JP2010226562A - Calibration system, and calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a calibration system and a calibration method, by which a print density can highly precisely be calibrated. <P>SOLUTION: The calibration system 1 includes a digital camera 40, a printer 70 and a paper sheet 41. The printer 70 includes a storage section 20, a print section 30, a communication section 10 and a control section 60. The storage section 20 stores image data 20D of a first test chart 42T. The print section 30 prints the first test chart 42T on the paper sheet 42 based on the image data 20D. The communication section 10 receives image data of the first test chart 42T and a second test chart 41T photographed by the digital camera 40. The control section 60 performs print density calibration based on a first correction value 43A calculated based on the first test chart 42T received by the communication section 10 and a differential of a density value of the first test chart 42T. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a calibration system and a calibration method for calibrating print density.

  In general, in a printer that performs printing processing on paper, it is necessary to adjust (calibrate) the print density using a test chart that is printed in advance on a sheet body.

  For this reason, conventionally, a test chart stored in advance in the internal memory of the printer is printed on paper, and the print density of the printed test chart is visually checked by an operator, and the print density is calibrated. .

  In addition, in a calibration system that calibrates the print density, a test chart stored in a memory is printed on a sheet, and the printed test chart is captured by a digital camera (external photographing apparatus), Some print density calibration is performed by comparing image data of a test chart stored in a memory (see, for example, Patent Document 1).

JP 2006-165660 A

  In the calibration system disclosed in Patent Document 1, calibration is performed using image data obtained by photographing a test chart printed on paper with a digital camera. However, when a test chart printed on paper is photographed with a digital camera, the density value of the image data changes depending on the brightness of the surrounding environment and the color of the irradiated light. For this reason, there has been a problem that calibration of print density cannot be performed with high accuracy.

  SUMMARY An advantage of some aspects of the invention is that it provides a calibration system and a calibration method capable of accurately executing print density calibration.

  The calibration system of the present invention includes an external photographing device, a printer, and a sheet body. The external photographing device takes an image. The printer includes a print unit, a storage unit, a communication unit, and a control unit. The printing unit performs a printing process on the paper. The storage unit stores data of a first test chart used for print density calibration in advance. The communication means communicates with the external photographing device. The control unit calculates the first correction value based on the data received by the communication unit and calibrates the print density. On the sheet body, a second test chart having the same image as the first test chart having a density serving as a reference for calibration is formed in advance. The control unit calculates a first correction value based on the difference between the density values of the image data of the first test chart printed on the paper by the printing unit and the second test chart formed on the sheet body, and calibrates the print density. Execute.

  In this configuration, the print density calibration is performed using the difference between the image data of the first test chart and the second test chart taken by the external photographing apparatus.

  Therefore, it is possible to calibrate the print density while eliminating the influence of the brightness of the surrounding environment and the color condition of the irradiation light.

  In this configuration, the control unit further calculates a second correction value corresponding to a difference in density value between the first test chart stored in advance in the storage unit and the second test chart photographed by the external photographing apparatus. Preferably, the print density calibration is performed based on the first correction value and the second correction value.

  Thus, the calibration can be performed in consideration of a print density shift between the second test chart photographed by the external photographing apparatus and the image data for performing calibration stored in the storage unit.

  The calibration system of the present invention includes an external photographing device, an information processing terminal, a printer, and a sheet member. The external photographing device takes an image. The information processing terminal includes a storage unit, a first communication unit, and a correction data generation unit. The storage unit stores data of a first test chart used for print density calibration in advance. The first communication means communicates with the external photographing device. The correction data generation unit calculates a first correction value based on the data received by the first communication means, and generates calibration data for calibrating the print density. The printer includes second communication means and a control unit. The second communication means receives calibration data generated by the information processing terminal. The control unit performs calibration based on the print density calibration data received by the second communication unit. On the sheet body, a second test chart having the same image as the first test chart having a density serving as a reference for calibration is formed in advance. The correction data generation unit calculates the first correction value based on the difference between the density values of the image data of the first test chart printed on the paper by the printing unit and the second test chart formed on the sheet body, and performs calibration. Generate data. The control unit executes print density calibration based on the calibration data generated by the first correction data generation unit.

  In this configuration, the information processing terminal generates calibration data based on the difference between the image data of the first test chart and the second test chart captured by the external imaging device. The printer executes calibration based on the calibration data generated by the information processing terminal.

  Therefore, it is possible to calibrate the print density while eliminating the influence of the brightness of the surrounding environment and the color condition of the irradiation light.

  In this configuration, the correction data generation unit calculates a second correction value corresponding to the difference in density value between the first test chart stored in advance in the storage unit and the second test chart photographed by the external photographing apparatus. It is preferable to further calculate and calibrate the print density based on the first correction value and the second correction value.

  Thereby, the calibration can be performed in consideration of the shift of the print density between the second test chart photographed by the external photographing apparatus and the image data for calibration stored in the storage unit.

  The calibration method according to the present invention is a calibration method for calibrating print density using an external photographing device for photographing an image, and includes first to fifth steps. In the first step, a first test chart used for calibration of print density stored in advance in the printer is printed on paper. In the second step, the first test chart and the second test chart that is the same image as the first test chart and that is formed in advance on the sheet body with a reference density for calibration are externally photographed. Shoot with. In the third step, the image data of the first test chart and the second test chart is transmitted from the external photographing device to the printer. In the fourth step, a correction value is calculated based on the difference between the density values of the image data of the first test chart and the second test chart. In the fifth step, the print density is calibrated based on the correction value calculated in the fourth step.

  In this configuration, the print density calibration is performed using the difference between the image data of the first test chart and the second test chart taken by the external photographing apparatus.

  Therefore, it is possible to calibrate the print density while eliminating the influence of the brightness of the surrounding environment and the color condition of the irradiation light.

  The calibration method according to the present invention is a calibration method for calibrating print density using an external photographing apparatus for photographing an image, and includes first to seventh steps. In the first step, a first test chart stored in advance in the information processing terminal is printed on paper. The second step is a first test chart printed on a sheet, and a second test chart that is the same image as the first test chart and is formed in advance on the sheet body with a density that serves as a reference for calibration. And shoot with an external camera. The third step transmits the image data of the first test chart and the second test chart to the information processing terminal. In the fourth step, a correction value is calculated based on the difference between the density values of the image data of the first test chart and the second test chart. In the fifth step, calibration data for calibrating the print density is generated based on the correction value calculated in the fourth step. In the sixth step, calibration data is transmitted to the printer. In the seventh step, the print density is calibrated based on the calibration data.

  In this configuration, the information processing terminal generates calibration data based on the difference between the image data of the first test chart and the second test chart captured by the external imaging device. The printer executes calibration based on the calibration data generated by the information processing terminal.

  In the fourth step of this configuration, the correction value is calculated by further calculating the difference in density value between the first test chart stored in advance and the second test chart photographed by the external photographing apparatus. It is preferable.

  Accordingly, calibration can be performed in consideration of a print density shift between the second test chart photographed by the external photographing apparatus and the first test chart stored in advance.

  According to the present invention, it is possible to accurately calibrate the print density while eliminating the influence of the brightness of the surrounding environment.

1 is a schematic diagram of a calibration system according to a first embodiment of the present invention. 10 is a flowchart when the control unit performs printer density calibration using the first correction value and the second correction value. It is a flowchart in the case of calibrating the printer density using only the first correction value in the second embodiment of the present invention. It is the schematic of the calibration system which concerns on 3rd Embodiment of this invention. It is a flowchart explaining the flow of the calibration data creation process in a personal computer. 6 is a flowchart illustrating a flow of a print density calibration process using calibration data in a printer.

  A calibration system 1 according to a first embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the calibration system 1 includes a digital camera (external photographing apparatus) 40, a printer 70, and paper (sheet body) 41.

  The printer 70 includes a communication unit (communication means) 10, a storage unit 20, a printing unit 30, a control unit 60, and an operation unit 80.

  The communication unit 10 receives image data from the digital camera 40 via the communication cable 50. A communication cable 50 is detachably attached between the digital camera 40 and the communication unit 10. Thereby, the image data captured by the digital camera 40 can be transmitted to the printer 70.

  Instead of the digital camera 40, a mobile phone having a digital camera function may be used. In addition, when the resolution of the image sensor incorporated in the digital camera is low, it is conceivable that the first test chart 42T and the second test chart 41T are enlarged at the same magnification and printed on the sheets 42 and 41, respectively.

  The storage unit 20 stores test chart image data 20D in advance. The storage unit 20 temporarily stores image data received by the communication unit 10. Note that the communication unit 10 may transmit the image data to the control unit 60 without using the storage unit 20.

  The printing unit 30 reads image data from the storage unit 20 and performs printing processing on a sheet. The operation unit 80 includes an operation panel 81 for performing various operation inputs, and a display panel 82 for displaying an operation guidance screen and the like.

  The control unit 60 controls the printing process in the printing unit 30 according to the operation input. When an operation input for performing print density calibration is performed, the control unit 60 causes the printing unit 30 to execute a calibration process.

  A second test chart 41T is printed on the paper 41 in advance. The second test chart 41T is obtained by printing the same image as the image data 20D with a density value serving as a reference for performing calibration. In the second test chart 41T, each color component having different shades is printed in a mesh pattern in a preset pattern. In FIG. 1, only an overview of the second test chart 41 </ b> T represented in a mesh shape is illustrated. The color components printed in the mesh are not shown. In the present embodiment, an example is given in which the second test chart 41T is printed on the paper 41. For example, the second test chart 41T may be printed in advance on a resin member or the like.

  The second test chart 41T and the first test chart 42T are not limited to those provided in a mesh shape. For example, it is sufficient that each color component is printed in a pattern with different shades. Further, when the print density calibration is performed using grayscale image data, the image data represented in grayscale may be used as the second test chart 41T and the first test chart 42T.

  Here, the print density calibration method will be specifically described as follows.

  First, the operator operates the operation panel 81 to print the image data 20 </ b> D on the paper 42 by the printing unit 30.

  Next, the operator uses the digital camera 40 to photograph the second test chart 41T and the first test chart 42T in this order.

  Then, the communication cable 50 is connected to communication ports (not shown) of the digital camera 40 and the printer 70.

  Furthermore, the operator presses a print density calibration start button provided on the operation panel 81.

  When the calibration start button is operated, the control unit 60 confirms that the digital camera 40 is connected via the communication unit 10. When the connection with the digital camera 40 is confirmed, the image data of the first test chart 42T and the second test chart 41T is read from the digital camera 40 and stored in the storage unit 20. At this time, the control unit 60 converts the image data of the first test chart 42T and the second test chart 41T from R (red), G (green), B (blue) to Y (yellow), M (magenta), C ( (Cyan) data and stored in the storage unit 20.

  In the following, the image data of the second test chart 41T is referred to as first image data 41D. Further, the image data of the first test chart 42T is denoted as second image data 42D.

  The control unit 60 determines the second image data 42D and the first image data 41D based on the shooting date and time of the image data stored in the storage memory of the digital camera 40. Specifically, the image data with the newest shooting date is determined as the second image data 42D. Further, the image data having the latest shooting date and time after the image data of the second image data 42D is determined as the image data of the first image data 41D.

  In this embodiment, an example is given in which the first image data 41D and the second image data 42D are discriminated in the order in which they are photographed. For example, the first image data is first photographed by the digital camera 40. 41D is transferred to the printer 70, and the operation unit 80 is operated and stored in the storage unit 20 as the second test chart 41T. Thereafter, the sheet 42 may be photographed by the digital camera 40, the second image data 42D may be transferred to the printer 70, and the operation unit 80 may be operated and stored in the storage unit 20 as the first test chart 42T.

  The controller 60 calculates the first correction value 43A based on the difference in density between the first image data 41D and the second image data 42D. Thereby, it is possible to obtain correction data from which the influence of ambient light is removed.

  Here, it is also conceivable that the print density of the second test chart 41T formed on the paper 41 slightly changes due to aging or the like.

  For this reason, it is preferable to correct the deviation of the print density values of the first image data 41D and the image data 20D.

  Therefore, the control unit 60 creates the third image data 44D obtained by correcting the second image data 42D with the first correction value 43A, and sets the second correction value 43B based on the difference between the third image data 44D and the image data 20D. calculate. Thereby, it is also possible to correct the deviation of the density values of the first image data 41D and the image data 20D.

  The control unit 60 performs calibration of the printing unit 30 based on the first correction value 43A and the second correction value 43B.

  In the present embodiment, the second correction value 43B is calculated based on the difference between the density values of the third image data 44D and the image data 20D. For example, the density values of the first image data 41D and the image data 20D are calculated. The second correction value 43B may be calculated from the difference between the two.

  Here, the flow of the calibration process performed by the control unit 60 will be described more specifically with reference to the flowchart shown in FIG.

  When receiving the calibration start operation from the operation unit 80 (S1), the control unit 60 causes the digital camera 40 to transmit the first image data 41D and the second image data 42D (S2).

  The controller 60 compares the density values of the first image data 41D and the second image data 42D for each color component of Y (yellow), M (magenta), and C (cyan). The controller 60 calculates the first correction value 43A based on the difference between the density value of the first image data 41D and the density value of the second image data 42D (S3). The first correction value 43A may be obtained by comparing the average values of the density values of the first image data 41D and the second image data 42D. Further, the density values at the same corresponding positions of the first image data 41D and the second image data 42D may be obtained by comparison. Thereby, it is possible to obtain a correction value from which the influence of ambient light is removed.

  The controller 60 determines whether or not the first correction value 43A is within a preset allowable range (S4). Here, the allowable range is set in advance in a range in which calibration can be performed with high accuracy according to the specifications of the printer 70.

  When the first correction value 43A is within the allowable range, the control unit 60 adds the first correction value 43A to the second image data 42D and creates the third image data 44D (S5).

  Further, the control unit 60 obtains the second correction value 43B based on the difference between the average value of the density values of the third image data 44D and the average value of the density values of the image data 20D (S6). Thereby, correction data for correcting so as to coincide with the density value of the image data 20D can be obtained.

  The control unit 60 calibrates the print density of the print unit 30 based on the first correction value 43A and the second correction value 43B (S7).

  As a result, the print density calibration can be performed by removing the influence of the ambient light.

  When the first correction value 43A is not within the preset allowable range in step S5, the control unit 60 displays an error on the display panel 82 (S8). Thereby, it is possible to notify the operator that the sheets 41 and 42 need to be imaged again to perform calibration again.

  In the first embodiment, the control unit 60 performs the calibration using the first correction value 43A and the second correction value 43B. However, only the first correction value 43A is used for the print density. It is good to perform the calibration. In the print density calibration according to the second embodiment in this case, as shown in FIG. 3, when the calculated first correction value 43A is within the allowable range, the control unit 60 is based on the first correction value 43A. Calibration is executed (S15). The processes of steps S11 to S13 are the same as the processes of steps 1 to 3, and the processes of steps S14 and S16 are the same processes as steps S4 and S8.

  As a result, the print density can be calibrated as in the first embodiment. However, since the deviation of the density value between the image data 20D and the first image data 41D cannot be corrected, it is better to perform the calibration using the second correction value 43B as in the first embodiment. preferable.

  In the first embodiment, the calibration system 1 is described with an example including the digital camera 40 and the printer 70, but the present invention is not limited to this. The calibration system may further include a personal computer, and image data captured by the digital camera 40 may be transmitted to the printer 70 via the personal computer 90.

  In the first embodiment, the control unit 60 of the printer 70 has been described with an example in which the first correction value 43A and the second correction value 43B are calculated and the print density of the printing unit 30 is calibrated. However, the present invention is not limited to this. For example, the personal computer (information processing terminal) 90 may generate calibration data based on the first correction value 43 </ b> A and the second correction value 43 </ b> B and transmit the calibration data to the printer 70. In the calibration system 2 according to the third embodiment in this case, portions different in configuration from the calibration system 1 according to the first embodiment will be described with reference to FIG.

  The personal computer 90 includes a storage unit 91, a communication unit (first communication unit) 92, a correction data generation unit 93, a reading unit 94, and an operation unit 95. The storage unit 91 stores image data 20D. The communication unit 92 receives image data from the digital camera 40 via a communication cable that is detachably provided (not shown). Thereby, the image data of the first test chart 42T and the second test chart 41T can be read.

  The correction data generation unit 93 calculates the first correction value 43A and the second correction value 43B in the same manner as the control unit 60 in the first embodiment, and based on the calculated first correction value 43A and second correction value 43B. To create calibration data. Here, the calibration data is data for calibrating the print density of the printing unit 30.

  Note that when it is not necessary to consider the shift in the print density between the first image data 41D and the image data 20D, the calibration data may be generated based only on the first correction value 43A.

  The communication unit (second communication unit) 10 of the printer 70 receives calibration data from the personal computer 90 via the communication cable 50.

  The control unit 60 calibrates the print density of the print unit 30 based on the calibration data.

  Here, the print density calibration method will be specifically described as follows.

  First, the operator operates the operation unit 95 including a mouse and a keyboard connected to the personal computer 90 to cause the printing unit 30 to print the image data 20D on the paper 42.

  Next, the operator uses the digital camera 40 to photograph the second test chart 41T and the first test chart 42T in this order. The second test chart 41T and the first test chart 42T taken by the digital camera 40 are stored in a storage memory 40M that is detachably attached to the digital camera 40.

  Then, the operator extracts the storage memory 40M from the digital camera 40 and inserts it into the reading unit 94 of the personal computer 90.

  Here, a method for generating calibration data using the second test chart 41T and the first test chart 42T stored in the storage memory 40M and calibration of the printing unit 30 using the calibration data are shown in FIGS. Will be described.

  FIG. 5 is a flowchart for explaining processing for creating calibration data in the personal computer 90.

  When the personal computer 90 receives an operation for starting creation of calibration data from the operation unit 95 (S21), the personal computer 90 reads the first image data 41D and the second image data 42D from the storage memory 40M (S22).

  The personal computer 90 compares the density values of the first image data 41D and the second image data 42D for each color component of Y (yellow), M (magenta), and C (cyan). The personal computer 90 calculates the first correction value 43A based on the difference between the density values of the first image data 41D and the second image data 42D (S23). Thereby, it is possible to obtain a correction value from which the influence of ambient light is removed.

  The personal computer 90 determines whether or not the first correction value 43A is within a preset allowable range (S24). Here, the allowable range is set in advance in a range in which calibration can be performed with high accuracy according to the specifications of the printer 70.

  If the first correction value 43A is within the allowable range, the personal computer 90 adds the first correction value 43A to the second image data 42D to create the third image data 44D (S25).

  Further, the personal computer 90 obtains the second correction value 43B based on the difference between the average value of the density values of the third image data 44D and the average value of the density values of the image data 20D (S26). Thereby, correction data for correcting so as to coincide with the density value of the image data 20D can be obtained.

  If the first correction value 43A is not within the preset allowable range in step S24, the personal computer 90 displays an error on the monitor 96 of the personal computer 90 (S29). Thereby, it is possible to notify the operator that it is necessary to re-shoot the sheets 41 and 42 and re-create the calibration data.

  The personal computer 90 creates calibration data based on the first correction value 43A and the second correction value 43B and transmits it to the printer 70 (S27, S28). As a result, print density calibration data can be created by removing the influence of ambient light.

  As shown in FIG. 6, the printing unit 30 executes print density calibration based on the calibration data transmitted from the personal computer 90 (S31, S32).

  Thus, the same effect as that of the calibration system 1 can be obtained also by the calibration method of the calibration system 2.

  In the above embodiment, an example is described in which the first image data 41D and the second image data 42D are discriminated by photographing the paper 41 and the paper 42 in order with the digital camera 40 and transferring them to the printer 70. For example, identification marks may be provided on the second test chart 41T and the first test chart 42T, respectively. In this case, the control unit 60 accesses the storage memory of the digital camera 40 via the communication cable 50 and discriminates and reads out the respective test charts from a large number of image data, thereby causing the first image data 41D and the second image data to be read out. The calibration according to the embodiment can be executed by discriminating the image data 42D.

  In addition, it should be thought that description of the above-mentioned embodiment is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

1 Calibration System 10 Communication Unit (Communication Means)
20 storage unit 20D image data (data of the first test chart)
30 Print section 40 Digital camera (external photography device)
41 Paper (sheet body)
41T Second Test Chart 42 Paper 42T First Test Chart 60 Control Unit 70 Printer

Claims (7)

An external photographing device for photographing an image;
A print unit for performing print processing on paper, a storage unit in which data of a first test chart used for calibration of print density of the print unit is stored in advance, and a communication unit for communicating with an external photographing device; A printer having a control unit for calculating a first correction value based on data received by the communication unit and calibrating a print density;
A sheet body in which a second test chart of the same image as the first test chart having a density serving as a reference for calibration is formed in advance;
With
The control unit calculates the first correction value based on a difference between density values of image data of the first test chart printed on the paper by the printing unit and the second test chart formed on the sheet member. Execute calibration of the print density,
Calibration system. The control unit further includes a second correction value corresponding to a difference in density value between the first test chart stored in advance in the storage unit and the second test chart photographed by the external photographing apparatus. Calculating and calibrating the print density based on the first correction value and the second correction value;
The calibration system according to claim 2. An external photographing device for photographing an image;
Based on the storage unit in which the data of the first test chart used for the calibration of the print density is stored in advance, the first communication unit for communicating with the external photographing apparatus, and the data received by the first communication unit. An information processing terminal having a correction data generation unit that calculates correction values and generates calibration data for performing calibration of the print density;
A second communication unit for receiving the calibration data generated by the information processing terminal; and a control unit that executes calibration based on the print density calibration data received by the second communication unit; A printer having
A sheet body in which a second test chart of the same image as the first test chart having a density serving as a reference for calibration is formed in advance;
With
The correction data generation unit calculates the first correction value based on a difference between image data density values of the first test chart printed on the paper by the printing unit and the second test chart formed on the sheet member. Calculate to generate the calibration data,
The control unit executes calibration of the print density based on the calibration data generated by the first correction data generation unit.
Calibration system. The correction data generation unit includes a second correction value corresponding to a difference in density value between the first test chart stored in advance in the storage unit and the second test chart photographed by the external photographing apparatus. Is calculated, and the print density calibration is performed based on the first correction value and the second correction value.
The calibration system according to claim 3. A calibration method for calibrating print density using an external photographing device for photographing an image,
A first step of printing on a sheet a first test chart used for calibration of print density stored in advance in the printer;
Photographing the first test chart and the second test chart, which is the same image as the first test chart and is formed in advance on the sheet body with a density serving as a reference for the calibration, with the external photographing device A second step of:
A third step of transmitting image data of the first test chart and the second test chart from the external photographing device to the printer;
A fourth step of calculating a correction value based on the difference between the density values of the image data of the first test chart and the second test chart; and the print density based on the correction value calculated in the fourth step. A fifth step of performing calibration;
Calibration method with A calibration method for calibrating print density using an external photographing device for photographing an image,
A first step of printing a first test chart stored in advance in the information processing terminal on paper;
The first test chart printed on the paper and the second test chart that is the same image as the first test chart and is formed in advance on the sheet body with a density that serves as a reference for the calibration are externally provided. A second step of photographing with a photographing device;
A third step of transmitting image data of the first test chart and the second test chart to the information processing terminal;
A fourth step of calculating a correction value based on a difference between density values of image data of the first test chart and the second test chart;
A fifth step of generating calibration data for calibrating the print density based on the correction value calculated in the fourth step;
A sixth step of transmitting the calibration data to the printer;
A seventh step of calibrating the print density based on the calibration data;
Calibration method with In the fourth step, the correction value is calculated by further calculating a difference in density value between the first test chart stored in advance and the second test chart photographed by the external photographing device;
The calibration method according to claim 5 or 6.

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