IL101938A - Method and apparatus for computerized working of precious stones - Google Patents

Description

METHODANDAPPARATUS FOR COMPUTERIZED WORKING OF PRECIOUS STONES Method and Apparatus for Computerized Working of Precious Stones Field of the Invention The various stages of the processing of precious stones require great precision and diagnostic skill. Each stone has to be examined by a highly skilled craftsman to determine the location of the basal plane and of the central axis which enable the maximal finished stone in conformance with the specific structural requirements of the; workshop.

A skilled decision of the basal plane and central axis of a rough stone requires information concerning imperfections in the circumference of the stone such as "knives" - radial incisions which unless carefully observed and taken into consideration will ruin the finished stone. In order to locate all such imperfections without any exception the stone must be viewed and examined from all directions. Any planar view of the stone may hide several knives which lie in a different plane.

The bruting process of diamonds is also dependent upon the experience and skill of the individual worker who must be well trained to estimate the actual radius of the rough diamond at work and to achieve the final radius with precision.

It has been the goal of the industry for quite some time to eliminate the dependence upon skilled craftsmen and to achieve improved precision and yield with the aid of computer processing of the optical data available by viewing the stone from various perspectives and computer controlled working of the stone.

In IL 087499 an apparatus is described whereby a silhouette image of the stone is created by processing a series of camera shots taken from several facets of the stone as it revolves on its dope.

The apparatus of IL 087499 is only applicable to stones that were previously sawn in half, such stones constituting less than 50% of the variety of rough diamonds. Another precondition for the operation of the said apparatus is that the position of the table must be fully predetermined.

It is a further disadvantage of the said apparatus that only a two dimensional image of the stone can be created whereby some of the knives that occur on the perimeter of the base may remain unobserved. Under those limitations the method of IL 087499 cannot be operated by other than highly skilled workers capable of observing and taking into consideration the actual three dimensional data of the stone.

A further drawback of IL 087499 lies in the stone being viewed indirectly by artificial light through an array of mirrors allowing for multiple distortions which affect the precision of the calculations involved in data processing as well as the precision of the image.

The same array of mirrors is a limiting factor in minimization of the apparatus.

The only reference to the third dimension in IL 087499 is made by measuring the height of the stone and taking it into account in the calculations.

The method of IL 087499 involves the use of a dope that does not fit into existing machinery and requires considerable investment in expensive special dopes and adaptation of existing machines for the system to be introduced into the workshop.

Object of the Invention It is the object of the present invention to provide a method and apparatus for the processing of rough stones which overcomes the disadvantages of the prior art.

It is specifically the object of the present invention to enable determination of the optimal position of the board plane as well as the central axis of a stone and to provide a small size apparatus at low cost, available to most of the workshops in the art and compatible with all existing machinery.

It is further the object of the present invention to provide a method by which a true three dimensional real time graphic image of a rough stone can be achieved through continuous presentation of "slices" accomplished with the aid of original algorythms specially developed for the purposes of the apparatus and by using an ordinary PC.

Another object of the invention is to achieve an accurate image of the real stone by direct viewing of the stone in natural daylight while dispensing with any auxiliary optical means such as mirrors, prisms or collimation filters. The invention thus replaces the magnifying glass with a much more convenient means of accurate observation, the said accurate image being comparable with the graphic image by simultaneous display.

According to the invention, the th^ee dimensional images created by the unique processing method are compared with variations of a three dimensional image of a finished stone as created by the computer to conform with the limitations of parameters prestored in the computer memory whereby the size and placing of the finished stone allowing for the biggest finished stone as well as its position within the rough stone are suggested by the computer. The parameters for the comparison process are preselected by the computer in accordance with an aesthetic criterion. A further selection of parameters is effected by elimination of stones that do not conform with one of several aesthetic criterions chosen by the user. The said aesthetic criterion defines the relations between the various dimensions of the finished stone such as the pavillion angle of a diamond.

It is a further advantage of the invention that a presentation is made upon the display means of the selected finished stone within the real magnified three dimensional image of the rough stone and the operator may "negotiate" with the computer by controlling the position of the selected stone within the image of the rough stone and arranging it according to any additional requirements.

According to the method of the invention the processor directly controls a pair of powerful electric motors that execute the centring of the stone on the dope according to the data computed by the processor with a high degree of precision and the error introduced by manual operation that exists in the prior art is eliminated.

According to the method of the invention the angle of bruting of a diamond, the amount of material to be removed by bruting and the number of steps required to remove the said amount are calculated by the processor and the finished radius of the diamond is computer-controlled throughout the bruting process.

It is a further advantage of the invention that said computer controlled process is applicable in existing automatic bruting machinery.

Description of a Preferred Embodiment of the Invention According to the present invention a method and apparatus for computerized c centring, measuring and appraising of rough stones and computer controlled bruting of diamonds is provided comprising a work surface, two standard video cameras positioned for top view photography and side view photography respectively, a transmission gear assembly for fine adjustment of the cameras, step engines enabling 360° rotation of the rough stone and its centring upon the dope, mechanical centring device, servo mechanism, a dope computer, a graphic screen, and a "mouse".

According to the method of the invention a rough stone is mounted on a dope and viewed from above by the upper video camera at a multitude of cross sections which scan the stone along the perpendicular axis while a continuous rotation of the stone around the same axis enables a scan of the whole perimeter of the stone. At the same time the lower video camera views the stone along the horizontal radial axis that coincides with the optical center of the camera at a given moment during the rotation, at a multiple of cross sections along the said axis and perpendicular to said axis.

According to another aspect of the invention, during photography a continuous real three dimensional image of the stone is presented on the screen and may be viewed from all sides as well as from above while being compared with variations of the optimum finished stone suggested by the computer.

According to a further aspect of the invention, data from the various views of the two cameras accumulated while the rough stone completes a 360° revolution are processed by the PC in real time into a continuous three dimensional "sliced" graphic image of the stone which immediately appears on the screen and which is rotatable around any of its axes. At the same time the data of the rough stone are stored in the computer memory for future reference.

According to another aspect of the invention the photography data are processed to give the primary weight of the rough stone as a function of its volume and said primary weight is presented on the screen.

According to a further aspect of the invention a three dimensional graphic image of a finished stone - said image being created by the processor computer memo)Ύ which suit the aesthetic criteria and any other requirements characteristic to t e workshop operating the apparatus as well as the size of the rougl* stone under inspection - instantly appears within the previously de cribed three dimensional image of the rough stone, in a position which was calculated by the processor to give the optimum yield, that is the ldi"6est finished stone that can be achieved after elimination of the flaws observed in the rough stone.

According to * further aspect of the invention the weight of the finished stone and the efficiency ratio appear on the screen.

According to another aspect of , the invention the placing of the finished stone image wi hin the rough stone image is controllable by the operator to achieve a posl'ion of the central axis and/or board plane that differs from that calculate' hy the processor, thus enabling the experienced operator to adapt the finished stone to any further considerations arising from the observation ø' tne stone by the human eye or to additional requirements whether aesthft ic or economic.

According to a further aspect of the invention the photography data are processed by averaging the various observed axes to give the rotation axis of the rough !- one according to which the centring is performed.

According to a further aspect of the invention the actual centring is effected by t:l»e said step motors operating under control of the processor to move the roufih stone to its proper position on the dope by means of a threaded rod revolving within a rod housing.

According to * further aspect of the invention the data of the position of the finished diamond within the rough diamond are further processed to determine the appropriate angle for bruting as well as the final radius of the table the amount of material to be removed through bruting and the the computer memory. The centred rough diamond and dope are then removed from the apparatus to be bruted at any convenient time.

At the bruting the pre stored bruting angle and number of steps are fed to an automatic bruting machine of any existing type. The bruting process itself is computer-controlled so that a precise finished radius is attained.

Description of the Drawings Fig. 1 is a side elevational view of a preferred embodiment of the apparatus of the invention.

Fig. 2 is a side elevational view of a perpendicular section through points I-II of fig. 1.

Fig. 3 is an enlarged top view of the part of Fig. 1 delineated by dashed line E.

Fig. 1 shows mechanical centring device A, movably mounted onto support column D and comprising fine adjustment means F for moving the stone to the focal point of viewing means B;C, computer E, dope G with glued rough stone H, viewing means B;C movably mounted upon support columns I;J respectively for viewing the stone from above and from the side; and working surface K supporting said columns I;J;D. Dashed line L delineates area enlarged in Fig. 4.

Fig. 2 shows motors 1;4, gears 2, protruding part of rod 3, threaded part of rod 3a within rod housing 5, dope 6, Fig. 3 shows gears 2 for rotating dope-moving rod 3, centring dope 6, rod housing 5.

Claims (2)

Claims:

1. Apparatus for precise measuring, appraising and centring of rough stones comprising: optical means for viewing and photographing a rough stone from various perspectives by natural light; a processor; a memory; a mouse and a display; a servo mechanism and motors; whereby said rough stone is viewed by said optical means; a real time three dimensional image of said rough stone is displayed upon said display means; said processor creates a real time continuous three dimensional graphic image of said rough stone based upon said optical data received from said optical means; said graphic image is rotatably displayed upon said display means in real time; said processing means creates an image of an optimal finished stone using parameters that conform , with the limitations stored in said memory; said limitations being determined in accordance with preferred aesthetic criteria; said processing means computes the optimum position of the central axis and the optimum position of the board of said optimal finished stone within said rough stone; whereupon said image of said optimal finished stone is displayed within any of said three dimensional images of said rough stone at said optimal position.

2. Apparatus according to claim 1 whereby said optimal position of said optimal finished stone is controllable by the user in accordance with any further requirements. Apparatus according to claims 1 and 2 whereby precise centring is effected by said motors moving the said rough stone, controllably by said processor via said servo-mechanism, to the location upon the dope that conforms with said optimal central axis and said optimal position of the board stored in the memory of said processor. Apparatus according to claim 3 whereby said processor means determines the amount of material to be removed from said rough stone and the number of steps required for removing said material, and said data are stored in said memory. Apparatus according to claims 1-4 whereby said rough stone is a rough diamond. Method for appraising, measuring and centring a precious stone comprising the steps of claims 1-5. Method according to claim 6 whereby a rough diamond centred upon said dope is fitted into existing automatic bruting machinery to cut the girdle of said diamond. Method according to claim 7 whereby the bruting of said rough diamond is controlled by said data from said processor means to stop the bruting with precision when the optimal radius has been achieved. Apparatus for measuring, appraising and centring a rough stone substantially as shown and described hereinabove. Apparatus for measuring, appraising and centring a rough stone substantially as shown in the drawings. Method for measuring, appraising and centring a rough stone substantially as shown and described hereinabove. Method for bruting a diamond substantially as shown and described hereinabove. H iaanriaa CCaallddeernon, Adv. 00108/hanard/h6 for the applicant