KR102229270B1 - Method and 3d oral scanner for forming structured light for a subject using a complementary color pattern - Google Patents

Abstract

The present invention enhances the saturation of the color pattern by reversing the color pattern formed through a de bruijn sequence, and deletes and corrects the remaining areas except for the color pattern with enhanced saturation, so that a subject in the oral cavity within the image data is For example, a method of forming structured light for a subject in the oral cavity using a complementary color pattern that enables robust real-time image data to be obtained by deleting colors other than the color pattern (e.g., unique color to be scanned, surrounding color, etc.), and 3D using the same It relates to an oral scanner.

Description

A method of forming structured light for a subject in the oral cavity using a complementary color pattern, and a three-dimensional oral scanner using it {METHOD AND 3D ORAL SCANNER FOR FORMING STRUCTURED LIGHT FOR A SUBJECT USING A COMPLEMENTARY COLOR PATTERN}

The present invention relates to a method of forming structured light for an intraoral subject using a complementary color pattern and a three-dimensional oral scanner using the same, and more specifically, in forming structured light on an intraoral subject, brine By reversing the color pattern formed through the sequence (De bruijn sequence), the saturation of the color pattern is enhanced, and the remaining areas except for the color pattern with enhanced saturation are deleted and corrected. A method of forming a structured light for an intraoral subject by using a complementary color pattern that enables robust real-time image data to be obtained by deleting colors (e.g., an inherent color to be scanned, an ambient color, etc.), and a 3D oral scanner using the same. .

In general, a dental 3-Dimensional scanner refers to image information identical to the actual image of the subject by deriving a 3D image from a 2D image obtained by photographing a subject having a three-dimensional shape such as an oral tooth. This device is used to obtain a 3D image of the shape of a tooth and oral tissue during dental treatment such as restoration or prosthesis of a tooth.

At this time, a two-dimensional image is obtained by forming structured light on such an intraoral subject. In the past, the texture of the subject to be scanned (for example, teeth, etc.) greatly affects the quality of the 2D image, causing noise. There were quality problems such as.

Therefore, there is a need for a technology for obtaining high-quality image data regardless of the texture of a subject to be scanned.

Korean Patent Publication No. 10-2011-0068954

The present invention was derived to solve the above-described problem, and in forming structured light on a subject in the oral cavity, the color pattern formed through a de bruijn sequence is reversed to enhance the saturation and saturation of the color pattern. Complementary to obtain robust real-time image data by deleting and correcting the rest of the area except the color pattern that has been enhanced in the image data, except for the color pattern (e.g., the unique color to be scanned, the surrounding color, etc.) An object is to provide a method of forming structured light for an intraoral subject using a red color pattern and a 3D oral scanner using the same.

A method of forming structured light for an oral subject using a complementary color pattern according to an embodiment of the present invention includes forming a color pattern and projecting it onto an intraoral subject, and inverting the formed color pattern by inverting it. Forming a pattern and additionally projecting it onto an intraoral subject, and correcting the image data based on the projection area of the color pattern and the inversion pattern in the image data for the intraoral subject. .

In one embodiment, the step of forming the color pattern and projecting it onto an intraoral subject may be characterized in that the color pattern is formed using a de bruijn sequence.

In one embodiment, as the inversion pattern is additionally projected onto the color pattern projected onto the intraoral subject through the 3D oral scanner, the color saturation for each color constituting the color pattern is applied to the intraoral subject. It can be characterized in that the saturation is higher than the contrast when the bay is projected.

In one embodiment, in the image data for the intraoral subject, the step of correcting the image data based on the projection area of the color pattern and the inversion pattern comprises the color pattern and the inversion in the image data for the intraoral subject. Distinguishing the projection area and the non-projection area of the pattern, deleting the non-projection area from the image data of the intraoral subject, and storing image data on the intraoral subject from which the non-projection area has been deleted It can be characterized by that.

A 3D oral scanner that forms structured light for an intraoral subject using a complementary color pattern according to another embodiment of the present invention includes a color pattern forming unit forming a color pattern projected onto the subject in the oral cavity, and the formed color pattern. The color pattern and the inversion pattern in the image data of the inverted pattern forming unit to form an inverted pattern by inverting, the projection unit for projecting the formed color pattern and the inverted pattern to an intraoral subject, respectively, and the intraoral subject. It may be characterized in that it comprises a correction unit for correcting the image data based on the projection area.

In one embodiment, the color pattern forming unit may be characterized in that it forms the color pattern using a de bruijn sequence.

In one embodiment, as the inversion pattern is additionally projected onto the color pattern projected onto the intraoral subject through the 3D oral scanner, the color saturation for each color constituting the color pattern is applied to the intraoral subject. It can be characterized in that the saturation is higher than the contrast when the bay is projected.

In one embodiment, the correction unit divides the projection area and the non-projection area of the color pattern and the inversion pattern from the image data of the intraoral subject, and deletes the non-projection area from the image data of the intraoral subject. , It may be characterized in that the image data of the intraoral subject from which the non-projection area has been deleted is stored.

According to an aspect of the present invention, by reversing the color pattern to enhance the saturation of the color pattern and by deleting and correcting the remaining areas except for the color pattern with enhanced saturation, the intraoral subject within the image data is not affected by the texture of the subject. It has the advantage of obtaining more robust real-time image data by deleting colors other than the color pattern (for example, a scan target intrinsic color, an ambient color, etc.).

1 is a diagram schematically showing the configuration of a 3D oral scanner 100 for forming structured light for an intraoral subject using a complementary color pattern according to an embodiment of the present invention.
2 is a diagram illustrating an example of applying a brew sequence to a color change of a color pattern.
3 is a diagram illustrating a state in which the color pattern formed through the color pattern forming unit 110 shown in FIG. 1 is projected by the projection unit 130.
FIG. 4 is a diagram illustrating a state in which the inversion pattern formed through the inversion pattern forming unit 120 shown in FIG. 1 is projected by the projection unit 130.
FIG. 5 is a diagram illustrating a state in which an object to be scanned through the correction unit 140 shown in FIG. 1 is compared to surrounding colors.
6 is a diagram illustrating a state in which the color patterns and inversion patterns shown in FIGS. 3 to 5 are combined.
7 is a sequence of steps of forming structured light for an intraoral subject using a 3D oral scanner 100 that forms structured light for an intraoral subject using the complementary color pattern shown in FIG. 1 It is a drawing as shown.

Hereinafter, a preferred embodiment is presented to aid the understanding of the present invention. However, the following examples are provided for easier understanding of the present invention, and the contents of the present invention are not limited by the examples.

1 is a diagram schematically showing the configuration of a 3D oral scanner 100 for forming structured light for an intraoral subject using a complementary color pattern according to an embodiment of the present invention.

Referring to FIG. 1, a 3D oral scanner 100 for forming structured light for an intraoral subject using a complementary color pattern according to an embodiment of the present invention has a large color pattern forming unit 110, forming a reverse pattern. The unit 120, the projection unit 130, and the correction unit 140, and a digital projector that irradiates the pattern light to the intraoral subject by forming a predetermined pattern on the light emitted from the light source, and the intraoral subject by the pattern light. An image sensor that senses 2D image data formed by reflected reflected light, a focus lens that controls pattern light emitted from a digital projector to an intraoral subject and reflected light reflected by the pattern light, optical parts, and 2D image data. It may be configured to include a computer that converts into 3D image data and a wireless transmission device capable of wireless data communication with the computer.

The 3D oral scanner 100 serves to irradiate structured light (pattern light) onto an intraoral subject (eg, oral structure) and acquire image data formed by reflected light reflected from the intraoral subject.

In this case, the color pattern forming unit 110 forms a color pattern among the structured lights projected onto the intraoral subject, and the formed color pattern may be projected onto the intraoral subject through the projection unit 130.

The color pattern forming unit 110 forms a color pattern for an intraoral subject using a de bruijn sequence, which will be described in more detail with reference to FIG. 2.

2 is a diagram illustrating an example of applying a brew sequence to a color change of a color pattern.

Referring to FIG. 2, the brew sequence generates a sequence without duplicates. For example, in the case of a sequence consisting of 0, 0, 0, 1, 0, 1, 1, 1, a 3-digit binary number When forming a sequence without duplicates (0,0,0), (0,0,1), (0,1,0), (0,1,1), (1,0,0), (1, It is represented as 0,1), (1,1,0), (1,1,1), etc.

At this time, when applying the brew sequence to the color change of the color pattern,

If you add 1 to each digit of the sequence 0, 0, 0, 1, 0, 1, 1, 1, it becomes a sequence of 1, 1, 1, 2, 1, 2, 2, 2, where each digit is When expressed in binary numbers (0,0,1), (0,0,1), (0,0,1), (0,1,0), (0,0,1), (0,0, It is represented by 1), (0,0,1), (0,0,1).

When this binary number is considered as an RGB channel and the color is changed by XOR operation, the edge of the part where the color changes has a unique index by the brew sequence.

The inversion pattern forming unit 120 inverts the color pattern formed through the color pattern forming unit 110 to form an inversion pattern, and the formed inversion pattern is projected onto the oral subject through the projection unit 130. I can.

The projection unit 130 projects a color pattern and a reversal pattern formed from each of the color pattern forming unit 110 and the reversing pattern forming unit 120 to an intraoral subject.

More specifically, the projection unit 130 preferentially projects the color pattern formed through the color pattern forming unit 110, and additionally projects the inversion pattern formed through the reversal pattern forming unit 120 thereon, The saturation of the color pattern increases due to the combination between the and inversion patterns. This will be described with reference to FIGS. 3 to 6 to be described later.

The correction unit 140 serves to correct the intraoral subject to stand out more based on the projection area of the color pattern and the inversion pattern in the image data photographing the intraoral subject.

More specifically, the correction unit 140 separates the projection area and the non-projection area of the color pattern and the reverse pattern from the image data of the intraoral subject, and deletes the non-projection area from the image data of the intraoral subject. After that, the image data of the intraoral subject from which the non-projection area has been deleted is stored.

Through this, the surface saturation of the object to be scanned among the entire display area of the image data is more clearly displayed, and the remaining areas other than this may be displayed in black and white or in a color contrasting with the scan target.

A more detailed look at this is as follows.

3 is a view showing a state in which the color pattern formed through the color pattern forming unit 110 shown in FIG. 1 is projected by the projection unit 130, and FIG. 4 is a view showing a state in which the inverted pattern forming unit 120 shown in FIG. 1 is projected. ) Is a view showing a state in which the inversion pattern formed through the projection unit 130 is projected, and FIG. 5 shows a state in which the object to be scanned through the correction unit 140 shown in FIG. 1 is compared to the surrounding color. FIG. 6 is a diagram illustrating a state in which the color patterns and inversion patterns shown in FIGS. 3 to 5 are combined.

Referring to FIG. 3, as a color pattern formed through a brew sequence is projected onto a tooth row corresponding to an intraoral subject, a pattern having a different color for each layer is formed on the tooth row. At this time, the saturation (or brightness) of the color pattern is not high due to the unique color of the tooth row and the surrounding color of the surrounding (gum, etc.).

Referring to FIG. 4, as the color pattern shown in FIG. 3 is inverted by the inversion pattern forming unit 120 and then projected onto the tooth row, a reverse pattern inverted from the color pattern for each layer is formed on the tooth row. In this case, as in FIG. 3, the saturation (or brightness) of the inversion pattern is not high due to its own unique color and surrounding color of the tooth row.

Referring to FIG. 5, it can be seen that in FIG. 5, as the color pattern and the inversion pattern overlap, the saturation of the formed light is increased, so that the color of each layer constituting the color pattern is reinforced. In particular, in FIG. 5, as the correction unit 140 corrects to remove ambient light in the remaining areas (eg, gums, etc.) excluding the tooth row, the tooth row may be more prominently displayed in the image data. In particular, since the color change of the color pattern becomes clear, it is possible to obtain more precise 3D data.

Here, an operation process for correcting image data in the correction unit 140 will be described as follows.

For example, when the pattern image on which the color pattern is projected is referred to as A in FIG. 3 and the inverse pattern image in which the color pattern is inverted is referred to as B in FIG. It is established.

Here, the correction unit 140 calculates a histogram of effective pixels (Image Histogram From VP (Difference Image) (IHVP)) and then substitutes it into the following equation.

In addition, the correction unit 140 calculates a pixel saturation ratio (SR) for reducing the amplification amount for the pixels exceeding the brightness saturation threshold, as follows.

In addition, the correction unit 140 calculates an adaptive amplification factor (AAF), which calculates the adaptive amplification factor by first calculating the standard deviation (STD) and then substituting it. This is as follows.

Then, the correction unit 140 acquires the pattern image data as shown in FIG. 5, which has been finally corrected based on the following equation. The equation is as follows.

In this case, the above operation is not a calculation for obtaining a simple difference between a pattern and an inverse pattern, but is adaptive to the difference between the pattern and the inverse pattern by considering the pixel saturation by projector illumination and the pattern reflection amount according to the medium of the scanned object. It means an operation that amplifies with.

Next, a process of forming structured light using such a color pattern and an inversion pattern will be described in order through FIG. 7.

7 is a sequence of steps of forming structured light for an intraoral subject using a 3D oral scanner 100 that forms structured light for an intraoral subject using the complementary color pattern shown in FIG. 1 It is a drawing as shown.

Referring to FIG. 7, first, a color pattern is formed by using a brew sequence in a color pattern forming unit, and then a corresponding color pattern is projected onto an intraoral subject in the projection unit (S701).

Then, in the inversion pattern forming unit, the color pattern is inverted to form an inversion pattern, and then the projection unit additionally projects it onto the color pattern (S702), and accordingly, the saturation of the initially projected color pattern increases and scans. The color of the target object (eg, tooth row, etc.) is reinforced.

Then, in the correction unit, the object to be scanned stands out more through correction by deleting the light for the rest of the area except for the object to be scanned (S703), through which 3D image data can be generated (S704). have.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You will understand that you can.

100: 3D oral scanner that forms structured light for an intraoral subject using a complementary color pattern
110: color pattern forming unit
120: inversion pattern forming portion
130: projection unit
140: correction unit

Claims (8)

In forming structured light on a subject in the oral cavity using a 3D oral scanner,
Forming a color pattern and projecting it onto a subject in the oral cavity;
Inverting the formed color pattern to form an inversion pattern and further projecting it on the subject in the oral cavity; And
Compensating the image data based on the projection area of the color pattern and the inversion pattern in the image data for the intraoral subject; including,
In the image data for the intraoral subject, the step of correcting the image data based on the projection area of the color pattern and the inversion pattern,
Dividing the projection area and the non-projection area of the color pattern and the inversion pattern from the image data of the intraoral subject;
Deleting the non-projection area from image data for an intraoral subject; And
And storing image data on the subject in the oral cavity from which the non-projection area has been deleted.
A method of forming structured light for a subject in the oral cavity using a complementary color pattern.
The method of claim 1,
Forming the color pattern and projecting it onto the subject in the oral cavity,
A method of forming structured light for an oral subject using a complementary color pattern, characterized in that the color pattern is formed using a De bruijn sequence.
The method of claim 1,
As the inversion pattern is additionally projected onto the color pattern projected onto the intraoral subject through the 3D oral scanner, the saturation of each color forming the color pattern is compared to when only the color pattern is projected onto the subject in the oral cavity. A method of forming a structured light for a subject in the oral cavity using a complementary color pattern, characterized in that higher than the saturation.
delete A color pattern forming unit for forming a color pattern projected onto the subject in the oral cavity;
An inversion pattern forming unit configured to invert the formed color pattern to form an inversion pattern;
A projection unit for projecting the formed color pattern and the inversion pattern onto an intraoral subject, respectively; And
Including; a correction unit for correcting the image data based on the projection area of the color pattern and the inversion pattern in the image data for the intraoral subject,
The correction unit,
The projection area and the non-projection area of the color pattern and the inversion pattern are distinguished from the image data of the intraoral subject, and the non-projection area is deleted from the image data of the intraoral subject, and the non-projection area is deleted. Characterized in that to store the image data for the subject in the oral cavity,
A 3D oral scanner that uses a complementary color pattern to form structured light for an intraoral subject.
The method of claim 5,
The color pattern forming part,
A 3D oral scanner for forming structured light for an intraoral subject using a complementary color pattern, characterized in that the color pattern is formed using a De bruijn sequence.
The method of claim 5,
As the inversion pattern is additionally projected onto the color pattern projected onto the intraoral subject through the 3D oral scanner, the saturation of each color forming the color pattern is compared to when only the color pattern is projected onto the subject in the oral cavity. 3D oral scanner for forming structured light for an intraoral subject using a complementary color pattern, characterized in that higher than the saturation.
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