IL91625A - Apparatus for advance edge detection - Google Patents

Description

Will ΠΠ2Π7 Ί7Ά7 IPJKI APPARATUS FOR ADVANCE EDGE DETECTION FIELD OF THE INVENTION The present invention relates to computerized sewing apparatus in general and, in particular, to a method for edge location analysis of sewn pieces preliminary to the sewing process.

BACKGROUND OF THE INVENTION Computerized sewing devices are known in the art. Two pieces to be sewn together are placed on a work holder and moved by an X-Y table in the necessary directions for the desired sewing path.

Since the sewing path is pre-programmed and carried out by machine, it is possible that the sewn pieces will move from the ideal position for sewing. This can be caused by improper placement on the work holder, by deformation due to environmental conditions or by deformation due to the sewing process itself. To solve this problem, edge detecting means have been added to the sewing apparatus . These include devices according to U.S. Patents Nos. 4,834,008 and 4,784,071 to the same applicants which include cameras and illumination means for scanning the instantaneous location of the sewn edge, by utilizing edge enhancement, and comparing it with the expected location.

These methods serve very well to identify the edge of the sewn piece and to provide instantaneous correction of the sewing path when necessary, thereby compensating accurately for all the causes of edge variation .

However, this ideal solution requires overall precision in the x-y table and other components for exact correction in real time, resulting in relatively costly components being required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for edge location analysis permitting the use of a relatively inexpensive X-Y manipulator and simpler components than that known in the prior art.

There is thus provided in accordance with the present invention a method for edge location analysis including a scanning cycle wherein a piece to be sewn is moved under a scanning assembly in accordance with a predetermined path, collecting the data of the measured edges in a data bank, transferring the data to a sewing system, and carrying out the sewing cycle using the predetermined path as modified by the data from the data bank.

According to a preferred embodiment, the method for edge location analysis includes the steps of mounting a piece to be sewn onto a workholder, mounting the workholder on an X-Y manipulator, moving the X-Y manipulator in accordance with a pre-programmed sewing path while performing edge location analysis, generating sewing path correction data by the analysis, storing the sewing path correction data in computer readable data storage means, transferring the workholder to a computerized sewing machine, reading the sewing path correction data into the computer of the sewing machine, causing correction of the pre-programmed sewing path in accordance with the correction data, and sewing in accordance with the pre-programmed sewing path as amended in accordance with the sewing path correction data.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be further understood and appreciated from the following detailed description taken in conjunction with the drawings in which: Fig. 1 is a perspective schematic illustration of scanning apparatus constructed and operative in accordance with one embodiment of the present invention; Fig. 2 is a schematic view of one alternate embodiment of illumination means operative in the present invention; Fig. 3 is a schematic view taken along section A-A of Fig. 2; and Fig. 4 is a block diagram illustrating the operative elements of the scanning apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to preliminary scanning apparatus for use with any apparatus requiring edge location analysis followed by processing along the edge. The invention is particularly useful with computerized sewing apparatus, and is described hereinbelow with specific relation to this type of apparatus .

According to the invention, the scanning apparatus has incorporated therein edge position sensing means and cooperates with a microprocessor which has the capability to modify, during a later sewing cycle, a pre-programmed sewing path in accordance with the actual position of the piece being sewn. The scanning apparatus comprises a workholder, a microprocessor, means for scanning segments of an object on the workholder and arranged to provide an output signal corresponding thereto to the microprocessor, means for causing relative movement between the workholder and the scanning means during scanning, means for determining the true edge position from the scanning means 1 output signal, comparator means in the microprocessor to compare the actual edge position with the programmed expected edge position and to determine any deviation, means coupled to the microprocessor for determining any necessary modification of the sewing path during sewing to compensate for any such deviation and means coupled to the microprocessor for recording any such modification data for transfer to a computerized sewing apparatus .

It is a particular feature of the present invention that the edge location analysis is done separately and prior to the sewing process. The data calculated from the edge location analysis is collected in a data file which is later transferred to the sewing system to be used in combination with the pre-programmed sewing program for sewing along the edge.

It is an advantage of the present system of using a separate station to measure and analyze the edges of an assembly of pieces that a lower cost X-Y system and scanner can be used. Since there is no need to mount the vision system around the sewing head and to subject the measurement process to the critical time requirements of the sewing process, as is the case with real-time modification of the sewing program, simpler and less costly equipment is quite satisfactory.

Another advantage is the ability to incorporate edge detection into the computerized sewing of the presently available sewing systems. No modifications to these systems are required except for the construction of a data link between the scanning system and the sewing system.

Referring to Figs. 1 and 2 there is shown scanning apparatus constructed and operative in accordance with one embodiment of the present invention. It will be appreciated, however, that many other alternatives embodying this principle may also be utilized.

The scanning apparatus illustrated in Figs. 1 and 2 comprises a workholder 1 0 on which is mounted an object to be sewn 1 2 . Coupled to workholder 1 0 is a two-dimensional manipulator 1 4 comprising two carriages, 1 6 and 1 8 , for translating the workholder relative to the scanning system in any direction in the horizontal (X-Y) plane. Manipulator 1 0 may comprise any X-Y table mechanism which is adapted to be driven by computerized commands .

In the illustrated embodiment, the workholder is moved by the X-Y mechanism relative to the scanning syster. According to an alternate embodiment, the scanning camera is moved by an X-Y mechanism relative to a stationary workholder. It will be appreciated that it is the relative movement which is important for the scanning process .

The scanning system illustrated in Fig. 1 comprises a scanning camera 20 with associated lens 22 mounted on a camera support 25 . Camera 20 is disposed vertically above the workholder 1 0 so that a section of the edge of object 1 2 is in the field of view 24 of the camera. Illumination of the edge is provided by a plurality of lights 26 mounted concentrically to the camera 20 . Lights 26 are activated selectively by a microprocessor (not shown) so as to illuminate the edge diagonally at all times. According to the illustrated embodiment, lights 26 are mounted on a fixed ring 28 attached to the camera support 25 .

Lights 26 are selectively activated under computer control so that only a selected light or lights from selected directions is activated for a particular image frame. This serves to enhance the edge segment present in the field of vie of the particular frame.

In the embodiment of Fig. 1 , lights 26 comprise a plurality of light bulbs which are turned on and off as required. Alternatively, each light 26 may comprise a flash lamp activated by the computer.

According to another embodiment, as shown in Figs. 2 and 3 , lights 26 may comprise a plurality of optical fibers 30 originating from a light source (not shown) . Each fiber end is covered by a mechanical shutter 32 which is opened and closed by a rotary solenoid 34 , for permitting or preventing the passage of light.

Operation of the scanning apparatus of the present invention is as follows, with reference to Fig. 4 , a block diagram illustration of the scanning apparatus of the present invention. An object 1 2 whose edge is to be analyzed is mounted on workholder 1 0 , as known. A pre-programmed sewing program by which object 1 2 is to be sewn is introduced to the microprocessor 40 which is operative to manipulate workholder 1 0 to move object 1 2 according to the pre-programmed sewing path. In other words, workholder 1 0 and object 1 2 are moved precisely as they will be during the sewing process but in the absence of a sewing head and without actual sewing.

As the object moves, microprocessor 40 activates lights 26 as required, and scanner 20 scans the portion of the edge within field of view 24 and sends data corresponding thereto via frame capture means 38 which converts the scanning signal into digital data in the microprocessor's memory. The microprocessor analyses the scanning data to determine the true edge location in each image frame.

According to one embodiment of the invention, the true edge location data is recorded in a true edge data file on any suitable data storage media, for example on a data diskette 42, for later transfer to the computerized sewing apparatus.

According to an. alternate embodiment a direct data link 44 from the microprocessor 40 to the processor of the sewing apparatus can be utilized for direct downloading of the true edge data.

Once the scanning is complete, the workholder 10, with object 12 still affixed thereto, is moved to the computerized sewing apparatus and mounted on the X-Y manipulator associated therewith. The true edge data file from the scanning cycle is introduced to the processor of the sewing apparatus together with the pre-programmed sewing path.

According to one embodiment, comparator means within the sewing apparatus' processor is adapted to compare the actual edge position with the programmed expected edge position and to determine any deviation. If there is any deviation, the processor determines the necessary modification of the pre-programmed sewing path according to the actual location and deformation of the edges of the object. Sewing is now accomplished according to the pre-programmed path as modified in accordance with the modification data.

According to an alternate embodiment, comparator means within microprocessor 40 in the scanning apparatus itself is adapted to compare the actual scanned edge position with the programmed expected edge position and to determine the deviation, as well as the necessary modification of the pre-programmed sewing path to compensate therefor. This modification data is recorded, for example on a data diskette, for later transfer to the computerized sewing apparatus, which merely reads the modification data and modifies the sewing program accordingly.

It will further be appreciated that the scanning apparatus of the present invention can be utilized with any conventional computerized sewing apparatus and with any known scanning system, including that shown in U.S. Patents 4,784,071 and 4,834,008 to the same applicants.

It will be appreciated by those skilled in the art that the invention is not limited to what has been shown and described hereinabove by way of example. Rather, the scope of the invention is limited solely by the claims which follow. 91625/4 - 11 -

Claims (7)

1. Apparatus for preliminary scanning of an object to be sewn on a computerized sewing apparatus comprising: a workholder arranged to hold the object and means for moving the object from said scanning apparatus to a separate sewing apparatus; mean^Tof^scanning segments of said object on the workholder prior to sewing and arranged to provide an output signal corresponding to the scanned image data to the microprocessors ; means for causing relative movement between the workholder and said scanning means in accordance with a pre-determined sewing path during scanning, said means for causing movement being controlled by said microprocessor; means for determining the true edge locations of the object from said output signal; comparator means to compare the true edge locations with pre-programmed expected edge locations and to determine any deviation; and means for determining any necessary modification of the sewing path during processing to compensate for any such deviation .

2. Apparatus according to claim 1 and wherein: said comparator means and means for determining modification are coupled to said microprocessor; and further comprising means coupled to the microprocessor for recording any such modification data for transfer to said computerized sewing apparatus. 91625/4 - 12 -

3. Apparatus according to claim 1 and further comprising means coupled to the microprocessor for recording said edge location data for transfer to said computerized sewing apparatus ; and wherein said comparator means and means for determining modification are coupled to said computerized sewing apparatus.

4. Apparatus for edge location analysis according to claim 1 and further comprising: means for projecting light onto an object whose edge is to be detected; scanner means, whose optical axis is disposed in a diagonal relationship with the light projection source axis, arranged to provide an output signal corresponding to the scanned object; and microprocessor means for analyzing the location of the edge of. the object in accordance with said output signal.

5. Apparatus according to claim 1 wherein said means for scanning segments of said object comprise: a scanning camera disposed above said object; and at least two illuminating lamps coupled to said camera and disposed for diagonal illumination of the edge of said object being scanned, said lamps being activated by said microprocessor.

6. Apparatus according to claim 5 wherein said illuminating lamps comprise optical fibers coupled to a 91625/4 - 13 - light source, each having at its end a shutter element for selectably permitting or preventing passage of light.

7. A method for edge location analysis for use in a computerized sewing system comprising: scanning edges of an object to be sewn in a preliminary scanning cycle to generate images thereof, said scanning cycle comprising the steps of: causing relative motion of the object relative to a scanning assembly in accordance with a predetermined sewing path; scanning sequential segments of the object and generating image date corresponding to each scanned frame; generating true edge location data from the scanned images in an image analysis step, said image analysis step comprising the steps of: determining the true edge locations of the object from said image data; and determining necessary modifications of the predetermined sewing path in light of the true edge location data; sewing adjacent the . object edge utilizing the predetermined path as modified in accordance with the true edge location data on a sewing machine separate from said scanning assembly; and transferring the object to be sewn from said scanning assembly to said sewing machine before said step of sewing. AGENT FOR APPLICANT