The present invention relates to cutting a sheet material, and more particularly to a method and apparatus for acquiring independent images of a plurality of sections of the sheet material, calibrating the independent images aligning the calibrated images to form a composite image and displaying a composite representation of the sheet material for user nesting or computer nesting.
In the creation of many goods such as shoes, certain car seats and even luggage, hides of various animal are used. Although a majority of the hides are of similar size and shape, the nesting of parts to be cut from the hide requires a knowledge of the particular periphery and flaws in the hide.
Traditionally, a hide is disposed on a support surface and inspected by an operator. The operator identifies the periphery and relevant flaws. The operator then manually places patterns of the parts on the hide and cuts the hide accordingly. However, this method is extremely labor intensive and time consuming. This increases the cost of the resulting goods. In addition, skilled operators must be employed to enhance the number of parts that may be cut from a given hide, as costs are also increased when the hide, is not efficiently employed.
Other material such as high end patterned sheet material that is relatively expensive, and custom made sheet materials are often subject to irregularities that preclude fully automated mass handling and processing.
To assist in the handling and processing of such sheet material, prior systems have employed a camera sufficiently spaced from a support surface to allow a single picture to encompass the entire area of the sheet material. While these systems allow an operator to view the entire sheet material, there is insufficient resolution to allow details to be determined. Alternatively, if high resolution cameras are employed, the cameras are prohibitively expensive.
Therefore, a need exists for a system of acquiring and presenting a display of a sheet material to an operator, wherein the display has sufficient resolution to allow for accurate placement of parts to be cut, as well as identification of flaws. The need further exists for such a system that employs commercially available and economically feasible components, while providing a higher resolution than previously available with comparable components.
The present invention provides for the display of a sheet material, wherein the display is constructed from a plurality of independent calibrated images, each image being of a different portion of the sheet material.
Generally, the present invention includes acquiring image data representing a plurality of different portions of the sheet material and forming calibrated image data by calibrating the acquired image data to correct for image distortions such as pincushioning, perspective distortions and rotation. The system then employs the calibrated image data to form a composite representation of the plurality of portions and displays the composite representation to an operator.
In one embodiment, an image capture device acquires a plurality of images of a sheet material, wherein each image corresponds to a particular portion of the sheet material at a recorded location. Each acquired image is then calibrated to address distortions, such as pincushioning. The calibrated images are then aligned by a program based upon the recorded locations to form a composite image that accurately represents the actual sheet material. The composite image is displayed to an operator. The operator is able to recall part patterns from a database and locate the part patterns on the displayed composite image. The operator can thereby readily try a multitude of part locations on the sheet material (hide) without requiring physical manipulation of actual size templates.
In a further aspect of the invention, a computer algorithm or program may be applied to the composite image to automatically locate a periphery of the sheet material, or hide. Once the periphery of the sheet material is identified by the computer, a nesting program may be applied to maximize utilization of the sheet material.
As shown in
Referring to
The sheet material 12 may be any of a variety of materials such as hides, screen printed material, relatively high end or expensive fabrics, custom or hand formed materials or any other sheet material.
Support Surface
The support surface 20 is a surface upon which the sheet material 12 is spread. The support surface 20 may be any of a variety of structures without departing from the broader aspects of the invention. The support surface 20 may be in the form of a conveyor or an elongate flat table which preferably provides a multiplicity of workstations, such as a projecting/identifying station, a cutting station and a picking station. The support surface 20 may be sufficiently long to accommodate a number of spread sheets. Alternatively, the support surface 20 can be in the form of a drum or inclined plane.
The specific construction and material of the support surface 20 are at least partially dictated by the type of sheet material 12 to be cut as well as the particular type of cutter assembly 40. The support surface 20 may be any of a variety of materials, such as a vacuum permeable surface that permits vacuum retention of the sheet material on the support surface, as known in the field. For example, the support surface 20 may be a penetrable bed formed by a continuous bristle blocks or mats, or by a contiguous blocks of foam material. If desired, one or more vacuum chambers can be provided beneath the penetrable bed. Air passages extend through the bed so that the lay up can be compressed and firmly held against the support surface during the cutting operation.
As shown in
Cutter Assembly
The cutter assembly 40 includes a gantry 42 movable relative to the support surface 20 along the length of the support surface in an X direction. The gantry 42 carries a Y-carriage 44 movable perpendicular to the length of the support surface 20. The Y-carriage 44 carries a cutter 46, such as a circular blade, wheel cutter, reciprocating knife, laser or water jet. In a configuration of the cutter assembly 40 having a laser cutter, the laser cutter includes a laser beam generator mounted to the cutter assembly, and a laser cutting head supported by the Y-carriage 44 for movement in a direction parallel to and above the support surface 20. The laser cutting head includes a focusing lens. The laser beam is initially directed from the generator toward the mirror, then reflected by the mirror along a path to be focused by the lens onto the sheet material located on the support surface. By way of example, the laser beam is focused to a 0.002 inch diameter spot on the sheet material. A preferred laser is Coherent General Diamond Series.
Controller
The controller 60 controls the cutter assembly 40 as well as movement of the cutter 46. The controller 60 includes a computer such as an IBM compatible PC that accesses a database of cutting instructions such as a marker, or part peripheries. The controller 60 includes or has access to a memory for restoring the database. The controller 60 includes, or is connected to a storage device for retaining sufficient data to form the marker or the periphery of parts to be cut as well as the programs for nesting and generation of cutting instructions. A marker which includes the cutting instructions is formed and stored in the database. The marker is generated by any of a variety of commercial programs from Gerber, Lectra or Polygon.
Operator input to the controller 60 is accomplished through standard input devices 64 including a keyboard or remote pointing device, such as a mouse/track ball. The remote pointing device may include a plurality of buttons as well as the track ball for moving a pointer or indictor. The controller 60 also includes a motion controller, such as a DMC-600 from Galil for effecting motion of the gantry, Y-carriage and the cutter. Industry available software is employed to effect motion of the cutter along a path in response to cutting instructions stored in the database.
It is understood that those skilled in the art, that the controller 60 may employ software to directly control the gantry 42, the cutter 46, the conveyor (if used), all critical input and output such as an emergency stop and cutter termination and other safety related functions, if present, using an operating system in the controller. Alternatively, a commercially available Computer Numerical Control (CNC) controller may be provided between peripheral devices such as the scanners and digitizers and the work station to directly control the devices. CNC controllers are widely available from many suppliers such as Model 8400 marketed by Alan Bradley (Cleveland, Ohio).
The controller 60 also includes or is operably connected to a nesting program. The nesting program may utilize any of the commercially available platforms.
The controller 60 includes a display 66 for displaying the image on a CRT or LCD, or other display. The display is accessible to the operator and is preferably of sufficient size and resolution to permit utilization of the resolution of the acquired image data.
Database
The database includes the periphery of the parts P1, P2, P3 . . . , as well as notch and drill information. That is, the database includes the marker. Preferred orientation of the cut parts or sequencing instructions may also be included in the database as well as any grade requirements for the sheet material from which the part is to be cut.
The database is generated from a variety of inputs including a digitizer/scanner, operator input, part design parameters and nesting programs. It is understood the database may be a single database or a plurality of limited databases or files. Alternatively, the database may be formed of a number of linked or connected files.
Image Capture System
The image capture system 80 includes a camera 82 and associated hardware and software for processing a captured image.
The camera 82 is connected to the gantry 42 and carriage 44 to be movable with the cutter 46. Specifically, the camera 82 is connected to the Y-carriage 44 and is thus relatively near the support surface 20 and any sheet material 12 disposed on the support surface. The camera 82 may be between from approximately 3 inches to approximately 30 inches from the support surface 20. A preferred distance is approximately 16 inches from the support surface 20. The actual distance between the camera 82 and the support surface 20 is at least partially dictated by the particular construction of the cutter assembly 40 and the associated gantry.
As the camera 82 is located on the cutter assembly gantry 42 and carriage 44, and therefore, closer to the sheet material 20 than prior systems, the camera employs a relatively wide angle lens. The lens is sufficient to capture an area of approximately 15 inches by approximately 12 inches of the sheet material on the support surface spaced approximately 16 inches from the camera.
The camera 82 is a readily available camera having a standard resolution of approximately 768 pixels by 576 pixels. While higher resolution cameras may be employed, the present configuration allows the use of relatively inexpensive cameras to provide a relatively high resolution image to a substantially larger area. A preferred camera 82 is a commercially available Hitachi KP-M1E, or equivalent.
As the lens of the camera 82 is a relatively wide angle lens, the lens produces optical distortions due to the short focal length in relation to the size of the portion imaged. This is not a perspective “distortion” that results when a camera is tilted, but a true optical aberration. Straight lines appear curved towards or away from the extreme corners of the image. Straight lines that pass through the center of the image are unaffected. This is sometimes called “barrel” or “pincushion” distortion. That is, a nonlinear geometrical aberration occurs in which magnification changes with field height (i.e. no distortion at center), defined at maximum field. If imaging a square grid, positive distortion gives a pincushion effect while negative distortion yields a barrel effect. The pincushion distortion is of particular importance in the present invention.
A frame grabber for digitally processing image data is employed in the controller 60. A preferred frame grabber includes the Data Translation 3155, a commercially available board for computers.
In one configuration of the apparatus of the present invention, a lighting system may be employed in conjunction with the camera 82 and software. The lighting system provides either a uniform or known and controllable lighting intensity for illuminating the sheet material and particularly the local portions of the sheet material 12 that are being imaged.
Calibration
The present system includes a calibration for accommodating distortion of the captured images of the portions of the sheet material 12. Specifically, the calibration accommodates at least pincushioning and brightness.
Referring to
That is, as the image data is captured pincushioning is introduced into the data. The calibration program calibrates the captured image data to correct for the distortions and provide an accurate correspondence between the captured image data and the actual sheet material 12.
In addition, the calibration program may account for brightness of the captured image data. That is, for a given lighting system, it is typical that the light is non uniform across the portion of the sheet material imaged, much less across the entire sheet material to be imaged.
Referring to
As the controller 60 then has access to image data of portions of the sheet material 12 and knows the specific location of the image data as well as area of the respective image data, the controller can readily align the calibrated portions to recreate sections or even the entire sheet material as a composite image 92. The composite image 92 is readily shown on the display to the operator.
Operation
In operation, a sheet material 12, such as a hide, is disposed on the support surface.
The gantry of the cutter assembly 40 that retains the camera 82 is moved with respect to the support surface 20 to locate the camera at a given location. An image of the relevant portion is then acquired by the image capture system 80 and the controller 60. The image data is recorded along with the location of the portion imaged. As the camera 82 images an area that is substantially less than the total area of the hide, a plurality of images must be acquired to capture the entire relevant area of the sheet material 12. That is, as the camera 82 images an area of approximately 15 inches by approximately 12 inches, within a hide area that may span 60 inches by 120, a plurality of portions 94 are imaged as shown in FIG. 3.
The image capture system 80 acquires image data for a sufficient number of portions 94 to encompass the relevant area of the sheet material 12. In a preferred operation, the image capture system 80 acquires a sufficient number of images of portions 94 to encompass the entire sheet material 12. In addition, to ensure that distortions do not result in a failure to acquire sufficient data, the portions 94 of the sheet material 12 are slightly overlapped. The amount of overlap is sufficient to substantially preclude the omission of data intermediate adjacent imaged portions 94.
The calibration program then calibrates each acquired image to correct for pincushioning and form a tile 96. The tile 96 is a calibrated image of a portion of the sheet material 12. Thus, the periphery of each tile 96 accurately represents the actual corresponding portion of the sheet material 12. As the periphery of each tile 96 is accurate, the program then aligns the respective tiles based upon the recorded location of the camera 82 at the moment of capture and a requirement that a continuous line segment cross adjacent tiles in a continuous manner. Depending upon the program, the tiles 96 may be cropped and aligned to abut adjacent tiles. Alternatively, as shown in the right hand side of
The program is thus able to create a composite representation 92 of the entire sheet material 12 from a plurality of tiles 96, wherein each tile is an image of less than the entire area of the sheet material. That is, the present system acquires data representing subsections of the entire relevant area, corrects/calibrates each subsection then aligns the subsections to create a composite image 92 that accurately portrays the particular sheet material 12.
In a further preferred configuration, the calibration program accommodates the variations in lighting intensity and corrects the intensity of each tile. This may be done before or after each tile has been aligned to form the composite image.
The composite image 92 is then displayed to the operator on the display 66. The operator may then selectively recall part patterns from the memory and locate the parts with respect to the composite image on the display 66. Upon obtaining a desired location of the parts with respect to the composite image 92, the controller may give the instruction to cut the sheet material accordingly.
The present system also provides recognition of flaws in the sheet material 12. Once the sheet material 12 is spread on the support surface 20, the operator visually inspects the sheet material and marks the flawed areas on the sheet material. A chalk or other marking device recognizable by the image capture system 80 is used. Thus, upon the respective portions being captured and calibrated tiles 96 formed, the captured image data includes flaw locations and types, if so marked by the operator. The flaw information can then be accommodated upon locating the parts on the display of the composite image 92.
It is further contemplated that a more automated configuration of the system may be provided. Specifically, the controller 60 may be provided with an edge recognition program or software. The edge recognition program operates on the acquired and tiled composite image 92. The controller 60 may thus learn the periphery of the respective sheet material 12. The nesting program may then be employed to locate the necessary parts with respect to the hide and its periphery.
Alternatively, the controller 60 may provide a checking of the operator selected nesting. Further, if flaws are marked prior to acquiring the respective images, the controller 60 may automatically identify the flaws as well as the periphery of the sheet material 12 and automatically nest the parts with respect to a particular sheet material.
As the present system locates at least a portion of the image capture system 80 on the cutter assembly 40, the overhead gantry of prior systems is not required. Thus, the present system requires fewer components. In addition, by calibrating the acquired image data prior to forming the composite image 92, accuracy and speed of the system is increased.
The present system also provides a relatively high resolution image of the sheet material 12, by capturing a plurality of sections, portions, of the sheet material and then creating a composite image. For example, the system may be employed to form a composite image of a sheet material having an area of 10′ by 12′ or even a web like sheet of 6′ by 30′ to 40′. The relation of the tiles (image sizes) and, the resolution of the camera is selected to provide the necessary detail, in pixels, of resolution. Thus, the system segments, or breaks the sheet material into a plurality of portions and each portion is captured at the available resolution, calibrated and assembled with respect to adjacent tiles 96 to form the composite image. The composite image 92 thus has significantly higher resolution than previously available with the same camera resolution.
While a preferred embodiment of the invention has been shown and described with particularity, it will be appreciated that various changes and modifications may suggest themselves to one having ordinary skill in the art upon being apprised of the present invention. It is intended to encompass all such changes and modifications as fall within the scope and spirit of the appended claims.
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