first, a color scan is performed of any desired original image (the original image may be of any desired type, without limitation); the scanning may be performed with the aid of a scanner or by means of any other reading system.

The original image read in this way can be visualized by video by means of a considerable number of colors. The number of colors is closely related to the performance of the hardware system used and, therefore, the configuration of the hardware system.

In professional configurations, images with millions of image colors can be read and visualized by video. In practice, this is primarily a theoretical performance, since the probability of such visualization is very small: typically, the image from the scanner has thousands of image colors that are automatically selected from a spectrum of millions of colors during the reading operation. However, it must be ensured that each image read by the scanner contains a specific palette, or better still, a palette containing the colors of the image itself in a specific manner.

In this regard, the image undergoes a first operation to reduce the number of image colors present, that is, to reduce the original colors of the original image. The process of color reduction may be performed by means of different methods, such as by using specific mathematical algorithms that vary, in particular, according to the way in which the colors are eliminated and/or replaced by other colors in the image.

In any case, not to mention the nature of the color reduction used and of the mathematical algorithm used thereby, an original image with a large number of original colors is formed, for example, with 256 reduced colors. This is a step that is carried out by virtue of the fact that the images subsequently processed by the CAD for the jacquard fabric do not require a large number of colors. In general, it is assumed that 256 colors are sufficient for the end product and for the processing of the image itself, in particular based on a corresponding conversion into a pattern for jacquard.

The image processed in this way (reduced in the number of colours) is then transferred to a jacquard CAD system, in which all the operations are coordinated, making it possible to transform the image itself into a pattern for jacquard fabric. In this respect, one of the first steps is to further reduce the remaining already reduced color. In fact, the number of colors present in the image is reduced based on the type of fabric and on the effect to be achieved. Typically, in a fabric pattern, each individual color indicates a particular type of interlacing and, thus, a particular type of end effect on the fabric.

In this regard, the following steps are associated with additional work on the available images. On the other hand, reducing the number of colors and the information obtained from the image requires passing the available image through a considerable series of steps, so that once the selected number of colors is reached, the image is valid and it needs to undergo additional work in order to resemble the original image as much as possible.

The time required for "additional work" on the image is related to the complexity of the pattern. This clearly and clearly implies that even today, complex patterns require a long time to complete and terminate additional work despite the use of highly developed systems. At present, therefore, there are no mathematical algorithms available that can automatically convert the image read by the scanner (and therefore the image has rich information on the colors and chromatic aberrations present, etc.) and at the same time achieve an accurate reproduction of the original image without additional work.

In fact, the different steps described above, with the aim of reducing the number of colors present in the original image read, do not make it possible to keep the chromatic aberration, the tint and the variation of the different colors that the image originally had unchanged. All this occurs due to the drawback of image processing time, but also due to the drawback of the quality of the final fabric; the difference existing between the original image at the time of reading and the converted image reproduced onto the jacquard fabric is in this case denoted by the term "quality".

Of course, the number of colors that the image to be reproduced on the jacquard fabric possesses is limited at most by the maximum number of colors of weft threads that can be used in the knitting machine. Generally, at least in the present case up to 12 weft colors can be achieved in a weaving machine, and therefore the number of reproducible colors is necessarily limited.

Disclosure of Invention

The main object of the present invention is to realise a method for reproducing images in jacquard fabric which allows to maintain a very high definition of the image and in this case does not require additional work on the image itself.

Within the scope of this aim, an object of the invention is to realise a method for reproducing images in jacquard fabric which makes it possible to keep the graphic definition of the original image substantially unchanged, and precisely a specific operation, to carry out a reduction in the colour of the original image and to dispense with additional work on the image.

A further object of the present invention is to realise a method of reproducing images on jacquard fabric which allows the time of reproducing images on fabric to be accelerated to an extreme extent.

A further object of the present invention is to realise a method for reproducing images on jacquard fabric which allows reproducing as accurately as possible the chromatic aberration present in the original image and the overall image colour.

Last but not least, the object of the present invention is to realise a method for reproducing images in jacquard fabric which is distinguished by high reliability, relatively simple implementation and low cost.

The subject mentioned and all the objects (which will be more clearly described below) are achieved by means of a method for reproducing images in jacquard fabric with high definition, comprising the following stages: color scanning an original image to be reproduced on the fabric; video-visualizing an original image by means of the maximum possible number of colors possible for the means for video-visualizing; the method further comprises the following stages: selecting a plurality of primary colors to be used for reproducing an original image on a fabric; in this case, the number of primary colors is related to the number of warp and weft threads that can be used for the knitting machine and for knitting the fabric; by mixing the primary colors of the warp and weft, the original color of the original image is reduced to a plurality of reduced colors possible.

Further, advantageous developments of the invention can be gathered, in particular, from the dependent claims and from the exemplary embodiments.

It is particularly preferred if the reduced decomposition of image color is performed to include a predetermined warp/weft ratio and provides a weaving program for using a fully-woven irregular weave without repeat weaving. A weaving program is provided for using irregular weaves without repeating complete weaves.

The electronic image processed by the system makes the legend or image replica to be woven high definition. By using the warp/weft ratio in separating the image colors into the primary colors, this sharpness can advantageously be achieved without loss, and thus a high fidelity reproduction of the legend in the fabric. By using irregular weaves without repeating perfect textures, image points in the pattern blended into a color legend are produced as printed. In this case, the main points are: the image points can be generated directly from the original by a computer without correction by a person skilled in the art who has experience with weaving. After the colour decomposition, a weaveable data format including the warp/weft ratio is prepared in the CAD system from the legend to be woven and transferred to the weaving machine.

It is preferred if the warp/weft ratio is 2: 1. By this ratio, the conditions of twenty-eight wefts and fifty-six warps per cm can be precisely maintained during the weaving process.

By using groups of at least two primary colors it is possible to produce irregular weaves without repeating complete texture.

By reducing the legend of the original image to be woven to a maximum of 256 colors, an image copy can be woven with the aid of weft threads of only four primary colors. This simplifies the knitting machine.

The weft using the black and white primary colors has the following advantages: on the one hand, black/white legends with high definition can be woven; on the other hand, the contrast in a copy of a color image with the primary colors red, green, blue and yellow can be perfectly reproduced.

The freedom of choice of the primary colors provides unlimited combinations, in particular, to precisely adapt the woven image replica to the original image legend.

The advantage of inserting the weft groups in a uniform order is: making the knitting procedure to be prepared simpler.

It is advantageous to provide the weaving program for the combination of areas with irregular weave and regular weave with repeating repeat, since the structure of the fabric can thereby be considerably broadened.

Drawings

Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings, in which:

fig. 1 shows a schematic way of passing a weft thread through the warp threads of a jacquard fabric, which is shown in a sectional view;

fig. 2 shows a schematic way of passing two weft threads through the warp threads of a jacquard fabric, which is shown in a sectional view;

FIG. 3 shows a block diagram of one mode of a programming system for producing jacquard fabric according to the present invention;

fig. 4 shows an original image copy acting as an original to-be-woven image copy;

FIG. 5 shows, on an enlarged scale, an enlarged portion A of the original according to FIG. 4 after decomposition of the color of the legend into the selected primary colors;

FIG. 6 shows an enlarged detail B of FIG. 5;

FIG. 7 shows a view of the weft sequence of the fabric;

FIG. 8 shows a cross-sectional view of a fabric with an irregular weave;

FIG. 9 shows a top view of the fabric according to FIG. 8; and

FIG. 10 shows a weave point layout for a regular weave.

Detailed Description

The method according to the invention comprises an initial phase of color scanning any desired image, which may be of any type and without any restriction in terms of topology and dimensions.

The images read in this way are visualized by video by means of a considerable number of colors: the number of colors is related to the performance of the hardware system used and the configuration of the hardware system.

In this respect, the selection to start with requires a number of colors, in particular directly from the video image, or by selecting within the total spectrum of the visible range of colors, thus providing an infinite choice of shades and variations.

In fact, the worker selects the number of basic colors of weft and warp that he will use during the weaving process, that is to say, the number of basic colors corresponding to the number of warp and weft that the weaving machine can use. According to the invention, the method enables the original color of the original image to be reduced to within the maximum possible color by means of the selected primary colors.

Basically, a series of virtually infinite different shades appear in the original image; all these shades are obtained by reproduction of the original colour by means of a combination of one or more yarns of different colours, thus producing a visualization of the desired colour.

The combined result of one or more yarns selected by the worker as base colors is: the original image prepared by means of the scanner is restored (reduced) in color.

The method for converting the pixels of the restored image into the selected primary colors is called the "dithering" method. This method makes it possible to reproduce a very large number of image colors present in the original image by means of a relatively small number of colors without having to reprocess the image. In fact, by this method, no details of the image are lost, which would occur in the known art in which the image colors are reduced to a highly precise number of weft colors without reproducing the inevitable missing colors.

The interaction of the selected primary colors may visualize all other colors needed in the image to be consistent with the original image. The color discrepancy of the image is due to the number of colored pixels that are selected at a greater or lesser density, starting from the primary color initially selected by the worker.

The color shades are obtained by mixing pixels of primary colors, which can be chosen with greater or lesser density depending on the color shade to be reproduced. For example, if the following primary colors are selected due to the reduced number of colors: black, white, red, yellow, green and blue, a virtually infinite number of different shades (red, gray, green, yellow, etc.) are realized in the restored original image. All these shades are obtained by a combination of different basic-colour yarns (so that the shade can be simulated since the weft or warp yarns with this particular shade do not need to be inserted into the knitting machine), which (chosen from the colours to be reduced) produces a visualization of the desired colour.

For example, if a yellowish color is to be simulated, yellow and white yarns are combined, thereby producing a yellowish color visually. The yellowish shades to be achieved are, of course, very diverse and therefore the number of white and yellow primary colours combined must be treated so that all these shades can be obtained.

In view of the fact that the colour is always obtained by interlacing two types of yarns arranged at right angles to each other, one type of yarn being the warp and the other type of yarn being the weft, usually the weft with a specific colour is interlaced with the warp, the end result being the appearance of the specific colour on the upper and lower surfaces of the fabric.

Fig. 1 shows in cross section the warp threads 1 and the weft threads 2, the weft threads 2 crossing the warp threads. The final colour of the fabric is thus obtained by the corresponding colour of the weft 2, since this yarn is above the warp (the weft part is yellow, so the fabric surface will be yellow). The situation shown is a standard situation in which attempts are made to obtain a solid colour on the fabric.

In contrast, in the case where a specific yellow tinge is to be achieved, it is necessary to try to form the yellow weft thread 2 on the upper surface of the fabric (then, on the warp thread 1), in particular together with another weft thread 2', or together with a plurality of weft threads, in order to achieve the desired tinge.

Fig. 2 shows that the yellow weft thread runs over the warp thread 1 together with the white weft thread 2'; this results in a light medium yellow color. The amount of yellow and white color can then be determined from the different chromatic aberration. The term "amount" in this case means the number of warp threads 1 covered by weft threads 2, 2'. In fig. 2, it can be seen that, for example, the yellow weft thread 2 remains over five warp threads 1, while the white weft thread 2' remains over six warp threads. This means that in this case the yellow color is very light (whiter than yellow).

There is no limit to the amount of color to be used (weft or warp threads may also be interwoven to form individual warp threads) and there is no limit to the number of weft threads that may be used in order to create different shades. In fact, there are colors that can be produced by combining more than two yarns of different base colors.

Thus, the "dithering" method may separate each color into various points of a selected primary color. Thus, for some colors, it may be desirable to use all of the primary colors initially selected by the worker. This is due to the fact that the final colour of the fabric is not achieved by the direct presence of weft threads with a specific colour, but by the combination (in different quantities) of the primary colours selected: thus, the color is simulated and does not actually exist. It therefore seems obvious that in this case no reprocessing of the image is required, since the latter is converted into a fabric pattern without losing the original information.

Furthermore, by means of the method according to the invention, the original image can be processed as if it had been a pattern for jacquard fabric, and not just a graphic file. In practice, each original image consists of square pixels, while the equivalent textile image consists of right angles, the dimensions of which vary according to the parameters used. The conversion of an image consisting of rectangular pixels into a textile pattern creates the situation that the image has to undergo a change in shape and therefore the final textile pattern no longer has perfect graphic definition. The method according to the invention makes it possible to vary the size of the initial pixels so that the latter coincide with the rectangles on the drawing paper used for the textile pattern and vice versa.

Thus, no change in shape is experienced during conversion into a textile pattern and with the conversion from pixels to drawing paper, and therefore no further processing is required.

In practice it has been determined how the method according to the invention fully achieves or achieves the full set of objects indicated in the introductory part of the description, since it allows to reduce the number of colors of the image without losing the information of the image itself and without requiring a reprocessing of the image itself, which would inevitably entail long processing times.

The method conceived in this way can be subject to a wide variety of and different modifications, all of which are within the scope of the inventive concept. Thus, the method can be used, for example, for any type of meridian, so that even microparticles of the original image are possible. Moreover, all the details may be replaced with other technically equivalent elements. In practice, the materials used, as well as the dimensions, may be of any desired type according to requirements and to the state of the art, provided they are compatible with the respective use.

A more detailed description of various exemplary embodiments follows:

FIG. 3 illustrates one mode of the invention discussed herein. The programming system starts with a script in the form of an initial image 3 and includes the program steps of scanning 4, color reduction 5, color decomposition 6 and weaving program 7, the weaving program 7 being performed in a weaving machine 8 to produce a fabric 9 with the desired final image.

In a first step, an image having, for example, about 160 ten thousand colors is scanned and displayed on a display screen. The legend of an image appearing on a display screen typically has thousands of colors or shades depending on the resolution capabilities of the scanner and the display screen.

In a second step, the color of this image is reduced to a diagnosable amount, for example to 256 colors. In this color reduction process, various colors are lost and replaced by other colors within the color spectrum.

The third step comprises a plurality of sub-steps. First, a predetermined number of base colors are selected for the warp and weft yarns used in the weaving process. Preferably, the weft threads are selected to have the primary colors red, green, blue, yellow, black and white.

Subsequently, the 256 reduced colors are decomposed into primary colors. This decomposition process is automated and produces a chart showing the weave pattern (fig. 4 and 5).

In electronic image processing, colors are illustrated by pixels. The color map of the image is shown as color cells, each color cell being represented by a representative color. The chromatic aberration of the image colors is achieved by the number of pixels of the color selected with different color concentrations. In the color reduction process, the color is replaced by a color cell sample in which the color falls, however, rather than each pixel being imaged on a sample of color cells, it is shifted to one of the adjacent image colors.

Finally, the image color separation is performed, and the transfer is performed. By means of this transfer, on the one hand, the image colors are divided into image points of the basic colors and, on the other hand, the shades of the image colors are divided into image points of the basic colors in terms of color density, which combine to produce shades, for example red and white for light red. In each case, the image dots are formed by weft threads which have a basic color and pass through the weft threads over the visible side of the fabric. In this separation, a warp/weft ratio of 2: 1 is included, so that the legend to be woven is formed by rectangular color dots, as shown in fig. 5, forming the basis of the weaving procedure to be established.

In a fourth step, the programming of the image copy to be woven is performed on the computer. Refer to fig. 7 to 10. By means of the weaving procedure, the insertion of the weft threads and the movement of the warp threads (ascending and descending) are adjusted. As shown in fig. 7, six wefts having primary colors of red, green, blue, yellow, black and white are used. The weft threads are inserted in this order as thread groups in the transverse rows of the art paper and form color cells. The weft threads are knotted by means of the warp threads. For this purpose, a weaving program is provided for the irregular weave without repeating repeat and for the regular weave with repeat. The irregular weave is produced, for example, in such a way that, depending on the color points produced during the disintegration process, the red weft threads R of the thread group are visible as red color points on the visible side of the fabric, while the remaining weft threads float on the rear side. The same applies to the green color dots produced, the green weft G being visible. This is shown in fig. 8 and 9.

As described above, in the color decomposition process, color dots with chromatic aberration and different color densities are obtained. For such color points, the weaving procedure provides a color mixture which can be formed, for example, by means of at least two weft threads having different basic colors. The weaving procedure offers another possibility, for example with floating weft threads.

Claims (13)

1. A method for producing high-definition images in jacquard fabric, comprising the following phases:

color scanning an original image to be reproduced on the fabric;

video-visualizing an original image by means of the maximum possible number of colors possible for the means for video-visualizing;

characterized in that the method further comprises the following stages:

selecting a plurality of primary colors to be used for reproducing an original image on a fabric; in this case, the number of primary colors is related to the number of warp and weft threads that can be used for the knitting machine and for knitting the fabric;

by mixing the primary colors of the warp and weft, the original color of the original image is reduced to a plurality of reduced colors possible.

2. A method as claimed in claim 1, characterized in that the mix of selected primary colors is a pixel mix, in each case pixels being formed by interlacing at least one warp thread and at least one weft thread.

3. A method according to claim 1 or 2, wherein the conversion of the reduced colors of the restored original image into the selected number of primary colors comprises a dithering method.

4. A method as claimed in claim 1 or 2, characterized in that the color differences of the restored original image are reproduced by means of the number of pixels in the selected primary color.

5. Method according to claim 1 or 2, characterized in that the reduced colour separation is carried out with a predetermined warp/weft ratio included and a weaving program is provided for using a fully-woven irregular weave without repeat weaving.

6. A method according to claim 1 or 2, characterised in that the warp/weft ratio is 2: 1.

7. A method according to claim 1 or 2, wherein the reduced color is formed by at least two primary colors forming a line group.

8. A method as claimed in claim 1 or 2, characterized in that the original colors of the original image are reduced to a maximum of 256 colors.

9. A method as claimed in claim 1 or 2, characterized in that up to sixteen primary colors can be used.

10. The method of claim 9, wherein the primary colors are red, green, blue, and yellow.

11. The method of claim 10, wherein the primary colors are red, green, blue, yellow, black, and white.

12. A method according to claim 1 or 2, characterized in that a weaving program is provided for inserting the groups of weft threads in a uniform order.

13. Method according to claim 1 or 2, characterized in that the weaving procedure is provided for using a regular weave with a repeating repeat of the repeat of the repeat.