JP4759728B2 - Color stereoscopic print - Google Patents

Description

The present invention relates to a CMYK halftone dot placement technique for halftone dot printing of lenticular stereoscopic prints. Specifically , the present invention does not cause an inappropriate color change in the horizontal direction and expresses with a high gradation. relates to or color stereoscopic printing product can be expressed by increasing the dot density is.

  A stereoscopic print by the lenticular method (long lens method) includes a halftone dot print image 91 and a lenticular lens 92 disposed on the halftone dot print image 91 as shown in FIG. The lenticular lens 92 is configured by M cylindrical lenses 93 arranged in the vertical direction in parallel in the horizontal direction.

For creating the halftone print image 91, for example, images taken by four cameras C1, C2, C3, and C4 arranged in an arc as shown in FIG. 2 are used.
FIGS. 3A, 3B, 3C, and 3D show captured images G1, G2 when the two objects A, B are captured by the cameras C1, C2, C3, C4 shown in FIG. , G3, G4 are shown as models.

For example, to create a stereoscopic print, first, as shown in FIGS. 4A, 4B, 4C, and 4D, photographed images G1, G2, G3, and G4 are respectively M strips in the vertical direction. image,
s11, s12, ..., s1M
s21, s22, ..., s2M
s31, s32, ..., s3M
s41, s42, ..., s4M
Divide into

Then, M group images g1, g2,..., GM are created with four strip images having the same horizontal position as one image.
g1: s11 + s21 + s31 + s41
g2: s12 + s22 + s32 + s42
g3: s13 + s23 + s33 + s43
・ ・ ・ ・ ・ ・
gM: s1M + s2M + s3M + s4M
(Here, “+” means parallel strip images)

  Thereafter, the group images g1, g2,..., GM are connected as shown in FIG. 5A, and the connected images are compressed 1/4 times in the horizontal direction as shown in FIG. Thus, a halftone dot print image 91 is created.

In the present specification, an image on the back surface of the cylindrical lens is referred to as a vertically long image. In the example of FIG. 5B, the vertically long images v1, v2, v3,..., VM are images obtained by compressing the group images g1, g2,.
Image G1, G2, G3, G4 divided into strip images sxy (x = 1, 2,..., 4, y = 1, 2,..., M), and vertically long images by paralleling the strip images sxy Creation of g1 to gM and creation of portrait images v1, v2, v3,..., vM by compression of the created parallel images g1, g2,..., gM can be performed on a computer (image processing apparatus). it can. Although explanation is omitted, the method described above for taking a photographed image and the method for constructing a group image are merely examples, and various other methods are known.

  By the way, in screen printing or the like, colors and gradations are expressed by the size of the four colors of CMYK. Normally, if the angles of the halftone grid axes (biaxial) of these colors are not set appropriately, moire occurs as shown in FIG. 6 (however, in FIG. 6, four colors are the same monochrome color). Converted to).

  Usually, in order to eliminate moire, (1) C halftone lattice axis: 105 °, M halftone lattice axis: 75 °, Y halftone lattice axis: 90 °, K halftone lattice axis: 45 Or (2) a combination of C halftone lattice axis: 15 °, M halftone lattice axis: 75 °, Y halftone lattice axis: 90 °, K halftone lattice axis: 45 ° is used. The

  FIG. 7A shows halftone dots for the respective colors in the combination of (1), and FIG. 7B shows an image obtained by superimposing halftone dot lattices of these angles (however, FIG. (A) and (B) show four colors converted to the same monochrome color).

In the image of FIG. 7B, since the halftone dots are formed by AM screening, a turtle shell pattern called Rosette Pattern appears. However, when the halftone dots are formed by FM screening, the rosette pattern Does not appear. In addition, a print image is configured with halftone dots by digital processing on a computer, and an image with halftone dots is generated without using a screen.
Japanese Patent Laid-Open No. 11-2798

  By the way, in the printed image of the stereoscopic print using the above-described halftone dot arrangement, when the viewpoint is slightly moved in the horizontal direction, the color change in the horizontal direction in the image 91 seen through the lenticular lens 92 shown in FIG. May occur.

  This is because the dot grid axes of the CMYK colors are different from each other. In other words, the CMYK color dot grids do not have a common vertical axis.

  As a method of improving the image quality when a halftone dot print image is used with the lenticular lens method, a certain relationship is established between the arrangement of the lenses of the stereoscopic print product and the halftone dot arrangement of each color on the halftone print image. A technique for preventing the occurrence of moiré is also known (Japanese Patent Laid-Open No. 11-2798). However, even with this technique, the color change in the horizontal direction when the viewpoint described above slightly shifts in the horizontal direction cannot be resolved.

  An object of the present invention is to provide a color stereoscopic printed matter that does not cause a color change in the horizontal direction during stereoscopic viewing.

Another object of the present invention can be expressed by increasing the or dot density expressed by raising the gradation of the printed image disposed on the rear surface of the lenticular lens, providing a color stereoscopic printing object The purpose is to do.

The color stereoscopic print of the present invention is a lenticular lens in which a plurality of cylindrical lenses oriented in the vertical direction are continuously arranged in the horizontal direction;
A color halftone print image composed of a vertically long image composed of a plurality of pixel rows, which is disposed on the back surface of the lenticular lens and corresponds to each cylindrical lens;
A color stereoscopic print with
In the color halftone print image, a plurality of color halftone dots are formed on the two-dimensional axis of each color,
The two-dimensional axis is composed of a vertical axis parallel to the longitudinal direction of the cylindrical lens, and a horizontal axis orthogonal to the vertical axis,
The color of the other halftone dot closest to one halftone dot is different from the color of the one halftone dot,
A set of halftone dots of each color constituting one pixel is continuously formed on the same vertical axis,
A halftone dot of each color is formed in a state of being dispersed on a square lattice point or a rectangular lattice point formed by the two-dimensional axis,
The halftone dots have a substantially constant width, and the length is changed according to the gradation.
It is characterized by that.
Here, the “vertical axis” is a group of a plurality of vertical axes, and the “horizontal axis” is a group of a plurality of horizontal axes.

  In the color stereoscopic print of the present invention, a set of halftone dots of each color constituting one pixel can be constituted by f halftone dots of each color (f is a positive integer). In this case, the sum of the areas of f halftone dots represents the gradation of one pixel.

According to the color stereoscopic print of the present invention, the set of halftone dots of each color constituting one pixel column of the color halftone print image is formed on the common vertical axis parallel to the longitudinal direction of the cylindrical lens. No lateral color change occurs when viewing. In addition, since the halftone dots of each color are formed in a state of being dispersed on the square lattice points or the rectangular lattice points formed by the two-dimensional axis, the gradation expression of the printed image arranged on the back surface of the lenticular lens should be increased. Alternatively, the dot density can be increased.

  As shown in FIG. 8, the stereoscopic print 1 of the present invention includes a lenticular lens 11 and a halftone dot print image 12. The lenticular lens 11 includes a plurality of cylindrical lenses 111 oriented in the vertical direction and arranged in parallel in the horizontal direction.

  The halftone dot print image 12 is arranged on the back surface of the lenticular lens 11 and includes a plurality of pixel columns formed by halftone dots of a plurality of colors (four colors of CMYK in this embodiment) corresponding to the respective cylindrical lenses 111. It consists of a vertically long image 121.

In the present embodiment, the two-dimensional axis on which the CMYK halftone dots of the halftone print image 12 are formed is composed of a vertical axis parallel to the longitudinal direction of the cylindrical lens 111 and a horizontal axis perpendicular to the vertical axis. Yes.

As in the prior art, when the two-dimensional axes of the CMYK halftone dots are defined separately, the lateral color change of the image seen through the lenticular lens becomes noticeable when the viewpoint is slightly moved in the lateral direction. There is. On the other hand, in the present embodiment, the two-dimensional axis is composed of a vertical axis parallel to the longitudinal direction of the cylindrical lens 111 and a horizontal axis perpendicular to the vertical axis, and the vertical axis for halftone dots of CMYK colors. Are defined in common, there is no inconvenience that the color change in the horizontal direction becomes significant.

FIG. 9A shows a two-dimensional axis (here, composed of two orthogonal axes A and B). FIG. 9B shows each dot of CMYK on the two-dimensional axis AB. As shown in FIG. 9B, a set of halftone dots of CMYK colors constituting one pixel (PIX) is continuously formed on the vertical axis A. In FIG. 9B, the halftone dots of CMYK colors are all formed continuously in the horizontal direction. In the figure, “C” of each color of CMYK is “open circle”, “M” is “circle with minus sign”, “Y” is “circle with plus sign”, and “ K ” is “paint”. It is indicated by “collapsed circle”.

  9 (C), (D), (E), and (F) show halftone dots formed on the screens Sc, Sm, Sy, and Sk of CMYK colors.

  The halftone dots can be formed by AM screening as will be described later, or can be formed by FM screening (see FIGS. 17A and 17B).

  In the configuration of the halftone dots in FIG. 9B, as can be seen from FIGS. 9C, 9D, 9E, and 9F, adjacent halftone dots of the same color are close to each other. Since the size is limited, the gradation of halftone dots cannot be increased. In order to solve this, the combination of CMYK colors can be changed between adjacent rows of halftone dots.

  For example, in FIG. 10B, the halftone dots of the colors CMYK are arranged in the order of “→ C → M → Y → K →” and “→ Y → K → C → M →” from the top. As shown in FIG. 10 (A), the two-dimensional axes of the CMYK colors in FIG. 10 (B) are the two orthogonal axes of A and B, as shown in FIG. 9 (A). Consists of.

  In the halftone dot configuration of FIG. 10B, as can be seen from FIGS. 10C, D, E, and F, adjacent halftone dots that are adjacent to each other are not close to each other (halftone dots for each color). Is distributed on the screens Sc, Sm, Sy, Sk of each color on average, so that the gradation of each color (that is, the gradation due to the change in the area of the dot holes) can be increased.

  FIG. 11A shows a two-dimensional axis in which the two axes are not orthogonal (here, the A axis (vertical axis) and the B axis having an angle of 120 ° with respect to the A axis). FIG. 11B shows each dot of CMYK on the two-dimensional AB axis. As shown in FIG. 11B, a set of halftone dots of CMYK colors constituting one pixel (PIX) is continuously formed on the A axis. In FIG. 11B, the halftone dots of CMYK colors are zigzag shifted in the vertical direction by ½ of the distance between the centers of the halftone dots in adjacent columns.

  11C, 11D, 11E, and 11F show halftone dots formed on the screens Sc, Sm, Sy, and Sk of the CMYK colors. In the halftone dot configuration of FIG. 11B, as can be seen from FIGS. 11C, 11D, 11E, and 11F, adjacent halftone dots of the same color are close to each other. The gradation cannot be increased. In order to solve this, the combination of CMYK can be changed between adjacent rows of halftone dots.

Also in FIG. 12B, as in the case of FIG. 10B, the halftone dots of each color of CMYK are “→ C → M → Y → K →” and “→ Y → K → C → M →” from the top. It is arranged in the order.
As shown in FIG. 12A, the two-dimensional axes of each color of each halftone dot are not orthogonal to each other (here, the vertical axis A is the same as that shown in FIG. 11A). And A and B axes having an angle of 120 ° with respect to the vertical axis A).

By the way, the width of one cylindrical lens 111 corresponds to the lateral width of one pixel (“one pixel that looks”) when viewed through the lenticular lens 11. Therefore, assuming that the length of “one pixel that looks” is the same as or substantially the same as the horizontal width, the longer the number of halftone dots in the horizontal direction of the vertical image 121 (that is, the greater the number of captured images), the longer the vertical direction. The dot density is lower than the dot density in the horizontal direction (the vertical interval between the halftone dots is relatively longer than the horizontal interval).

  In other words, as the number of halftone dots in the horizontal direction of the vertically long image 121 increases, as shown in FIGS. 13A and 14A, the screens Sc, Sm, Sy, Sk for the respective colors (FIG. 9 ( (C), (D), (E), (F) and FIG. 10 (C), (D), (E), (F)), the area not used increases.

  Therefore, as shown in FIGS. 13B and 14B, one pixel is composed of a plurality of CMYK halftone dot groups that are continuous along the vertical axis (two pairs in FIGS. 13B and 14B). ), One pixel can be expressed with high gradation. For example, if 128 gradations can be expressed by one halftone dot, 256 gradations can be expressed by two halftone dots. In this way, since a gradation can be expressed by adding a plurality of halftone dots and adding their areas, each halftone dot can be made small. That is, the density of halftone dots can be increased.

  Of course, as shown in FIGS. 13C and 14C, if one pixel is represented by a set of one CMYK halftone dot, the vertical resolution is made higher than the horizontal resolution. (In FIGS. 13C and 14C, the vertical resolution is twice the horizontal resolution).

  This is also true for monochrome images. In the case of a monochrome image, one pixel can be represented with a high gradation as shown in FIG. 15A, and the vertical resolution is changed to the horizontal resolution as shown in FIG. 15B. Can be higher.

  In the above embodiment, for the convenience of explanation, it is assumed that different color halftone dots do not overlap each other, but different colors may overlap as shown in FIG.

In the above embodiment, each halftone dot is formed in a round shape. However, as shown in FIG. 16B, it can be formed in a shape having a substantially constant width and a different length . The gradation is expressed by the area of the halftone dot. When the horizontal width of the halftone dot changes depending on the gradation, the horizontal spread when one halftone dot is viewed through the cylindrical lens changes. Therefore, by making the halftone dot width substantially constant and changing the halftone dot length according to the gradation, the horizontal spread when one halftone dot is viewed through the cylindrical lens is kept constant. Gradation expression is possible.

  Further, as shown in FIG. 16C, the vertical pitch of the halftone dots can be made larger or smaller than the horizontal pitch. FIG. 16C shows an example in which the vertical pitch of halftone dots is made smaller than the horizontal pitch, and the vertical pitch and horizontal pitch of one apparent pixel are equal. However, the vertical and horizontal pitches of the halftone dots on the screens of the respective colors are equal.

Consider a case where halftone printing is performed at a density of 600 lines using the configuration shown in FIG. Usually, the density of 600 lines represents the dot density on the screen of each color after color separation, and represents the density in the direction of the oblique axis in FIG. Therefore, the halftone dot density in the horizontal direction is 600 × √2≈849 lines. If the cylindrical lenses are arranged in the horizontal direction at a density of 30 lines / inch, it is possible to correspond about 28 pixel rows to one cylindrical lens. Here, it is assumed that the density of halftone dots is the same in the horizontal direction and the vertical direction. Further, if the length and width of the “appearing one pixel” are made equal, about 14 halftone dots can be associated with each pixel in the vertical direction in each color. Therefore, when 16 gradations are expressed by one halftone dot, 224 gradations of each color can be expressed by one pixel.

  As described above, when 16 halftones are represented by one halftone dot, one halftone dot is usually represented by a group of 4 × 4 dots. In this case, if the method of making the halftone dot width substantially constant shown in FIG. 16B is applied, the gradation is expressed by the number of dots used in the vertical direction with the width of one halftone dot being four dots. become. As shown in FIG. 16A, halftone dots of different colors may be overlapped, so that 4 × 4 dots can be used in the vertical direction corresponding to four colors. The gradation can be expressed. In addition, the width of one halftone dot can be reduced to a minimum of 1 dot, and the number of pixel columns corresponding to the cylindrical lens can be increased. In the above example, the number of pixel columns can be increased to about 113.

  The above-described halftone dots can be formed in a concentrated manner (AM screening formation) as shown in FIG. 17A, or can be formed in a dispersed manner as shown in FIG. 17B (FM screening). Can also be formed). That is, in the AM screening shown in FIG. 17A, a single hole is formed in a region where one halftone dot is allowed to be formed on the screen. In the FM screening in FIG. 17B, a large number of fine holes are dispersed and formed in an area where one dot is allowed to be formed on the screen material.

  In the above-described embodiment, an example in which the colors of the halftone dots are arranged in the order of CMYK from the top is shown, but the method of the present invention is naturally effective even in the case of arranging in other orders.

  In the above embodiment, an example in which color separation into halftone dots is performed with four colors of CMYK has been described, but the method of the present invention is naturally effective even when performing color separation into other color combinations.

It is a figure which shows the stereoscopic vision printed matter by the conventional lenticular system. It is a figure which shows a mode that the image used for a stereoscopic printed matter is image | photographed by four cameras C1, C2, C3, and C4 arranged in parallel. (A), (B), (C), (D) are taken images G1, G2, G3 when the two objects A, B are photographed by the cameras C1, C2, C3, C4 shown in FIG. , G4 as a model. (A), (B), (C), and (D) are diagrams showing a state in which captured images G1, G2, G3, and G4 are each divided into M strip images in the vertical direction. (A) is a diagram showing a state in which group images g1, g2,..., GM are concatenated, and (B) is a halftone dot print image created by compressing the concatenated images by 1/4 times in the horizontal direction. FIG. It is a figure which shows the moire produced by the conventional halftone printing. (A) is a figure which shows a mode that the halftone dot was formed in each screen by the axial angle which does not produce the moire of each color by halftone printing, (B) is a figure which shows the printing result by halftone printing. It is a figure which shows the color stereoscopic vision printed matter in this invention. It is a figure which shows an example of the halftone dot structure at the time of creating the halftone dot printed matter in a color stereoscopic print, (A) is a figure which shows a two-dimensional axis, (B) is a figure of CMYK on the two-dimensional axis AB. FIGS. 5A to 5C are diagrams showing halftone dots, and FIGS. 5C and 5D are diagrams showing halftone dots formed on the screens of CMYK colors. It is a figure which shows the other example of a halftone dot structure at the time of creating the halftone dot printed matter in a color stereoscopic print, (A) is a figure which shows a two-dimensional axis, (B) is on the two-dimensional axis AB. FIGS. 5C, 5D, 5E, and 5F are diagrams showing halftone dots formed on the screens of CMYK colors. FIG. It is a figure which shows an example of the halftone dot structure at the time of creating the halftone dot printed matter in a color stereoscopic print, (A) is a figure which shows a two-dimensional axis, (B) is a figure of CMYK on the two-dimensional axis AB. FIGS. 5A to 5C are diagrams showing halftone dots, and FIGS. 5C and 5D are diagrams showing halftone dots formed on the screens of CMYK colors. It is a figure which shows the other example of a halftone dot structure at the time of creating the halftone dot printed matter in a color stereoscopic print, (A) is a figure which shows a two-dimensional axis, (B) is on the two-dimensional axis AB. FIGS. 5C, 5D, 5E, and 5F are diagrams showing halftone dots formed on the screens of CMYK colors. FIG. FIG. 10 is an explanatory diagram of a halftone dot pattern in which the number of halftone dots in the horizontal direction of the portrait image is increased in the halftone dot pattern shown in FIG. 9, and (A) is an increase in the number of halftone dots in the horizontal direction of the portrait image. The figure which shows a mode that the area | region which is not used for the screen of each color increased, (B) is a figure which shows a mode that high gradation was implement | achieved by expressing one pixel with the group of several CMYK halftone dots which continued on the vertical axis | shaft. (C) is a figure which shows a mode that the resolution of the vertical direction was made higher than the resolution of a horizontal direction by expressing one pixel with the group of one dot of CMYK. FIG. 11 is an explanatory diagram of a halftone dot pattern in which the number of halftone dots in the horizontal direction of the portrait image is increased in the halftone dot pattern shown in FIG. 10, and (A) is an increase in the number of halftone dots in the horizontal direction of the portrait image. The figure which shows a mode that the area | region which is not used for the screen of each color increased, (B) is a figure which shows a mode that a high gradation was implement | achieved by expressing one pixel by the group of several CMYK which followed the vertical axis | shaft. ) Is a diagram illustrating a state in which the resolution in the vertical direction is made higher than the resolution in the horizontal direction by representing one pixel by a set of halftone dots of CMYK. (A) is a diagram showing a state in which high gradation is realized by representing one pixel with a plurality of continuous halftone dots on a vertical axis for a monochrome image, and (B) is a set of a plurality of halftone dots for a monochrome image. It is a figure which shows a mode that the resolution of the vertical direction was made higher than the resolution of a horizontal direction by expressing one pixel. (A) is a diagram showing an example in which halftone dots of different colors overlap each other, (B) is a diagram showing an example in which halftone dots are formed vertically long, (C) is a vertical pitch of halftone dots, It is a figure which shows the example which became small compared with the pitch of the direction. (A) is an explanatory diagram of halftone dots in the case of AM screening, and (B) is an explanatory diagram of halftone dots in the case of FM screening.

1 Stereoscopic Printed Material 11 Lenticular Lens 12 Halftone Print Image 111 Cylindrical Lens 121 Long Image

Claims (2)

A lenticular lens in which a plurality of cylindrical lenses oriented in the vertical direction are continuously arranged in the horizontal direction;
A color halftone print image composed of a vertically long image composed of a plurality of pixel rows, which is disposed on the back surface of the lenticular lens and corresponds to each cylindrical lens;
A color stereoscopic print with
In the color halftone print image, a plurality of color halftone dots are formed on the two-dimensional axis of each color,
The two-dimensional axis is composed of a vertical axis parallel to the longitudinal direction of the cylindrical lens, and a horizontal axis orthogonal to the vertical axis,
The color of the other halftone dot closest to one halftone dot is different from the color of the one halftone dot,
A set of halftone dots of each color constituting one pixel is continuously formed on the same vertical axis,
A halftone dot of each color is formed in a state of being dispersed on a square lattice point or a rectangular lattice point formed by the two-dimensional axis,
The halftone dots have a substantially constant width, and the length is changed according to the gradation.
A color stereoscopic print characterized by the above.   A set of halftone dots of each color constituting one pixel is constituted by halftone dots arranged in the vertical direction of f colors (f is a positive integer), and the gradation of the one pixel is the sum of the areas of the f halftone dots. The color stereoscopic print according to claim 1, wherein: