JP3281135B2 - Automatic measurement method for diamond cut evaluation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CCD camera (Charge Coupled Diviced) in which unpolished or polished diamond is placed on a stage interlocked with a stepping motor controlled in advance by a computer.
The present invention relates to a method for taking a picture with a camera, processing the data with a graphic module and a computer, automatically measuring the size and angle of each part of the diamond, and thereby evaluating the cut of the diamond.

[0002]

2. Description of the Related Art Polished diamond shapes are shown in FIGS.
3 is shown. Round diamonds of this shape
It is called brilliant cut and more than 95% of diamonds on the market have this shape. An important evaluation criterion is how the dimensions and angles of each part of the polished diamond are polished, as shown in FIG. 4, which is an important evaluation criterion. In effect, most of the shine of diamonds
It is not an exaggeration to say that it depends on this cut evaluation.

According to a conventional evaluation method, the following is performed. Cut evaluation is determined by two items, proportion and finish. As shown in Table 1, the proportion evaluation items are [% of table diameter], [crown angle], [girdle thickness], [pavilion depth], [overall depth], [curet size], [Ratio between girdle facets and star facets] is an evaluation item, and the finish is subdivided into two items: [polished (polished state)] and [symmetric (symmetric)].

[0004]

[Table 1]

[0005] The dimensions of each evaluation item listed in Table 1 were measured with a caliper or liberic gauge and a proportion scope (simple projection device), and the measured data was applied to the following evaluation tables (Tables 2 to 10). Judgment of diamond cut evaluation.

[0006]

[Table 2]

[0007]

[Table 3]

[0008]

[Table 4]

[0009]

[Table 5]

[0010]

[Table 6]

[0011]

[Table 7]

[0012]

[Table 8]

[0013]

[Table 9]

Based on the deductions in Tables 2 to 9, the overall evaluation of the cut is determined as shown in Table 10 below.

[0015]

[Table 10]

In addition to the sum of the deductions for each item described above, Table 11
When the condition shown in (1) is satisfied, the corresponding cut evaluation is made.

[0017]

[Table 11]

The above table is based on the cut evaluation method of the Central Jewelry Laboratory, which has been in effect since September 3, 1990 and evaluates 80% or more of the diamonds circulating in Japan. The values of each of the evaluation items subdivided into these very many branches were measured with a vernier caliper or liberic gage and a proportion scope (simple projection device), and the measured data evaluated were as shown in Table 10. It was a conventional method to determine whether the diamond was cut properly by applying it to an evaluation table.

[0019]

According to the above conventional method, evaluation by a highly skilled judge is required, and measurement data obtained by a caliper or a proportion scope lacks accuracy and is extremely poor. Time-consuming measurement work. On the other hand, according to the measuring method of the present invention, it is simple and rich in accuracy, and can be measured in a short time, and there is no need for judgment by a skilled judge. Has the effect of being able to do so.

[0020]

According to the present invention, there is provided a measuring system comprising a light source, a stepping motor, a measuring stage, a lens, a CCD camera, and a graphic module, which is arbitrarily set on the measuring stage. The silhouette of the diamond is imaged with a CCD camera by transmitting light from the light source,
Each of the images is rotated by 4.5 degrees by a stepping motor receiving a signal under computer control, and images are taken.
The silhouette of each time is imaged, the captured image is sent to the graphic module, the size and angle of the diamond are calculated by computer processing, and the bezel facet position on the crown side and the main on the pavilion side are calculated by computer processing based on the obtained data. The facet position is determined, the stepping motor is further rotated to a predetermined position based on the obtained crown angle and pavilion angle, and eight images are taken at the crown angle position and eight times at the pavilion angle position. And subjecting it to computer arithmetic processing to automatically measure the size and angle of each part of the diamond.

[0021]

The structure of the present invention will be described in more detail below. [1] In FIG. 5, a computer-controlled stepping motor (3) having a hollow rotating shaft (4);
The rotating stage (4) is interlocked with the disk-shaped measuring stage (2), and the rotating shaft (4) is suctioned through a hollow hole by a vacuum pump. A measuring diamond is set at the center of the measuring stage (2) with the table surface facing down. Light is transmitted through the diamond by the light source (5), and the silhouette is imaged by the CCD camera (7) through the lens (6). After receiving the signal from the computer, rotate the stepping motor (3) by 4.5 degrees,
An image is taken again, and it is further rotated by 4.5 degrees and this operation is repeated. The captured images are transmitted to the graphic module, and this operation is repeated 40 times in total, so that the entire circumference of the diamond is imaged at 4.5 degrees × 40 × 2 = 360 degrees. After the 40 times of imaging, the size and angle of the diamond are determined by computer arithmetic processing based on the data transmitted to the graphic module.

[2] Further, based on the obtained data, the position of the bezel facet on the crown side and the position of the bezel facet on the pavilion side are obtained, and the angle (crown angle) between the bezel facet on the crown side and the girdle part and the pavilion side The angle formed by the main facet and the girdle part (pavilion angle) is determined by computer processing. In this measurement process, since the diamond (1) is arbitrarily set on the measurement stage (2), the crown angle and the pavilion angle are not accurately measured by the imaging process of the silhouette forty times. It is necessary because it is not limited. Based on the obtained crown angle position and pavilion angle position, the stepping motor (3) is rotated to a predetermined position, and the silhouette is imaged eight times at the crown angle position and eight times at the pavilion angle position. Each captured image is transmitted to the graphic module and subjected to computer arithmetic processing in the same manner as in [1].

[3] Data measured in [1],
The following points are measured based on the data measured in [2]. Girdle diameter = 40 places, overall depth = 1 place, crown height = 8 places, crown angle = 8 places, intersection ratio of star facet and girdle facet = 8 places, girdle thickness (valley) = 16 places Girdle thickness (mountain) = 16 places, pavilion depth = 8 places, pavilion angle = 8 places, curette size = 1 place. By applying the data measured by the above operations to the evaluation tables of Tables 2 to 10, the cut evaluation of the diamond (1) to be obtained can be obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The diamond (1) is set on a measurement stage (2). The measurement area can range from 1 mm to 20 mm (0.01 carat to about 30 carats). The shape of the measured diamond is a round brilliant cut and a main fancy cut. Light is transmitted from the light source (5) to the diamond (1), and a silhouette from the side is imaged by the CCD camera (7). The captured silhouette is represented by a set of 460 vertical dots. When a distance of about 5 mm is represented by 460 dots, 5 mm ÷ 460 dots = 0.0109 mm, and one dot corresponds to 0.0109 mm. As shown in FIG. 6, the image of the screen captured by the CCD camera (7) is displayed with the diamond (7) black and the background white.

This image is subjected to data processing by a graphic module and a computer, and the following measurement sites are automatically measured. (A) the average value of the girdle diameter of the diamond (1);
Displays the minimum and maximum values. (B) In the same manner, both the actual depth and the percentage of the total depth are displayed. (C) In the same manner, both the actual size and% of the table% are displayed (data at eight locations can be displayed). (D) Display both the actual size and% of the crown height and angle (data can be displayed at eight locations). (E) In the same manner, both the actual size and the percentage of the pavilion depth and angle are displayed (data at eight locations can be displayed). (F) Same, curette size (g) Same, mean, minimum, and maximum values of girdle thickness% are displayed. These parts are programmed in advance to be displayed automatically, but if there are other parts that require data, they can be measured by interactive computer operation according to the diamond to be processed.

[0026]

[Effect] Just by setting the diamond on the measurement stage, the cut evaluation can be easily performed without touching the hand. The measurement time is on average 15-20 seconds per piece, which is very fast. The predicted error is only one hundredth of a millimeter, which is extremely high in accuracy compared to the conventional manual measurement.

[Brief description of the drawings]

Fig. 1 Upper part (crown) of polished diamond (Brillian cut)

FIG. 2 Same bottom (pavilion section)

[Fig. 3]

FIG. 4 shows an example of a cut evaluation value as viewed from the side.

FIG. 5 is a flowchart according to the method of the present invention.

Fig. 6 Image of diamond captured by CCD camera

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diamond 2 Measurement stage 3 Stepping motor 4 Vacuum pump 5 Light source 6 Lens 7 CCD camera

Claims (1)

(57) [Claims] 1. A diamond cut evaluation measuring system comprising a light source, a stepping motor, a measuring stage, a lens, a CCD camera, and a graphic module, wherein a diamond arbitrarily set on the measuring stage is
Transmit the light from the light source to make the diamond silhouette C
Images are taken with a CD camera, each is rotated 4.5 degrees by a stepping motor that receives a signal under computer control, each image is taken, a total of 40 silhouette images are taken, and the taken image is sent to a graphic module, and the image is sent to a graphic module. The size and angle of the diamond are obtained, the bezel facet position on the crown side and the main facet position on the pavilion side are obtained by computer processing based on the obtained data, and the stepping motor is further predetermined based on the obtained crown angle and pavilion angle. Rotate to the position where the crown angle is 8
A method of automatically measuring the size and angle of each part of the diamond by imaging the image eight times at the position of the pavilion angle, sending the captured image to the graphic module and subjecting it to computer arithmetic processing.