JP2000206044A - Method for evaluating hair gloss - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for evaluating the gloss of hair easily and accurately. SOLUTION: Light is applied to hairs while the specific number of hairs are retained while being curved with a specific curvature, the image of a region including the region of hair in that regular reflection light in reflection light can be obtained from the bairs is picked up in the longitudinal direction of the hairs, a brightness distribution is obtained for the longitudinal direction of the hairs from the image pick-up data, and it is judged whether the gloss of hairs is appropriate or not according to the maximum value of the absolute value of the amount of change in the brightness distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the gloss of hair, which can easily and accurately evaluate the gloss of hair.

[0002]

2. Description of the Related Art Generally, an optical technique is used for evaluating a gloss of a hair. For example, Cosmetic Miscellaneous Vol. 24 No. 2 (1990) 12
On pages 9 to 135, the amount of reflected light from the hair is measured using goniospectroscopy (goniophotometry), and the value of “the amount of light in the regular reflection direction” − “the amount of diffusely reflected light at a light receiving angle of 0 °” is glossed. By using it as a value, the gloss of the hair is evaluated.

However, in the variable angle spectroscopy, the amount of reflected light is measured while continuously changing the light receiving angle by mounting the hair bundle on a flat sample stage and moving the light source or the detector. It is not easy to reduce the size of the measuring device.
In addition, the hair of the subject must be cut and provided for evaluation, and no one can easily become a subject.

[0004] Accordingly, an object of the present invention is to provide a method for evaluating the gloss of hair which can easily and accurately evaluate the gloss of hair. Another object of the present invention is to provide a method for evaluating the gloss of hair that can be used for evaluation without cutting the hair of the subject.

[0005]

SUMMARY OF THE INVENTION The present invention irradiates light to a predetermined number of hairs in a state where the hairs are curved at a predetermined curvature and held, and the light reflected from the hairs has a positive value. A region including the region of the hair from which the reflected light is obtained is imaged in the longitudinal direction of the hair, a luminance distribution in the longitudinal direction of the hair is obtained from the image data, and the absolute value of the amount of change in the luminance distribution is calculated. The object has been achieved by providing a hair gloss evaluation method for evaluating the quality of hair gloss from a maximum value.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of the method for evaluating hair gloss according to the present invention will be described. First, a hair gloss evaluation device preferably used in the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an evaluation device 1 used in the evaluation method of the present embodiment. The evaluation device 1 includes a hair holder 3 having a peripheral portion capable of holding a predetermined number of hairs in a state of being convexly curved at a predetermined curvature, and an optical device that applies light to the hair held by the hair holder 3. Light source 4 for irradiating light, and imaging means 5 for capturing reflected light from the hair
The hair holder 3, the light source 4, and the imaging means 5 are arranged so as to be located on a straight line in a plan view, and the imaging means 5 can obtain regular reflection light out of the reflected light. The region including the region of the hair is arranged at a position where an image can be taken in the longitudinal direction of the hair.

As shown in FIG. 1, the evaluation device 1 includes a housing 2, in which a hair holder 3, a light source 4, and an imaging unit 5 are arranged. The inner surface of the housing 2 is covered with a black light-shielding cloth so that the light emitted from the light source 4 is not reflected on the inner surface of the housing 2 and does not enter the hair to be measured. The housing 2 has a light-shielding structure so that light from the outside does not enter.

FIG. 2 is an exploded perspective view of the hair holder 3. The hair holder 3 includes a cylindrical rod 3a having a predetermined diameter and a holder 3b. The holder 3b has a pair of fitting portions 3b ', 3b' fitted to the cylindrical rod 3a along the circumferential direction of the cylindrical rod 3a.
And a pair of linear connecting portions 3b ", 3b" connecting the pair of fitting portions 3b 'to each other. The hair to be measured is arranged on the peripheral surface of the cylindrical rod 3a such that the hairs are substantially parallel along the circumferential direction of the cylindrical rod 3a. Then, by fitting the holder 3b from above the hair, the hair is connected to the fitting portion 3b 'and the connecting portion 3b.
b "against the peripheral surface of the cylindrical rod 3a,
The holding state as shown in FIG. 3 is obtained. In such a holding state, the fitting portions 3b ′, 3b ′ in the holder 3b
The space is an exposed portion E of the hair, and the exposed portion E is an area to be imaged by the imaging means 5. By using such a holder 3b, the lifting of the hair H and the jumping of the end of the hair H are effectively prevented, and the measurement accuracy is increased. The angle α of the exposed portion E (see FIG. 3), that is, the angle of the arc drawn by the hair H held along the circumferential direction of the cylindrical rod 3a is 6
It is preferable that the angle is 0 to 360 °, particularly 150 to 300 °, since the hair whose ends are not fixed by the holder 3b does not enter the imaging visual field of the imaging means 5.
The width W (see FIG. 3) of the exposed portion E in the axial direction is 0.1 to
It is preferably 100 mm, especially 1 to 30 mm, from the viewpoint that the hair can be fixed with good reproducibility.

As shown in FIG. 3, the hair H is held in a state of being convexly curved at a predetermined curvature.
By evaluating the hair H in such a holding state, unlike the conventional bending angle spectroscopy, it is not necessary to move the detector and the light source. As a result, it is easy to make the evaluation device itself compact and portable. In addition, since there are no movable parts, the measurement itself becomes easy. Therefore, for example, when the evaluation method of the present invention is used for demonstration purposes to promote sales of hair care products at stores, the evaluation device 1 is extremely useful. Further, by keeping the hair in a state of being convexly curved, evaluation in a state close to the actual state of the hair becomes possible, and the correlation with the visual sensory evaluation is further enhanced.

The curvature of the hair H in the holding state, that is, the radius of the cylindrical rod 3a in this embodiment is 1 to 1
The thickness is preferably from 00 mm, particularly from 10 to 50 mm, from the viewpoint that a constant curvature can be imparted to the hair with good reproducibility and that hair of a general length can be held.

There is no particular limitation on the number of hairs to be evaluated, but the greater the number, the higher the measurement accuracy. When a plurality of hairs are used, the hairs have a uniform thickness along the axial direction of the cylindrical rod 3a such that the hairs are substantially parallel along the circumferential direction of the cylindrical rod 3a as described above. It is preferable to be held.

The peripheral surface of the cylindrical rod 3a is covered with a black light-shielding cloth, which effectively prevents reflection on the peripheral surface of the cylindrical rod 3a itself, and further enhances measurement accuracy. . Further, on the peripheral surface of the cylindrical rod 3a, comb teeth 3c are arranged along the axial direction of the cylindrical rod 3a. Thereby, the hairs H are held on the peripheral surface in a state of being arranged in parallel with each other, and the measurement accuracy is further improved.

The hair holder 3 is detachably disposed near the bottom B in the evaluation device 1 as shown in FIG.
It can be taken out of the apparatus through a take-out opening (not shown) provided in the bottom B. Upon evaluation,
Since the hair to be evaluated can be fixed to the hair holder 3 in the same manner as the manner in which the hair is wound with a curler, the subject can fix the hair to the hair holder 3 without cutting off his or her own hair. The hair can be submitted for evaluation.

The light source 4 is fixed at a position above the housing 2. As the light source 4, a JIS standard A light source generally used for evaluation of hair quality is used, but the light source 4 is not limited to this. When the light source 4 is a continuous light source, the imaging means 5 usually has a surface illuminance of hair to be irradiated with light of 1 to 100,000 lux, particularly 10 to 10,000 lux. This is preferable in that an image input device having the above sensitivity can be used and hair is not excessively heated. Further, a discontinuous light source such as a strobe light source can be used as the light source 4.

It is preferable that the light from the light source 4 is irradiated so that the angle of view from the hair holder 3 is 0 to 180 °, particularly 45 to 135 °, from the viewpoint of further reducing the size of the housing 2. When the hair is held so as to be substantially parallel along the circumferential direction of the cylindrical rod 3a as shown in FIG. 3, a direction perpendicular to the longitudinal direction of the hair (this direction is cylindrical) Light is applied so that the surface illuminance of the hair in the same direction as the axial direction of the rod 3a) is substantially the same. This further increases the measurement accuracy.

As the imaging means 5, various cameras such as a digital camera and a video camera can be used. In particular, a digital camera which can easily process image data is preferably used. The imaging data obtained by the imaging unit 5 is sent to a data processing unit (not shown). The imaging data is sent to the data processing unit when the imaging unit is electrically, optically, or other means connected to the data processing unit. When importance is placed on the portability of the evaluation device 1, the imaging data may be sent to the data processing means via a removable data storage medium in which the imaging data is stored magnetically, electrically, optically, or by other means. preferable. When data is continuously sent to the data processing means, or when the control mechanism of the imaging means is incorporated in the data processing means, it is preferable to connect the two means by magnetic, electrical or optical communication means. As the data processing means, various computers capable of executing a predetermined image processing program are used.

The imaging means 5 is arranged at a position where an area including the area of the hair from which the reflected light from the hair to be evaluated can be obtained can be imaged in the longitudinal direction of the hair. ing. By imaging such an area, useful information on the gloss of the hair can be obtained.

As described above, in the evaluation device 1 of the present embodiment, the hair holder 3, the light source 4, and the imaging means 5 are arranged so as to be aligned on a straight line in plan view. Further, in the evaluation device 1, as shown in FIG. 1, the hair holder 3, the light source 4, and the imaging means 5 are arranged so as to form a predetermined angle θ. The value of the angle θ is preferably 0 to 180 °, particularly preferably 0 to 120 °, from the viewpoint of putting specularly reflected light into the imaging range.

In the evaluation device 1 shown in FIG. 1, a gray scale 6 is arranged at a position in the field of view of the image pickup means 5. Thus, when the imaging unit 5 images the hair, the gray scale 6 is imaged together with the hair. as a result,
When performing image processing on the captured image data of the hair, the image data of the hair can be corrected based on the image data of the clay scale 6, and the measurement accuracy is further improved.

A method for evaluating the gloss of hair using the above-described evaluation device 1 will be described below. First, a predetermined number of hair,
The hair holder 3 shown in FIG. 2 is used to hold and fix as shown in FIG. As described above, the use of the evaluation device 1 allows the hair to be held by the hair holder 3 without cutting the hair from the subject. Next, the hair holder 3 holding the hair is inserted into the evaluation device 1 from the bottom opening in the device,
It is attached to a predetermined position in the device.

Next, predetermined light is emitted from the light source 4 toward the hair, and the hair is imaged by the imaging means 5 in this state. As described above, the imaging region is a region extending in the longitudinal direction of the hair, including a region where regular reflection light is obtained from the reflection light from the hair. Further, when imaging, a gray scale 6
Are also imaged at the same time. The image data obtained by the imaging means 5 is subjected to image processing in the data processing means,
A luminance distribution in the longitudinal direction of the hair is obtained.

Specifically, first, using the RGB measurement values of the imaged gray scale 6, each RGB of the imaged hair is used.
Correct the B value. After the correction, the RGB values of the region in the imaging data corresponding to the exposed portion E (see FIG. 3) of the hair holding device 3 holding the hair are set in the width direction (the cylindrical rod 3).
(the same direction as the axial direction of a). This integration increases the S / N ratio and further improves the measurement accuracy. The integrated RGB values are converted into luminance values, and a luminance distribution in the longitudinal direction of the hair is obtained. The method of converting RGB values into luminance values is a known method in the field of image processing. For example, a luminance value having a value in a range of 0 to 255 is obtained from an RGB value obtained in a range of 0 to 255. be able to.

An example of the luminance distribution obtained in this way is as shown in FIG. In FIG. 4, the horizontal axis represents the distance from the reference point in the longitudinal direction (direction parallel to the longitudinal direction of the hair) in the imaging data, and the vertical axis represents the luminance. And
The position on the horizontal axis where the luminance takes the maximum value corresponds to the position where the specularly reflected light is obtained. The reference point can be arbitrarily determined according to the size of the imaging area. Preferably, the position where the luminance takes the maximum value (that is, the position where the regular reflection light is obtained)
Is set so that is located substantially at the center of the distribution curve.

Next, a luminance variation amount is obtained by differentiating the luminance distribution curve shown in FIG. When the absolute value of the change in luminance is plotted in the longitudinal direction of the image data, a graph shown in FIG. 5 is obtained. The quality of the gloss of the hair is evaluated from the magnitude of the maximum absolute value in this graph. Specifically, the larger the maximum value of the absolute value is, the more the hair is evaluated to be glossy, and the smaller the maximum value of the absolute value is, the less the hair is evaluated to be glossy.

[0025]

The following examples illustrate that the method for evaluating the gloss of hair of the present invention correlates very well with the sensory evaluation.

The evaluation was performed using an evaluation apparatus having the configuration shown in FIG. Details of each part and sample in the apparatus are as follows. [A: Hair holder] The radius of the cylindrical rod 3a is 14 mm
And its peripheral surface is covered with a black light-shielding cloth. The comb teeth are arranged thereon along the axial direction of the rod 3a. A plastic holder 3b was used to fix the hair to the rod 3a. [B: Imaging means] Digital camera [Ricoh DC-4
(Trade name)] was used. [C: Light source] Commercially available three-wavelength light-emitting white fluorescent lamp FPL27EX-N
(Trade name) was used under high frequency conditions by an inverter. The surface illuminance of the hair was 320 lux. The fluorescent lamp was covered with a cover, and a slit-shaped window was opened in the cover so that the angle of view from the hair holder was 5 °. [D: Arrangement of Each Part] The light source, the hair holder and the imaging means were arranged in the housing. The angle θ between the light source, the hair holder and the imaging means was set to 70 °. The inner surface of the housing was covered with a black light-shielding cloth to remove scattered light. [E: Gray Scale] A gray scale was arranged at a position within the field of view of the image taken by the image pickup means, and the gray scale was photographed together with the hair. A gray scale manufactured by Kodak Corporation was used. [F: Preparation of sample] A woman's hair is collected and a flat brush-like hair bundle (hair length 20 cm, width 4 cm, thickness 1 m)
m) was prepared and used as a measurement sample. As samples, six samples determined to be glossy by sensory evaluation by a sensory evaluation expert and three samples determined to be glossless were used.

Image processing is performed by the above-described method based on the image data obtained for each of the above-described samples, a luminance distribution in the longitudinal direction of the hair is obtained, and a change amount of the luminance distribution is obtained. The maximum of the absolute value was obtained. The result is as shown in FIG. 6. The sample determined to be glossy in the sensory evaluation and the glosslessness were determined to have a maximum value of the absolute value of the variation amount of the luminance distribution of about 0.8 as a boundary. The sample was clearly bisected. From these results, it was confirmed that the hair gloss evaluation method of the present invention had an extremely high correlation with the sensory evaluation and was objective and useful as a hair gloss evaluation method. In the results shown in FIG. 6, the maximum value of the absolute value of the change amount of the luminance distribution varies depending on the measurement conditions such as the type of the light source, the method of preparing the sample, and the type of the imaging means. In any case, it does not make sense as a boundary value as a criterion for judging the presence or absence of gloss of hair. Therefore, it is necessary to determine the boundary value in advance for each measurement condition.

[0028]

According to the present invention, there is provided a method for evaluating the gloss of hair, which allows easy evaluation of hair quality. Further, according to the present invention, there is provided a method for evaluating the gloss of hair which can be used for evaluation without cutting the hair of the subject.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the configuration of an example of an evaluation device preferably used in the hair gloss evaluation method of the present invention.

FIG. 2 is an exploded perspective view of the hair holder.

FIG. 3 is a diagram showing a state of holding the hair held by the hair holding device.

FIG. 4 is a diagram showing a luminance distribution in a longitudinal direction of hair measured according to the evaluation method of the present invention.

5 is a diagram showing an absolute value of a change amount of the luminance distribution shown in FIG.

FIG. 6 is a diagram showing a correlation between an evaluation result by the evaluation method of the present invention and an evaluation result by a sensory evaluation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaluation apparatus 2 Housing 3 Hair holder 3a Cylindrical rod 3b Holder 3b 'Fitting part 3b "Connecting part 3c Comb tooth 4 Light source 5 Imaging means 6 Gray scale

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yoshiaki Fujikura 2606, Akabane, Kaigamachi, Haga-gun, Tochigi Pref.

Claims (2)

[Claims] 1. A method according to claim 1, wherein the hair is irradiated with light in a state where a predetermined number of hairs are curved at a predetermined curvature and held, and the regular reflection light out of the reflection light from the hair is obtained. A region including the region is imaged in the longitudinal direction of the hair, a luminance distribution in the longitudinal direction of the hair is obtained from the image data, and the quality of the gloss of the hair is determined from the maximum value of the absolute value of the amount of change in the luminance distribution. How to evaluate the gloss of the hair to be evaluated. 2. The method according to claim 1, wherein a gray scale is imaged together with the hair, and the brightness distribution of the hair is corrected based on the gray scale image data.