Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2000-09-01
2003-01-21
Nerbun, Peter (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C112S475190
Reexamination Certificate
active
06510360
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is concerned with methods of producing object-based design description files for embroidery patterns from vector-based stitch files describing the pattern as a sequence of stitches.
It is known to use vector-based stitch files for controlling computer controlled embroidery machines. Such stitch files contain a sequence of individual stitch instructions to control the embroidery machine to move the needle in a specified co-ordinate direction prior to performing the next needle insertion. Apart from vector data, each stitch instruction may also include additional data for instructing the embroidery machine, e.g. to perform a thread color change, a jump stitch or a trim.
It is also known to use object-based design description files for embroidery pattern definition. Such files define areas of the embroidery pattern as software objects, which can then be easily manipulated for creating a new embroidery design or modifying an existing design. Once a design has been created or modified as an object-based design description file, conversion software create a vector-based stitch file from the object-based file and the vector-based stitch file is used to control the embroidery machine.
Typically, the object-based file consists of information describing geometric objects such as columns, lines, opaque or transparent complex polygons bounded by lines or curves, etc. and instructions for producing a stitch file from these objects. The additional instructions may include stitch densities, fill patterns, thread colors and compensation factors.
There is sometimes a requirement to modify an embroidery pattern for which the only available data is in the form of the vector-based stitch file. Since such a stitch file may consist of many thousands of vectors (as many as there are stitches in the embroidery pattern), modifying the stitch file to change the pattern would require changes to a very large number of these vectors. There is therefore a recognized need for methods, particularly software methods, for analyzing an existing vector-based stitch file and producing therefrom an object-based design description file which can then be readily manipulated by means of design software to modify an existing design.
EP-A-0221163 describes a method of producing a modified embroidery pattern for an embroidery machine in which a stitch-by-stitch definition of the embroidery pattern is analyzed to determine the stitch types, the area, the stitch lengths and the stitch spacings for each sequence of stitches in the pattern. According to the specification, the design represented by the pattern is then modified and a new series of stitch-by-stitch commands is produced for controlling the embroidery machine. However, there are no details as to how the stitch-by-stitch data is analyzed to enable the design to be varied as required.
EP-A-0545773 discloses a method of producing a new embroidery design from an existing design pattern in which vector-based stitch data are analyzed to identify the angle at each stitch point. Stitch runs are then defined based on a commonality of the angles for stitches of a stitch run having a particular stitch type. Outline points defining an outline of the stitch run are then selected which can be subsequently edited to produce a new embroidery design pattern. Essentially, the disclosed technique relies on identifying a sequence of stitches having a recognizable stitch type such as, satin stitching or tatami stitching (also known as fill stitching), and then identifying the outline of the region of the identified stitch type to allow subsequent editing of the overall pattern.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a method of operating a computer to produce an object-based design description file for an embroidery pattern, from a vector-based stitch file describing the pattern as a sequence of stitches, the method comprising the steps of analyzing the stitch file to identify stitch points qualifying as embroidery edge points at which the stitch direction substantially reverses, producing a list of said identified edge points in the order of the corresponding stitch points in the stitch file, further analyzing the stitch file to identify groups of successive edge points in the list wherein the edge points of each group define a respective embroidery region containing only contiguous area filling type stitches, and generating from the co-ordinate positions of edge points in each identified group an object describing the respective embroidery region for the object-based design description file.
Whereas, the prior art '773 specification looks for regions of a particular stitch type, the above-identified invention defines potential objects for the object-based design file by looking for stitch points which qualify as edges in the stitch pattern, at which the stitch direction substantially reverses. In this way objects are created for the design description file without limiting these objects to regions of a single stitch type, such as SATIN or FILL. This has considerable advantages because a single embroidery region of an embroidery pattern may be filled with contiguous area filling type stitches of different types, for example the narrower parts of the region may contain SATIN stitching whereas the broader parts may contain FILL stitching. It is generally desirable for any one object of the object-based design description file to describe as large an area of the embroidery pattern as possible, it being understood that each object would normally be a region of consistent contiguous area filling stitches of the same color and bounded by a continuous outline. Preferably, the stitch points qualifying as embroidery edge points are identified by
a) identifying as simple edge points stitch points for which the stitch angle between the stitches on either side of the respective stitch point is smaller than a precalculated threshold value, and
b) finding pairs of consecutive stitch points forming a complex edge in which the aggregate stitch angle of the respective pair is less than a precalculated threshold value and identifying the stitch point of each said pair which has the smallest stitch angle as a complex edge point.
The aggregate stitch angle of the pair of stitch points forming a complex edge means the angle between the stitch line up to the first of the pair of stitch points forming the complex edge and the stitch line after the second of the pair. Thus the value of the aggregate angle of the pair of stitch points is the difference between 180° and the sum of the stitch angles at each of the stitch points of the pair forming the complex edge.
Many embroidery patterns may contain such complex edge points, as well as simple edge points involving a simple substantial reversal of direction of stitching at an individual stitch point. By comparison complex edge points require two successive stitch points to accommodate a substantial reversal of the stitch direction. In a complex edge, the stitch angle at each of the two stitch points forming the complex edge may be greater than the precalculated threshold value for a simple edge point, but nevertheless the aggregate stitch angle is small indicating a substantial reversal of the stitch direction overall.
Preferably, said groups of edge points are identified by defining an edge point in the list as an end of group point if the edge point meets at least one of a set of group termination conditions, said set of group termination conditions including at least one of:
a) the nearest following stitch point which forms at least part of an identified edge is not preceded in the sequence of stitches in the stitch file by a run stitch or another stitch point forming at least part of an identified edge;
(b) the edge angle of the edge point has the same sign as the immediately preceding edge point in the list, the edge angle being the angle described at the respective edge point between the line from the preceding edge point to the line to the next edge point;
(c) the edge len
Bysh Martin
Kaymer Andrew Bennett
Nerbun Peter
Pearne & Gordon LLP
Viking Sewing Machines AB
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