JP7184130B2 - Rendering device and rendering method - Google Patents

Description

The present invention relates to a drawing apparatus and drawing method.

2. Description of the Related Art Conventionally, there is known a drawing device that draws a nail design on a nail (see, for example, Patent Document 1).
In addition, as a drawing device (nail printing device) for drawing nail designs such as colors and patterns on the surface of the nail, the use of a plotter-type drawing device equipped with a writing tool (a pen as a drawing tool) for drawing is also being considered. ing.
When drawing with a pen, there are restrictions on the viscosity of the ink that can be used and the particle size of the coloring material contained in the ink, compared to a drawing device that ejects small droplets of ink like an inkjet system. A highly viscous ink such as a light-curing ink or a highly colored ink containing a small amount of a coloring material having a large particle diameter can also be used. Therefore, it is possible to draw various nail designs similar to those applied at a nail salon.

When drawing on a nail, for example, after applying a base, a pattern or the like is drawn on the base region, and the drawing is performed in multiple steps and superimposed on the drawing region. In this case, in order to improve the finished quality of the nail print, it is preferable to detect the previously drawn area as accurately as possible so that the drawing positions do not deviate from each other.
For this reason, the fingernail is photographed with light, and a drawn area (already drawn area) is detected based on the obtained photographed image.

Japanese Patent Publication No. 2003-534083

However, for example, the background is drawn in white or a color close to it, and if the drawn color is white or a color close to it, the light applied to the nail to acquire the photographed image may be different from the nail. When the light is reflected on the surface of the surface, it is difficult to distinguish between the high-intensity part and the drawn area (already drawn area) due to the reflected light, and it is possible to accurately detect the drawn area (already drawn area). Sometimes you can't.
Also, even in a drawn area (already drawn area), if a shadow is partially formed due to light irradiation, it will be recognized as a part with a different color from other drawn areas (already drawn area). In some cases, it is not correctly determined as a drawn area (already drawn area).
It is conceivable to design lighting that does not produce reflections or shadows, but since the shape of nails varies from person to person and from finger to finger, reflections and shadows do not occur for any type of nail. It is difficult to do so.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drawing apparatus and a drawing method capable of accurately detecting an already drawn area without excess or deficiency.

In order to solve the above problems, the drawing apparatus of the present invention includes:
a drawing unit that draws on a nail that is a drawing target;
at least one light source for illuminating the nail ;
a photographing unit that photographs the nail after the first image has been drawn by the drawing unit a plurality of times while changing the direction in which the nail is illuminated by the light source in different directions;
a plurality of nail images obtained by photographing a plurality of times by the photographing unit are synthesized to generate a synthesized image; and based on the synthesized image, the first image of the nail is rendered in a drawn area. a drawn area detection unit that detects the
with
The already-drawn area detection unit extracts, from the synthesized image, an area in which the first image of the nail is estimated to be drawn as an estimated already-drawn area based on color distribution information in the synthesized image, Determining a color difference between pixels in a peripheral area of the already-drawn estimation area and the already-drawn estimation area, and detecting an area where the color difference is changed as the already-drawn area together with the already-drawn estimation area. characterized by
Further, the drawing method of the present invention is
a drawing step of drawing a first image on a nail, which is a drawing target, by a drawing unit;
a photographing step of photographing the nail after the drawing of the first image in the drawing step a plurality of times while changing the direction in which the nail is illuminated by at least one light source in different directions;
generating a composite image by synthesizing a plurality of nail images acquired by multiple times of photographing in the photographing step, and drawing the first image of the nail based on the composite image; a drawn area detection step for detecting
with
In the already-drawn area detecting step, extracting from the synthesized image an area in which the first image of the nail is estimated to be drawn as an estimated already-drawn area based on color distribution information in the synthesized image; Determining a color difference between pixels in a peripheral area of the already-drawn estimation area and the already-drawn estimation area, and detecting an area where the color difference is changed as the already-drawn area together with the already-drawn estimation area. characterized by

According to the present invention, it is possible to accurately detect an already-drawn area without excess or deficiency.

(a) is a front view of a drawing apparatus according to the present embodiment, and (b) is a side view showing the internal configuration of the drawing apparatus shown in (a). 3 is a block diagram of main parts showing the control configuration of the drawing apparatus according to the embodiment; FIG. FIG. 10 is an explanatory diagram showing a procedure for detecting an already-drawn area; 4 is a flow chart showing drawing processing of the drawing device according to the present embodiment.

An embodiment of a nail printing device (drawing device) and a drawing method in the nail printing device (drawing device) according to the present invention will be described with reference to FIGS.
Although various technically desirable limitations are attached to the embodiments described below for carrying out the present invention, the scope of the present invention is not limited to the following embodiments and illustrated examples.
In the following embodiments, the nail printing apparatus 1 is described as drawing on a fingernail as a drawing target, but the drawing target of the present invention is not limited to the fingernail. For example, toe nails may be drawn.

FIG. 1(a) is a front view showing the internal configuration of the nail printing device, and FIG. 1(b) is a side view showing the internal configuration of the nail printing device shown in FIG. 1(a).
As shown in FIGS. 1(a) and 1(b), the nail printing device 1 according to the present embodiment includes a drawing head 43 having a pen 41 serving as a drawing tool and an inkjet head 71, and a plotter system and an inkjet system. This is a drawing device that draws on the nail T in combination with .
The nail printing device 1 includes a case body (housing) 2 and a device body 10 housed in the case body 2 . The case body 2 has a structure for blocking external light so that external light does not enter the case body 2 .

As shown in FIG. 1(b), the case main body 2 has a lid portion 23 which can be opened and closed from the upper surface to the upper front surface thereof for exchanging the pen 41 and the inkjet head 71 of the drawing unit 40, which will be described later. is provided. The lid portion 23 is rotatable from a closed state to an open state, as shown in FIG. 1B, via a hinge or the like.

An operation unit 25 (see FIG. 2) is installed on the upper surface (top plate) of the case body 2 .
The operation unit 25 is an input unit through which a user performs various inputs.
The operation unit 25 includes, for example, a power switch button for turning on the power of the nail printing apparatus 1, a stop switch button for stopping the operation, a design selection button for selecting a design image to be drawn on the nail T, and a drawing start button for instructing the start of drawing. Operation buttons (not shown) for performing various inputs such as buttons are arranged.

Further, a display unit 26 is installed in a substantially central portion of the upper surface (top plate) of the case main body 2 .
The display unit 26 is configured by, for example, a liquid crystal display (LCD), an organic electroluminescence display, or other flat display.
In the present embodiment, the display unit 26 displays, for example, a nail image obtained by photographing the printing finger U1 (a finger image including an image of the nail T), an outline of the nail T included in the nail image, and the like. An image, a design selection screen for selecting a design image to be drawn on the nail T, a thumbnail image for design confirmation, an instruction screen for displaying various instructions, and the like are appropriately displayed.
A touch panel for performing various inputs may be integrally formed on the surface of the display unit 26 .

The apparatus main body 10 is formed substantially in the shape of a box and includes a lower machine frame 11 installed below the inside of the case body 2 and an upper machine installed above the lower machine frame 11 and above the inside of the case main body 2. A frame 12 is provided.

First, the lower machine frame 11 will be described.
The lower machine frame 11 has a back plate 111 , a bottom plate 112 , a pair of left and right side plates 113 a and 113 b , an X-direction moving stage housing portion 114 , a Y-direction moving stage housing portion 115 and a partition wall 116 .
The lower ends of the side plates 113a and 113b are connected to the left and right ends of the bottom plate 112, respectively, and the side plates 113a and 113b are provided in a state of being erected with respect to the bottom plate 112. As shown in FIG.
The lower part of the back plate 111 is formed so as to be recessed in two stages toward the front (the near side in the finger insertion direction). The lower end of the back plate 111 is connected to the front end of the bottom plate 112, and the back plate 111 divides the area surrounded by the bottom plate 112 and the side plates 113a and 113b into the front and rear.
A space formed on the rear side of the recessed rear plate 111 is an X-direction moving stage accommodating portion 114 and a Y-direction moving stage accommodating portion 115 (see FIG. 1B). The X-direction moving stage 45 of the drawing section 40 is accommodated in the X-direction moving stage accommodating section 114 when the drawing section 40 moves forward (toward the finger insertion direction). A Y-direction moving stage 47 of the drawing section 40 is arranged in the Y-direction moving stage housing section 115 .
In addition, the partition wall 116 divides the space on the front side inside the lower machine frame 11 (the space on the front side in the finger insertion direction surrounded by the back plate 111, the bottom plate 112, and the side plates 113a and 113b). is located inside the The partition 116 is provided substantially horizontally, and both left and right ends of the partition 116 are connected to the side plates 113 a and 113 b , respectively, and the rear end of the partition 116 is connected to the rear plate 111 .

The lower machine frame 11 is integrally provided with a finger fixing portion 30 (see FIG. 1(b)).
The finger fixing unit 30 includes a finger receiving unit 31 for receiving a finger (hereinafter referred to as a “printing finger U1”) corresponding to a nail T (that is, a drawing target) on which drawing is performed, and a finger other than the printing finger U1 (hereinafter referred to as a “printing finger U1”). , and this is referred to as a “non-printing finger U2”).
The finger receiving portion 31 is arranged above the partition wall 116 and, for example, slightly to the right of the center of the lower machine frame 11 in the width direction. Further, a space partitioned under the lower machine frame 11 by the partition wall 116 constitutes a finger evacuation section 32 .
For example, when drawing on the nail T of the ring finger, the ring finger as the printing finger U1 is inserted into the finger receiving portion 31, and the other four fingers (thumb, index finger, middle finger, and little finger) that are the non-printing fingers U2 are used. It is inserted into the evacuation section 32 .
The finger receiving portion 31 is open on the front side of the lower machine frame 11 (the front side in the printing finger insertion direction), and the lower side serves as a finger placing portion forming a part of the partition wall 116 . The finger placement unit is for placing the finger (printing finger U1) of the nail T on which drawing is to be performed on the XY plane.
The upper side of the finger receiving portion 31 is open so that the surface of the nail T of the printing finger U1 inserted into the finger receiving portion 31 (that is, the surface to be drawn) is exposed.

Front walls 31f (see FIG. 1(a)) that block the front side of the lower machine frame 11 are erected on both sides of the upper surface of the partition wall 116 on the front side of the lower machine frame 11. As shown in FIG. A pair of guide walls 31g ( (see FIG. 1(a)) is erected.
The user can sandwich the partition 116 between the printing finger U1 inserted into the finger receiving portion 31 and the non-printing finger U2 inserted into the finger retraction portion 32 . Therefore, the printing finger U1 inserted into the finger receiving portion 31 is stably fixed.

On the upper surface of the lower machine frame 11 and on the side of the finger receiving portion 31 (the position corresponding to the medium insertion opening 24 of the case body 2, in this embodiment, on the left side in FIGS. 1A and 2) is provided within the drawable range of the drawing head 43, which will be described later.
The document part 61 is a flat plate-like part, and a drawing medium (not shown) inserted from the medium insertion port 24 of the case main body 2 is placed thereon.
The drawing medium placed on the writing section 61 may be any medium on which preliminary writing can be performed with the pen tip (tip) 413, such as a piece of paper.

Although illustration is omitted, on the upper surface of the lower machine frame 11, a pen waiting unit for keeping the pen 41 waiting when drawing is not performed and an inkjet head 71, which will be described later, are provided within a movable range of the drawing head 43, which will be described later. An ink jet maintenance section and the like are provided for standby.
The pen standby section is provided with, for example, a cap section or the like that prevents the pen tip 413 from drying.
Further, the inkjet maintenance section is provided with a mechanism for cleaning the ink ejection portion (nozzle surface) of the inkjet head 71, a cap portion for keeping the ink ejection portion (nozzle surface) in a moist state, and the like.

The drawing unit 40 includes a drawing head 43, a unit support member 44 for supporting the drawing head 43, and an X direction for moving the drawing head 43 in the X direction (the X direction in FIG. 1A, the horizontal direction of the drawing apparatus 1). A moving stage 45, an X-direction moving motor 46, a Y-direction moving stage 47 for moving the drawing head 43 in the Y direction (the Y direction in FIG. 1B, the front-rear direction of the drawing apparatus 1), a Y-direction moving motor 48, and the like. is configured with

As shown in FIGS. 1A and 1B, the drawing head 43 of the present embodiment is provided with a pen holder 42 that detachably holds a pen and an inkjet holder 72 that holds an inkjet head 71. placed together.
The inkjet head 71 faces, for example, ink cartridges (not shown) corresponding to yellow (Y; YELLOW), magenta (M; MAGENTA), and cyan (C; CYAN) inks, and a drawing target (nail T) in each ink cartridge. It is an ink cartridge-integrated head integrally formed with an ink discharge section (not shown) provided on a surface (in this embodiment, the lower surface in FIG. 1(a), etc.). The ink ejection section has a nozzle array consisting of a plurality of nozzles for ejecting ink of each color, and the inkjet head 71 forms ink into fine droplets, which are ejected from the ink ejection section onto the drawing surface of the drawing target (nail T). Drawing is done by spraying ink directly on the surface. In addition, the inkjet head 71 is not limited to one that ejects the three colors of ink described above. An ink cartridge for storing other ink and an ink discharge section may be provided.

The pen holding portion 42 holds at least one pen 41 in an attachable manner, and in this embodiment, one pen holding portion 42 holding one pen 41 is provided in the drawing head 43 . .
The pen 41 is a drawing tool that draws on the nail T by using the surface of the nail T as a drawing target surface, and the tip of the pen 41 is in contact with the surface of the nail T, which is the drawing target surface.
As shown in FIG. 1(a), the pen 41 has a pen tip 413 on the tip side (lower side in FIG. 1(a)) of a rod-shaped pen shaft portion 411 inserted in a hollow cylindrical pen holder 410. It was established.
The interior of the pen shaft portion 411 serves as an ink containing portion that contains various types of ink.
Various types of ink can be applied as the ink contained inside the pen shaft portion 411 . The viscosity of the ink and the particle size (particle size) of the coloring material are not particularly limited. Coating ink, nail polish, and the like can also be used.
In this embodiment, the case where the pen 41 is a base pen in which white ink for base coating is contained in the pen shaft portion 411 will be described as an example.

In the present embodiment, the pen tip 413 of the pen 41 is of a ballpoint pen type. is a pen.
Note that the pen 41 is not limited to a ballpoint pen type. For example, it may be a felt-tip pen type that draws by impregnating the felt pen tip with ink, or a brush pen type that draws by impregnating bundled hair with ink. In addition, various thicknesses of the pen tip 413 can be prepared.

The pen holding portion 42 is a member for holding and fixing one pen 41 by a locking portion (not shown) and moving it together with the drawing head 43 . In this embodiment, the pen holder 42 is supported by the side of the drawing head 43 .
Further, the pen holding portion 42 is configured to be vertically movable by being driven by a pen vertical movement motor 426 (see FIG. 2) mounted on the drawing head 43 .

Also, the unit support member 44 is fixed to an X-direction moving part 451 attached to the X-direction moving stage 45 . The X-direction moving part 451 is driven by the X-direction movement motor 46 to move on the X-direction movement stage 45 along a guide (not shown) in the X direction. The drawing head 43 is moved in the X direction (the X direction in FIG. 1(a), the lateral direction of the nail printing device 1).
Also, the X-direction moving stage 45 is fixed to the Y-direction moving part 471 of the Y-direction moving stage 47 . The Y-direction moving part 471 is driven by the Y-direction moving motor 48 to move on the Y-direction moving stage 47 along a guide (not shown) in the Y direction. The drawing head 43 is moved in the Y direction (the Y direction in FIG. 1(b), the front-rear direction of the nail printing device 1).
In this embodiment, the X-direction moving stage 45 and the Y-direction moving stage 47 are configured by combining the X-direction moving motor 46, the Y-direction moving motor 48, and ball screws and guides (not shown).
In this embodiment, the X-direction movement motor 46, the Y-direction movement motor 48, and the like constitute a head moving section 49 as an XY driving section that drives the drawing head 43 having the pen 41 in the X and Y directions.

The pen up/down motor 426, the inkjet head 71, the X-direction movement motor 46, and the Y-direction movement motor 48 in the drawing unit 40 are connected to a drawing control unit 814 (see FIG. 2) of the control device 80, which will be described later. 814.

The imaging unit 50 also includes an imaging device 51 and illumination devices 52 and 55 .
The photographing unit 50 illuminates the nail T of the printing finger U1 that is inserted into the finger receiving unit 31 and visible from the upper opening with the illumination device 52 and the illumination device 55 . Then, the printing finger U1 is photographed by the imaging device 51, and a nail image (a finger image including the nail image), which is a photographed image of the nail T of the printing finger U1, is acquired. In the present embodiment, the imaging device 51 acquires a plurality of nail images in which the light irradiation angles with respect to the nail T are different.
In this embodiment, the imaging device 51 and the illumination device 52 are fixedly arranged on the side of the drawing head 43 of the drawing unit 40 (on the right side of the drawing head 43 in FIG. 1A).
That is, as shown in FIGS. 1(a) and 1(b), the drawing head 43 of the drawing unit 40 has a projecting portion that projects sideways on one end side of the upper surface (on the right side in FIG. 1(a)). 401 to which the substrate 53 is attached. The imaging device 51 and the lighting device 52 that constitute the imaging unit 50 are provided on the lower surface of the substrate 53 so as to face the partition wall 116 .
The size of the substrate 53 and the positions of the imaging device 51 and the lighting device 52 attached to the substrate 53 are not particularly limited.

The imaging device 51 is, for example, a compact camera configured with a solid-state imaging device having pixels of about 2 million pixels or more, a lens, and the like.
In the present embodiment, based on the photographed image (nail image) acquired by the imaging device 51, a drawn area detection unit 815 (see FIG. 2), which will be described later, draws a drawn area Fa that has been drawn with the pen 41. determine the situation.
Further, the nail shape detection unit 812 detects other nail information such as the position of the nail T on the xy plane and the vertical position of the nail T based on the photographed image (nail image).
In order to detect the curved shape and the like of the nail T of the printing finger U1, the image capturing device 51 captures the nail T from different positions and angles by moving the head moving unit 49 to obtain a plurality of captured images (nail images). ) is preferably obtained.
When a plurality of photographed images (nail images) are acquired by the imaging device 51, the nail shape detection unit 812 (see FIG. 3) detects the curved shape of the nail T based on these photographed images (nail images). can be detected.

The lighting device 52 is a light source such as a white LED, for example.
The illumination device 52 is directed downward and emits light downward to illuminate at least the shooting range below the imaging device 51 . The position of the illumination device 52 with respect to the imaging device 51 is constant. It should be noted that the number of lighting devices 52 provided, their arrangement, and the like are not limited to the illustrated example.

Further, in this embodiment, apart from the illumination device 52, an illumination device 55 is provided above the finger receiving portion 31 and at a position where the nail T exposed from the opening can be irradiated with light from an obliquely upward direction. are placed.
Like the lighting device 52, the lighting device 55 is a light source composed of a white LED or the like.
The illumination device 55, as indicated by a two-dot chain line arrow in FIG. The lighting device 52 can irradiate the nail T with light from a direction that illuminates the nail T from a direction different from that of the lighting device 52 . In the above description, a plurality of light sources are provided by the lighting device 52 and the lighting device 55, and the lighting device 52 and the lighting device 55 are selectively used (switched) to change the direction in which the nail T is illuminated. , the present invention is not limited to this configuration. For example, only one light source may be provided, and a mechanism for changing the position of the light source may be provided so that the direction in which the nail T is illuminated can be changed by changing the position of the light source using this mechanism.

The photographing unit 50 is connected to a photographing control unit 811 (see FIG. 2) of the control device 80, which will be described later, and is controlled by the photographing control unit 811. As shown in FIG.
The image data of the image captured by the imaging unit 50 is stored in a nail image storage area 821 of the storage unit 82, which will be described later.

The control device 80 is installed, for example, on the substrate 13 arranged on the upper machine frame 12 .
FIG. 2 is a main block diagram showing the control configuration in this embodiment.
As shown in FIG. 2, the control device 80 includes a control unit 81 configured by a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. (none of them are shown). It is a computer provided with a storage unit 82 composed of.

The storage unit 82 stores various programs, various data, and the like for operating the nail printing device 1 .
Specifically, the ROM of the storage unit 82 stores a drawn detection program for detecting a drawn area from the nail image (photographed image), a curved shape in the width direction of the nail T from the nail image (photographed image), Various programs such as a nail information detection program for detecting various nail information such as nail width and nail area, a drawing data generation program for generating drawing data, and a drawing program for drawing processing are stored. By executing these programs by the control device 80, each part of the nail printing device 1 is controlled in an integrated manner.
In the present embodiment, the storage unit 82 also includes a nail image storage area 821 that stores a nail image (photographed image) of the nail T of the user's printing finger U1 acquired by the imaging unit 50, and a nail shape detection unit 812 that stores the nail image. A nail information storage area 822 for storing nail information (contour line indicating the shape of the nail T, curved shape of the nail T, etc.) and a nail design storage area for storing image data of the nail design to be drawn on the nail T. 823 and the like are provided.

From a functional point of view, the control unit 81 includes an imaging control unit 811, a nail shape detection unit 812, a drawing data generation unit 813, a drawing control unit 814, a drawing area detection unit 815, a display control unit 816, and the like. . The functions of the photographing control unit 811, the nail shape detection unit 812, the drawing data generation unit 813, the drawing control unit 814, the drawn area detection unit 815, the display control unit 816, etc. It is realized by cooperation with a program stored in ROM.

The imaging control unit 811 controls the imaging device 51, the lighting device 52, and the lighting device 55 of the imaging unit 50, and the imaging device 51 captures the image of the finger including the nail T of the printing finger U1 inserted into the finger receiving unit 31. A nail image (photographed image), which is an image, is photographed to obtain the photographed nail image (photographed image).
In the present embodiment, the drawing unit 40 performs a first drawing operation (underground drawing operation with the pen 41) with a first color (for example, white for a base) for one nail T, and then a second color (inkjet When performing the second drawing operation (drawing of a pattern or the like by the inkjet head 71) with each color that can be drawn by the head 71), the photographing control unit 811 controls the photographing unit 50 so that at least before the second drawing operation Then, the nail T is photographed a plurality of times while changing the irradiation direction of the light to obtain a plurality of nail images.
During this photographing, the photographing control unit 811 causes the photographing device 51 to photograph the nail T a plurality of times while irradiating the nail T with light from different positions by appropriately switching between the lighting device 52 and the lighting device 55. to acquire a plurality of nail images (photographed images).
The number of captured images to be acquired for one nail T is not particularly limited, but the more captured images are acquired, the more accurate the composite image generated by the drawn area detection unit 815 is. Therefore, it is preferable.
At least one of the images acquired by the imaging control unit 811 is a shadowed portion (at least the area drawn in the first drawing operation on the surface of the nail T) on the surface of the nail T ( The image is set so that the shadow area) does not appear.
The image data of the nail image acquired by the imaging control unit 811 is stored in the nail image storage area 821 of the storage unit 82 .

The nail shape detection unit 812 obtains nail information about the nail T of the printing finger U1 based on the image (photographed image) of the nail T of the printing finger U1 inserted in the finger receiving unit 31 acquired by the imaging control unit 811. to detect.
In this embodiment, the nail shape detection unit 812 detects the contour shape of the nail T as nail information based on the photographed image (nail image).
The nail information acquired by the nail shape detection unit 812 is not limited to the contour shape of the nail T. For example, the XY coordinates of the horizontal position of the nail T, the height of the nail T (the vertical position of the nail T, hereinafter Also referred to as “the vertical position of the claw T” or simply “the position of the claw T”), the shape of the claw T in the width direction, that is, the inclination angle of the surface of the claw T with respect to the XY plane (the curved shape of the claw T, the position of the claw T angle of inclination) and the like.
The nail information acquired by nail shape detection unit 812 is stored in nail information storage area 822 of storage unit 82 .

The drawing data generation unit 813 generates drawing data for drawing applied to the nail T of the printing finger U1 by the drawing head 43 based on the nail information detected by the nail shape detection unit 812 .
Specifically, the drawing data generation unit 813 enlarges, reduces, cuts out, or the like the image data of the nail design based on the shape (outline shape) of the nail T detected by the nail shape detection unit 812 to obtain the nail T. A matching process is performed to match the shape of the .
Further, the drawing data generation unit 813 performs appropriate curved surface correction or the like on the image data of the nail design designated to be drawn on the nail T according to the curved shape of the nail T detected by the nail shape detection unit 812 . It also functions as a data corrector.
As a result, data for drawing a nail design to be drawn by the pen 41 or the inkjet head 71 is generated.

The drawing control unit 814 outputs a control signal to the drawing unit 40 based on the drawing data generated by the drawing data generation unit 813, and controls the drawing unit 40 to perform drawing on the nail T according to the drawing data. It is a control unit that controls the operations of the X-direction movement motor 46, the Y-direction movement motor 48, the pen up/down motor 426, the inkjet head 71, and the like.

The drawn area detection unit 815 generates a composite image by synthesizing a plurality of nail images acquired by the imaging control unit 811, and based on the composite image, performs a first drawing operation (background drawing operation with the pen 41). This is for detecting a drawn area (for example, a base coating area coated with white ink).
The already-drawn area detection unit 815 of the present embodiment first synthesizes a plurality of nail images so that the already-drawn area looks white due to light reflection (specular reflection, etc.), but the already-drawn area actually looks white. By excluding high-brightness areas that have not been drawn, the "estimated drawn area", which is an area that is estimated to have already been drawn, is detected. However, the shadow area, which is actually an already drawn area, is taken in and detected as the final "already drawn area".
Hereinafter, a method for detecting an already-drawn area by the already-drawn area detection unit 815 will be specifically described with reference to FIG.

In the present embodiment, the already-drawn area detection unit 815 synthesizes a plurality of nail images acquired by the imaging control unit 811 by changing the irradiation direction of the light from the illumination devices 52 and 55 by the HDR synthesis technique, and produces an HDR synthesized image. Generate Ibh (see FIG. 3). It should be noted that there is no particular limitation as to what kind of technique is used as a specific technique for HDR synthesis, and a generally used HDR synthesis technique can be applied. Here, the tip side of the nail T is a pre-drawn area PA to which, for example, white base ink is applied by the first drawing operation, and the area of the nail T other than the pre-drawn area PA is , the non-rendering area N where no ink is applied will be described.
Among the plurality of nail images acquired by the imaging control unit 811, there is an area (hereafter referred to as a “high-brightness portion HA”) where the brightness is high (overexposed) due to the reflection of light. area indicated by a dashed line) and a darkened area (hereinafter referred to as a "shadow area SA") that becomes a shadow when irradiated with light. In HDR synthesis for synthesizing a plurality of these images, roughly speaking, by performing processing such as replacing the blown-out high-luminance portion HA with another image that does not have the high-luminance portion HA, this high-luminance Since most of the portion HA can be removed, the high brightness portion HA hardly appears in the HDR composite image (image Ibh shown in FIG. 3) obtained by HDR combining the plurality of nail images. Note that even if the HDR composite image Ibh still has some high-brightness areas HA, it is possible to provide a color difference that can be clearly distinguished from the already drawn areas PA. However, since shadows that are not crushed black cannot be removed in HDR synthesis, the HDR composite image Ibh includes shadows that are not crushed black, as shown in FIG. Sometimes.
Further, the drawn area detection unit 815 detects the surface of the nail T (at least the drawing area PA drawn in the first drawing operation on the surface of the nail T) from among the plurality of nail images acquired by the imaging control unit 811. ), at least one nail image (image Ib0 in FIG. 3) photographed in a state where no shadow appears.

Based on the color distribution information in the HDR composite image Ibh, the already-drawn region detection unit 815 first extracts from the HDR composite image Ibh an area of the nail T that is estimated to have already been drawn as an estimated already-drawn region P1. .
Specifically, the already-drawn area detection unit 815 detects one nail image (image Ib0 in FIG. ) or the HDR composite image Ibh generated by HDR-combining a plurality of nail images acquired in photographing after the first drawing operation (background drawing operation by the pen 41), the drawing area drawn by the first drawing operation Acquire the color distribution information of PA and the color distribution information of other non-rendering areas N (for example, color distribution information of unrendered nails T, finger skin, other backgrounds, etc.), and use this color distribution information Based on this, one nail image (image Ib0 in FIG. 3) that does not include the shadow area SA acquired in photographing before the second drawing operation (for example, pattern drawing operation by the inkjet head 71) or the second drawing operation ( For example, a segmentation process is performed for extracting an already-drawn estimated region P1 from an HDR synthesized image Ibh generated by HDR synthesizing a plurality of nail images acquired before (for example, pattern drawing operation by the inkjet head 71).
By this segmentation processing, from one nail image (image Ib0 in FIG. 3) that includes the high-luminance area HA but does not include the shadow area SA acquired in the photographing before the second drawing operation, the pre-drawn estimated area P2 and A segmentation map (map M0 in FIG. 3) that divides the high-brightness region H1 into white and the other regions into black, and the high-brightness obtained by HDR combining the image acquired in the photographing before the second drawing operation. A segmentation map (map Mh in FIG. 3) is created from the HDR composite image that does not include the area HA but includes the shadow SA and divides the pre-drawn estimated area into white and the other areas into black.
As a method of segmentation processing for the already-drawn area detection unit 815 to extract an estimated already-drawn area from the HDR composite image Ibh, for example, a graph cut technique is used. The method of segmentation processing for extracting the already-drawn estimated area is not particularly limited, and a method such as determining the boundary of the already-drawn estimated area by using a color difference as a threshold value may be used.

Furthermore, the drawn area detection unit 815 creates a segmentation map (map Mxor in FIG. 3) by EXORing the segmentation map M0 and the segmentation map Mh. In this map Mxor, as shown in FIG. 3, the shadow area S1 in the pre-drawn estimation area P2 and the high brightness area H1 outside the pre-drawn estimation area P2 are divided into white, and the other areas are divided into black. It is unknown whether or not it is the already drawn area PA.
Further, the drawn area detection unit 815 creates a segmentation map (map Mand in FIG. 3) by ANDing the segmentation map M0 and the segmentation map Mh. In this map Mand, as shown in FIG. 3, the drawn presumed area P1 is divided into white, and the other areas are divided into black.
Further, the drawn area detection unit 815 creates a segmentation map (map Mnot in FIG. 3) by ORing the inversion of the segmentation map M0 and the inversion of the segmentation map Mh. In this map Mnot, as shown in FIG. 3, the undrawn area S2 is divided into white, and the already drawn estimated area P2 and the high brightness area H1 are divided into black.

Furthermore, the drawn area detection unit 815 obtains color distribution information CDt of the drawn estimated area P1 in the HDR composite image Ibh by overlapping the segmentation map Mand on the HDR composite image Ibh.
Further, the drawn area detection unit 815 obtains color distribution information CDr of the undrawn area S2 in the HDR synthesized image Ibh by overlapping the segmentation map Mnot on the HDR synthesized image Ibh.
Further, the already-drawn area detection unit 815 superimposes the segmentation map Mxor on the HDR composite image Ibh to obtain the colors of the areas S1 and H1 detected in the segmentation map Mxor and the color distribution information CDt in the HDR composite image Ibh. And from the color distribution information CDr, it is determined whether each area is a high brightness area HA and not an already drawn area PA, or whether it is a shadow area SA in an already drawn area PA.

In determining whether each area is a high-brightness area HA and not an already-drawn area PA, or a shadow area SA in an already-drawn area PA, the already-drawn area detection unit 815 detects the already-drawn area. The color difference between the pixels in the peripheral area of the estimation area and the already drawn estimation area P1 is determined, and the area where the color difference changes step by step is assumed to be the shadow area SA in the already drawn area PA, and the already drawn estimation is performed. It is detected as the drawn area PA together with the area P1.
That is, the already-drawn area detection unit 815 detects each area in the segmentation map Mxor outward from a position close to the outline of the already-drawn estimated area P1 detected in the segmentation map Mand so that each area in the segmentation map Mxor becomes the color distribution CDt of the already-drawn area PA. and whether it is close to the color distribution information CDr of the non-rendering area N.
The color of the shadow SA in the already drawn area PA gradually changes from the color of the already drawn area PA. Therefore, in the shadow area SA, the difference in color between pixels adjacent to the outside is small. On the other hand, in the case of the high brightness area HA and not the already drawn area PA, the color is relatively greatly different from the color of the already drawn area PA (such as the color of the raw nail T). Therefore, in the region corresponding to each white region of the segmentation map Mxor in the HDR composite image, the color information of each pixel is examined outward from the pixels near the boundary (outline) of the segmentation map Mand. , the color distribution information CDt of the already-drawn area PA is sequentially updated so that the color of the already-drawn area PA includes a color having a relatively small difference with respect to the color of the already-drawn area PA. As a result, it is possible to include the shadow area SA in the already drawn area PA while not including the high brightness area HA due to the reflected light in the already drawn area PA.

The display control unit 816 controls the display unit 26 to display various display screens on the display unit 26 . In this embodiment, the display control unit 816 displays, for example, a nail design selection screen, a thumbnail image for confirming the design, a nail image acquired by photographing the printing finger U1, various instruction screens, an operation screen, etc. on the display unit 26. It is designed to be displayed.

Next, a drawing method by the nail printing device (drawing device) according to the present embodiment will be described with reference to FIG.

When drawing with the nail printing device 1, the user first turns on the power switch to activate the control device 80. As shown in FIG.
The display control unit 816 causes the display unit 26 to display a design selection screen, and the user operates the operation buttons or the like of the operation unit 25 to select a desired nail design from among the plurality of nail designs displayed on the design selection screen. select. As a result, a selection instruction signal is output from the operation unit 25 and a nail design to be drawn on the nail T is selected.
When the user inserts the printing finger U1 into the finger receiving portion 31, inserts the non-printing finger U2 into the finger retraction portion 32, and operates a drawing switch (not shown) of the operating portion 25, the printing finger U1 is inserted into the finger receiving portion 31. Fixed.

When an instruction is input from the drawing switch, before the drawing operation is started, the drawing control unit 814 first controls the head moving unit 49 to move the imaging unit 50 to a predetermined imaging position to photograph the print finger U1. to acquire a nail image (photographed image) (photographing before drawing in step S1). Incidentally, in this photographing before drawing, it is preferable to photograph the nail T from a plurality of positions and angles while moving the photographing unit 50 . In this way, by acquiring a plurality of nail images having different photographing positions, etc., the nail shape detection unit 812 can detect the contour shape, curved shape, etc. of the nail with higher accuracy.
When the nail image (photographed image) is acquired, the nail shape detection unit 812 detects the contour shape, which is the outer shape of the nail T, based on the nail image (photographed image). Further, the nail shape detection unit 812 detects the curved shape of the nail T and other nail information based on the nail image (photographed image) (step S2).
Next, based on the nail information detected by the nail shape detection unit 812, the drawing data generation unit 813 generates a drawing target area with the first color pen 41 (for example, the pen 41 that draws with white ink for the background). is determined, and the drawing data of the nail design is generated by appropriately performing correction such as curved surface correction on the image data. When the drawing data is generated, the drawing control unit 814 outputs the drawing data to the drawing unit 40 and operates the head moving unit 49 to appropriately move the drawing head 43 to draw the nail T in the first color. Processing (that is, the first drawing operation with the pen 41 of the first color) is performed (step S3).
When the drawing by the first pen 41 is completed, the printing finger U1 is photographed by the photographing unit 50 to obtain a plurality of nail images (photographed images) in which the direction of light irradiation with respect to the nail T is different (after the first drawing operation). , step S4).
The already-drawn area detection unit 815 obtains at least one nail image Ib0 that does not include the shadow area SA from among the nail images, and creates an HDR composite image Ibh by HDR-combining a plurality of nail images ( step S5).
Then, the drawn area detection unit 815 obtains color distribution information from the obtained nail image Ib0 and HDR composite image Ibh (step S6).

After that, the nail T subjected to the first drawing process is dried (step S7), and before the second drawing process (for example, the drawing process by the inkjet head 71) is performed with the ink of the second color. Then, the printing finger U1 is photographed by the photographing unit 50 to obtain a plurality of nail images (photographed images) in which the directions of light irradiation to the nail T are different (photographing before the second drawing operation, step S8).
The already-drawn area detection unit 815 obtains at least one nail image Ib0 that does not include the shadow area SA from among the nail images, and creates an HDR composite image Ibh by HDR-combining a plurality of nail images ( step S9).
Then, the already-drawn area detection unit 815 performs segmentation processing using a graph cut method or the like (step S10), and creates segmentation maps (maps M0, Mh, Mxor, Mand, and Mnot in FIG. 3) (step S10).

Further, the already-drawn area detection unit 815 acquires color distribution information from the acquired nail image Ib0 and HDR composite image Ibh (step S12), and based on this color distribution information, pre-drawn estimation is performed for each pixel in the nail image. It is sorted as to whether it is an area or not (step S13). In the present embodiment, the pixels corresponding to the regions shown in white in the segmentation map Mh in FIG. 3 are sorted as the pixels in the pre-drawn estimation region P1.
In the present embodiment, as shown in FIG. 3, the white base ink, which is the first color, is drawn only on the tip portion of the nail T in the length direction. Only the pixels positioned above the half are set as target pixels for sorting as to whether or not they are in the drawn estimation area P1. By doing so, it is possible to omit the processing for portions that do not need to be sorted as to whether or not they are the already-drawn estimation region P1, thereby shortening the processing time. It should be noted that it is not essential to set the target pixel, and sorting may be performed for each pixel of the entire nail T as to whether it is the already-drawn estimation area P1 or not.
The already-drawn area detection unit 815 determines whether or not all of the target pixels have been sorted (step S14), and if not (step S14; NO), repeats the process of step S13.
On the other hand, if the drawing has ended (step S14; YES), the pixels assigned to the pre-drawn estimation area P1 are detected as the pre-drawn area PA that has already been drawn in the first color (step S15).

Next, the already-drawn area detection unit 815 determines whether or not there is a pixel satisfying a predetermined color condition in the area surrounding the estimated already-drawn area P1 (step S16).
Specifically, the color difference from the already-drawn estimated area is determined, and the pixels in the area where the color difference changes step by step are determined as the pixels that satisfy the predetermined color condition.
There is a possibility that a high-luminance area HA and a shadow area SA exist in the area surrounding the already-drawn estimated area P1. As described above, the color of the shadow area SA in the already-drawn area PA is Since the color gradually changes from the color of the drawn area PA, the color difference between the pixels adjacent to the outside is small in the shadow area SA. On the other hand, in the case of the high luminance area HA and not the already-drawn area PA, the color is relatively greatly different from the color of the already-drawn area PA. Therefore, by observing the change in the color difference, it is possible to appropriately distinguish between the high brightness area HA and the shadow area SA.
If there is a pixel that satisfies a predetermined color condition in the peripheral area of the estimated already drawn area P1 (step S16; YES), the already drawn area detection unit 815 determines that the difference in color from the estimated already drawn area is If there is a pixel in the area that changes stepwise, it is detected as the already drawn area PA together with the already drawn estimated area, assuming that this is the shadow SA in the already drawn area PA (step S17). In this case, the already-drawn area detection unit 815 updates the color information of the already-drawn area PA so that the color of the already-drawn area PA includes a color with a relatively small difference from the color of the already-drawn area PA. (step S18).
On the other hand, if there is no pixel that satisfies the predetermined color condition in the peripheral area of the estimated drawn area (step S16; NO), the process proceeds to the next step.

When the already-drawn area PA is detected by the already-drawn area detection unit 815, the drawing unit 40 performs the drawing process (second drawing operation) with the second color on the area (step S19). Specifically, for example, as the second drawing operation, the pattern is drawn by the inkjet head 71 in the already drawn area PA where the white background has been drawn by the first drawing operation.
Then, the drying operation is performed again (step S20), and after drying for a predetermined time sufficient to complete the drying, the fixation of the print finger U1 is released, and the drawing process ends.

As described above, according to the present embodiment, after the drawing unit 40 performs the first drawing operation (for example, applying white ink with the pen 41) with the first color for one nail, the second color is applied. When performing the second drawing operation (for example, drawing a pattern by the inkjet head 71) in , the nail T is photographed a plurality of times while changing the light irradiation direction before the second drawing operation to acquire a plurality of nail images, A composite image is generated by combining the acquired nail images. Based on the composite image, the drawn area PA drawn by the first drawing operation is detected.
As a result, the high-brightness area HA caused by specular reflection of light can be excluded from the already-drawn area PA, and the darkened shadow area SA within the already-drawn area PA can be included in the already-drawn area PA. Therefore, it is possible to appropriately detect the already-drawn area PA without excess or deficiency. Therefore, the second drawing operation can be accurately performed on the area already drawn by the first drawing operation, and the drawing operation is divided into a plurality of times and overlapped so as to draw the pattern on the background. Even in such a case, high-definition drawing can be performed without shifting the drawing position.
Further, in the present embodiment, the already-drawn area detection unit 815 extracts from the synthesized image an area of the nail T that is estimated to have already been drawn as an estimated already-drawn area P1 based on the color distribution information in the synthesized image. At the same time, the color difference between the pixels in the surrounding area of the already-drawn estimation area P1 and the already-drawn estimation area P1 is determined, and the area where the color difference changes stepwise is designated as the already-drawn estimation area P1 together with the already-drawn area PA. Detect as As a result, the high brightness area HA can be excluded from the already drawn area PA, and only the shadow area SA can be properly included in the already drawn area PA. 2. The drawing apparatus according to claim 1, characterized by:
Further, in this embodiment, the drawn area detection unit 815 generates a composite image by HDR synthesis. By using the HDR synthesis method for generating the synthesized image, the high brightness area SA generated by the reflection of light can be appropriately removed.
Further, in this embodiment, the already-drawn area detection unit 815 extracts the already-drawn estimated area P1 from the synthesized image by a graph cut method. By extracting the pre-drawn estimated area P1 by the graph cut method, the area extraction P1 can be performed more accurately than when the boundary of the area is specified by a threshold or the like.
Further, in this embodiment, the already-drawn area detection unit 815 detects the color of each pixel and the already-drawn estimated area P1 in a direction that gradually moves away from the already-drawn estimated area P1 from pixels adjacent to the already-drawn estimated area P1. By determining the difference, an area where the color difference changes gradually is detected. Although there is a possibility that the high-luminance portion HA and the shadow portion SA exist in the peripheral region of the drawn estimated region P1, as described above, the drawn region PA The way in which the color difference changes from Therefore, by observing the change in the color difference, it is possible to properly distinguish between the high brightness area HA and the shadow area SA, and incorporate only the shadow area SA into the already drawn area PA.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and it goes without saying that various modifications are possible without departing from the scope of the invention.

For example, in the present embodiment, the first drawing operation for drawing the first color is the application of white ink for the base with the pen 41, and the second drawing operation for drawing the second color is the inkjet head 71. Although the case of drawing a pattern by drawing is exemplified, the first drawing operation and the second drawing operation are not limited to those exemplified here. For example, the second drawing operation may be drawing a line pattern with the pen 41 or the like.

Further, in the present embodiment, photographing is performed after the first drawing operation (immediately after the first drawing operation) and before the second drawing operation (immediately before the second drawing operation) to acquire nail images. Although the case of creating an HDR composite image, obtaining color distribution information, and the like has been exemplified, shooting immediately after the first drawing operation is not essential. For example, the color information of the drawn area PA when the color drawn in the first drawing operation specified in the nail design is actually drawn on the nail T (it may be a model nail of an ordinary person instead of the user's nail). In addition, if the color information around the drawing area PA, such as a soft nail or the skin of a finger, is grasped by being registered in advance in the storage unit 82 or the like, the image is captured immediately after the first drawing operation and the image is captured. It is not necessary to create an HDR composite image based on the nail image, acquire color distribution information, and the like (that is, the processes from step S4 to step S6 in FIG. 4).

In the present embodiment, the drawing head 43 of the nail printing device (drawing device) 1 is provided with the ink jet head 71 in addition to the pen holding portion 42 that holds the pen 41 for drawing. This is not an essential configuration, and a drawing device that draws only with the pen 41 may be used.

In each of the above-described embodiments, the drawing head 43 is provided with one pen holding portion 42, but the number of pen holding portions 42 provided in the drawing head 43 is not limited to one. For example, two or more pen holders 42 may be provided to hold two or more drawing pens 41 .

Further, in each of the above-described embodiments, the imaging device 51 and the lighting device 52 are mounted on the drawing head 43 as an example, but the positions where the imaging device 51 and the lighting device 52 are provided are not limited to this.
For example, a mechanism for moving the imaging unit 50 may be provided separately from the mechanism for moving the drawing head 43 .

Further, in each of the above-described embodiments, the nail printing device 1 that sequentially draws by inserting fingers into the device one by one was taken as an example, but a plurality of fingers can be continuously drawn without inserting and removing each finger. It is also possible to have a configuration in which drawing can be performed on the

Although several embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the claims and equivalent ranges thereof. .
The invention described in the scope of claims originally attached to the application form of this application is additionally described below. The claim numbers in the appendix are as in the claims originally attached to the filing of this application.
[Appendix]
<Claim 1>
a drawing unit that draws on a drawing target;
at least one light source that illuminates the drawing target;
a photographing unit that photographs the object to be drawn after the first image has been drawn by the drawing unit a plurality of times while changing the direction in which the object to be drawn is illuminated by the light source in different directions;
generating a composite image by synthesizing a plurality of images to be drawn acquired by the imaging unit a plurality of times; a drawn area detection unit for detecting a drawing area;
A rendering device comprising:
<Claim 2>
When the drawing unit draws a second image on the drawing target to overlap at least a part of the first image after drawing the first image on the drawing target, the second image is drawn on the drawing target. 2. The image according to claim 1, wherein at least one of the drawing position of the image of and the size of the second image is adjusted based on the already-drawn area detected by the already-drawn area detection unit. drawing device.
<Claim 3>
Having a plurality of the light sources,
each of the plurality of light sources illuminates the object to be drawn in a different direction;
3. The photographing unit according to claim 1, wherein the photographing unit photographs the drawing object a plurality of times while changing a direction in which the object to be drawn is illuminated in different directions by using one of the plurality of light sources. drawing device.
<Claim 4>
4. The rendering apparatus according to claim 1, wherein the rendered area detection unit generates the synthesized image by HDR synthesis.
<Claim 5>
The plurality of drawing target images include at least one of the plurality of light sources whose direction of illuminating the drawing target is set so as not to cast a shadow on a region of the drawing target on which the first image is drawn. 5. The drawing apparatus according to claim 1, further comprising a first drawing target image photographed using a first light source in .
<Claim 6>
The plurality of drawing target images include at least one of the plurality of light sources whose direction of illuminating the drawing target is set so as to cast a shadow in an area of the drawing target on which the first image is drawn. 6. The drawing apparatus according to any one of claims 1 to 5, further comprising a second drawing target image photographed using a second light source in .
<Claim 7>
The already-drawn area detection unit extracts, from the synthesized image, an area in which the first image of the nail is estimated to be drawn as an estimated already-drawn area based on color distribution information in the synthesized image, A color difference between pixels in a peripheral area of the already-drawn estimation area and the already-drawn estimation area is determined, and an area where the color difference changes step by step is defined as the already-drawn area together with the already-drawn estimation area. 7. The drawing apparatus according to any one of claims 1 to 6, wherein detection is performed.
<Claim 8>
8. The rendering apparatus according to claim 7, wherein the already-drawn area detection unit extracts the estimated already-drawn area from the synthesized image by a graph cut technique.
<Claim 9>
The already-drawn area detection unit determines a color difference between each pixel and the already-drawn estimated area in a direction gradually moving away from the already-drawn estimated area from a pixel adjacent to the already-drawn estimated area. 9. The drawing apparatus according to claim 7, wherein an area in which the difference in is changed stepwise is detected.
<Claim 10>
A drawing method for a drawing device,
The drawing device includes a drawing unit that draws on a drawing target, and at least one light source that illuminates the drawing target,
photographing the object to be drawn after the first image has been drawn by the drawing unit a plurality of times while changing a direction in which the object to be drawn is illuminated by the light source to a plurality of mutually different directions;
generating a composite image by synthesizing a plurality of nail drawing target images acquired by the plurality of times of photographing;
Detecting an already-drawn area in which the first image has been drawn in the drawing target based on the synthesized image;
A drawing method for a drawing device, characterized by:

1 nail print device 40 drawing unit 41 pen 43 drawing head 50 imaging unit 51 imaging device 52 lighting device 55 lighting device 81 control unit 82 storage unit 812 nail shape detection unit 815 already drawn area detection unit T nail U1 printing finger

Claims (4)

a drawing unit that draws on a nail that is a drawing target;
at least one light source for illuminating the nail ;
a photographing unit that photographs the nail after the first image has been drawn by the drawing unit a plurality of times while changing the direction in which the nail is illuminated by the light source in different directions;
a plurality of nail images obtained by photographing a plurality of times by the photographing unit are synthesized to generate a synthesized image; and based on the synthesized image, the first image of the nail is rendered in a drawn area. a drawn area detection unit that detects the
with
The already-drawn area detection unit extracts, from the synthesized image, an area in which the first image of the nail is estimated to be drawn as an estimated already-drawn area based on color distribution information in the synthesized image, Determining a color difference between pixels in a peripheral area of the already-drawn estimation area and the already-drawn estimation area, and detecting an area where the color difference is changed as the already-drawn area together with the already-drawn estimation area. A drawing device characterized by: 2. The rendering apparatus according to claim 1, wherein the already-drawn area detection unit extracts the estimated already-drawn area from the synthesized image by a graph cut technique. The already-drawn area detection unit determines a color difference between each pixel and the already-drawn estimated area in a direction gradually moving away from the already-drawn estimated area from a pixel adjacent to the already-drawn estimated area. 3. The drawing apparatus according to claim 1, wherein an area in which the difference between the .times..times..times. a drawing step of drawing a first image on a nail, which is a drawing target, by a drawing unit;
a photographing step of photographing the nail after the drawing of the first image in the drawing step a plurality of times while changing the direction in which the nail is illuminated by at least one light source in different directions;
generating a composite image by synthesizing a plurality of nail images acquired by multiple times of photographing in the photographing step, and drawing the first image of the nail based on the composite image; a drawn area detection step for detecting
with
In the already-drawn area detecting step, extracting from the synthesized image an area in which the first image of the nail is estimated to be drawn as an estimated already-drawn area based on color distribution information in the synthesized image; Determining a color difference between pixels in a peripheral area of the already-drawn estimation area and the already-drawn estimation area, and detecting an area where the color difference is changed as the already-drawn area together with the already-drawn estimation area. A drawing method characterized by

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