JP2003329599A - Printer matter measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed matter measuring apparatus capable of accurately correcting shading even if variations occur in the light quantity of a flash light source. <P>SOLUTION: In the correction of the light quantity variations in the printed matter measuring apparatus, the light quantity variation ratios μα and μβ of two white reference plates provided at a far location and a close location of the light source are computed in a step S11. Interpolation computation is performed on a light quantity variation ratio μ at a predetermined location on the basis of the light quantity ratios μα and μβ in a step S12. Correction based on the light quantity variation ratio μ is appropriately performed according to the location of each image data in a step S13. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed matter measuring apparatus for picking up an image by placing a printed matter on a table having a relatively wide range.

[0002]

2. Description of the Related Art A printed matter measuring apparatus is known which measures a printing color or color density of a printed matter and feeds back the measured data to a printing apparatus. For example, Japanese Patent Laid-Open No. 2001-35
The printed matter measuring apparatus disclosed in Japanese Patent No. 3852 discloses a printed matter placed on a table by a two-dimensional image pickup device to collectively capture image data, image-processes the image data, and measures color density of the printed matter. It is a device to perform. In the printed matter measuring apparatus, a printed matter is illuminated by a flash light source that emits light in synchronization with the image pickup means to perform image pickup.

As a result of various tests conducted by the applicant, the illumination by the flash light source is shallow to the table so that the reflected light specularly reflected on the table surface does not directly enter the imaging means. It is preferable to illuminate with an angle, for example, 2α >> θ, where α is an incident angle at which the center of the optical axis of the illumination light is incident on the table surface and θ is an angle of view of the image pickup means. I knew that.

Therefore, in the improved apparatus, as described in the specification of 2001 Patent Application No. 210554, the illumination is performed from the side of the table at a shallow angle with respect to a wide table surface. In such a measuring device, if the amount of light illuminated on the table is non-uniform, an error occurs in the measurement result. This can be a problem in the commercial printing field where very strict color management is required.

In the above apparatus, since the table is illuminated at a shallow angle, it is difficult to keep the illuminance distribution on the table uniform. For this reason, Patent Application No. 88 of 2002
As described in the specification of No. 039, a standard reference object has been measured in advance to obtain correction data, and shading correction is applied to imaged image data based on the correction data.

[0006]

The above shading correction method is very effective and can reduce the influence of the uneven illuminance distribution of the light source. However, the flash light source used in the printed matter measuring apparatus has a characteristic of causing a slight change in the light amount each time the image is captured. According to an experiment conducted by the applicant, the standard deviation of the light quantity variation rate of the flash light source for each lighting is 0.
It was found that there was a fluctuation of about ± 3% for both flash light sources. If there is a light quantity variation due to each flash light source, more accurate measurement may not be performed. In particular, when a plurality of flash light sources are used, the variation of the respective light amounts act in combination to cause a color density measurement error at each measurement point.

The present invention has been made in order to solve the above problems, and is intended to make it possible to perform more accurate measurement by correcting the variation of each emission of the flash light source.

[0008]

According to a first aspect of the present invention, a printed matter placed on a table is illuminated by a flash light source, and the table is imaged by an imaging means in synchronization with the illumination operation. A printed matter measuring device for calculating a color density or the like of a printed matter based on the obtained image data, and calculating a light quantity variation ratio of the flash light source for each light emission by the flash light source in correspondence with the coordinate position on the table, It is characterized in that the image data is corrected for each coordinate position on the table according to the light quantity variation ratio.

According to the first aspect of the present invention, the measurement result can be appropriately corrected according to each coordinate position on the table even if the light amount of the flash light source changes every lighting.

A second aspect of the present invention is the printed matter measuring apparatus according to the first aspect, wherein the printed matter is not placed on the non-placed area of the table end portion and the image pickup area by the image pickup means. A reference area corresponding to a plurality of positions is provided therein, and the light quantity fluctuation ratio of the flash light source is calculated from the image data obtained by capturing the image data of the reference area for each image pickup, and the printed material placement area on the table is set. It is characterized in that it is obtained in response to.

According to the second aspect of the present invention, a reference amount region for obtaining the light amount variation ratio is provided in the non-placement region on the table, and this is used to use the light amount variation ratio at the position corresponding to the placement region. Therefore, it is possible to image the reference area in parallel with the work of imaging the printed matter.
In addition, it is not necessary to prepare a reference amount area for each imaging.

According to a third aspect of the present invention, a table on which the printed matter is placed, a flash light source for illuminating the table,
A printed matter measuring apparatus comprising: an image pickup means for picking up an image of an illuminated printed matter; and a computing means for computing a color density of the printed matter based on image data of the picked up printed matter, wherein the flash light source is on the table upper surface. A plurality of the tables are arranged so as to irradiate from two directions facing each other, and the table has at least a perspective 2 on the upper surface thereof with respect to the flash light source.
A white reference area is provided at one position, and the calculation means is
Each time the flash light source is turned on, a reference correction value is calculated based on the image data obtained by capturing the white reference amount area, and the variation amount of the light amount emitted using the calculated reference correction value is set to the distance from the flash light source. It is characterized in that the correction is made based on the above.

According to the third aspect of the present invention, the measurement result can be properly corrected according to the distance from each light source on the table even if the light amount of the flash light source changes each time the light source is turned on.

According to a fourth aspect of the present invention, in the printed matter measuring apparatus according to the third aspect, the white reference area is fixed to the edge of the table by a predetermined distance and is fixed. It is characterized by consisting of.

According to the invention described in claim 4, the white reference amount area is provided in the non-placement area on the table, and using this, the light quantity variation ratio of the position corresponding to the placement area is obtained. The white reference area can be imaged at the same time as the work of imaging the printed matter, and the white reference amount area can be permanently installed on the table without preparing for each imaging.

According to a fifth aspect of the present invention, in the printed matter measuring apparatus according to the third or fourth aspect, the flash light sources are controlled so as to individually emit light on one side, and the flash light sources are obtained based on the respective light emission. It is characterized in that the light amount of each flash light source is corrected based on image data obtained by capturing the white reference area.

According to the fifth aspect of the present invention, since the light amount variation can be corrected for each light source, more accurate correction can be performed.

[0018]

DETAILED DESCRIPTION OF THE INVENTION

[Description of Printed Matter Measuring Device] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of a printed matter measuring apparatus according to the present invention.

In FIG. 1, a printed matter measuring apparatus includes a table 1 on which a printed matter (printing paper) is placed, and a suction means 2 (FIG. 3) for adsorbing and fixing the printed matter placed on the table 1.
), A stand 3 for supporting the table 1, illumination means 4 provided on the left and right of the table 1, an image pickup means 5 provided above the table 1, and a light-shielding roof member 6
And a control calculation means 7 for controlling the printed matter measuring apparatus.
And a touch panel 8 for operating this printed matter measuring apparatus.

The table 1 is a flat-table-shaped table member which has an area on which a relatively large printed material of A3 size or more can be placed and which is inclined by 0 to 20 degrees from the horizontal. 1 is provided with a suction plate 1a having suction holes 13 and suction grooves 14 (both are shown in FIG. 2) for sucking and holding a printed matter. The table 1 and the suction plate 1a are formed in a dark color so as not to be transparent even when a double-sided printed matter is placed thereon, and a fine uneven surface treatment such as matte treatment or satin treatment so as not to generate unnecessary reflected light. Is preferably applied. Although the suction plate 1a is provided on the table 1 in this embodiment, the suction groove 13 and the like may be directly processed on the table 1. Also, the suction plate 1a
Two positioning members 11 for positioning the printed matter are fixed on the top.

Further, as shown in FIG. 2, two white reference plates 12a and 12b according to the present invention are fixed to the table 1. Since the white reference plates 12a and 12b are arranged outside the positioning member 11 extending in the left-right direction, they are outside the area on which the printed matter is placed, but they are arranged so as to be within the imaging area by the imaging means 5. There is. That is, when the printed matter or the like placed on the table is imaged, the white reference plates 12a and 12b can be imaged at the same time.

Hereinafter, when distinguishing the left and right illumination means,
The left side is referred to as illumination means α, and the right side is referred to as illumination means β. In this case, the white reference plate 12a is provided for the left illumination means α.
Is near and the white reference plate 12b is far. On the contrary, the white reference plate 12b is close and the white reference plate 12a is far from the illumination means β on the right side.

The suction means 2 will be described with reference to FIGS. 2 and 3. 2 is a top view of the table 1, and FIG. 3 is a piping diagram showing a piping path of the adsorption means 2.

As shown in FIG. 2, a plurality of suction holes 13 and a plurality of suction grooves 14 for sucking printed matter are formed on the surface of the suction plate 1a constituting the suction means 2. It should be noted that some of the suction holes 13 and the suction grooves 14 are denoted by reference numerals for the sake of clarity.

The suction holes 13 are divided into three groups corresponding to a plurality of areas a to c indicated by dotted lines so as to suck the areas corresponding to the size of the printed matter.
When distinguishing the suction holes of each set, they are denoted by 13a to 13b.

Of the areas a to c, the size of the area a is set so as not to exceed the minimum size according to the size of the minimum size printed matter to be measured. The printed matter is positioned by the positioning member 11 with the lower left side of the table 1 as a positioning origin O.

As shown in FIG. 3, the suction holes 13a to 13c are connected to a vacuum pump 18 via a solenoid valve 15, a solenoid valve 16 and a solenoid valve 17, respectively. Further, a vacuum switch 19 which is turned on when a predetermined vacuum degree is reached is connected in the middle of the piping between the vacuum pump 18 and the solenoid valves 15 to 17. In this embodiment, the solenoid valves 15-1
The suction holes 13 to be evacuated can be switched by appropriately combining and opening and closing 7. As a result, the suction area can be set according to the size of the printed matter.

The suction grooves 14 are formed on the suction plate 1a so as to communicate with any of the suction holes 13, respectively. Further, the suction groove 14 includes a main suction groove 14a (one of which is indicated by a thick line in the drawing) which is formed substantially along a diagonal line of the suction plate 1a, and a plurality of sub-suctions branched from the main suction groove 14a. Groove 14b
It consists of and. Note that some sub suction grooves 14b
Is directly branched from the main suction groove 14a and further branched from the sub suction groove 14b, but here, it is divided as the same sub suction groove 14b.

The main suction groove 14a is extended from a corner of the suction plate 1a where the positioning origin O is located to a diagonal corner so that the main suction groove 14a is located on a diagonal line. On the other hand, the sub suction groove 14b is branched from the main suction groove 14a with a spread of about 60 to 20 degrees. This is because the vacuum exhaust expands to the left and right around the diagonal line. Further, it is preferable that the distance between the sub suction grooves 14b is set to about 100 mm or less so that air is not easily accumulated. Further, both of the suction grooves 14a and 14b reach the right side or the upper side of the table 1, respectively.
It is in a state of being open to the end side of a.

Returning to FIG. 1, the gantry 3 is a casing for supporting the table 1, and inside thereof, electrical components such as the control calculation means 7 and the vacuum pump 18 are stored. Further, the front side of the gantry 3 has a drawer (not shown) for inserting various preliminary members.

Next, the structure of the illumination means 4 will be described with reference to FIGS. 4 is a schematic view showing a cross section of the illumination means 4 as seen from the front of the device, and FIG. 5 is one illumination means 4
FIG. 3 is a perspective view of the table 1 as viewed obliquely from above, and is partially transparent and omitted for clarity.

As shown in the figure, the illumination means 4 has a flash light source 20 provided below the table 1, a slit member 21 for cutting excess light, and the illumination light emitted from the flash light source 20 on the table 1 surface. Parabolic mirror 22 for folding back
And a cover 23.

Two flash light sources 20 are provided on the lower surface of the table 1 and are arranged so that their light emitting directions are directed to the outside of the table 1. The flash light source 20 has a problem that the illuminance becomes non-uniform due to the shape of the light emitting portion. This is because, for example, when a U-shaped arc tube is built in as the flash light source 20, the distribution of the emitted light is biased depending on the installation direction of the U-tube. In the present invention, in order to correct the non-uniformity of the illuminance due to the shape of the light emitting portion, the light emitting portion of the flash light source 20 is covered with the semi-cylindrical diffuser member 24. The light scattering member 24 is formed of, for example, a transparent resin material having a scattering layer that scatters light.

The slit member 21 is a light-shielding plate having an opening at its substantially central portion, and shields extra light emitted from the flash light source 20, particularly light reflected by the light-scattering member 24 in an unnecessary direction. Is. That is, the slit member 2
1 can give a desired directivity to the light passing through the opening. In this embodiment, in order to improve the illuminance distribution, the opening has an elongated trapezoidal slit shape extending in the front-rear direction of the device.

The parabolic mirror 22 is a mirror member having a parabolic surface that is curved so as to uniformly irradiate light on the surface of the table 1, and the illumination light emitted from the flash light source 20 is applied to the surface of the table 1. It is a means for folding back and guiding light. The height and angle of setting the parabolic mirror 22 are set so that the illumination light with which the table is illuminated has a shallow angle with respect to the table. For example, the incident angle α formed by the ray axis (the arrow in the figure) of the illumination light from the parabolic mirror 22 toward the table center and the perpendicular to the table is 2α >> θ, where θ is the angle of view of the image pickup means 5. To be large enough.

The parabolic mirror 22 is, as shown in FIG.
A mirror surface support 22a having a parabolic surface curved along the front-rear direction of the apparatus, a mirror surface 22b adhered to the parabolic surface of the mirror surface support 22a, and a pair for holding the mirror surface support 22a in the cover 22. Holding means 22c.

The mirror surface support 22a is a three-dimensional object made of, for example, styrofoam, which can be easily processed.
2b is formed by attaching a metal tape having a high reflectance to the parabolic surface. Of course, one flexible reflecting mirror may be curved and held, but in the case of the above configuration, there is an advantage that a paraboloid of arbitrary shape can be easily created.

The cover 23 is a light-shielding cover for preventing the illumination light emitted from the flash light source 20 from leaking out of the apparatus, and the transparent plate 25 is provided only at a position facing the table 1. An ND filter 26 is attached to the translucent plate 25 for adjusting the amount of light for making the illuminance distribution uniform.

As shown in FIG. 6 (A), the ND filter 26 decreases the light quantity near the table as compared with the light quantity at the remote table center so that the density temporarily or gradually decreases from the top to the bottom. It is a filter plate with a concentration gradient so as to increase gradually. Note that FIG. 6B is a graph showing the amount of change in the transmittance of the illumination light due to the density gradient.
As shown in the figure, the ND filter 26 has the transmission plate 25.
On the other hand, when it is attached, the transmittance is set to decrease temporarily from top to bottom due to the density gradient of the ND filter 26. This ND filter 26 is a transmission plate 2
It may be provided, for example, in the opening of the slit member or the like, without being attached to 5.

Returning to FIG. 1, the image pickup means 5 is a digital camera constructed so that incident light is divided into RGB three primary colors by a dichroic mirror and each of them is received by a separate CCD array. That is, from printed matter to RG
Image data can be obtained for each color plane of B.
The image pickup means 5 is fixed downwardly toward the table 1 by a pillar 24 supported by the gantry 3, and picks up an image of the printed matter through an opening (not shown) provided in the light-shielding roof member 6.

The light-shielding roof member 6 is a light-shielding member that is supported by the pedestal 3 and is supported by two columns 25 extending on the table 1 while having its upper end curved, and has a shape curved in the front-rear direction of the apparatus. This light-shielding roof member 6 is a table 1
It is provided so as to block the light that is specularly reflected and incident on, for example, the light installed on the ceiling of the room.

The control calculation means 7 comprises a microcomputer and is stored in the gantry 3. The control calculation means 7 controls the entire printed matter measuring apparatus and the image pickup means 5.
It is used for the calculation of the image data obtained by the above, and is connected to each part of the printed matter measuring apparatus by a cable (not shown).

The touch panel 8 is a liquid crystal monitor having a pressure-sensitive input function, and functions as an input means for operating the printed matter measuring apparatus and a display means for showing the calculation result. Of course, instead of the touch panel 8, a CRT
The display means such as and the input means such as the keyboard may be used in combination.

In the printed matter measuring apparatus, the printed matter is first placed on the suction plate 1a and suction-held. Then, the flash light source 20 is turned on, and in synchronization with this, the image pickup means 5 picks up an image of the printed matter. The captured image data is subjected to predetermined image processing to calculate the color density of the printed matter.

[Correction Method of Image Data According to First Embodiment] Next, a correction method of image data in the printed matter measuring apparatus according to the first embodiment will be described. Figure 7
3 is a flowchart showing an image data correction procedure in the present invention.

First, in the flow shown in FIG. 7A, in step S1, the white reference material prepared in advance is the table 1
It is placed on top and an image is taken. The image data of this white reference object is used as white reference data, and in step S2, shading correction data at each position of the table is created. Note that shading correction may be performed using a black reference object or a gray reference object other than the white reference object as described in the above-mentioned 2002 Patent Application No. 88039. Since this shading correction method is described in the above specification, a detailed description thereof will be omitted here.

On the other hand, the image data of the white reference plates 12a and 12b arranged at the ends of the table 1 when the white reference object is imaged in advance is stored in step S1. The captured image data is equivalent to the amount of light in the area.

In this embodiment, the white reference plate 12 is used when, for example, the left and right two illumination means α and β are simultaneously turned on.
The image data obtained by capturing a and 12b is stored as a0 and b0. When the illumination means α and β are individually turned on, the image data a0 and b0 are obtained by adding the image data obtained by the two image pickups.

In the next step S3, the actual printed matter is placed on the table and imaged. This step S
3, the image data of the white reference plates 12a and 12b simultaneously illuminated by the illumination means α and β is a1,
It is stored as b1.

In step S4, shading correction is performed based on the white reference data and the like obtained in step S2. In the next step S5, the white reference plate 12a,
The light amount fluctuation is corrected by the image data a0, b0, a1, b1 obtained by imaging 12b. The detailed procedure of this light amount variation correction will be described with reference to the sub-flow of FIG.

First, in step S11, the image data a
Using 0, b0, and a1, b1, the light amount fluctuation ratios μa, μb are calculated by the following arithmetic expression. The light amount variation ratio μa is the ratio of the light amount a1 to the light amount a0.
Similarly, the light amount variation ratio μb is the ratio of the light amount b1 to the light amount b0.

Μa = a1 / a0 (1) μb = b1 / b0 ··· (2)

Next, in step S12, the light amount fluctuation ratio μ at any position between the white reference plates 12a and 12b is obtained by interpolation using the light amount fluctuation ratios μa and μb. FIG. 8 is a diagram for explaining an example of this interpolation method.
As shown in the figure, the light quantity variation ratio μ (x) at the coordinate x position between the white reference plates 12a and 12b is m and n when the distance between the point of the coordinate x and the white reference plates 12a and 12b is m and n, respectively. , Can be defined as follows. Coordinate x
Is the coordinate position in the direction in which the white reference plates 12a and 12b are in series (the left-right direction of the table).

[0054]       μ (x) = (n · μa + m · μb) / (n + m) ··· (3)

In the next step S13, each image data is converted into a light amount variation ratio μ corresponding to the coordinates where the image data is located.
By multiplying by, it is possible to obtain image data in which the fluctuation of the light amount is corrected. If the image data D after shading correction at the coordinates (x, y) on the table is D (x, y), the image data D ′ (x, y) after light amount variation correction is calculated as follows. .

[0056]     D '(x, y) = μ (x) · D (x, y) ··· (4)

However, the coordinate x is the white reference plate 12a,
12b is a coordinate position in the left-right direction of the table in series, but when the image pickup means 5 is fixed, the pixel position in the image pickup means 5 may be used.

In the present embodiment, the light amount variation ratio μ is calculated based on the two white reference plates that are located far and far from the illumination, so that the light amount variation of the illumination means can be corrected.

[Image Data Correction Method According to Second Embodiment] In the above-described first embodiment, the light amount variation ratio μ is obtained in a state where the two illumination means 5 are simultaneously made to emit light. . However, in reality, there is a variation in the amount of light emission for each illumination means 5, and if they are made to emit light at the same time, the amount of variation for each illumination means is unknown. For this reason, in the following second embodiment, an image is taken when each illuminating device is individually made to emit light, and a more accurate correspondence is performed.

First, FIG. 9 is a diagram for explaining the illumination and calculation operation according to the second embodiment. In FIG. 9A, first, only the illumination means α is turned on to turn on the white reference plate 12.
Imaging data αa and αb of a and 12b are obtained. Further, the image data at a predetermined position on the table at this time is defined as Mα.

Similarly, in FIG. 9B, only the illuminating means β is turned on, and the image pickup data βa of the white reference plates 12a and 12b,
Get βb. Further, the image data at a predetermined position on the table at this time is set as Mβ.

Next, as shown in FIG. 9C, the illumination means α,
Image data a of the white reference plates 12a and 12b by lighting β
0 and b0 are obtained. In addition, the image data at a predetermined position on the table at this time is M0.

The work shown in FIGS. 9A to 9C is performed at the same time when the reference object is imaged when the shading correction is performed.

Next, as shown in FIG. 9D, a printed matter is placed and an image is picked up. Also in this case, the illumination means α and β are simultaneously turned on. The image data obtained by imaging the white reference plates 12a and 12b at this time are defined as a1 and b1.

The light amounts of the illuminating means α and β in FIG. 9D vary, and the variation ratio is S with respect to the light amounts of the illuminating means α and β at the time of shading correction shown in FIG. 9C.
Let α and Sβ. In this case, since the ratio of the amount of light caused by the illumination means α and the amount of light caused by the illumination means beta at a predetermined position is substantially constant, the following relationship is established.

[0066]   a1 / a0 = Sα ・ αa / (αa + βa) + Sβ ・ βa / (αa + βa)                                                           ・ ・ (5)   b1 / b0 = Sα ・ αb / (αb + βb) + Sβ ・ βb / (αb + βb)                                                           ・ ・ (6)

If the above two equations are combined, the fluctuation ratios Sα and Sβ of the illumination means α and β can be obtained. The fluctuation ratios Sα and Sβ
9 is used, the light amount variation ratio μ at a predetermined position on the table when the printed matter is imaged in FIG. 9D can be calculated by the following equation.

[0068]   μ = Sα ・ Mα / (Mα + Mβ) + Sβ ・ Mβ / (Mα + Mβ) ・ ・ (7)

In this embodiment, since the individual variation ratios Sα and Sβ of the respective illumination means α and β are obtained, the correction can be performed with higher accuracy than in the first embodiment.

[Image Data Correction Method According to Third Embodiment] The image data a0 and b0 in FIG. 9C can be substituted as follows, respectively.

A0 = αa + βa (8) b0 = αb + βb (9)

Therefore, by using the substitution formulas (8) and (9), the procedure of FIG. 9C can be omitted. In this case, equations (8) and (9) are substituted into equations (5) and (6) to obtain the following two equations.

A1 = Sα · αa + Sβ · βa ··· (10) b1 = Sα · αb + Sβ · βb ··· (11) By solving the above two equations simultaneously, the fluctuation ratios Sα and Sβ can be obtained. Then, if the fluctuation ratios Sα and Sβ are used, the light amount fluctuation ratio μ on the table can be calculated from the equation (7).

[Other Embodiments] 1. In the above-described embodiment, the two white reference plates 12a and 12b are arranged apart from each other, but a long white reference plate is provided so that the white reference plates 12a and 12b are continuous, and interpolation is performed. The calculation may be unnecessary.

2. In the above-described embodiment, the light quantity variation ratio μ is obtained along the left-right direction with which the illumination means 5 is illuminated, but the light quantity variation ratio is also obtained in the front-back direction from the front side of the device to the back side. May be calculated. In this case, if a white reference plate is provided in the front-back direction of the device, the same correction calculation can be performed. For example, white reference plates may be provided at the four corners of the table 1 to calculate the light amount variation ratio μ two-dimensionally.

[0076]

According to the present invention, highly accurate shading correction can be performed even if the light amount of the flash light source fluctuates, and it is particularly suitable for printing plate making work in which color management is severe.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a printed matter measuring apparatus including a flash lighting device according to the present invention.

FIG. 2 is a top view showing an arrangement of suction holes and suction grooves on a suction plate.

FIG. 3 is a piping diagram showing a piping path of an adsorption means.

FIG. 4 is a cross-sectional view showing a schematic configuration of illumination means.

FIG. 5 is a perspective view in which a part of the illuminating means is seen through.

FIG. 6 is a diagram showing an example of an ND filter and a graph showing its transmittance.

FIG. 7 is a flowchart of an image data correction method according to the present invention.

FIG. 8 is an explanatory diagram related to an interpolation calculation of a light amount variation ratio μ.

FIG. 9 is an explanatory diagram illustrating an imaging operation according to the second and third embodiments.

[Explanation of symbols]

1 table 2 Adsorption means 3 mounts 4 Lighting means 5 Imaging means 6 light-shielding roof material 7 Control calculation means 20 flash light source 21 Slit member 22 Parabolic mirror 23 cover 24 Diffuser 26 ND filter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Morikawa             4-chome Tenjin, which runs up to Teranouchi, Horikawa-dori, Kamigyo-ku, Kyoto             1 Kitamachi No. 1 Dai Nippon Screen Manufacturing Co., Ltd.             Inside the company (72) Inventor Kyoko Kawada             4-chome Tenjin, which runs up to Teranouchi, Horikawa-dori, Kamigyo-ku, Kyoto             1 Kitamachi No. 1 Dai Nippon Screen Manufacturing Co., Ltd.             Inside the company F term (reference) 2G051 AA34 AA90 AC21 BA01 BB07                       BB11 BC02 CA04 CB05 EA17                       EA23                 5B047 AA01 AB04 BA02 BB06 BC09                       BC12 BC15 CA19 DA04 DA06

Claims (5)

[Claims] 1. A printed matter placed on a table is illuminated with a flash light source, and the color density of the printed matter is determined based on image data obtained by imaging the table with an imaging means in synchronization with the illumination operation. A printed matter measuring device for calculating, wherein a light quantity variation ratio of the flash light source is calculated for each light emission of the flash light source in correspondence with a coordinate position on the table, and the image data is stored in the table according to the light quantity variation ratio. A printed matter measuring device characterized in that correction is made for each coordinate position above. 2. A reference area corresponding to a plurality of positions is provided in the non-mounting area of the table end portion on which the printed matter is not substantially placed and in the image pickup area by the image pickup means. 2. The printed matter according to claim 1, wherein the light quantity variation ratio of the flash light source is obtained from the image data obtained by capturing the image data for each image pickup in correspondence with the printed matter placement area on the table. measuring device. 3. A table on which a printed matter is placed, a flash light source that illuminates the table, an imaging unit that images the illuminated printed matter, and a color density of the printed matter based on image data of the captured printed matter. A printed matter measuring apparatus comprising: a computing unit for computing; a plurality of the flash light sources are arranged so as to irradiate from the two directions facing the table upper surface, and the table has the flash light source on the upper surface thereof. With respect to at least two far and near positions, white reference areas are provided, and the calculation means calculates a reference correction value based on image data obtained by capturing the white reference amount area each time the flash light source is turned on. The printed matter measuring device is characterized in that the variation amount of the emitted light amount is corrected based on the distance from the flash light source using the reference correction value. 4. The printed matter measuring apparatus according to claim 3, wherein the white reference area is formed of a white reference plate fixedly provided on an edge of the table at a predetermined distance. 5. The flash light sources are controlled so as to individually emit light on one side, and the light amount of each flash light source is corrected based on image data obtained by capturing a white reference region obtained based on each light emission. The printed matter measuring device according to claim 3 or 4, wherein