SKIN COLOR CHART AND METHOD FOR MANUFACTURING THE SAME
20230026416 · 2023-01-26
Assignee
Inventors
Cpc classification
International classification
Abstract
A skin color chart (10) according to an example aspect of the present disclosure includes: a substrate (11); a first skin color display part (BK) configured to show a skin color of a Negroid, the first skin color display part being formed on the substrate (11); and a second skin color display part (WT) configured to show a skin color of a Caucasoid, the second skin color display part being formed on the substrate (11). Lightness L* of the first skin color display part (BK) in a CIE L*a*b* color space satisfies 20≤L*≤37, and lightness L* of the second skin color display part (WT) in the CIE L*a*b* color space satisfies 74≤L*≤81.
Claims
1. A skin color chart for determining an environment where face authentication is performed, the skin color chart comprising: a substrate; a first skin color display part configured to show a skin color of a Negroid, the first skin color display part being formed on the substrate; and a second skin color display part configured to show a skin color of a Caucasoid, the second skin color display part being formed on the substrate, wherein lightness L* of the first skin color display part in a CIE L*a*b* color space satisfies 20≤L*≤37, and lightness L* of the second skin color display part in the CIE L*a*b* color space satisfies 74≤L*≤81.
2. The skin color chart according to claim 1, wherein each of the first and the second skin color display parts is formed in a three-dimensional shape imitating a human face.
3. The skin color chart according to claim 1, further comprising a plurality of gray display parts having different reflectances, the gray display parts being formed on the substrate.
4. The skin color chart according to claim 1, further comprising a third skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the second skin color display part, the third skin color display part being formed on the substrate, wherein lightness L* of the third skin color display part in the CIE L*a*b* color space satisfies 62≤L*≤68.
5. The skin color chart according to claim 4, further comprising, on the substrate, at least one of: a fourth skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the third skin color display part; and a fifth skin color display part configured to show a skin color between the skin color in the second skin color display part and the skin color in the third skin color display part.
6. The skin color chart according to claim 1, wherein the substrate is black.
7. A method for manufacturing a skin color chart for determining an environment where face authentication is performed, the method comprising: forming, on a substrate, a first skin color display part configured to show a skin color of a Negroid; and forming, on the substrate, a second skin color display part configured to show a skin color of a Caucasoid, wherein lightness L* of the first skin color display part in a CIE L*a*b color space satisfies 20≤L*≤37, and lightness L* of the second skin color display part in the CIE L*a*b* color space satisfies 74≤L*≤81.
8. The method according to claim 7, wherein each of the first and the second skin color display parts is formed in a three-dimensional shape imitating a human face.
9. The method according to claim 7, further comprising forming a plurality of gray display parts having different reflectances on the substrate.
10. The method according to claim 7, further comprising forming, on the substrate, a third skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the second skin color display part, wherein lightness L* of the third skin color display part in the CIE L*a*b* color space satisfies 62≤L*≤68.
11. The method according to claim 10, further comprising forming, on the substrate, at least one of: a fourth skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the third skin color display part; and a fifth skin color display part configured to show a skin color between the skin color in the second skin color display part and the skin color in the third skin color display part.
12. The method according to claim 7, wherein the substrate is black.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
DESCRIPTION OF EMBODIMENTS
[0028] Specific example embodiments will be described hereinafter in detail with reference to the drawings. The same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant descriptions will be omitted as necessary for the clarification of the description.
First Example Embodiment
<Structure of Skin Color Chart>
[0029] First, a skin color chart according to a first example embodiment will be described with reference to
[0030] As shown in
[0031] The substrate 11 is made of, for example, cardboard, plastic, wood, metal, glass and combinations thereof, but is not limited to being made of any particular material. When the substrate 11 is made of cardboard, plastic, and wood, it is lightweight and thus can be easily carried. In the example shown in
[0032] As shown in
[0033] Further, chromaticity a* and chromaticity b* of the first skin color display part BK satisfy, for example, 8≤a*≤12 and 7≤b*≤10, respectively. The chromaticity a* and the chromaticity b* are more preferably 9≤a*≤11 and 8≤b*≤9, respectively.
[0034] Note that, in the example shown in
[0035] As shown in
[0036] Further, chromaticity a* and chromaticity b* of the second skin color display part WT satisfy, for example, 10≤a*≤12 and 23≤b*≤25, respectively. The chromaticity a* and the chromaticity b* are more preferably a*=11 and b*=24, respectively.
[0037] Note that, in the example shown in
[0038] Note that
[0039] When a face authentication environment is determined using the skin color chart 10, the skin color chart 10 is captured by a camera for face authentication (not shown). Then, in the captured image of the skin color chart 10, it can be determined that the environment is suitable for face authentication if blocked-up shadows do not occur in the first skin color display part BK and blown-out highlights do not occur in the second skin color display part WT.
[0040] As described above, in the skin color chart 10 according to this example embodiment, the lightness L* of the skin color in the first skin color display part BK satisfies 20≤L*≤37, and the first skin color display part BK shows the skin color near the limit of the distribution of the skin colors of black people on the blackest part of the distribution. Thus, it is extremely unlikely that a person whose skin is blacker than the first skin color display part BK will be a person on whom face authentication is to be performed. Therefore, in the environment which it has been determined using the skin color chart 10 according to this example embodiment is suitable for face authentication, it is also extremely unlikely that blocked-up shadows will occur in the face image and then face authentication cannot be performed.
[0041] On the other hand, the lightness L* of the skin color in the second skin color display part WT satisfies 74≤L*≤81, and the second skin color display part WT shows the skin color near the limit of the distribution of the skin colors of white people on the whitest part of the distribution. Thus, it is extremely unlikely that a person whose skin is whiter than the second skin color display part WT will be a person on whom face authentication is to be performed. Therefore, in the environment which it has been determined using the skin color chart 10 according to this example embodiment is suitable for face authentication, it is also extremely unlikely that blown-out highlights will occur in the face image and then face authentication cannot be performed.
[0042] As described above, by using the skin color chart 10 according to this example embodiment, it is possible to more appropriately determine a face authentication environment.
<Method for Manufacturing Skin Color Chart>
[0043] Next, a method for manufacturing a skin color chart according to the first example embodiment will be described with reference to
[0044] Although a specific example of a method for manufacturing a skin color chart according to the first example embodiment will be described below, the method is not limited to this specific example.
[0045] First, the first skin color display part BK and the second skin color display part WT prepared in advance are stuck on a mount made of cardboard. For example, paints that have been adjusted to the colors of the first skin color display part BK and the second skin color display part WT are respectively applied to pieces of paper, whereby the first skin color display part BK and the second skin color display part WT can be prepared. The paint is, for example, a non-glossy lacquer paint, but is not limited to a particular paint.
[0046] Next, a black cardboard of the same size as that of the mount is prepared, and parts of the black cardboard corresponding to the first skin color display part BK and the second skin color display part WT that have been stuck on the mount are cut out. Then the black cardboard and the mount on which the first skin color display part BK and the second skin color display part WT have been stuck are bonded to each other. Note that the black cardboard has been processed so that the reflectance of the surface thereof becomes 0 (zero).
[0047] In this way, the skin color chart 10 can be manufactured. In the skin color chart 10 manufactured according to this specific example, the substrate 11 is formed of a mount and a black cardboard.
[0048] As described above, in the skin color chart 10 according to this example embodiment, the first skin color display part BK shows the skin color near the limit of the distribution of the skin colors of black people on the blackest part of the distribution, and the second skin color display part WT shows the skin color near the limit of the distribution of the skin colors of white people on the whitest part of the distribution. Thus, it is extremely unlikely that a person whose skin is blacker than the first skin color display part BK or a person whose skin is whiter than the second skin color display part WT will be a person on whom face authentication is to be performed. Therefore, in the environment which it has been determined using the skin color chart 10 according to this example embodiment is suitable for face authentication, it is also extremely unlikely that blocked-up shadows or blown-out highlights will occur in the face image and then face authentication cannot be performed. That is, by using the skin color chart 10 according to this example embodiment, it is possible to more appropriately determine a face authentication environment.
Second Example Embodiment
[0049] Next, a skin color chart according to a second example embodiment will be described with reference to
[0050] In the skin color chart 10 according to the first example embodiment shown in
[0051] In a case in which the skin color chart 10 according to the first example embodiment is used, for example, blocked-up shadows may occur in a recessed part of the face (e.g., a part of the face near the shadow formed by the nose) in the face image of Negroid, and hence there is a possibility that face authentication cannot be performed even in the environment which it has been determined is suitable for face authentication. Alternatively, for example, blown-out highlights may occur in a projection part of the face (e.g., a part of the face near the top of the nose) in the face image of Caucasoid, and hence there is a possibility that face authentication cannot be performed.
[0052] On the other hand, in a case in which the skin color chart 10 according to the second example embodiment is used, when a face authentication environment is determined, it is possible to determine that the environment in which blocked-up shadows occur in the recessed part and the like of the first skin color display part BK is not suitable for face authentication. Further, it is possible to determine that the environment in which blown-out highlights occur in the projection part and the like of the second skin color display part WT is also not suitable for face authentication.
[0053] Therefore, by using the skin color chart 10 according to this example embodiment, it is possible to further appropriately determine a face authentication environment.
[0054] The structures other than the above ones are similar to those of the first example embodiment, and thus the descriptions thereof will be omitted.
Third Example Embodiment
[0055] Next, a skin color chart according to a third example embodiment will be described with reference to
[0056] As shown in
[0057] In the example shown in
[0058] In the example shown in
[0059] By using the gray scale parts GS1 and GS2, it is possible, for example, to evaluate the dynamic range of the camera for face authentication (not shown) and adjust it.
[0060] Note that, in the example shown in
[0061] The structures other than the above ones are similar to those of the first example embodiment, and thus the descriptions thereof will be omitted. The second example embodiment may be combined with the third example embodiment.
Fourth Example Embodiment
[0062] Next, a skin color chart according to a fourth example embodiment will be described with reference to
[0063] As shown in
[0064] As shown in
[0065] The third skin color display part YL shows a skin color between the skin color in the first skin color display part BK and the skin color in the second skin color display part WT. The third skin color display part YL shows, for example, an average skin color of Mongoloid. Specifically, lightness L* of a skin color in the third skin color display part YL expressed in the CIE L*a*b* color space satisfies, for example, 62≤L*≤68. Further, chromaticity a* and chromaticity b* of the third skin color display part YL satisfy, for example, a*=11 and 18≤b*≤19, respectively.
[0066] By providing the third skin color display part YL, when a face authentication environment is being determined, it is possible to evaluate the environment in more detail than it is in the cases of the first to the third example embodiments. Specifically, it can be understood that the environment in which blocked-up shadows occur in the third skin color display part YL in addition to the first skin color display part BK is blacker than the environment in which blocked-up shadows occur only in the first skin color display part BK. It can also be understood that the environment in which blown-out highlights occur in the third skin color display part YL in addition to the second skin color display part WT is brighter than the environment in which blown-out highlights occur only in the second skin color display part WT. Based on the above-described evaluations, for example, the position where a camera is installed, the orientation of the camera, and the brightness of a place where a face image is captured can be easily adjusted.
[0067] Note that, in the example shown in
[0068] The structures other than the above ones are similar to those of the third example embodiment, and thus the descriptions thereof will be omitted. The second example embodiment may be combined with the fourth example embodiment. Further, in the fourth example embodiment, the gray scale parts GS1 and GS2 may not be formed. That is, a structure in which the third skin color display part YL is added to the skin color chart 10 according to the first example embodiment may be employed.
Fifth Example Embodiment
[0069] Next, a skin color chart according to a fifth example embodiment will be described with reference to
[0070] As shown in
[0071] As shown in
[0072] The fourth skin color display part 14 shows a skin color between the skin color in the first skin color display part BK and the skin color in the third skin color display part YL.
[0073] The fifth skin color display part 15 shows a skin color between the skin color in the second skin color display part WT and the skin color in the third skin color display part YL.
[0074] By providing the fourth skin color display part 14, when a face authentication environment is being determined, the environment can be evaluated in much more detail than it is in the case of the fourth example embodiment. Specifically, it is possible to distinguish the environment in which blocked-up shadows occur in the first skin color display part BK and the fourth skin color display part 14 from the environment in which blocked-up shadows occur only in the first skin color display part BK. Further, it is possible to distinguish the environment in which blocked-up shadows occur in the first skin color display part BK, the fourth skin color display part 14, and the third skin color display part YL from the environment in which blocked-up shadows occur only in the first skin color display part BK and the fourth skin color display part 14.
[0075] Similarly, by providing the fifth skin color display part 15, when a face authentication environment is being determined, the environment can be evaluated in much more detail than it is in the case of the fourth example embodiment. Specifically, it is possible to distinguish the environment in which blown-out highlights occur in the second skin color display part WT and the fifth skin color display part 15 from the environment in which blown-out highlights occur only in the second skin color display part WT. Further, it is possible to distinguish the environment in which blown-out highlights occur in the second skin color display part WT, the fifth skin color display part 15, and the third skin color display part YL from the environment in which blown-out highlights occur only in the second skin color display part WT and the fifth skin color display part 15.
[0076] Based on the above-described evaluations, for example, the position where a camera is installed, the orientation of the camera, and the brightness of a place where a face image is captured can be more easily adjusted.
[0077] Note that, in the example shown in
[0078] Further, a plurality of fourth skin color display parts 14 showing skin colors different from each other may be provided in the skin color chart 10. Similarly, a plurality of fifth skin color display parts 15 showing skin colors different from each other may be provided in the skin color chart 10.
[0079] Further, in this example embodiment, the skin colors of the third skin color display part YL, the fourth skin color display part 14, and the fifth skin color display part 15 may show, for example, average skin colors in specific countries or regions.
[0080] The structures other than the above ones are similar to those of the fourth example embodiment, and thus the descriptions thereof will be omitted. The second example embodiment may be combined with the fifth example embodiment. Further, in the fifth example embodiment, the gray scale parts GS1 and GS2 may not be formed. That is, a structure in which the third skin color display part YL, the fourth skin color display part 14, and the fifth skin color display part 15 are added to the skin color chart 10 according to the first example embodiment may be employed.
[0081] Although the present disclosure has been described with reference to the example embodiments, the present disclosure is not limited to the above-described example embodiments. Various changes that may be understood by those skilled in the art may be made to the configurations and details of the present disclosure within the scope of the disclosure.
[0082] The whole or part of the example embodiments disclosed above can be described as, but not limited to, the following supplementary notes.
(Supplementary Note 1)
[0083] A skin color chart for determining an environment where face authentication is performed, the skin color chart comprising:
[0084] a substrate;
[0085] a first skin color display part configured to show a skin color of a Negroid, the first skin color display part being formed on the substrate; and
[0086] a second skin color display part configured to show a skin color of a Caucasoid, the second skin color display part being formed on the substrate, wherein
[0087] lightness L* of the first skin color display part in a CIE L*a*b* color space satisfies 20≤L*≤37, and
[0088] lightness L* of the second skin color display part in the CIE L*a*b* color space satisfies 74≤L*≤81.
(Supplementary Note 2)
[0089] The skin color chart according to Supplementary note 1, wherein each of the first and the second skin color display parts is formed in a three-dimensional shape imitating a human face.
(Supplementary Note 3)
[0090] The skin color chart according to Supplementary note 1 or 2, further comprising a plurality of gray display parts having different reflectances, the gray display parts being formed on the substrate.
(Supplementary Note 4)
[0091] The skin color chart according to any one of Supplementary notes 1 to 3, further comprising a third skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the second skin color display part, the third skin color display part being formed on the substrate,
[0092] wherein lightness L* of the third skin color display part in the CIE L*a*b* color space satisfies 62≤L*≤68.
(Supplementary Note 5)
[0093] The skin color chart according to Supplementary note 4, further comprising, on the substrate, at least one of:
[0094] a fourth skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the third skin color display part; and
[0095] a fifth skin color display part configured to show a skin color between the skin color in the second skin color display part and the skin color in the third skin color display part.
(Supplementary Note 6)
[0096] The skin color chart according to any one of Supplementary notes 1 to 5, wherein the substrate is black.
(Supplementary Note 7)
[0097] A method for manufacturing a skin color chart for determining an environment where face authentication is performed, the method comprising:
[0098] forming, on a substrate, a first skin color display part configured to show a skin color of a Negroid; and
[0099] forming, on the substrate, a second skin color display part configured to show a skin color of a Caucasoid, wherein
[0100] lightness L* of the first skin color display part in a CIE L*a*b* color space satisfies 20≤L*≤37, and
[0101] lightness L* of the second skin color display part in the CIE L*a*b* color space satisfies 74≤L*≤81.
(Supplementary Note 8)
[0102] The method according to Supplementary note 7, wherein each of the first and the second skin color display parts is formed in a three-dimensional shape imitating a human face.
(Supplementary Note 9)
[0103] The method according to Supplementary note 7 or 8, further comprising forming a plurality of gray display parts having different reflectances on the substrate.
(Supplementary Note 10)
[0104] The method according to any one of Supplementary notes 7 to 9, further comprising forming, on the substrate, a third skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the second skin color display part,
[0105] wherein lightness L* of the third skin color display part in the CIE L*a*b* color space satisfies 62≤L*≤68.
(Supplementary Note 11)
[0106] The method according to Supplementary note 10, further comprising forming, on the substrate, at least one of:
[0107] a fourth skin color display part configured to show a skin color between the skin color in the first skin color display part and the skin color in the third skin color display part; and
[0108] a fifth skin color display part configured to show a skin color between the skin color in the second skin color display part and the skin color in the third skin color display part.
(Supplementary Note 12)
[0109] The method according to any one of Supplementary notes 7 to 11, wherein the substrate is black.
REFERENCE SIGNS LIST
[0110] 10 SKIN COLOR CHART [0111] 11 SUBSTRATE [0112] BK FIRST SKIN COLOR DISPLAY PART [0113] WT SECOND SKIN COLOR DISPLAY PART [0114] YL THIRD SKIN COLOR DISPLAY PART [0115] 14 FOURTH SKIN COLOR DISPLAY PART [0116] 15 FIFTH SKIN COLOR DISPLAY PART [0117] GR GRAY DISPLAY PART [0118] GS1, GS2 GRAY SCALE PART