JP2003057170A - Melanin evaluation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily evaluate melanin situated at the interface between the epidermis and the corium regarding a melanin evaluation apparatus with which melanin existing inside a skin is evaluated by using a confocal microscope. SOLUTION: The melanin evaluation apparatus is provided with a scanning confocal microscope 2 in which a laser beam is horizontally scanned with reference to the skin 4 to irradiate the skin and in which reflected light reflected at a position at a prescribed depth of the skin 4 is received to obtain the plane image of the skin 4 at the position at the prescribed depth on the basis of the luminance intensity of the reflected light, a three-dimensional voxel generation means by which plane images of the skin 4 at a plurality of depths of the skin 4 obtained by the microscope 2 are piled up so as to generate a three- dimensional voxel and a melanin evaluation means which evaluates the melanin on the basis of luminance information contained in the three-dimensional voxel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melanin evaluation device, and more particularly to a melanin evaluation device for evaluating melanin present in skin using a confocal microscope.

[0002]

2. Description of the Related Art Conventionally, in the case of noninvasively measuring the structure of internal tissue of the skin, an ultrasonic tomography apparatus, an MRI (Magnetograph) is used.
The measurement was performed using a tic resonance imaging device or the like. However, it is difficult to obtain cell-level resolution by any of the measuring methods using these devices.

On the other hand, a device for visualizing the skin tissue structure using light waves has also been proposed. This device includes one that detects forward scattered transmitted light and one that detects back scattered light. Normally, in this type of device, light having a wavelength from visible light to near-infrared light, which is less absorbed in the skin, is used, but the light (electromagnetic wave) in this region is smaller than X-ray and radio wave (MRI). Strong scattering in the skin.

Further, in the device configured to detect the forward scattered transmitted light, it is necessary to process the light scattering process in order to improve the accuracy, which complicates the arithmetic processing and slows the processing speed. On the other hand, in the method of detecting backscattered light, it is possible to obtain a relatively highly accurate intra-skin image more easily and at higher speed than in the case of detecting forward scattered transmitted light. recent years,
A confocal microscope has come to be used as a device for visualizing this kind of skin tissue structure.

[0005]

However, conventional confocal microscopes that are generally used in biological systems utilize fluorescence (luminescence), and it is necessary to stain the tissue with a fluorescent dye. However, there is a problem that the observation is troublesome.

Further, with the conventional confocal microscope, a two-dimensional image at a predetermined depth (depth) of the skin can be obtained, but a three-dimensional image cannot be obtained. Therefore, there is a problem that the interface between the epidermis and the dermis in the skin cannot be visually detected.

By the way, the interface between the epidermis and the dermis (ie,
The basal layer) is a particularly important site in the production of melanin. That is, since the melanocytes that produce melanin are scattered everywhere in the basal layer cells present in this basal layer,
To elucidate the mechanism of melanin production, it is necessary to accurately detect the interface between the epidermis and the dermis.

Further, it is known that the interface between the epidermis and the dermis is not flat, but has a three-dimensional undulated state, and therefore, in the conventional two-dimensional measurement, the undulated epidermis is The interface with the dermis could not be detected accurately.

Further, conventionally, as described above, melanin was dyed with a fluorescent dye, and this was detected to evaluate melanin. However, since the fluorescence has a weak light intensity, there is a problem that the accuracy of the evaluation is lowered in the configuration in which the fluorescence is detected and the melanin is evaluated.

The present invention has been made in view of the above points, and an object of the present invention is to provide a melanin evaluation apparatus capable of easily evaluating melanin located at the interface between the epidermis and the dermis.

[0011]

In order to solve the above problems, the present invention is characterized by taking the following means.

The invention according to claim 1 is a melanin evaluation apparatus for evaluating melanin existing in cells of the skin by using an optical means, wherein the skin is planarly scanned with laser light. A scanning confocal microscope that irradiates and receives the reflected light reflected at the position of the predetermined depth of the skin, and obtains a planar image of the skin at the position of the predetermined depth based on the brightness intensity of the reflected light, and the scanning. Type three-dimensional voxel generating means for stacking planar images of the skin at a plurality of depths of the skin obtained by a confocal microscope to generate a three-dimensional voxel, based on the luminance information contained in the three-dimensional voxel, the evaluation of the melanin And a melanin evaluation means for carrying out.

According to the above invention, the skin is measured by a scanning confocal microscope, and the melanin is evaluated from the three-dimensional voxels generated based on the brightness intensity of the obtained reflected light. It is possible to make an assessment of the melanin present.

At this time, since the photorefractive index of melanin is higher than that of other cell tissues, the brightness of the skin containing a large amount of melanin is high. Three-dimensional voxel
Since it is the three-dimensional luminance information of the skin, the distribution and the abundance of melanin can be evaluated from this three-dimensional voxel.

The invention according to claim 2 is the melanin-evaluating apparatus according to claim 1, further comprising an interface between the epidermis and dermis of the skin with respect to the three-dimensional voxel generated by the three-dimensional voxel generating means. Boundary voxel detection means for detecting the boundary voxels corresponding to the, provided, and, the melanin evaluation means, the brightness measurement in the vicinity of the boundary voxel, and configured to evaluate the melanin based on the measured brightness. It is what

According to the above invention, by providing the boundary voxel detecting means, it is possible to detect the basal layer which is the interface between the epidermis and the dermis of the skin. In this basal layer,
Since there are basal cells containing melanocytes that produce melanin, it becomes possible to easily observe melanocytes. In addition, since the basal layer can be easily detected, melanin in most of the basal layer can be efficiently evaluated.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an optical inspection apparatus 1 applied to a three-dimensional image generation apparatus for skin, which is an embodiment of the present invention. Further, FIG. 2 shows a drive system of the optical inspection device 1. In the present invention, a scanning microscope is used as the optical inspection device 1.

In the figure, 2 is a scanning microscope main body, and a light source 10 is provided in the confocal microscope main body 2. As will be described later in detail, the light source 10 irradiates the surface of the skin 4 of the measurement subject, which is a sample, with laser light. The laser light emitted from the light source 10 passes through the half mirror 11 and advances to the optical scanning device 12.

The optical scanning device 12 two-dimensionally scans the laser light from the light source 10 on a predetermined measurement region of the skin 4 in the XY direction in accordance with the drive control command from the XY direction drive control device 13. As shown in FIG. 2, the optical scanning device 12 is configured to have a polygon mirror 25, a polygon driver 26, a galvano mirror 27, a galvano driver 28, and the like.

The polygon mirror 25 driven by the polygon driver 26 scans the laser beam in the X direction. The galvano mirror 27 driven by the galvano driver 28 scans the laser light in the Y direction. Therefore, the light scanning device 12 can scan the laser light on the skin 4 in the XY directions.

The optical scanning device 12 is also connected to an X-Y direction drive control device 13. The X-Y direction drive control device 13 is connected to the polygon driver 26 and the galvano driver 28 via the / O 33 and 35.
It has a Y-direction control circuit 30. The XY direction control circuit 30 is connected to the computer 3 and controls the polygon driver 26 and the galvano driver 28 in accordance with a command from the computer 3 as described later. As a result, the operations of the polygon mirror 25 and the galvanometer mirror 27 are controlled by the computer 3.

As described above, the optical scanning device 12 causes the XY
The laser light scanned in the direction is applied to the skin 4 via the objective lens 14. The objective lens 14 is attached to the depth of focus adjusting device 15. Further, the focal depth adjusting device 15 moves the objective lens 14 in the optical axis direction (Z direction) according to a control command of a Z direction drive control device 16 described later, and thereby changes the focal depth.

As shown in FIG. 2, the focal depth adjusting device 15 is provided.
Has a focus adjusting mechanism 31 and a focus depth adjusting driver 32. The focus adjustment mechanism 31 adjusts the focus position of the laser light by the objective lens 14 by moving the position of the objective lens 14 in the Z direction. Therefore, by focusing the objective lens 14 inside the skin 4, it is possible to measure the tissue inside the skin 4 based on the reflected light.

A focal depth adjusting driver 32 for driving the focal point adjusting mechanism 31 is connected to the Z direction drive control device 16.

The Z-direction drive control device 16 is connected to the depth-of-focus adjustment driver 32 via the I / O 36, and the X-Y drive control device 16 is connected.
It has a direction control circuit 30. The XY direction control circuit 30 is connected to the computer 3 and controls the focal depth adjusting driver 32 in accordance with a command from the computer 3 as described later. As a result, the operation of the focus adjustment mechanism 31 is controlled by the computer 3.

On the other hand, the laser beam applied to the skin 4 via the objective lens 14 is reflected at a predetermined depth within the skin 4 determined by the focal position of the objective lens 14. This reflected light passes through the objective lens 14 and returns to the optical scanning device 12,
Further, it is returned from the optical scanning device 12 to the half mirror 11.

The half mirror 11 is a semitransparent mirror and is provided on the optical path between the light source 10 and the optical scanning device 12. The half mirror 11 is provided to guide the reflected light from the skin 4 traveling from the optical scanning device 12 toward the photodetector 20.

The reflected light whose direction is changed by the half mirror 11 is received by the photodetector 20 through the lens 18 and the pinhole of the pinhole plate 19. The lens 18 focuses the reflected light toward the photodetector 20. The photodetector 20 has a photodetector element that converts light obtained through the pinhole of the pinhole plate 19 into an electric signal corresponding to the light amount.

The pinhole plate 19 has a pinhole with a predetermined diameter and is arranged between the lens 18 and the photodetector 20. Further, the disposition position is set so that the pinhole coincides with the focal position of the lens 18.

The reflected light from the skin 4 incident on the photodetector 20 is converted into an electric signal by the photodetection element and sent to the computer 21. The computer 21 generates a three-dimensional image by performing the processing described below based on the transmitted electric signal, and displays the three-dimensional image on the monitor 22.

Further, the computer main body 21 includes the above-mentioned X-Y direction drive control device 13 and Z direction drive control device 1.
6 is also connected. And the computer 21 is X
-Y direction drive control device 13 and Z direction drive control device 16
By controlling the scanning of the laser light in the XY direction and the control of the depth of focus by driving the objective lens 14.

In the optical inspection apparatus 1 configured as described above, the confocal microscope main body 2 constitutes a scanning confocal microscope. In this confocal microscope, the laser light emitted from the light source 10 is applied by scanning the surface of the skin 4 in a point-like manner, and the reflected light from the illuminated skin 4 is pinholes of the lens 18 and the pinhole plate 19. This is a microscope utilizing the confocal action of condensing light into a point shape again to form an image on the photodetector 20, and obtaining the brightness information of the image formation by the photodetector 20.

In such a scanning confocal microscope, a two-dimensional image in which the image of the skin 4 at a predetermined depth in the range scanned by the laser beam is focused in all ranges by the above confocal action. Can be obtained as This utilizes the fact that the brightness of the skin 4 (sample) obtained at the focus position becomes the maximum brightness.

Specifically, the reflected light of the laser light is not reflected only at a predetermined depth of the skin 4, but is reflected within a predetermined thickness range centered on this predetermined depth. Therefore, of the reflected light, the light reflected at a portion other than the predetermined depth becomes noise. In the confocal microscope, the light reflected at a portion other than the predetermined depth, which becomes the noise, is removed by using the pinhole plate 19. That is, the pinhole plate 19
The reflected light passing through is only the light focused on a predetermined depth of the skin 4, and the image of the skin 4 finally obtained is a two-dimensional image focused on the entire image.

Next, various measuring processes of the skin 4 using the optical inspection device 1 having the above-mentioned configuration will be described.
First, a three-dimensional image generation process for generating a three-dimensional image of the skin 4 using the optical inspection device 1 will be described.

FIG. 3 is a flow chart showing a three-dimensional image generation process of the skin 4. When the process shown in the figure is started, the starting process is first executed. Specifically, in step 10 (in the figure, step is abbreviated as S), the focal depth D (μm) is set to an initial value α (D =
α), and in step 11, a count value N indicating the number of two-dimensional images generated as described later is set to “1” (N = 1). Although not shown in the flowchart,
In this startup processing, startup processing of the computer 3 and the light source 10 (laser light source) is also performed.

In the following step 12, the setting process of the depth of focus D is performed. In this optical scanning device 12, the computer 3 uses the Z direction control circuit 3 of the Z direction drive control device 16.
A control signal is transmitted so that the focal depth is set to the initial focal depth D set in step 10.

The Z-direction control circuit 33 includes the objective lens 14
The focal depth adjusting driver 32 of the focal depth adjusting device 15 is driven and controlled so that the focal seismic intensity of D becomes D. As a result, the objective lens 14 is driven in the Z direction by the focus adjustment mechanism 31 so that the depth of focus becomes D. Normally, the measurement of Sample 4 is performed from the skin surface toward the deeper layers one by one,
The depth of focus D as an initial value is set to be the outermost surface of the sample 4.

When the depth of focus D is set as described above,
In the following step 13, a laser beam is emitted from the light source 10 and a process of scanning the laser beam is performed. Specifically, as described above, the laser light emitted from the light source 10 and passing through the half mirror 11 is emitted by the optical scanning device 12
The provided polygon mirror 25 scans in the X direction, and the galvano mirror 27 scans in the Y direction. As a result, the laser light scans the skin 4 two-dimensionally in the XY directions. The scanning speed of the laser light is controlled by the computer 3 via the XY direction control circuit 30, the polygon driver 26, the galvano driver 28, and the like so as to be an optimum speed for image generation described later.

In the following step 14, the brightness of the reflected light is detected. That is, the laser light applied to the skin 4 is reflected by the skin 4. The reflected light from the skin 4 returns to the two-dimensional scanning mechanism 12 through the objective lens 14, and from the two-dimensional scanning mechanism 12, the half mirror 11 and the lens 1.
Then, the light enters the photodetector 20 through the pinhole plate 19, is photoelectrically converted by the photodetector 20, and is transmitted to the computer 3 as an electric signal.

At this time, as described above, in the scanning confocal microscope, the laser light emitted from the light source 10 scans the surface of the skin 4 in a point-like manner and irradiates the reflected light from the illuminated skin 4. Is condensed by the pinhole of the lens 18 and the pinhole plate 19 again to form an image on the photodetector 20, and the photodetector 20 obtains the brightness information of the image formation. It is said that. Since the brightness of the skin 4 (sample) obtained at the focus position is the maximum brightness,
Therefore, it is possible to improve the dynamic range of the electric signal photoelectrically converted and output from the photodetector 20.

In the following step 15, a two-dimensional image generation process is executed based on the luminance signal of the reflected light obtained in step 14. As described above, the laser light emitted from the light source 10 is scanned as spot light, and the reflected light is detected by the photodetector 20. In the computer 3, the laser light emitted from the light source 10 is synchronized with the scanning of the laser light by the optical scanning device 12. The detection signal from the photodetector 20 is taken in.
As a result, the computer 3 can generate a two-dimensional image in the range scanned by the laser light based on the detection signal transmitted from the photodetector 20.

The two-dimensional image generated in step 15 is
In step 16, it is stored in a storage device (not shown) provided in the computer 3. In the following step 17, it is determined whether or not the count number N has become "80". Here, the number “80” is the number of two-dimensional images to be stacked when a three-dimensional image to be described later is generated. That is, in this embodiment, a three-dimensional image is generated by stacking 80 two-dimensional images. However, the number of stacks is not limited to 80, and can be appropriately selected.

At step 17, the count number N is "80".
If it is determined that the above condition is not satisfied (NO determination), the count number N is incremented in step 18, and 3.6 (μm) is added to the depth of focus D in step 19. Then, this value is newly set as the depth of focus D (D = D + 3.6).

When the processing of steps 18 and 19 is completed, the processing returns to step 12 and the above-mentioned step 12 is executed.
~ The process of step 17 is repeatedly performed. This repetitive processing is executed until the count number N reaches “80”, in other words, the computer 3 captures 80 two-dimensional images.

At this time, the two-dimensional image taken into the computer 3 by the processing of step 19 is 3.6 (μm).
The images have different depths of focus D. That is, in this embodiment, 80 two-dimensional images having a depth of 3.6 (μm) are generated from the surface of the skin 4. Although the distance between the upper and lower two-dimensional images adjacent to each other in the depth direction is set to 3.6 (μm) in this embodiment, the interval of the focal depth D for generating the two-dimensional image is limited to 3.6 (μm). Not a thing. This interval is 1
By setting the thickness to be 5 μm or more and 5 μm or less, an image that clearly displays the cell state of the skin 4 can be generated.

On the other hand, in step 17, an affirmative judgment (Y
ES determination), that is, when 80 two-dimensional images having different focal depths D of 3.6 (μm) are captured, the process proceeds to step 20, and a stacking process of 80 two-dimensional images is performed. It

By the way, in this embodiment, since the objective lens 14 can be driven as described above, the depth of focus D can be changed (in this embodiment, 3.6 μm).
Are changing one by one). Thereby, it is possible to irradiate the laser light so that each layer (skin epidermis, spinous layer, predetermined layer, etc.) constituting the skin 4 is focused.

When the skin 4 is irradiated with laser light, the laser light is reflected mainly at the depth of focus position, but the brightness of this reflected light changes depending on the refractive index of the reflected portion of the skin 4. At this time, since the respective layers such as the epidermis, the spinous layer, and the predetermined layer that form the skin 4 are different, the brightness when the laser light is reflected by each layer is different. Therefore, it is possible to perform the detection processing of each layer by utilizing the fact that the brightness of the reflected light in each layer of the skin 4 is different.

This will be described in more detail with reference to FIGS. 4 and 5. FIG. 4 is a sectional view showing the structure of the skin 4. As shown in the figure, the skin 4 is roughly divided into an epidermis and a dermis. In addition, the epidermis is from the top to the skin surface (in the figure,
It is classified into a spinous layer (indicated by arrow B in the figure) and a basal layer (indicated by arrow C in the figure). Then, the dermis (indicated by an arrow E in the figure) exists under the epidermis.

FIG. 5 shows a two-dimensional image of each layer of the skin 4 generated by the optical inspection device 1. Figure 5
5A is a two-dimensional image of the skin surface, FIG. 5B is a two-dimensional image of the spinous layer, FIG. 5C is a two-dimensional image of the basal layer, and further FIG. 5D. Is the interface between the skin and the dermis 2
It is a three-dimensional image.

As shown in each figure, the two-dimensional images in each layer are very different. This is because the layers of the skin 4, such as the epidermis, the spinous layer, and the predetermined layer, have different refractive indices. In this embodiment, since a two-dimensional image is generated based on the reflected light of the laser light applied to each layer of the skin 4, when the refractive index of each layer is different, the light reflectance of each layer is also different due to this. The brightness detected by the photodetector 20 also differs. Therefore, as described above, it is possible to perform the detection processing of each layer by utilizing the fact that the brightness of the reflected light in each layer of the skin 4 is different.

The interface between the epidermis and the dermis (arrow D in the figure)
It is known that melanocytes producing melanin are scattered in some places in the basal cells present in (1). The observation of this melanocyte is important for the study of spots, freckles, etc. generated by melanin. Since melanin has a higher refractive index than other skin cell tissues, in the two-dimensional image obtained by the optical inspection device 1, this melanin is displayed in a high brightness state (white state). Therefore, it becomes possible to detect melanin with high accuracy by using the optical inspection device 1 (confocal microscope).

Returning to FIG. 3, the description of the three-dimensional image generation processing will be continued. The stacking process of the two-dimensional images executed in step 20 will be described with reference to FIG. Now
It is assumed that the two-dimensional image 40 generated in step 16 is an image of P pixels (pixels) in the X direction and Q pixels (pixels) in the Y direction, and thus P × Q pixels (pixels) in total. Then, N pieces (80 pieces in this embodiment) of the two-dimensional images 40 of P × Q pixels are stacked.

However, only N two-dimensional images 40
By simply stacking, the pair of two-dimensional images 40 vertically adjacent to each other has an interval of 3.6 μm, that is, a region where no information exists. In order to improve the accuracy of the three-dimensional image, it is desirable to reduce the interval between the pair of vertically adjacent two-dimensional images 40.

However, if this interval is reduced,
As the number of two-dimensional images 40 to be captured increases, the computer 3
It becomes necessary to increase the storage capacity of the storage device and the amount of data increases, which increases the time required for the arithmetic processing for generating a three-dimensional image. Therefore, in step 21, the area where this information does not exist is interpolated by performing interpolation processing between a pair of two-dimensional images 40 that are vertically adjacent to each other.

As a concrete method of the interpolation processing, a method of interpolating the values of the two-dimensional image to be interpolated by a distance ratio between a pair of vertically adjacent two-dimensional images 40, or a two-dimensional image to be interpolated A method is conceivable in which two-dimensional images above and below the image are converted into distance images, and the converted images are interpolated and interpolated with the distance ratio between the images (Yasuzo Suto, Three-dimensional image processing in medicine 87 Pp.-88).

This makes it possible to interpolate a tomographic image space point between the pair of two-dimensional images 40 in which information is insufficient, and improve the sharpness of the generated three-dimensional sectional image. Further, it is possible to suppress an increase in the storage capacity of the storage device of the computer 3 and to reduce the amount of data required for the processing, so that it is possible to reduce the time required for the arithmetic processing for generating a three-dimensional image.

When the interpolation processing in step 21 is completed, a three-dimensional voxel 50 as a set of minute hexahedrons (voxels) is generated based on the processing in steps 20 and 21 (step 22). ). The three-dimensional voxel 50 is composed of a total of P × Q × N minute hexahedrons (voxels). In addition, each minute hexahedron (voxel) that constitutes the three-dimensional voxel 50 is
Each has brightness information.

In the following step 23, the step monitor 2
The three-dimensional image is generated based on the three-dimensional voxel 50 generated in step 2, and the generated three-dimensional image is displayed on the monitor 22 of the computer 3 in step 24.

At this time, as described above, in this embodiment, the three-dimensional voxels 50 are generated by stacking the two-dimensional images 40 of the skin 4 at a plurality of depths of focus, and the three-dimensional voxels 5 are generated.
Since the three-dimensional image of the skin 4 is generated from 0, the cross section of the skin 4 can be three-dimensionally observed non-invasively. Also,
The optical inspection device 1 (scanning confocal microscope) has a high resolution, and since the confocal action is used as described above, it is possible to prevent reflected light other than a predetermined depth from invading information as a disturbance. A level three-dimensional image can be displayed clearly.

FIG. 7 shows an example of the three-dimensional image generated in this way. In the figure, of the three-dimensional image,
The XZ plane is illustrated. In the conventional confocal microscope, only a two-dimensional image of the XY plane can be obtained, but in the present embodiment, a three-dimensional image can be generated. That is, in this embodiment, since it is possible to obtain each screen (XZ plane, YZ plane) in the depth direction (Z direction) of the skin 4, measurement of the interface between the epidermis and the dermis in the skin 4,
Thickness measurement of skin 4 and evaluation of melanin (amount of melanin,
It is possible to measure the melanin distribution).

Next, the optical inspection device 1 configured as described above.
The detection process of the epidermis-dermis interface, which is performed based on the above-described three-dimensional image generation process of the skin 4, will be described.

8 and 9 are flow charts showing the first and second embodiments of the epidermis-dermis interface detection processing. The epidermis-dermis interface detection process according to the first embodiment shown in FIG.
The feature is that the epidermis-dermis interface is detected by performing a filtering process on a three-dimensional voxel 50 with a three-dimensional Laplacian filter (LOG filter) using an edge detection method. Also,
The epidermis-dermis interface detection processing according to the first embodiment shown in FIG. 9 is characterized in that the area discrimination method is used to detect the epidermis-dermis interface based on the texture obtained in advance. .

The process up to the determination of the three-dimensional voxel 50 is the same as the process of steps 10 to 22 in the three-dimensional image generation process described with reference to FIG. The process after obtaining is described.

First, prior to the description of the epidermis-dermis interface detection processing according to the first and second embodiments, the principle of epidermis-dermis interface detection in this embodiment will be described.

As described above, basal cells present at the interface between the epidermis and the dermis (portion indicated by arrow D in FIG. 4) have melanin-producing melanocytes scattered here and there, and this melanocyte should be observed. Is important for the study of spots, freckles, etc. caused by melanin. On the other hand, when measuring changes in the skin due to ultraviolet rays, changes in the thickness of the epidermis are measured (so-called thickening measurement). This thickening is the distance from the surface of the skin to the epidermis-dermis interface. Therefore, detection of the epidermis-dermis interface is important in various skin measurements.

By the way, most of the basal cells constituting the basal layer existing at the epidermis-dermis interface contain melanin as compared with the cells constituting the dermis. In addition, since melanin has a high refractive index as described above, when it is detected by the optical inspection device 1, it is detected as a high brightness state (white state). Therefore, by detecting the basal cells containing melanin located at the epidermis-dermis interface, it becomes possible to detect the epidermis-dermis interface. Specifically, three-dimensional voxel 5
At 0, it becomes possible to detect the epidermis-dermis interface by detecting voxels corresponding to basal cells (hereinafter referred to as boundary voxels).

The epidermis-dermis interface detection processing according to the first embodiment based on the above detection principle will be described. Step 30 is the same as step 22 in the three-dimensional image generation process of FIG. When the three-dimensional voxel 50 is generated in step 30 (step 22), a three-dimensional Laplacian filter (L
OG filter) to perform filtering processing. The filtering process using the LOG filter is to perform a smoothing process on the luminance distribution of the three-dimensional voxel 50 and further calculate a second-class differential value.

The result of the filtering process by this LOG filter becomes a P × Q × N three-dimensional voxel of the same size as the voxel distribution of the three-dimensional voxel 50 generated in step 30. Also, due to the nature of the LOG filter,
The sign of the luminance value of this three-dimensional voxel is reversed (that is,
A voxel whose brightness changes drastically) becomes a boundary voxel.

That is, as described above, the boundary voxel is the skin-
Since it is a basal cell containing melanin located at the dermal interface, the brightness of the reflected light of the laser light with which the basal cell is irradiated is higher than the brightness of the reflected light of the laser light with which the dermal cell is irradiated. Become. That is, the change in luminance changes greatly at the epidermis-dermis interface. Therefore, a boundary voxel can be detected by detecting a voxel having a large luminance change. In step 32, the voxels having a large luminance change as described above are extracted, and the boundary voxels are detected from the results.

In a succeeding step 33, the extracted boundary voxels are connected to each other to restore the epidermis-dermis interface. In a succeeding step 34, the restored three-dimensional image of the epidermis-dermis interface is stored in the computer 3. It is displayed on the monitor 22. As described above, according to this embodiment, a three-dimensional image of the epidermis-dermis interface can be displayed non-invasively. Further, as described above, the epidermis-dermis interface has a rugged shape that is difficult to detect in a planar image, but by detecting the boundary voxels as in the present embodiment, a three-dimensional image becomes possible. The dermis interface can be reliably detected.

Subsequently, the epidermis-dermis interface detection processing according to the second embodiment will be described with reference to FIG. Step 40
Is the same as step 22 in the three-dimensional image generation processing of FIG. 3D voxel 50 is step 40
When the three-dimensional voxel 50 is generated in (step 22), the boundary voxel is detected using the texture analysis parameter (step 41).

The texture analysis parameters used here are prepared in advance. Specifically, three-dimensional voxels are prepared based on a tomographic image of the skin including a known epidermis-dermis interface, and based on this, texture analysis parameters near the epidermis-dermis interface are prepared. And
In step 41, the voxels similar to the texture analysis parameters (that is, the boundary voxels) are calculated from the 3D voxels 50.
Is extracted.

In the following step 42, the extracted boundary voxels are connected to restore the epidermis-dermis interface, and in the following step 42, the restored three-dimensional image of the epidermis-dermis interface is stored in the computer 3. It is displayed on the monitor 22.

Therefore, according to the present embodiment as well, the three-dimensional image of the epidermis-dermis interface can be displayed non-invasively and the epidermis-dermis interface can be surely detected.
Further, as in the first and second embodiments described above, the method of detecting a boundary voxel using a three-dimensional LOG filter or texture is a relatively simple detection process,
Boundary voxels can be detected in a short time.

Next, using the optical inspection apparatus 1 shown in FIGS. 1 and 2, the skin thickness measurement is performed based on the above-described three-dimensional image generation processing of the skin 4 and the epidermis-dermis interface detection processing. The processing will be described.

FIG. 10 is a flowchart showing the skin thickness measuring process. Step 50 to Step 5 in FIG.
The process of 3 is the same as the process of steps 30 to 33 in FIG. Therefore, the description of steps 50 to 53 is omitted.

In step 54, the three-dimensional voxel 50 is subjected to a three-dimensional filtering process using a LOG filter to detect the epidermal uppermost point of the skin 4. The uppermost point of the epidermis of the skin 4 is also a part where the change in luminance changes greatly. Therefore, it is possible to detect the voxel at the epidermal uppermost point of the skin 4 (hereinafter referred to as surface voxel) by performing three-dimensional filtering processing using the LOG filter.

In the following step 55, the extracted upper surface voxels are connected to restore the uppermost surface of the skin. In the next step 56, step 5
The three-dimensional image of the epidermis-dermis interface reconstructed in step 3 and the three-dimensional image of the top surface of the epidermis reconstructed in step 55 are combined and displayed on the monitor 22 of the computer 3. Note that FIG. 11 shows an example of a three-dimensional image in which the epidermis-dermis interface and the top surface of the epidermis are combined.

In the following step 57, the skin thickness is measured based on the epidermis-dermis interface generated in step 56 and the three-dimensional image of the uppermost surface of the epidermis. The skin thickness in this example is
The thickness of the epidermis. Therefore, the skin thickness can be measured by measuring the distance between the epidermis-dermis interface and the uppermost surface of the epidermis.

Specifically, the X and Y coordinates (X _A , Y _A ) on the uppermost surface of the skin are specified, and the Z coordinate (Z _A ) at that time is measured. Further, the epidermis - the dermis interface, the same X as identified above epidermis uppermost surface, Y coordinates _(X A, _{Y A)} to identify and measure the Z coordinate _{(Z B)} at that time. The skin from the Z-coordinate of the epidermis uppermost surface _{(Z A)} - by subtracting the dermal surface Z coordinate _{(Z B) (Z A -Z} B), it is possible to obtain the skin thickness.

According to this embodiment, the skin thickness is determined based on the epidermis-dermis interface determined from the boundary voxels and the epidermis uppermost surface determined from the surface voxels, so that the accurate skin thickness can be measured. In addition, along with this, it becomes possible to accurately measure changes in skin thickening.

Further, as shown in FIG. 11 and as described above, the epidermis-dermis interface and the uppermost surface of the epidermis are not flat surfaces but undulating surfaces. Therefore, one point X, Y
Coordinates _(X A, _{Y A)} in the measurement of skin thickness at _(Z A -Z _B) alone can not large error correct skin thickness measurements. Therefore, the X and Y coordinates (X _{1
~ N} , Y _1-N ), the skin thickness (Z _1-N-
It is possible to measure the skin thickness more accurately by measuring Z ₁ to _{N 1} and taking the average thereof.

Although the method of measuring the thickness of the epidermis has been described in the above example, as described above, the layers of the spinous layer, the basal layer, etc. which constitute the skin have different reflected light intensities. Therefore, it is possible to measure the thickness of each layer separately based on this.

Further, in the above-mentioned embodiment, an example in which the epidermis-dermis boundary detection method according to the first embodiment shown in FIG. 8 is applied to detect the epidermis-dermis boundary, is shown in FIG. It is also possible to apply the epidermis-dermis boundary detection method according to the second embodiment.

Next, using the optical inspection apparatus 1 shown in FIGS. 1 and 2, and based on the above-described three-dimensional image generation process of the skin 4 and the epidermis-dermis interface detection process, a melanin evaluation process. Will be described.

FIG. 12 is a flowchart showing the melanin evaluation process. The processing of steps 60 to 62 in the figure is the same processing as the epidermis-dermis interface detection processing of steps 30 to 32 of FIG. Therefore, the description of steps 60 to 62 is omitted.

In step 63, the luminance of the boundary voxel detected in step 62 and the voxels located in the vicinity thereof are measured. Further, in the subsequent step 64, based on the luminance measurement result (luminance intensity and luminance distribution) obtained in step 63, since melanin has a high light reflectance, it is assumed that the melanin content in the high luminance portion is high. That is, the brightness of each voxel correlates with the melanin content, and this tendency is particularly strong at the epidermis-dermis interface where melanin is produced. Therefore, melanin can be evaluated by measuring the brightness of the boundary voxels located at the epidermis-dermis interface and the voxels located in the vicinity thereof.

As described above, for the study of spots, freckles and the like caused by melanin, it is effective to evaluate melanin in the vicinity of basal cells in which melanocytes producing melanin are scattered. In addition, basal cells correspond to border voxels. Therefore, by measuring the brightness of the boundary voxels and the voxels located in the vicinity thereof, it is possible to obtain melanin evaluation results effective for the study of spots, freckles, and the like.

FIG. 13 is a diagram imitating the vicinity of the basal layer of the skin 4, FIG. 14 is a two-dimensional image of the skin at the X1 position in FIG. 13, and FIG. 15 is an X2 image in FIG.
2D shows a two-dimensional image of skin at a position. In the two-dimensional image of the skin at the X1 position shown in FIG. 14, it was possible to obtain an image with high brightness considered to be derived from the melanosome aggregate (melanin cap structure) in the vicinity of the basal layer as indicated by the arrow. Further, in the two-dimensional image of the skin at the X2 position shown in FIG. 15, it was possible to obtain an image with high brightness considered to be melanin located at the interface between the dermis and the basal layer as indicated by the arrow.

As described above, by performing the melanin evaluation according to this example, it is possible to non-invasively evaluate the melanin present in the skin. Further, since it becomes possible to detect the basal layer which is the interface between the epidermis and the dermis of the skin 4, it becomes possible to observe melanocytes. Furthermore,
Since the basal layer can be easily detected by detecting the boundary voxels, the melanin in many of the basal layers can be efficiently evaluated.

[0093]

As described above, according to the present invention, various effects described below can be realized.

According to the invention described in claim 1, it becomes possible to non-invasively evaluate the melanin present in the skin.

According to the second aspect of the present invention, it is possible to easily detect the basal layer, so that it is possible to easily observe the melanocytes existing in the basal layer. In addition, since the basal layer can be easily detected, melanin in most of the basal layer can be efficiently evaluated.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an optical inspection device used in the present invention.

FIG. 2 is a configuration diagram showing a drive system of an optical inspection device.

FIG. 3 is a flowchart showing a three-dimensional image generation process performed using the optical inspection device.

FIG. 4 is a diagram for explaining the structure of skin.

FIG. 5 is a drawing-substituting photograph showing a two-dimensional image of each layer of skin taken by an optical inspection device.

FIG. 6 is a diagram for explaining a method of generating a three-dimensional image from a two-dimensional image.

FIG. 7 is a drawing-substituting photograph showing a generated three-dimensional image of skin.

FIG. 8 is a flow chart showing a first embodiment of an epidermis-dermis interface detection process carried out by using an optical inspection device.

FIG. 9 is a flowchart showing a second embodiment of the epidermis-dermis interface detection processing executed by using the optical inspection device.

FIG. 10 is a flowchart showing a skin thickness measurement process performed using the optical inspection device.

FIG. 11 is a drawing-substituting photograph showing a three-dimensional image obtained by performing a skin thickness measurement process.

FIG. 12 is a flowchart showing a melanin evaluation process executed by using the optical inspection device.

FIG. 13 is a diagram imitating the vicinity of the basal layer of the skin.

FIG. 14 is a drawing-substituting photograph showing a two-dimensional image of skin at the X1 position in FIG.

FIG. 15 is a drawing-substitute photograph showing a two-dimensional image of skin at the X2 position in FIG.

[Explanation of symbols]

1 Optical inspection device 2 Operation type microscope body 3 computers 4 samples (skin) 10 light sources 12 Optical scanning device 13 X-Y direction drive control device 14 Objective lens 15 Depth of focus adjustment device 16 Z-direction drive controller 18 lenses 19 pinhole plate 20 photo detector 21 Computer body 22 monitors 25 polygon mirror 26 polygon driver 27 Galvo Mirror 28 Galvo Driver 30 XY direction control device 31 Focus adjustment mechanism 32 Driver for focus adjustment mechanism 33 Z direction control device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomohiro Kuwahara             2-2-1 Hayabuchi, Tsuzuki Ward, Yokohama City, Kanagawa Prefecture             Shiseido Research Center (Shin-Yokohama)             Within (72) Inventor Genji Takahashi             2-2-1 Hayabuchi, Tsuzuki Ward, Yokohama City, Kanagawa Prefecture             Shiseido Research Center (Shin-Yokohama)             Within (72) Inventor Shinji Ozawa             Kei, 3-14-1, Hiyoshi, Kohoku Ward, Yokohama City, Kanagawa Prefecture             Faculty of Science and Engineering, University of Tokyo (72) Inventor Hideo Saito             Kei, 3-14-1, Hiyoshi, Kohoku Ward, Yokohama City, Kanagawa Prefecture             Faculty of Science and Engineering, University of Tokyo F term (reference) 2G059 AA05 BB12 BB14 CC16 EE02                       FF01 FF02 FF03 GG01 JJ11                       JJ13 JJ15 JJ22 KK01 LL01                       LL04 MM10 PP04

Claims (2)

[Claims] 1. A melanin evaluation apparatus for evaluating melanin existing in cells of the skin by using an optical means, which comprises irradiating a skin with a laser beam by scanning the skin in a planar manner. At a predetermined depth position, receives reflected light, and obtains a planar image of the skin at the predetermined depth position based on the intensity of the reflected light, and a scanning confocal microscope. 3D voxel generating means for stacking planar images of the skin at a plurality of depths of the skin to generate 3D voxels, and luminance information included in the 3D voxels, based on luminance information contained in the 3D voxels, melanin evaluation means for performing the evaluation of the melanin A melanin evaluation apparatus comprising: 2. The melanin evaluation apparatus according to claim 1, further comprising detecting a boundary voxel corresponding to an interface between the epidermis and the dermis of the skin with respect to the three-dimensional voxel generated by the three-dimensional voxel generating means. An apparatus for evaluating melanin, comprising boundary voxel detecting means for performing the measurement, and the melanin evaluation means configured to measure the brightness in the vicinity of the boundary voxel and evaluate the melanin based on the measured brightness.