JP2022083508A - Measurement method, information processing device and program - Google Patents

Abstract

To enable the correction amount of a printing position to be appropriately measured.SOLUTION: A communication unit 13 receives from an imaging apparatus 20 an image 60 obtained by imaging a medium 30 from above a member 40 having a first refractive index and transmitting light, wherein the medium 30 is installed on a top surface 21a of a pedestal 21 and is held down from above the top surface 21a by the member 40. A processing unit 12 calculates an error E(r) in the position of a point that corresponds to a distance r from the center of gravity C1 of the image 60 received by the communication unit 13 to each of a plurality of points on the image and the first refractive index, and measures the correction amount of a printing position to the medium 30 on the basis of the calculated error E(r).SELECTED DRAWING: Figure 1

Description

The present invention relates to a measuring method, an information processing apparatus and a program.

Currently, printers that print on media such as passbooks and forms are used. Printing by a printer may cause printing misalignment. Therefore, a technique for correcting a printing deviation of a printer has been considered.

For example, there is a proposal of a print misalignment correction method for a passbook printer that corrects print misalignment in the forward and reverse directions of a passbook printer that prints in a forward direction and a reverse direction on a medium such as a passbook by a medium processing device.

In addition, the print position on the print medium is measured and the correction value is automatically calculated by reading the print position of the pre-printed print medium with the image reader and obtaining the correction value with the data processing device. There is also a proposal for how to set the correction value for.

Japanese Unexamined Patent Publication No. 3-146378 Japanese Unexamined Patent Publication No. 7-125314

Some media have warps and creases. If the medium has warpage or creases, a part of the medium floats from the surface on which the medium is placed, and the printed surface of the medium is not flat. Therefore, even if the medium on the surface is read by the image reader, the information processing device cannot appropriately obtain the print position from the read image, and the correction amount of the print position for the print misalignment can be measured. difficult.

In one aspect, it is an object of the present invention to provide a measuring method, an information processing apparatus and a program that enable an appropriate measurement of a correction amount of a print position.

In one aspect, a measuring method is provided in which a correction amount of a print position with respect to a medium is measured by using an image obtained by capturing an image of the medium. In this measurement method, the image pickup device is a medium installed on the first surface, and the medium having the first refractive index and being pressed from the upper side of the first surface by a member that transmits light is used. An image is taken from the upper side of the member, and the information processing apparatus acquires an image of the medium captured by the image pickup device, and the distance from the center of gravity of the image to each of the plurality of points on the image and the first refractive index correspond to the distance. The error in the position of the point is calculated, and the correction amount is measured based on the calculated error.

Further, in one aspect, an information processing apparatus is provided.
Also, in one aspect, the program is provided.

On one side, the correction amount of the print position can be appropriately measured.

It is a figure explaining the information processing apparatus of 1st Embodiment. It is a figure which shows the hardware example of the information processing apparatus of 2nd Embodiment. It is a figure which shows the example of the image pickup apparatus. It is a figure which shows the comparative example of the installation of the medium with respect to the image pickup apparatus. It is a figure which shows the functional example of an information processing apparatus. It is a figure which shows the parameter example. It is a figure which shows the example of the parameter information. It is a figure which shows the example of the error calculation result data. It is a figure which shows the example of the relationship between the distance from the center of a camera, and an error. It is a figure explaining the correction example of the distance in the Y-axis direction between two points. It is a flowchart which shows the measurement example of the correction amount of a print position.

Hereinafter, the present embodiment will be described with reference to the drawings.
[First Embodiment]
The first embodiment will be described.

FIG. 1 is a diagram illustrating an information processing apparatus according to the first embodiment.
The information processing device 10 is connected to the image pickup device 20. The image pickup apparatus 20 takes an image of the medium 30 and generates an image 60 of the medium 30. Characters are printed on the surface of the medium 30 by a printer. The image 60 includes characters printed on the medium 30. However, the printing position by the printer may be misaligned with respect to the reference position of the medium 30. Therefore, the work of setting the correction amount for adjusting the print misalignment is performed for the printer.

The information processing apparatus 10 acquires an image 60 from the image pickup apparatus 20, and measures the correction amount of the print position with respect to the medium 30 by using the image 60 obtained by capturing the image 60.
The information processing device 10 has a storage unit 11, a processing unit 12, and a communication unit 13.

The storage unit 11 may be a volatile storage device such as a RAM (Random Access Memory) or a non-volatile storage device such as an HDD (Hard Disk Drive) or a flash memory.
The processing unit 12 may include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), and the like. The processing unit 12 may be a processor that executes a program. A "processor" may include a set of multiple processors (multiprocessors).

The communication unit 13 is a connection interface connected to the image pickup device 20. The communication unit 13 communicates with the image pickup device 20 and receives the image 60 from the image pickup device 20.
The image pickup apparatus 20 has a pedestal 21, a support column 22, and a camera 23.

A support column 22 is attached to the pedestal 21. The medium 30 is installed on the upper surface 21a, which is the upper surface of the pedestal 21, so that the printing surface of the medium 30 faces upward.
The support column 22 supports the camera 23.

The camera 23 takes an image of the medium 30 installed on the upper surface 21a from the upper side of the upper surface 21a. The camera 23 is arranged at a position separated from the upper surface 21a by a first distance. The one-time imaging range of the camera 23 can include the entire printed surface of the medium 30.

Here, some media 30 have warpage or creases. When the medium 30 is warped or deformed due to creases, when the medium 30 is installed on the upper surface 21a, a part of the medium 30 floats from the upper surface 21a, the printed surface of the medium 30 becomes a curved surface, or the medium 30 becomes curved. The image is taken by the camera 23 in a state where a part of the image is raised from the upper surface 21a. The print position cannot be appropriately obtained from the image captured in such a state, and it is difficult to measure the correction amount of the print position with respect to the print misalignment.

Therefore, a member 40 that transmits light is placed on the medium 30 to correct the deformation due to the warp or the crease of the medium 30. That is, the member 40 brings the printed surface of the medium 30 along the upper surface 21a. In order to correct the medium 30, the weight of the member 40 may be used, or the member 40 itself may be pressed against the medium 30 with a clamp or the like. Acrylic, glass, or the like can be used as the material of the member 40. The member 40 has a first refractive index depending on the material. Further, the member 40 has a predetermined thickness. The shape of the member 40 can be a prism, a cylinder, or the like. The bottom surface in contact with the top surface 21a of the member 40 and the upper surface facing the bottom surface are substantially parallel to the top surface 21a and cover the entire printing surface of the medium 30 when viewed from the camera 23 side. The upper surface of the member 40 and the camera 23 are separated by a second distance. The image pickup device 20 is used in the air.

The light directed from the printing surface of the medium 30 toward the camera 23 passes through the member 40. Therefore, the refractive index differs between the member 40 and the air outside the member 40, and the traveling direction of light changes at the boundary between the member 40 and the air. The refractive index (first refractive index) of acrylic or glass used as the member 40 is usually larger than the refractive index of air. Therefore, at the boundary between the member 40 and the air, the angle of incidence is less than the angle of refraction with respect to the light traveling from the member 40 side to the air side. Further, with respect to the light traveling from the air side to the member 40 side, there is a relationship of incident angle> refraction angle at the boundary between the air and the member 40. The optical paths 51 and 52 show an example of the traveling direction of the light traveling through the member 40 from the medium 30 to the camera 23.

The image pickup apparatus 20 is installed on the upper surface 21a and takes an image of the medium 30 pressed from the upper side of the upper surface 21a by the member 40 from the upper side of the member 40 to generate an image 60 of the medium 30. The shape of the entire region of the image 60 is, for example, a rectangle, and the image of the medium 30 is included in the entire region. In the image 60, the image of the medium 30 is distorted as the distance from the center of gravity of the image 60 increases due to the influence of the refractive index of the member 40.

The processing unit 12 acquires the image 60 captured by the image pickup device 20 via the communication unit 13. The processing unit 12 stores the acquired image 60 in the storage unit 11.
The processing unit 12 calculates an error in the position of the points according to the distance from the center of gravity C1 of the image 60 to each of the plurality of points on the image and the first refractive index of the member 40. The center of gravity C1 of the image 60 is a point corresponding to the center of the pixel of the camera 23. The center of gravity C1 is also called the geometric center. Here, the direction from the left side to the right side of the image 60 is the positive direction of the x-axis, and the direction from the lower side to the upper side is the positive direction of the y-axis.

For example, the processing unit 12 calculates an error E (r) with respect to the distance r between the center of gravity C1 and the point P1 on the image 60. Based on Snell's law, the processing unit 12 has a first refractive index of the member 40, a second distance between the camera 23 and the upper surface of the member 40, and a direction from the bottom surface to the upper surface. The error E (r) can be calculated using the thickness of the member 40. The error E (r) is an error in the direction from the center of gravity C1 to the point P1. The processing unit 12 may calculate the error Ex of the x-axis component of the error E (r) and the error Ey of the y-axis component of the error E (r) based on the error E (r). In the case of the point P1 exemplified in FIG. 1, the error Ex is an error in the negative direction of the x-axis. Further, the error Ey is an error in the negative direction of the y-axis. The error Ex, Ey includes a sign indicating a positive direction or a negative direction. In the positive direction, it is a positive (+) sign, and in the negative direction, it is a negative (−) sign.

The processing unit 12 measures the correction amount of the print position based on the calculated error. For example, it is assumed that the image 60 includes a reference line 61 pre-printed on the medium 30 and character strings 62 and 63 printed by the printer to be adjusted. The reference line 61 indicates the x-coordinate that should be the head position of the character strings 62 and 63. The point P1 is included in the reference line 61. The print position of the character string 63 is deviated from the reference line 61 in the positive direction of the x-axis.

In this case, for example, the processing unit 12 obtains the distance Xa in the x-axis direction between the head position of the character string 63 and the reference line 61 based on the image 60. Then, the processing unit 12 sets the absolute value Δ = | Ex-Ex'| of the difference between the error Ex at the point P1 and the error Ex'in the x-axis direction at the point P2 corresponding to the head position of the character string 63. The value (Xa + Δ) added to Xa is obtained as the correction amount. The correction amount can be obtained in the y direction as well as in the x direction. For example, the processing unit 12 converts the number of pixels between two points on the image 60 into a physical length (for example, a unit length such as mm) corresponding to the resolution of the image 60 to obtain a correction amount. ..

The above correction amount calculation method is an example, and other calculation methods can be considered. For example, the processing unit 12 corrects the image 60 based on the error obtained for each point on the image 60 to generate a corrected image, and the printing position is based on the corrected image. The correction amount may be obtained.

For example, the information processing apparatus 10 may store the measured correction amount in the storage unit 11, or may present it to the user by displaying it on a display device connected to the information processing apparatus 10. Alternatively, the information processing apparatus 10 may transmit the correction amount measured via the network to another computer, or may output the correction amount to the printer and set the correction amount for the printer.

According to the above measurement method, the medium 30 installed on the first surface (upper surface 21a) by the image pickup apparatus 20 is the first by the member 40 having the first refractive index and transmitting light. The medium 30 pressed from the upper side of the surface of the member 40 is imaged from the upper side of the member 40. The information processing device 10 acquires an image 60 of the medium 30 captured by the image pickup device 20. The information processing apparatus 10 calculates an error in the position of the point according to the distance from the center of gravity C1 of the image 60 to each of the plurality of points on the image 60 and the first refractive index, and based on the calculated error. , The amount of correction is measured.

As a result, the correction amount of the print position can be appropriately measured.
Specifically, even if the medium 30 has a warp or a crease, the member 40 corrects the deformation of the medium 30. Further, since the refractive index (first refractive index) of the member 40 and the refractive index of air are different by using the member 40, the first refractive index is located at the position of the image 60 captured by the camera 23. An error will be included according to. Therefore, the information processing apparatus 10 can appropriately measure the correction amount of the print position based on the error by obtaining the error.

Hereinafter, a method for measuring the correction amount of the print position by the information processing apparatus 10 and the image pickup apparatus 20 will be described in detail by showing a more specific example.
[Second Embodiment]
Next, a second embodiment will be described.

FIG. 2 is a diagram showing a hardware example of the information processing apparatus according to the second embodiment.
The information processing apparatus 100 includes a CPU 101, a RAM 102, an HDD 103, a connection IF (InterFace) 104, an image signal processing unit 105, an input signal processing unit 106, a medium reader 107, and a NIC (Network Interface Card) 108. The CPU 101 is an example of the processing unit 12 of the first embodiment. The RAM 102 or the HDD 103 is an example of the storage unit 11 of the first embodiment.

The CPU 101 is a processor that executes a program instruction. The CPU 101 loads at least a part of the programs and data stored in the HDD 103 into the RAM 102 and executes the program. The CPU 101 may include a plurality of processor cores. Further, the information processing device 100 may have a plurality of processors. The processes described below may be performed in parallel using multiple processors or processor cores. Also, a set of multiple processors may be referred to as a "multiprocessor" or simply a "processor".

The RAM 102 is a volatile semiconductor memory that temporarily stores a program executed by the CPU 101 and data used by the CPU 101 for calculation. The information processing apparatus 100 may include a type of memory other than the RAM, or may include a plurality of memories.

The HDD 103 is a non-volatile storage device that stores software programs such as an OS (Operating System), middleware, and application software, and data. The information processing device 100 may be provided with other types of storage devices such as a flash memory and an SSD (Solid State Drive), or may be provided with a plurality of non-volatile storage devices.

The connection IF 104 is an interface for connecting to the image pickup apparatus 200. For the connection IF 104, for example, USB (Universal Serial Bus) or the like can be used. The connection IF 104 may be a wireless interface such as Bluetooth®. The image pickup apparatus 200 is a stand-type image scanner that reads an image of a medium such as a passbook or a form. The image pickup apparatus 200 may be an OHR (Over Head Reader).

The image signal processing unit 105 outputs an image to the display 111 connected to the information processing apparatus 100 in accordance with a command from the CPU 101. As the display 111, any kind of display such as a CRT (Cathode Ray Tube) display, a liquid crystal display (LCD: Liquid Crystal Display), a plasma display, and an organic EL (OEL: Organic Electro-Luminescence) display can be used.

The input signal processing unit 106 acquires an input signal from the input device 112 connected to the information processing device 100 and outputs the input signal to the CPU 101. As the input device 112, a pointing device such as a mouse, a touch panel, a touch pad, or a trackball, a keyboard, a remote controller, a button switch, or the like can be used. Further, a plurality of types of input devices may be connected to the information processing apparatus 100.

The medium reader 107 is a reading device that reads programs and data recorded on the recording medium 113. As the recording medium 113, for example, a magnetic disk, an optical disk, a magneto-optical disk (MO: Magneto-Optical disk), a semiconductor memory, or the like can be used. The magnetic disk includes a flexible disk (FD) and an HDD. Optical discs include CDs (Compact Discs) and DVDs (Digital Versatile Discs).

The medium reader 107 copies, for example, a program or data read from the recording medium 113 to another recording medium such as the RAM 102 or the HDD 103. The read program is executed by, for example, the CPU 101. The recording medium 113 may be a portable recording medium and may be used for distribution of programs and data. Further, the recording medium 113 and the HDD 103 may be referred to as a computer-readable recording medium.

The NIC 108 is an interface that is connected to the network 70 and communicates with other computers via the network 70. The NIC 108 is connected to a communication device such as a switch or a router by a cable. The NIC 108 may be a wireless communication interface that wirelessly communicates with a wireless access point belonging to the network 70.

FIG. 3 is a diagram showing an example of an image pickup device.
The image pickup apparatus 200 takes an image of the medium 300. The medium 300 is a passbook, a form, or the like. A character string is printed on the medium 300 by a printer. However, the printing position by the printer may be deviated from the reference position provided in advance on the medium 300. The information processing apparatus 100 measures a correction amount for correcting a print misalignment of a printer based on an image captured by the image pickup apparatus 200. The image pickup device 200 is used in the air. Let the refractive index of air be η ₁ . For example, at 0 ° C. and 1 atm, η ₁ = 1.000292.

The image pickup apparatus 200 has a pedestal 210, a support column 220, an arm 230, and a camera 240.
The medium 300 is installed on the pedestal 210. Further, a support column 220 is attached to the pedestal 210.

The stanchion 220 supports the arm 230 and the camera 240. The height of the arm 230 may be variable in the support column 220.
The arm 230 supports the camera 240.

The camera 240 has an image pickup device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and generates an image of the medium 300. The camera 240 is supported by the columns 220 and the arm 230 so as to be located above the pedestal 210. The camera 240 can accommodate the entire medium 300 within a range that can be imaged at one time.

The medium 300 is pressed from above by a cover 400 made of a material that transmits light. As the material of the cover 400, for example, acrylic or glass can be used. The shape of the cover 400 is, for example, a rectangular parallelepiped. The shape of the cover 400 may be a prism or a cylinder other than a rectangular parallelepiped as long as it covers the entire surface of the medium 300 when viewed from the camera 240. The cover 400 is an example of the member 40 of the first embodiment. The cover 400 has a refractive index η ₂ . η ₂ ≠ η ₁ .

Note that FIG. 3 illustrates how the medium 300 and a part of the image pickup apparatus 200 existing under or behind the cover 400 can be seen through, but the influence of the refractive index of the cover 400 is ignored.

FIG. 4 is a diagram showing a comparative example of installation of a medium with respect to an image pickup device.
FIG. 4A illustrates a case where the medium 300 has a warp. If the medium 300 is warped, when the medium 300 is installed on the pedestal 210, the medium 300 floats from the upper surface of the pedestal 210 and the medium 300 does not become a flat surface. , The print position cannot be specified properly.

FIG. 4B shows an example in which the cover 400 is placed on the medium 300. The warp of the medium 300 is corrected by the cover 400. The surface of the medium 300 becomes a flat surface along the upper surface of the pedestal 210.

By placing the cover 400 on the medium 300, deformation due to warpage or creases of the medium 300 can be corrected, but the refractive index of the cover 400 causes an error in the position of each point on the image captured by the camera 240. .. The information processing apparatus 100 provides a function of calculating the error and appropriately measuring the correction amount of the print position from the captured image of the medium 300.

FIG. 5 is a diagram showing a functional example of the information processing apparatus.
The information processing apparatus 100 has a storage unit 120, an error calculation unit 130, and a correction amount measurement unit 140. The storage area of the RAM 102 or the HDD 103 is used for the storage unit 120. The error calculation unit 130 and the correction amount measurement unit 140 are realized by the CPU 101 executing the program stored in the RAM 102.

The storage unit 120 stores information such as an image acquired from the image pickup apparatus 200 and parameters used for calculation by the error calculation unit 130 and the correction amount measurement unit 140.
The error calculation unit 130 calculates the error of the position of each point on the image caused by the refractive index of the cover 400. The error is expressed as a function of the distance from the center of gravity of the image, that is, the position corresponding to the center of the image sensor of the camera 240 to the corresponding point. Snell's law is used to derive the function. Details of the error calculation method by the error calculation unit 130 will be described later.

The correction amount measuring unit 140 measures the correction amount of the print position based on the error of each point on the image calculated by the error calculation unit 130. For example, the correction amount measuring unit 140 obtains the correction amount of the print position by correcting the distance between two points on the image based on the error calculated for each of the two points. The correction amount measuring unit 140 may store the measured correction amount in the storage unit 120, or may present it to the user by displaying it on the display 111. Alternatively, the information processing apparatus 100 may transmit the measured correction amount to another computer via the network 70, or may output the correction amount to the printer and set the correction amount for the printer. good.

FIG. 6 is a diagram showing an example of parameters.
t is the thickness of the cover 400 in the height direction (direction from the bottom to the top in FIG. 6).
h is the distance between the camera 240 and the cover 400.

D is the distance from the point on the upper surface of the cover 400 corresponding to the center of the camera 240 to other points on the upper surface.
θ ₁ is the angle of incidence on the cover 400 when the light travels straight from the center of the camera 240.

θ ₂ is the refraction angle of the light incident from the outside (air side) of the cover 400 at the cover 400.
L ₁ is a distance from the top surface to the bottom surface of the cover 400 when the light traveling straight from the center of the camera 240 travels straight through the cover 400 without being affected by refraction.

L ₂ is the distance that the light refracted by being incident on the cover 400 travels from the upper surface to the bottom surface of the cover 400.
e1 is _a point where light traveling straight from the center of the camera 240 is incident on the cover 400, and a point where the light travels straight through the cover 400 without being affected by refraction in the cover 400 and reaches the bottom surface of the cover 400. Is the distance in the direction perpendicular to the height direction.

e ₂ is the height direction of the point where the light traveling straight from the center of the camera 240 is incident on the cover 400 and the point where the light refracted by the light incident on the cover 400 reaches the bottom surface of the cover 400. The distance in the vertical direction.

e = e (D) is an error due to the influence of refraction in the cover 400, and is e = e ₁ − e ₂ .
In this case, according to Snell's law, equation (1) holds.

L ₁ and L ₂ are represented by the equations (2) and (3).

Further, e ₁ and e ₂ are represented by the equations (4) and (5).

From equations (4) and (5), e is represented by equation (6).

Further, θ ₁ and θ ₂ are represented by the equations (7) and (8).

Equation (9) is obtained by rearranging equation (6) using each of the above equations.

As shown in equation (9), the error e is expressed as a function of the distance D. The function includes t, h and η ₂ as constants.
FIG. 7 is a diagram showing an example of parameter information.

The parameter information 121 is stored in the storage unit 120 in advance.
For example, the material of the cover 400 is acrylic.
The parameter information 121 includes information that the refractive index η ₂ is “1.492”, the distance h is “192”, and the thickness t is “8”. The unit of length such as distance and thickness is mm.

FIG. 8 is a diagram showing an example of error calculation result data.
The error calculation result data 122 is generated by the error calculation unit 130 based on the equation (9) and the parameter information 121, and is stored in the storage unit 120.

In the error calculation result data 122, for example, the errors e ₂ and e calculated for the values of D, θ ₁ , θ ₂ , L ₁ and L ₂ are registered.
FIG. 9 is a diagram showing an example of the relationship between the distance from the center of the camera and the error.

Graph 123 shows the relationship expressed by the equation (9) between D and e in the error calculation result data 122. The error calculation unit 130 can also obtain an approximate curve obtained by approximating the graph 123 with a quadratic function or the like, for example.

FIG. 10 is a diagram illustrating an example of correcting the distance between two points in the Y-axis direction.
The image 500 is an image of the medium 300 captured by the image pickup apparatus 200 through the cover 400. For example, the number of pixels between two points on the image 500 is converted into a physical length according to the resolution of the image 500. However, the image 500 is an image including an error due to the influence of the refractive index of the cover 400. As described above, the larger the distance from the point on the image 500 corresponding to the center of the camera, that is, the center position of the image sensor of the camera 240, the greater the influence of the error.

Here, the lower left of the image 500 is the origin, the direction toward the right side is the X-axis direction, and the direction toward the upper side is the Y-axis direction. Further, the lower side of FIG. 10 is the lower end of the image 500, and the upper side of FIG. 10 is the upper end of the image 500.

Consider finding the distance Ly in the Y-axis direction between points A and B on the image 500. The point C is the center of gravity of the image 500. That is, the point C corresponds to the center position of the image sensor of the camera 240.

Cy is the distance between the origin and the point C in the Y-axis direction.
Ay is the distance between the origin and the point A in the Y-axis direction.
By is the distance between the origin and the point B in the Y-axis direction.

Acy is the distance between the point C and the point A in the Y-axis direction.
Bcy is the distance between the point C and the point B in the Y-axis direction.
Let Kay be the error correction value for point A. Kay is a component in the Y-axis direction of the error e (Da) with respect to the distance Da between the point C and the point A. Further, it is assumed that the sign of Kay is positive.

Let Kby be the error correction value for point B. Kby is a component in the Y-axis direction of the error e (Db) with respect to the distance Db between the points C and B. Further, it is assumed that the sign of Kby is positive.
In this case, Acy is calculated by the following equation.

When Ay <Cy, Acy = Ay-Cy-Ky.
When Ay ≧ Cy, Acy = Ay−Cy + Ky.
Bcy is calculated by the following equation.

When By <Cy, Bcy = By-Cy-Ky.
When By ≧ Cy, Bcy = By−Cy + Ky.
As described above, the sign attached to Ky changes depending on whether the points A and B are below or above the point C.

Ly can be obtained by Ly = | Bcy-Acy |.
The correction amount measuring unit 140 prints, for example, the distance between the reference position in the image 500 and the printing position of the character printed on the image 500 from the reference position in the same manner as the distance Ly between the above two points. Measure as a deviation correction amount. The correction amount measuring unit 140 can measure the distance between two points in the same manner in the X-axis direction. In the X-axis direction, when the point of interest is on the right side of the point C, the sign attached to the X component of the error is +, and when the point of interest is on the left side of the point C, it is attached to the X component of the error. The sign is-.

Next, the processing procedure of the information processing apparatus 100 will be described.
FIG. 11 is a flowchart showing a measurement example of the correction amount of the print position.
(S10) The error calculation unit 130 acquires the image 500 captured by the image pickup apparatus 200 and stores it in the storage unit 120.

(S11) The error calculation unit 130 calculates the error e at the position of each point in the image 500. For example, the error calculation unit 130 calculates the error e based on the parameter information 121 and the equation (9) stored in the storage unit 120, and generates the error calculation result data 122. The error calculation unit 130 may calculate the error e at the position of each point in the image 500 in advance to generate the error calculation result data 122, and store the error calculation result data 122 in the storage unit 120. good. That is, the error calculation result data 122 may be generated before the image 500 is acquired.

(S12) The correction amount measuring unit 140 measures the correction amount of the print position based on the error e calculated by the error calculation unit 130. For example, the correction amount measuring unit 140 analyzes the image 500, extracts a print position deviated by a threshold value or more from a specific reference position of the image 500, and sets the distance between the reference position and the print position at each position. Calculated as a correction amount based on the error e. As illustrated in FIG. 10, the correction amount measuring unit 140 may decompose the error e at the corresponding position into a predetermined axial component in the image 500 and calculate the correction amount in the axial direction.

(S13) The correction amount measuring unit 140 outputs the measured correction amount. Then, the measurement of the correction amount of the print position is completed. In step S13, the correction amount measuring unit 140 may store the measured correction amount in the storage unit 120, or may present it to the user by displaying it on the display 111. Alternatively, the information processing apparatus 100 may transmit the measured correction amount to another computer via the network 70, or may output the correction amount to the printer and set the correction amount for the printer. good.

As described above, according to the information processing apparatus 100, the correction amount of the print position can be appropriately measured.
For example, even if the medium 300 has a warp or a crease, the cover 400 corrects the deformation of the medium 300. Further, since the refractive index (first refractive index) of the cover 400 and the refractive index of air are different by using the cover 400, the first refractive index is located at the position of the image 500 captured by the camera 240. An error e corresponding to the above will be included. Therefore, the information processing apparatus 100 can appropriately measure the correction amount of the print position based on the error e by obtaining the error e.

Specifically, when the medium 300, which is the object to be measured, is imaged from a fixed camera 240 such as the image pickup apparatus 200, it is obtained as the distance from the center of the camera increases due to the influence of the refraction of the cover 400 such as a glass plate or an acrylic plate. The problem of image distortion occurs and affects dimensional measurement.

The image captured by the image pickup apparatus 200 is handled in units of square pixels through the image pickup element of the camera 240. Since the dimension per pixel can be obtained from the distance to the object to be measured and the angle of view of the camera lens, the distance can be obtained by counting the number of pixels between two points to be measured. For example, in order to remove various errors, a method of measuring a reference object to be measured and correcting the dimension per pixel based on the length may be used.

On the other hand, when a substance such as a glass plate exists between the object to be measured and the camera 240, the distance from the center position of the camera 240 is affected by the refraction of light, and the size of the object to be measured looks relatively different. It ends up. When the measurement object with the same dimensions as the reference is placed at the same position, it is not affected, but the measurement objects with different dimensions and different positions are subject to refraction error and adversely affect the measurement accuracy.

Therefore, the information processing apparatus 100 adds an error caused by the influence of refraction to the distance between two points measured from the image according to the distance from the position on the image corresponding to the center of the camera, thereby causing the refraction. Correct the effect.

If the distance between the object to be measured and the camera 240 and the thickness and index of refraction of the cover 400 in close contact with the object to be measured are known, the amount of refraction varies non-linearly depending on the distance from the position on the image corresponding to the center of the camera. ..

The distance of the measurement point from the position (center of gravity) on the image corresponding to the center of the camera is derived as the length of the hypotenuse of a right triangle having two sides orthogonal to the X and Y directions from the center.
By considering the above-mentioned amount of refraction, it is possible to correct the error due to the refraction between the center of gravity on the image and the measurement point. For example, when the error correction value to be added to the array direction of the pixels is obtained, the error e obtained by the equation (9) may be decomposed in the X direction and the Y direction by using a trigonometric function. When finding the distance between any two points, the position of each point is corrected by an error according to the distance from the center of gravity, and then the distance between the corrected two points is found by refraction. It is possible to obtain the distance with the error removed.

For example, consider the case of measuring the position of characters printed on the 2000 passbook, which is widely used in financial institutions. The 2000 passbook is an example of the medium 300.
Normally, dot impact printing is performed on passbooks, but positioning accuracy is required for pre-printed ruled lines and the like, and measurement of character positions is indispensable for adjusting the printer.

Here, consider a case where the camera is placed at a position 200 mm away from the printing surface and the passbook is photographed through a glass plate having a thickness of 8 mm in order to hold the page. The glass plate is an example of the cover 400.

Assuming that the refractive index of the glass plate is 1.5, when the vertical direction of the passbook is aligned with the center of the camera 240, the position 100 mm away from the position of the center of gravity on the image in the vertical direction looks about 1.6 mm shorter. On the other hand, the vertical direction at a position 50 mm away from the position of the center of gravity on the image appears to be about 0.7 mm shorter.

For example, when a method of taking a reference (regulator, etc.) and calculating the distance for each pixel of an image based on the length of a reference (regulator, etc.) is used as a correction for measuring the distance on the image, the above-mentioned 100 mm is included in the error for each pixel. When calculating the distance, an error of about 0.1 mm occurs depending on the presence or absence of correction of the influence of refraction at a position 50 mm away from the position of the center of gravity on the image, so for a printer that prints at a resolution of about 200 DPI (Dots Per Inch). It is possible to correct errors that cannot be ignored.

As described above, the information processing apparatus 100 of the second embodiment measures the correction amount of the print position with respect to the medium by using the image obtained by capturing the medium. The measurement method using the information processing device 100 and the image pickup device 200 includes, for example, the following procedure.

The image pickup apparatus 200 is a medium 300 installed on the first surface (upper surface) of the pedestal 210, and is pressed from the upper side of the first surface by a member having a first refractive index and transmitting light. The medium 300 is imaged from above the member. The cover 400 is an example of a member.

The information processing device 100 acquires an image of the medium 300 captured by the image pickup device 200, and the position of the points according to the distance from the center of gravity of the image to each of the plurality of points on the image and the first refractive index. The error is calculated, and the correction amount of the print position is measured based on the calculated error.

As a result, the correction amount of the print position can be appropriately measured.
The information processing apparatus 100 corrects the coordinates of the first point by using the first error corresponding to the first point among the plurality of points, and corresponds to the second point among the plurality of points. The coordinates of the second point are corrected using the error of 2. The information processing apparatus 100 uses the difference in the coordinates of the corrected second point with respect to the corrected first point as the correction amount.

As a result, the accuracy of the correction amount can be improved.
The information processing apparatus 100 includes the first refractive index, the length from the upper surface of the member to the camera 240 included in the image pickup apparatus 200, and the thickness from the medium side surface of the member to the upper surface of the member as constants. , The error is calculated based on the relational expression between the distance from the center of gravity of the image to the point on the image and the error.

Thereby, the error at the point can be easily calculated from the distance from the center of gravity of the image to the point on the image. The relational expression is expressed by the expression (9). The calculated error may be decomposed into components related to a specific direction, for example, the X-axis direction and the Y-axis direction in the image of the medium.

The member is a glass plate or an acrylic plate.
As described above, by using a substantially transparent substance having a relatively high transparency as a member, the print position in the image of the medium can be appropriately detected, and the correction amount can be appropriately measured. Here, glass is a substance containing silicic acid (SiO ₂ ) as a main component. Acrylic is a substance containing acrylic resin as a main component.

The information processing of the first embodiment can be realized by causing the processing unit 12 to execute the program. Further, the information processing of the second embodiment can be realized by causing the CPU 101 to execute the program. The program can be recorded on a computer-readable recording medium 113.

For example, the program can be distributed by distributing the recording medium 113 on which the program is recorded. Alternatively, the program may be stored in another computer and distributed via the network. For example, the computer may store (install) a program recorded on the recording medium 113 or a program received from another computer in a storage device such as RAM 102 or HDD 103, read the program from the storage device, and execute the program. good.

10 Information processing device 11 Storage unit 12 Processing unit 13 Communication unit 20 Imaging device 21 Pedestal 21a Top surface 22 Support column 23 Camera 30 Medium 40 Member 51, 52 Optical path 60 Image 61 Reference line 62,63 Character string C1 Center of gravity P1, P2 points

Claims (6)

In a measurement method in which a correction amount of a print position with respect to a medium is measured using an image obtained by capturing an image of the medium.
The image pickup apparatus is the medium installed on the first surface, and the medium is pressed from above the first surface by a member having a first refractive index and transmitting light. Imaged from above,
The information processing apparatus acquires an image of the medium captured by the imaging device, and the distance from the center of gravity of the image to each of the plurality of points on the image and the first refractive index of the points. The position error is calculated, and the correction amount is measured based on the calculated error.
Measuring method. The information processing apparatus corrects the coordinates of the first point using the first error corresponding to the first point of the plurality of points, and makes the second point of the plurality of points. The coordinates of the second point are corrected using the corresponding second error, and the difference in the coordinates of the corrected second point with respect to the corrected first point is used as the correction amount.
The measuring method according to claim 1. The information processing device has the first refractive index, the length from the upper surface of the member to the camera included in the image pickup device, and the thickness from the medium side surface of the member to the upper surface of the member. Is included in the constant, and the error is calculated based on the relational expression between the distance and the error.
The measuring method according to claim 1. The member is a glass plate or an acrylic plate.
The measuring method according to claim 1. In an information processing apparatus that measures the amount of correction of the print position with respect to a medium using an image obtained by capturing the medium.
The medium installed on the first surface, which has a first refractive index and is pressed from the upper side of the first surface by a member that transmits light, is imaged from the upper side of the member. With the communication unit that receives the image
An error in the position of the point according to the distance from the center of gravity of the image received by the communication unit to each of the plurality of points on the image and the first refractive index is calculated, and based on the calculated error. , The processing unit that measures the correction amount, and
Information processing device with. In a program that measures the amount of correction of the print position with respect to the medium using the image obtained by capturing the medium, the computer is used.
The medium installed on the first surface, which has a first refractive index and is pressed from the upper side of the first surface by a member that transmits light, is imaged from the upper side of the member. The image is acquired from the image pickup device and
An error in the position of the point according to the distance from the center of gravity of the image to each of the plurality of points on the image and the first refractive index is calculated, and the correction amount is measured based on the calculated error. do,
A program that executes processing.

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