JP2006268213A - Image processing method, image processing device, and server device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce effects of instrumental error and environmental variation in an image processing device having a gradation correcting function. <P>SOLUTION: Various data relevant to environmental variation are acquired by carrying out environmental tests, and correction calculation data for correcting a gradation correction parameter per environmental condition is specified (S41). In actual use, to carry out correction calculation relevant to environmental variation factors, correction calculation data conforming to a present environmental condition is read from a correction calculation data table (S42), and a data correction amount is calculated for conforming to the present environmental condition (S44). By using the determined data correction amount, correction calculation of a reference gradation correction parameter is carried out to conform to the present environmental condition (S46). Gradation correction processing is carried out with respect to image data by using the corrected reference gradation correction parameter in regard to an environmental factor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing method, an image processing apparatus, and a server apparatus. More specifically, the present invention relates to a mechanism for correcting gradation characteristics of an output image, which is preferably used for an image processing function of an image forming apparatus such as a copying machine, a printer, a FAX, or a multifunction machine having these functions in combination. .

  In an image forming apparatus that forms an image on a predetermined recording medium such as a color copying machine, the density gradation of the recorded image on the recording medium that is output based on the image data representing the processing target image having gradation In order to ensure consistency with the image data, a mechanism for performing gradation conversion of image data is employed (see, for example, Patent Documents 1 to 3).

Japanese Patent No. 3441994 Japanese Patent No. 3325765 Japanese Patent No. 3518913

  For example, Patent Document 1 proposes a mechanism for adjusting the correction amount of the density characteristic correction unit. Specifically, a gradation pattern for inspection is output, the density characteristic of the device is detected using a reading device or a density detection sensor on the image carrier, and the deviation amount from the target density and the stored density characteristic are obtained. Based on the used density characteristic correction amount calculation result, a correction table is generated so as to coincide with the reference density value. Then, the gradation of the image output apparatus is held in the best state by processing the correction table into the input image.

  Patent Document 2 proposes a mechanism for correcting a gradation correction curve. Specifically, the initial gradation correction curve data is processed and output using test image data (gradation pattern), and is based on the data read by the optical reading means, the initial gradation correction data, and the reference output curve data. Thus, the gradation correction curve data is calculated, and the gradation correction curve data is set in the image output apparatus and the correction curve data is processed, thereby maintaining the gradation of the image output apparatus in the best state.

  Further, Patent Document 3 has a correction gradation curve B for correcting the reference gradation conversion curve A and the reference gradation correction curve A, and the correction gradation curve B is corrected to a desired data gradation for correction. Thus, a mechanism for maintaining the gradation of the image output apparatus in the best state has been proposed.

  However, the mechanisms described in Patent Documents 1 to 3 still have difficulties in terms of machine differences, environmental fluctuations, and errors.

  For example, the gradation correction parameters that are designed exclusively for each model are fixedly applied, and environmental fluctuations and deterioration due to temperature, humidity, etc., and machine differences are not considered.

  Further, for example, an automatic density detection control function in which an exclusive gradation correction sensor for detecting the density on the image carrier is provided inside the output device and a correction operation by the user such as calibration is required. Since the correction work by the work is performed, the adjustment work is complicated, and it takes a long time for the adjustment, and image quality deterioration due to an operation error may occur due to individual differences among the adjustment workers.

  In addition, even if there is an automatic tone correction function, the reference tone correction curve is fitted to the base tone correction curve (correction curve calculation), so it is a member that often occurs due to quantization errors, minor changes, etc. In dealing with changes and differences between consumables production lots, the larger the difference from the reference, the greater the quantization error and the higher the accuracy.

  Further, it is necessary to provide a gradation measurement sensor such as a dedicated density (gradation) detection sensor in the apparatus, which increases the apparatus cost.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a mechanism capable of solving at least one of the above-described problems.

  For example, an object is to provide a mechanism that can reduce the influence of machine differences in tone reproduction.

  Another object is to provide a mechanism that can reduce the influence of environmental fluctuations in gradation reproduction.

  Alternatively, it is an object to provide a mechanism capable of good tone reproduction without quantization error.

  In the first mechanism according to the present invention, the correction data generation unit measures the test image for measuring the gradation characteristic output on the predetermined recording medium by the output device without correcting the gradation characteristic. The tone correction parameters for correcting the tone characteristics of the output device are electronically generated by electronically analyzing the tone characteristics of the output device specified in (1).

  Further, in the second mechanism according to the present invention, the correction data generation unit sets the gradation correction parameter for correcting the gradation characteristic based on the predetermined gradation data specifying the gradation characteristic of the output device. It is generated electronically and stored in association with the environmental conditions of the output device in the generation process. In addition, the correction data generation unit electronically outputs a gradation correction parameter for correcting gradation characteristics based on the environmental condition of the output device during actual use and the environmental condition of the output device in the generation process of the gradation correction parameter. Generate automatically. This second mechanism can be combined with the first mechanism.

  In the first and second mechanisms, the output device outputs a test image for measuring the tone characteristics on a predetermined recording medium without correcting the tone characteristics, and the output test image is output to the output device. A gradation characteristic measurement processing unit may be provided that specifies the gradation characteristic of the output device by measuring with a measuring device provided outside.

  For example, in the first mechanism, the output device has a configuration in which a gradation detection sensor or the like is eliminated, and a gradation patch for obtaining gradation characteristics of the output device is used as a test image from the output device without correction. Output the gradation patch by reading the gradation patch by the own apparatus or another original reading apparatus (scanner), or by using a measuring apparatus connected to the client server. Based on the gradation data, a reference gradation correction parameter is automatically generated, and the gradation characteristic of the processing target image data is corrected using the gradation correction parameter, and then output processing is performed by the output device. To do.

  Further, in the second mechanism, when the reference gradation correction parameter is automatically generated in the first mechanism, the gradation correction parameter and its generation condition (month, day, region, etc.) are associated with each other and predetermined. Save it at the location. After this, in actual use, it is adapted to the actual use environment based on the generation conditions of the gradation correction parameters that are automatically generated and the environmental conditions such as temperature and humidity that affect gradation characteristics fluctuations. A gradation correction parameter is automatically generated, and the gradation characteristic of the processing target image data is corrected using the gradation correction parameter, and then output processing is performed by the output device.

  Note that multiple types of reference gradation correction parameters are stored in advance in accordance with environmental conditions such as temperature and humidity that affect fluctuations in gradation characteristics. By selecting the most suitable one, a mechanism that facilitates acquisition of gradation correction parameters suitable for the environment during actual use may be used. For example, the timer function (month / day) of the aircraft and the correction amount (correction calculation data) for correcting the standard gradation correction parameters based on temperature, humidity, etc. that affect fluctuations based on regional information for each regional zone It is good to hold in advance.

  In addition, in the first and second mechanisms, the generation conditions of the created gradation correction parameter serving as a reference, the timer function (month / day) of the aircraft, and the temperature that affects fluctuations based on regional information, The difference between the reference gradation correction amount due to humidity and the output conditions such as resolution and screen type is determined as the difference correction amount from the reference gradation correction parameter stored in advance, and the image is subjected to gradation correction processing. Also good. By setting the gradation correction amount according to the output condition, output processing can always be performed with optimum gradation characteristics even when the resolution and screen type are switched.

  The third mechanism according to the present invention is a system configuration that realizes the first and second mechanisms according to the present invention by using an external server device. In this case, various system forms can be taken depending on how far each functional unit provided in the image processing apparatus having the first or second mechanism is placed on the server apparatus side.

  As an example, the environmental condition of the output device in the process of electronically generating the gradation correction parameter and the environmental condition of the output device during actual use are notified to a predetermined server device.

  In this case, the external device side obtains a gradation correction parameter suitable for the generation process in the same manner as the correction data generation unit in the first mechanism. Further, on the external device side, in the same manner as the correction data generation unit in the second mechanism, based on the environmental conditions of the output device during actual use and the environmental conditions of the output device in the gradation correction parameter generation process, A tone correction parameter for correcting tone characteristics is generated electronically.

  The gradation correction unit receives the gradation correction parameter returned from the external device in response to the notification, and corrects the gradation characteristic of the processing target image using the received gradation correction parameter.

  The image processing mechanism according to the present invention can be realized by software using an electronic computer (computer), and a program for this and a recording medium storing the program can be extracted as an invention. . For example, it may be provided as a printer driver for the image forming apparatus. The program may be provided by being stored in a computer-readable storage medium, or may be provided by distribution via wired or wireless communication means.

  According to the first mechanism of the present invention, the gradation characteristic of the output device is specified by outputting the test image without correcting the gradation characteristic and measuring with a measuring device outside the output device. Since the characteristics unique to the aircraft can be reflected more accurately, the influence of machine differences can be eliminated.

  Further, since the gradation correction parameter is generated electronically by electronically analyzing the gradation characteristics of the output device, gradation correction can be performed without bothering the user. In other words, since most of the work for adjusting the output gradation of the output device can be automated, the output gradation adjustment work can be completed in a short period of time, and it is affected by the skill level of the operator. The output device can be reliably adjusted to an appropriate state.

  Even if the characteristics of the output device fluctuate due to changes in parts or between consumables production lots, the gradation characteristics of the output device can be specified by measurement, so that the influence of quantization errors can be reduced. become.

  According to the second mechanism of the present invention, the gradation correction parameter is stored in association with the environmental condition of the output device in the gradation correction parameter generation process, and the environmental condition of the output device during actual use is stored. Since the tone correction parameters are generated more electronically based on the environmental conditions of the output device in the process of generating the tone correction parameters, the output device is surely kept in an appropriate state without being affected by environmental fluctuations. Can be adjusted.

  Further, according to the third mechanism of the present invention, an external server device is used. Thus, for example, necessary information is notified to an external server device, and a gradation correction parameter is generated on the server device side. The image processing device side receives the gradation correction parameter generated on the server device, Tone correction can be performed. More flexible operation is possible than when all the processes in the first and second mechanisms are handled by the own apparatus. Moreover, the cost of the own apparatus can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overall configuration of image forming apparatus>
FIG. 1 is a mechanism diagram of a color copying apparatus which is an example of an image forming apparatus equipped with an embodiment of an image processing apparatus according to the present invention. The image processing apparatus according to the present invention may be provided as a single apparatus in addition to being used in an image forming apparatus.

  As shown in the figure, the color copying apparatus 1 controls an image acquisition unit (IIT; Image Input Terminal) 10 that reads an original image and converts it into an electrical signal, a hard disk (HD), etc. by controlling page rearrangement of the read original image. An internal controller unit 20 having an image processing (IPS) function for performing desired image processing on input image data or a control function for controlling the operation of the entire apparatus, And an image output terminal (IOT) 30 that converts an electrical signal into an optical signal and forms an image using xerography using an electrostatic latent image.

  Further, the color copying apparatus 1 includes a platen cover 116. Although not shown, near the platen cover 116 at the top of the housing is provided a user interface (UI) for performing user instructions such as selection of various functions and various reading / printing designations. Although not shown, a reversing mechanism for reversing the orientation of the output paper P with the image printed on the front surface can be provided for duplex printing.

  The internal controller unit 20 is provided on a substrate disposed at a boundary portion between the image acquisition unit 10 and the image output unit 30. An external output unit (ESS; Electronic Subsystem) for transferring the output image data to another apparatus may be provided.

  The image acquisition unit 10 includes a housing 112 and a platen glass (original placement table) 11 having a substantially A3 size and made of transparent glass provided on the housing 112.

  The image acquisition unit 10 also has a light source 12 that emits light toward a surface (back surface) opposite to the document placement surface of the platen glass 11 in the housing 112, and the light emitted from the light source 12 is platen glass. And a full-rate carriage (F / R-CRG) 134 that reflects toward the 11th side. As the light source 12, a fluorescent lamp whose longitudinal direction is the main scanning direction (the direction orthogonal to the paper surface in the figure) is used.

  The image acquisition unit 10 also includes a half rate carriage (H / R-CRG) 138 that deflects the reflected light deflected by the full rate carriage 134 in the housing 112. The full rate carriage 134 and the half rate carriage 138 are configured to reciprocate in the sub-scanning direction (in the direction of arrow X in FIG. 1) and in the opposite direction in conjunction with a stepping motor (not shown).

  Furthermore, the image acquisition unit 10 includes a lens 140 that converges the reflected light deflected by the half-rate carriage 138 in the housing 112, and a main light that is substantially orthogonal to the sub-scanning direction by receiving the reflected light converged by the lens 140. And a light receiving unit 13 that reads an image in the scanning direction (the depth direction in FIG. 1) and sequentially outputs an image signal corresponding to the density. The light receiving unit 13 is disposed on the substrate together with a drive circuit such as a CCD driver for driving a line sensor (not shown), a read signal processing unit 14 and the like.

  Although not shown, the image acquisition unit 10 also includes a wire, a drive pulley, and the like for moving the reading optical system, the light receiving unit 13, and the like under the platen glass 11 in the housing 112. The driving pulley is reciprocally rotated by the driving force of the driving motor, and the reading optical system and the like are moved at a predetermined speed below the platen glass 11 by winding the wire around the driving pulley by the rotational driving.

  In the above configuration, at the time of reading, the document G is manually placed on the platen glass 11 serving as a document placing table, and is fixed (stop-locked) at an arbitrary position on the platen glass 11. Using the position G as the leading edge reference, the reading optical system is moved and scanned at a constant speed in the direction of arrow X to expose the document and read the image.

  For example, in a state where the document G placed on the platen glass 11 is covered with the platen cover 116, the light from the light source 12 irradiates the document G placed on the platen glass 11, and the reflected light is the full rate carriage 134. The light is split into red, green, and blue colors via a reading optical system including a half-rate carriage 138 and a lens 140. Each color light enters a corresponding line sensor divided for each color light, and an input image is read at a predetermined resolution, thereby obtaining an analog captured image signal of each color component of red, green, and blue. It is done.

  The captured image signal obtained by this reading is converted into digital image data of each color component of red (R), green (G), and blue (B), and the digital image data of red, green, and blue is converted into the internal controller unit 20. Send to. At the time of reading, the reading optical system including the light source 12 is such that the light from the light source 12 irradiates the entire surface of the document and the light receiving unit 13 reads the entire surface of the input image via the reading optical system such as the lens 140. The system, the light receiving unit 13 and the like are relatively moved in the sub-scanning direction in FIG.

  The read original image is changed in optical path by the full-rate carriage 134 or the half-rate carriage 138 and reduced by the lens 140 to reach the light receiving unit 13. Then, after receiving processing by the read signal processing unit 14, it is sent to the internal controller unit 20.

  The internal controller unit 20 processes the image data received from the image acquisition unit 10 and actually forms image formation data such as an image format used when the image output unit 30 transfers the image to the output paper P (forms an image). Convert to

  In this case, for example, RGB color system image data is converted into YCrCb color system image data, and at least three (preferably four) from the YCrCb color system, for example, the CMY color system or the CMYK color system are used. Mapping to the system is performed and color-separated raster data is generated for print output.

  In such raster data conversion processing, under color removal (UCR) for reducing the CMY components of the color image or gray component replacement (GCR) for partially replacing the reduced CMY components with the K component is performed. Furthermore, in order to adjust the toner image of the output image created in response to the output data (CMYK or the like), color separation linearization or similar processing is performed.

  In this example, black (K), yellow (Y), magenta (M), and cyan (C) image formation data are obtained based on red, green, and blue image data R, G, and B.

  The internal controller unit 20 acquires image data from a client terminal via a communication network (not shown), performs predetermined image processing based on the image data, and then outputs a binarized signal for each print color. You may make it obtain (it is a structure of what is called a network printer).

  The image output unit 30 of the present embodiment has an image forming unit (transfer unit) 31 corresponding to the color material colors K, Y, M, and C (K, Y, M, and C are attached to each of them; the same applies to other members; In other words, the image forming unit 31 has a so-called tandem configuration in which the image forming units 31 are sequentially juxtaposed at a predetermined interval in the sheet conveyance direction.

  Each image forming unit 31 corresponding to the color material color considers, for example, the relationship between the dark attenuation and the characteristics of each toner, or the difference in the influence of the mixed color of the other color toner on the black toner. The arrangement order in the paper conveyance direction is determined, and the illustrated example is merely an example.

  A photosensitive drum 32 is disposed at the center of the image forming unit 31, and a primary charger 33, a developing unit 34, a transfer charger 35, and the like are disposed around the photosensitive drum 32. A writing scanning optical system (exposure device) including a semiconductor laser 38, a polygon mirror 39, and other mirrors for recording a latent image on the photosensitive drum 32 based on the formation data is provided.

  The image output unit 30 also includes a manual document cassette (hereinafter also referred to as a manual feed tray) 41 for conveying the output paper P to the image forming unit 31, a conveyance path 42 having a transfer belt 43, rollers, and the like, and paper feeding A tray 52 is provided. Although only one sheet feeding tray 52 is shown in the figure, a structure in which a plurality of stages are arranged can be used.

  Further, the image output unit 30 includes a leading end detector 44 in the vicinity of the transport path 42 of the output paper P transported from the document cassette 41 and the paper feed tray 52 to each image forming unit 31. The leading edge detector 44 optically detects the leading edge of the output paper P sent onto the transfer belt 43 through the registration roller 42a, for example, and obtains a leading edge detection signal. In synchronization with this leading edge detection signal, image forming data of each color of K, Y, M, and C is sequentially input to the image output unit 30 at regular intervals.

  In addition, the color copying apparatus 1 includes a functional element that acquires environmental information related to the operation of the apparatus. As an example, first, the color copying apparatus 1 includes an operating temperature detection unit 84 that detects the temperature in the apparatus. In the present embodiment, the operating temperature detection unit 84 includes a temperature sensor 85, and uses the temperature sensor 85 to detect the temperature at a desired position in the apparatus. As an example, a temperature sensor 85 may be disposed so as to detect the temperature in the vicinity of the photosensitive drum 32 and the fixing unit 45 of the image forming unit 31.

  As temperature sensor 85, it is preferable to use an electronic sensor composed of, for example, a platinum resistance thermometer, thermistor, thermocouple, or the like. Alternatively, a non-contact method such as a thermopile that measures infrared rays emitted from an object and measures the temperature of the object from the amount of the infrared rays may be used.

  Further, the color copying apparatus 1 includes an operating humidity detection unit 86 that detects humidity in the apparatus as another example of a functional element that acquires environmental information related to the operation of the apparatus. In the present embodiment, the operating humidity detection unit 86 includes a humidity sensor 87, and the humidity sensor 87 is used to detect the humidity at a desired position in the apparatus. As an example, a humidity sensor 87 may be disposed so as to detect the humidity near the paper in the vicinity of the paper feed tray 52. This is because the paper is greatly affected by humidity.

  As the humidity sensor, for example, various sensors such as an electronic sensor that mainly uses a change in electrical properties due to adsorption / desorption of moisture in the atmosphere can be used. For example, a wet and wet bulb type, a hair type, a quartz crystal type, a polymer type sensor, a metal oxide sensor or the like can be used. In particular, a polymer or a metal oxide is a small sensor having good compatibility with a circuit, and is preferable for application of this embodiment.

  Although not shown, the color copying apparatus 1 includes a consumable material detection unit that is a functional element that detects the type and state of the consumable material used by the apparatus. In the present embodiment, as an example of the consumable material detection unit, first, a reflected light detection light sensor or a transmitted light detection light sensor is provided, and the thickness of the printing paper (pyeong A paper information collection unit that detects paper information such as a paper type and a paper type. Further, as another example of the consumable material detection unit, a colorant remaining amount detection unit that detects the remaining amount of toner (colorant) is included in a colorant cartridge (not shown) disposed in the vicinity of the developing device 34. Is provided.

  In the foregoing, an example of a mechanism for monitoring the operating state of the apparatus has been described. However, what is shown here is only an example and is not limited to the above-described one. For example, a mechanism for monitoring the applied voltage supplied to the primary charger 33 may be provided in order to monitor the state of the image forming unit 31 (engine unit) centered on the photosensitive drum roll 32.

  In the image output unit 30 having such a configuration, first, the semiconductor laser 38K as a light source is driven by the black image formation data from the internal controller unit 20 to convert the black image formation data into an optical signal. The converted laser light is irradiated toward the polygon mirror 39.

  The laser beam further scans the photosensitive drum 32K charged by the primary charger 33K via the reflection mirrors 47K, 48K, and 49K, thereby forming an electrostatic latent image on the photosensitive drum 32K.

  This electrostatic latent image is converted into a toner image by the developing device 34K to which black toner is supplied. Further, while the output paper P on the transfer belt 43 passes through the photosensitive drum 32K, the output paper is output by the transfer charger 35K. The toner image is transferred onto P. After the transfer, excess toner is removed from the photosensitive drum 32K by the cleaner 36K.

  Similarly, the semiconductor lasers 38Y, 38M, and 38C are driven by the corresponding Y, M, and C color image formation data obtained from the internal controller unit 20 sequentially with respect to the black image formation data at regular intervals. As a result, the image forming data of each color is converted into an optical signal, and the converted laser light is irradiated toward the polygon mirror 39.

  The laser light further scans the photosensitive drums 32Y, 32M, and 32C charged by the primary chargers 33Y, 33M, and 33C via the reflection mirrors 47Y to 49Y, 47M to 49M, and 47C to 49C, thereby exposing the photosensitive drums. Electrostatic latent images are sequentially formed on the body drums 32Y, 32M, and 32C.

  Each electrostatic latent image is sequentially converted into a toner image by developing units 34Y, 34M, and 34C to which each color toner is supplied. Each toner image is a photosensitive drum 32Y, 32M, and 32C corresponding to the original on the transfer belt 43. Are sequentially transferred onto the output paper P by the corresponding transfer chargers 35Y, 35M, and 35C.

  The output paper P onto which the toner images of K, Y, M, and C are sequentially transferred in this manner is peeled off from the transfer belt 43, and the toner is fixed by the fixing unit 45. To be discharged.

  The image output unit 30 causes the transfer belt 43 to function as an intermediate transfer belt, and transfers (primary transfer) the toner image on the photosensitive drum 32 to the transfer belt 43 by a primary transfer device, and then secondary. A secondary transfer method in which the toner image on the transfer belt 43 is transferred (secondary transfer) to the printing paper at the transfer portion can be used. In such a configuration, image formation is performed on each photoconductor drum 32 with each color toner of YMCK, and this toner image is multiplex-transferred to the transfer belt 43, and then transferred to a predetermined printing paper, thereby forming a color image. To get.

  Further, the image output unit 30 sequentially forms an electrostatic latent image of each color of K, Y, M, and C on one photosensitive drum by one laser light scanner, and the electrostatic latent image is formed on the photosensitive drum. Are sequentially formed into toner images by a developing device provided with toners of respective colors K, Y, M, and C, and the toner images are sequentially transferred onto a document adsorbed on a transfer drum. It may be configured.

<Image quality correction function>
FIG. 2 is a functional block diagram of the color copying apparatus 1 paying attention to the image quality correction (particularly gradation correction) function in the internal controller unit 20.

  In the first configuration example shown in FIG. 2A, the gradation correction function unit 22 includes a gradation characteristic measurement processing unit 300 that acquires gradation characteristic information of the image forming unit 31 of the own apparatus, and gradation characteristics. The correction data generation unit 400 that generates correction data for correcting the gradation characteristics based on the gradation characteristic information acquired by the measurement processing unit 300, and the gradation based on the correction data generated by the correction data generation unit 400 And a tone correction unit 500 that corrects the characteristics.

  The gradation correction function unit 22 monitors the usage status of the color copying apparatus 1 and the component status information acquisition unit 412 that acquires component information indicating the operation status of the component as observation data information. A history information acquisition management unit 413 that manages history information by registering and storing the information in the storage medium.

  In addition, the gradation correction function unit 22 acquires, as environmental information, ambient environment conditions that affect the state of components such as temperature and humidity based on information detected by the operating temperature detection unit 84 and the operating humidity detection unit 86. Based on the information detected by the environmental information acquisition unit 414 and the consumable material detection unit, information on the consumable materials used by the apparatus, such as the thickness of the printing paper, the paper type, or the color type, type, and remaining amount of the colorant, is obtained. A consumable material information acquisition unit 415 to acquire, and a specification information acquisition unit 416 to acquire specification information (for example, information on the installation area) of the color copying apparatus 1 are provided.

  The gradation characteristic measurement processing unit 300 reads a reference pattern using a scanner (for example, the image acquisition unit 10 of its own device), and determines the lightness gradation data by performing data determination on the read reference pattern image within the own device. get. In this case, the image acquisition unit 10 constitutes a part of a measurement device outside the output device, and the gradation characteristic measurement processing unit 300 is in charge of the function of a data analysis unit that acquires lightness gradation data.

  Alternatively, brightness gradation data may be acquired using a measuring device such as a colorimeter. In this case, the color copying apparatus 1 does not need to be provided with a gradation measurement sensor such as the gradation characteristic measurement processing unit 300 or a dedicated density (gradation) detection sensor, and the apparatus cost can be reduced. It is also possible to adopt a configuration in which only measurement data is acquired using a measurement apparatus, and the measurement data is transmitted to the gradation characteristic measurement processing unit 300 of the color copying apparatus 1 to acquire brightness gradation data.

  The correction data generation unit 400 includes not only the gradation characteristic information acquired by the gradation characteristic measurement processing unit 300 but also information acquired by the component state information acquisition unit 412 and the environment information acquisition unit 414 as necessary. Based on this, correction data for correcting the gradation characteristics is generated.

  In the first configuration example shown in FIG. 2A, the correction data generation unit 400 provided in the apparatus itself is configured to obtain the reference gradation correction parameter electronically. It is also possible to leave the processing for electronically obtaining the tone correction parameter to an external measuring device (for example, a server device).

  For example, the second configuration example illustrated in FIG. 2B illustrates a configuration example at that time. In the second configuration example, the color copying apparatus 1 includes a communication control unit 420 that performs data communication with the server apparatus 8. On the other hand, on the server device 8 side, a gradation characteristic measurement processing unit 830 corresponding to the gradation characteristic measurement processing unit 300 included in the color copying apparatus 1 of the first configuration example shown in FIG. A correction data generation unit 840 corresponding to the unit 400 and a communication control unit 860 that performs data communication with the color copying apparatus 1.

  First, the communication control unit 420 sets gradation correction parameters for correcting gradation characteristics based on gradation data specifying the gradation characteristics of the output device (image output unit 30 in this example) to the external server device 8. The environmental conditions of the output device in the generation process (corresponding to the output of the original reference pattern image here) when electronically generating in the server are sent to the server apparatus 8 as an external measuring apparatus via the communication IF unit 999. Notice.

  In the server device 8, the communication control unit 860 receives the environmental condition of the output device, and the gradation characteristic measurement processing unit 830 and the correction data generation unit 840 generate the gradation characteristic measurement processing unit 300 and the correction data generation. Similar to the unit 400, a gradation correction parameter suitable for outputting the reference pattern image is obtained.

  The communication control unit 420 also transmits information (environment information, specification information, etc.) acquired by the component state information acquisition unit 412, the environment information acquisition unit 414, the specification information acquisition unit 416, and the like during actual use to the communication IF unit 999. The server device 8 is notified via In the server device 8, in the same manner as the correction data generation unit 400, the actual use time for correcting the gradation characteristics based on the information acquired by the component state information acquisition unit 412, the environment information acquisition unit 414, and the like. Correction data (gradation correction parameters) suitable for the above conditions is generated and transmitted to the color copying apparatus 1 via the communication control unit 860.

  In response to the information notification at the time of actual use via the communication IF unit 999, the communication control unit 420 transmits a gradation correction parameter that is returned from the server device 8 and that matches the conditions at the time of actual use via the communication IF unit 999. And receives the gradation correction parameters suitable for the received actual use conditions to the gradation correction unit 500. The tone correction unit 500 performs tone correction processing using a tone correction parameter suitable for the actual use condition.

  By adopting the configuration of the second example as described above, the image output unit 30 can perform output processing with gradation correction characteristics adapted to conditions during actual use. In addition, image quality fluctuations and deterioration due to the environment can be suppressed, and the color copying apparatus 1 can be made more compact.

  When the system configuration is realized by using the external server device 8, the system is not limited to the second configuration example shown in FIG. 2B but is provided in the color copying apparatus 1 shown in FIG. Various system forms can be taken depending on how much of each functional unit is placed on the server device 8 side. For example, as shown in FIG. 2A, the server device 8 may be configured to perform only the measurement of the data of the reference pattern image, or the gradation characteristic measurement without the correction data generation unit 840. A configuration including a processing unit 830 and a communication control unit 860 can also be employed.

<Regarding the configuration using an electronic computer>
In the present embodiment, the mechanism for performing image quality correction processing is not limited to being configured by a hardware processing circuit, but may be realized by software using an electronic computer (computer) based on a program code that realizes the function. It is.

  Therefore, an image processing method or an image processing method according to the present invention is extracted as an invention from a program suitable for realizing software using an electronic computer (computer) or a computer-readable storage medium storing the program. You can also. By adopting a mechanism that is executed by software, it is possible to enjoy the advantage that the processing procedure and the like can be easily changed without changing hardware.

  When an electronic computer executes a series of image quality correction functions by software, a computer (such as an embedded microcomputer) in which a program constituting the software is incorporated in dedicated hardware or a CPU (Central Processing Unit) System on a chip (SOC) that implements a desired system by mounting functions such as logic circuits and storage devices on a single chip, or various functions by installing various programs It is installed from a recording medium in a general-purpose personal computer that can be executed.

  The recording medium causes a change state of energy such as magnetism, light, electricity, etc. to the reading device provided in the hardware resource of the computer according to the description content of the program, and in the form of a signal corresponding thereto. The program description can be transmitted to the reader.

  For example, a magnetic disk (including a flexible disk FD), an optical disk (CD-ROM (Compact Disc-Read Only Memory)), a DVD on which a program is recorded, which is distributed to provide a program to a user separately from a computer. (Including Digital Versatile Disc), magneto-optical disc (including MD (Mini Disc)), or package media (portable storage media) made of semiconductor memory, etc. It may be configured by a ROM, a hard disk, or the like in which a program is recorded, which is provided to the user in a state of being recorded.

  The program constituting the software is not limited to being provided via the recording medium without using the recording medium, and may be provided via a wired or wireless communication network.

  For example, a storage medium storing software program codes for realizing an image quality correction function is supplied to a system or apparatus, and a computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the storage medium By doing so, the same effect as the case where the hardware processing circuit is used is achieved. In this case, the program code itself read from the storage medium realizes the function of image quality correction processing.

  In addition, the program code read by the computer is executed, so that not only a function for performing image quality correction processing is realized, but also an OS (Operating Systems; basic software) running on the computer based on an instruction of the program code May perform a part or all of the actual processing, and the function of performing the image quality correction processing by the processing may be realized.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. There may be a case where the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing, and the function of performing the image quality correction processing by the processing is realized.

  Note that the program is provided as a file describing a program code for realizing the function of performing image quality correction processing. In this case, the program is not limited to being provided as a batch program file, and the hardware of the system configured by the computer Depending on the configuration, it may be provided as an individual program module.

  For example, FIG. 3 shows a color copying apparatus 1 having a function of performing image quality correction processing in software using a CPU and memory, that is, image quality correction processing using the function of a computer (electronic computer) such as a personal computer. It is a block diagram which shows an example of the hardware configuration in the case of implement | achieving in software.

  Of course, the configuration is not limited to such a computer, and an image processing apparatus that performs correction processing by a combination of dedicated hardware that performs processing of each functional unit shown in FIG. 2 can also be configured. By adopting a mechanism for executing processing by software, it is possible to enjoy the advantage that the processing procedure and the like can be easily changed without changing hardware.

  In the case where the image quality correction function is incorporated in the color copying apparatus 1 having a copying function, the electronic computer shown in FIG. 3 includes, for example, processing for a copying application, a printer application, a facsimile (FAX) application, or other applications. Software similar to that in a conventional image forming apparatus (multifunction machine) such as a program is incorporated. A control program for transmitting and receiving data to and from the outside via a network is also incorporated.

  At this time, the program is provided as a file describing a program code for realizing the image quality correction processing function. In this case, the program is not limited to being provided as a batch program file, and the hardware configuration of a system configured by a computer Depending on the case, it may be provided as an individual program module. For example, it may be provided as add-in software incorporated in existing copying apparatus control software or printer control software (printer driver).

  For example, the computer system 900 reads and records data from a controller unit 901 and a predetermined storage medium such as a hard disk device, a flexible disk (FD) drive, a CD-ROM (Compact Disk ROM) drive, a semiconductor memory controller, or the like. And a recording / reading control unit 902.

  The controller unit 901 includes a CPU (Central Processing Unit) 912, a ROM (Read Only Memory) 913 which is a read-only storage unit, and a RAM (Random Access) which can be written and read at any time and is an example of a volatile storage unit. Memory) 915 and RAM (described as NVRAM) 916 which is an example of a nonvolatile storage unit. The NVRAM 916 stores, for example, gradation correction data and specification information.

  In the above description, the “volatile storage unit” means a storage unit in which the stored contents are lost when the power of the color copying apparatus 1 is turned off. On the other hand, the “non-volatile storage unit” means a storage unit that maintains the stored contents even when the main power supply of the color copying apparatus 1 is turned off. Any memory device can be used as long as it can retain the stored contents. The semiconductor memory device itself is not limited to a nonvolatile memory device, and a backup power supply is provided to make a volatile memory device “nonvolatile”. You may comprise as follows. Further, the present invention is not limited to a semiconductor memory element, and may be configured using a medium such as a magnetic disk or an optical disk. For example, a hard disk device can be used as a nonvolatile storage unit.

  In addition, the computer system 900 includes an instruction input unit 903 as a functional unit that forms a customer interface, a display output unit 904 that presents a customer with predetermined information such as a guidance screen and a processing result at the time of operation, and each functional unit And an interface unit (IF unit) 909 that performs an interface function between them.

  An image reading unit (scanner unit) 905 that reads an image to be processed (corresponding to the image acquisition unit 10 in FIG. 1) and an image forming unit 906 that outputs the processed image to a predetermined output medium (for example, printing paper). (Corresponding to the image output unit 30 in FIG. 1) is also provided.

  As the instruction input unit 903, for example, the operation key unit 15b of the user interface unit 15 shown in FIG. 1 can be used. Alternatively, a keyboard or mouse can be used.

  The display output unit 904 includes a display control unit 942 and a display device. As the display device, for example, the operation panel unit 15a of the user interface unit 15 shown in FIG. 1 can be used. Alternatively, other display units such as CRT (Cathode Ray Tube) or LCD (Liquid Crystal Display) can be used.

  For example, the display control unit 942 displays guidance information, the entire image captured by the image reading unit 905, and the like on the operation panel unit 15a and the display unit. It is also used as a display device for notifying the user of various information. Note that an instruction input unit 903 for inputting predetermined information with a fingertip, a pen, or the like can be configured by using a display unit having a touch panel on the display surface.

  Examples of the interface unit 909 include a system bus 991 that is a transfer path of processing data (including image data) and control data, a scanner IF unit 995 that functions as an interface with the image reading unit 905, an image forming unit 906, and the like. It has a printer IF unit 996 that functions as an interface with other printers, and a communication IF unit 999 that mediates transfer of communication data with a network such as the Internet.

  In such a configuration, the CPU 912 controls the entire system via the system bus 991. The ROM 913 stores a control program for the CPU 912 and the like. The RAM 915 is configured by SRAM (Static Random Access Memory) or the like, and stores program control variables, data for various processes, and the like. Further, the RAM 915 stores an electronic document (not only character data but also image data) acquired by a predetermined application program, image data acquired by the image reading unit 905 provided in the apparatus, and externally. An area for temporarily storing acquired electronic data and the like is included.

  For example, a program that causes a computer to execute an image quality correction processing function is distributed through a recording medium such as a CD-ROM. Alternatively, this program may be stored in the FD instead of the CD-ROM. In addition, an MO drive may be provided to store the program in the MO, or the program may be stored in another recording medium such as a nonvolatile semiconductor memory card such as a flash memory. Furthermore, the program may be downloaded from another server or the like via a network such as the Internet, or may be updated or updated.

  As a recording medium for providing the program, in addition to FD and CD-ROM, an optical recording medium such as DVD, a magnetic recording medium such as MD, a magneto-optical recording medium such as PD, a tape medium, and a magnetic medium. A semiconductor memory such as a recording medium, an IC card, or a miniature card can be used. A part or all of the functions for realizing the image quality correction processing function can be stored in an FD or CD-ROM as an example of a recording medium.

  The hard disk device also includes an area for storing data for various processes by the control program and temporarily storing a large amount of image data acquired by the image reading unit 905, print data acquired from the outside, and the like. It is out. The hard disk device, FD drive, or CD-ROM drive is used, for example, for registering program data for causing the CPU 912 to execute processing such as content acquisition, address acquisition, or address setting by software. .

  Instead of performing all processing of each functional part for image quality correction processing by software, a processing circuit 908 that performs part of these functional parts by dedicated hardware may be provided. Although the mechanism performed by software can flexibly cope with parallel processing and continuous processing, the processing time becomes longer as the processing becomes complicated, so that a reduction in processing speed becomes a problem. On the other hand, it is possible to construct an accelerator system with a higher speed by using a hardware processing circuit. Even if the processing is complicated, the accelerator system can prevent a reduction in processing speed and can obtain a high throughput.

  For example, in the case of the present embodiment in which the image quality correction function is applied to the color copying apparatus 1, the processing circuit 908 obtains reference pattern data corresponding to the gradation characteristic measurement processing unit 300 shown in FIG. This corresponds to the unit 908a, the component state information acquisition unit 412, the environmental information acquisition unit 414 that acquires the environmental temperature and the environmental humidity, and the consumable material information acquisition unit 415 that acquires the information of consumables such as paper and color materials. The functional unit 908b that performs sensor data acquisition (observation data & environment data) may be configured by hardware. The functional unit 908c corresponding to the gradation characteristic measurement processing unit 300 and the functional unit 908d corresponding to the correction data generation unit 400 may be configured by hardware.

<Reference pattern>
FIG. 4 is a diagram illustrating an example of a reference pattern for inspection used in the present embodiment. As shown in the drawing, for each of the colorant colors used in the image output unit 30 (four colors Y, M, C, and K in this example), a predetermined gradation pitch within a range of high gradation to low gradation. A plurality of gradation test patches whose brightness and density change stepwise are outputted. Then, by measuring the reference pattern image output from the color copying apparatus 1, the gradation level of the color copying apparatus 1 (specifically, the image forming units 31 for Y, M, C, and K) is inspected. Data for gradations that are not actually output may be dealt with by obtaining interpolation data using the output gradation patches.

<Processing Procedure; First Embodiment>
FIG. 5 is a flowchart illustrating an example of an outline of a processing procedure according to the first embodiment for generating gradation correction parameters. In this example, a reference gradation correction parameter that is optimal for each apparatus is created by an automatic creation tool at the time of manufacturing, and stored and set, so that problems caused by detecting an inspection pattern before fixing, It is characterized by improving the problem. In particular, the first embodiment is characterized in that it has a mechanism capable of performing appropriate gradation correction without being affected by the difference in machine body.

  Specifically, first, the gradation characteristic measurement processing unit 300 causes the image output unit 30 to output a reference pattern made up of a set of gradation patches shown in FIG. 4 after shipment adjustment at the time of manufacture (S10). At this time, in order to acquire the characteristics of the image output unit 30, the gradation patch is output without correction.

  Then, for example, the brightness gradation data of the reference pattern is measured using a measuring device such as a spot luminance meter, and the measured data is captured (S12). Alternatively, by using the image acquisition unit 10 as a document reading apparatus, the reference pattern is read, and the gradation pattern data is acquired by performing data determination on the read reference pattern image within the apparatus (S12).

  Alternatively, the data may be acquired by a colorimeter connected to a client PC (PC: Personal Computer) that forms the main part of the server apparatus (S12). In this case, in order to maintain confidentiality, it is preferable that the color copying apparatus 1 be configured to be connectable to an external network line on which security measures have been taken, and to transmit / receive data by encrypting data.

  The gradation characteristic measurement processing unit 300 performs data communication with the server device (client PC), notifies the generation conditions and use conditions of the reference gradation correction parameter to the server, and the correction processing data of the best reference gradation correction parameter. Is obtained from the server.

  The lightness gradation data is obtained by measuring the lightness data of all the patch portions existing in the reference pattern shown in FIG. 4 and determining the data (S14). At this time, the gradation characteristic measurement processing unit 300 determines whether there is no abnormality in the acquired gradation data. As the determination processing here, as in the order of arrangement of the gradation test patches shown in FIG. 4, the brightness and density indicated by the acquired gradation data gradually increase or decrease. The method of checking by the magnitude of the numerical value is taken. For example, in the case of measurement data search → size comparison with previous data → inversion, it is determined as NG, and if not, it is determined as OK. In the case of NG, the gradation data is acquired again (S14-No).

  When the brightness gradation data is acquired based on all the gradation patch portions by measurement using the measurement device or measurement using the image acquisition unit 10 and the determination is finished (S14-Yes), the gradation characteristic measurement processing unit 300 is completed. Passes the acquired lightness gradation data to the correction data generation unit 400.

  The correction data generation unit 400 analyzes the lightness gradation data passed from the gradation characteristic measurement processing unit 300 to obtain a gradation correction curve that achieves the target gradation purely (automatically). (S20). Specifically, a reference gradation correction parameter representing this gradation correction curve is automatically generated (see FIG. 6 described later for details).

  The correction data generation unit 400 stores a reference gradation correction parameter representing a gradation correction curve in a predetermined storage medium in the own apparatus together with generation conditions such as a date and a region when the data is acquired. Information relating to the date may be obtained automatically by providing a timer function in the device itself. Information about the area may be acquired from the specification information acquisition unit 416. When data is acquired by a colorimeter connected to the client PC, the reference tone correction parameter is downloaded from the client PC and stored.

  Next, the correction data generation unit 400 determines whether the generated correction data (corrected gradation data; correction parameter in this example) is data that deviates from a predetermined range (S30). Even in step S14, the determination process is performed at the measurement data stage, but the determination process is also performed at the generation stage of the correction data so that double safety measures are taken. The determination process (S30) is referred to as generated data determination process 1 in the figure.

  When the correction data has deviated (S30-Yes), the correction data generation unit 400 corrects the deviated data portion (NG portion) by data processing if it is a small deviation (S40). Then, NG redetermination is performed only for the NG region (S50). In the figure, this NG redetermination process is referred to as a generation data determination process 2.

  On the other hand, when the data has deviated (S30-No), if the NG portion cannot be corrected by the data processing without a slight deviation, the process starts again from the output of the reference pattern (S50-No).

  That is, in the generation data determination process 1, when all gradation data are determined, an NG flag is bit-set in the NG portion at the determination stage, an NG correction area is obtained, and correction processing (filter smoothing or the like) is performed on the area. At the same time, only the NG area is judged again as NG (generated data judgment processing 2).

  In this example, all the data is determined and searched once, so that the NG area is extracted and the OK area is corrected and there is no waste of re-determination, the generated data is determined in two places (S30 and S50). There is a processing procedure that exists. However, since the difference in processing time is very small, the same processing may be performed or the processing may be returned to the generation data determination processing 1 after correcting the NG part.

  When the correction data does not deviate from the predetermined range (S30-Yes), or when the data deviates (S30-No), the correction data generation unit 400 converts the NG portion with a slight deviation. When the correction can be performed by the processing (S50-Yes), the corrected gradation data is stored in a predetermined nonvolatile storage medium (for example, a hard disk device) (S60). That is, the determined gradation data after correction (correction parameter in this example) is held as a final determined value in a so-called non-volatile data holding area so that no data is lost.

  Thereafter, in the output process in the image output unit 30, the gradation correction unit 500, which is an example of the image processing function unit of the internal controller unit 20, uses the obtained reference gradation correction parameter to process the image data. Tone correction processing is performed. This makes it possible to suppress image quality fluctuations and deterioration caused by machine differences.

  In the above processing procedure, the correction data generation unit 400 provided in the own apparatus electronically obtains the reference tone correction parameter. However, the processing for obtaining the reference tone correction parameter electronically is performed externally. It can also be left to a measuring device (for example, a server device). In this case, the color copying apparatus 1 electronically sets a gradation correction parameter for correcting the gradation characteristic based on predetermined gradation data specifying the gradation characteristic of the output device (in this example, the image output unit 30). The environmental conditions of the output device during the generation process and the environmental conditions of the output device during actual use are notified to an external measurement device via the communication IF unit 999.

  Then, the gradation correction unit 500 receives the gradation correction parameter returned from the measurement apparatus in response to the notification via the communication IF unit 999, and uses the received gradation correction parameter to perform gradation correction. Processing may be performed to cause the image output unit 30 to perform output processing.

  FIG. 6 is a flowchart showing a detailed example of the processing for obtaining the gradation correction curve in step S20 shown in FIG. The correction data generation unit 400 obtains a reference gradation correction parameter representing a gradation correction curve by performing arithmetic processing based on a predetermined procedure.

  Specifically, first, target data and measurement data acquired by the gradation characteristic measurement processing unit 300 are prepared (S21), and the target data and measurement data are compared (S22). Specifically, the difference between the two is calculated. Since the reference pattern is output at a predetermined gradation pitch as described above, the measurement data itself cannot indicate all the gradations. Therefore, for the insufficient gradation, difference data for all gradations is obtained arithmetically by data interpolation processing using the output gradation patches (S24).

  Thereafter, the reference tone correction parameter is obtained by correcting the reference parameter based on the difference data of each tone (S26). For example, an automatic reproduction level such as a highlight portion is corrected. Since this correction process itself is a known one, its detailed description is omitted here.

  The correction data generation unit 400 temporarily stores the obtained reference gradation correction parameter in a predetermined volatile memory as a setting storage unit that stores data being calculated (S28). This means that the data being calculated is stored internally in a so-called work memo.

  FIG. 7 is a flowchart showing a detailed example of steps S30 to S50 shown in FIG. The correction data generation unit 400 determines whether or not the generated correction data is abnormal in the generation data determination process 1 (S30), performs determination on all gradation data, and determines NG at the determination stage. The NG flag is bit-set to determine the NG correction area.

  For example, the data Max value and Min value of each point of the generated gradation correction curve based on the characteristic variation data of the image output unit 30 as an output device are stored as gradation patch data × 2 (Max, Min). deep.

  Then, it is determined whether or not the point data n to be processed (point number is x) of all the characteristic variation data is within the range of the Min value to the Max value, that is, the data range appropriateness determination process. Perform (S32). If it is not within the range (NG), an NG flag is set (S32-No). Thereafter, if it is within the range (OK), it is determined whether or not the point number x is equal to or less than the number of gradations (256 in this example). If the point number x is equal to or less than the number of gradations, the process returns to step S32 to repeat the same processing with the next point number x (S36-Yes). The process proceeds to the next process (NG part correction process S40, etc.) (S36-No).

  When the process proceeds to the NG part correction process S40 (S36-No), the correction data generation part 400 is a slight deviation from the NG correction area indicating the NG part at the determination stage in the generation data determination process 1. The deviated data portion (NG portion) is corrected by data processing using filter smoothing or the like, and at the same time, NG redetermination (generated data determination processing 2; S50) is performed only for the NG region.

  For example, if there is a slight deviation, the NG portion may be corrected by smoothing processing (smoothing), and it is repaired by data processing. As a method for the relief processing, for example, a filter or a region designation type regression equation can be used. The filter method is simple in processing. For example, it is preferable to perform smoothing by sequentially applying 1 × 9 filter coefficients to 256 gradation data centered on the target pixel. For example, [1], [2], [4], [7], [8], [7], [4], [2], [1] may be used as the filter coefficients.

  For example, first, it is determined whether or not the NG flag is set in the processing target data (S42). When the NG flag is set in the process target data (S42-Yes), the smoothing process start position is calculated (S44).

  Thereafter, it is determined whether or not NG is within the range of OK to OK, that is, whether or not the area calculation is OK (S46). If the area calculation is OK (S46-Yes), the smoothing process is performed on the NG area (S48).

  Thereafter, according to step S32, it is determined whether or not the point data n to be processed (point number is x) is within the range of Min value to Max value, that is, NG data range re-determination processing is performed. (S52). If it is not within the range (NG), the process returns to step S10, the reference pattern is output again, and the whole process is performed again (S52-No).

  On the other hand, when the NG flag is not set in the processing target data (S42-No), the area calculation is not OK (S46-No), and the point data n is within the range of the Min value to the Max value (OK). In this case (S48-Yes), it is determined whether or not the point number x is equal to or less than the number of gradations (256 in this example). If the point number x is less than the number of gradations, the process returns to step S42 and repeats the same process (S54-Yes). If the point number x is not less than the number of gradations (S54-No), step S48 is performed. The determined gradation data including the corrected gradation data is stored in the nonvolatile storage unit (S60).

  Thereafter, the image output unit 30 performs a tone correction process using the obtained reference tone correction parameter, and then performs an output process. For example, based on the conditions for generating the reference gradation correction parameters to be created, the timer function (month / day) in the aircraft, and regional information, reference gradation correction based on temperature, humidity, etc., which affects gradation characteristics fluctuations From the output mode such as the amount, resolution, and screen type, correction processing is applied to the image based on the difference correction amount with the reference gradation correction parameter held in advance.

  Thereby, for example, by storing the generated information (date, region, etc.) at the time of data acquisition in the setting storage unit and using the reference tone correction parameter in image processing, a particularly advanced detection correction system There is no need for bothersome user operations and output processing can be performed with the best image quality in consideration of machine differences. It is possible to construct an image processing system that can perform output processing by performing appropriate gradation correction without being affected by the machine difference.

  The system can automatically design and automatically correct the gradation correction parameters of copiers and multifunction devices, eliminating the need for user operations and eliminating problems such as troublesome users and work errors. Can do.

  In addition, since the data is acquired by actually outputting the reference pattern, a dedicated detection sensor for reading the density on the image carrier is not necessary, and the data acquisition is performed after fixing on the output paper, so that the influence of machine differences is eliminated. This makes it possible to eliminate the gradation and to correct the gradation according to the actual situation.

  Without having a special device in the machine, it eliminates the design man-hours incorporated in the cost and more accurately reflects the characteristics unique to the machine, so the best gradation correction can be realized and the machine can be It is possible to provide good image quality at a low cost.

<Processing Procedure; Second Embodiment>
FIG. 8 is a flowchart illustrating an example of an outline of a processing procedure according to the second embodiment for generating gradation correction parameters. The second embodiment is characterized in that it has a mechanism capable of performing proper gradation correction without being affected by environmental fluctuations.

  At the product development stage, various data related to environmental changes can be collected and analyzed by conducting environmental tests. At this time, the gradation variation due to the usage environment is grasped, and information regarding the gradation variation due to the usage environment is held in a predetermined nonvolatile storage medium omitted from the illustration of the color copying apparatus 1 (S41). ).

  For example, the correction data generation unit 400 is used for difference calculation in which area information related to an area where the color copying apparatus 1 will be installed is associated with an amount of correction in relation to an operation day (month, season, etc.) in the area. Table data (hereinafter also referred to as “correction calculation data table”) is prepared in association with generation information representing the date and area at the time of data collection as information regarding gradation fluctuations depending on the use environment.

  Next, the correction data generation unit 400 corrects the reference gradation correction parameter obtained in the first embodiment with respect to environmental variation factors. Specifically, first, a correction calculation data table is searched (searched), and correction calculation data suitable for the current environmental conditions is read from the correction calculation data table (S42). Next, based on the read information, a data correction amount for adapting to the current environmental conditions is calculated (S44).

  Next, the correction data generation unit 400 uses the calculated data correction amount to perform the correction calculation so that the reference tone correction parameter obtained in the first embodiment is adapted to the current environmental conditions (S46). For example, automatic reproduction levels such as γ (gamma) and area correction are corrected. Then, the environment-corrected reference gradation correction parameter is stored in a predetermined nonvolatile storage medium (S48). Information regarding the current environmental conditions may be acquired from the environmental information acquisition unit 414.

  Thereafter, in the output process in the image output unit 30, the tone correction unit 500, which is an example of the image processing function unit of the internal controller unit 20, converts the image data into image data using the reference tone correction parameter corrected for environmental factors. Then, gradation correction processing is performed. This makes it possible to suppress image quality fluctuations and deterioration caused by environmental fluctuations.

  9 and 10 are diagrams illustrating a configuration example of the correction calculation data table. Here, the first example shown in FIG. 9 is an example of a number system of area information, time information, and correction data corresponding thereto. The second example shown in FIG. 10 is a diagram showing the relationship of the correction amount in relation to the correction mode, the fixed position, and the like.

  Regarding the regional division method of the table for calculating coefficient data for correction calculation, when data is retained inside the aircraft, for example, using a rough climate classification such as Köppen climate classification, `` tropical climate '', `` dry climate '', `` It is preferable to classify and hold according to the average climate information of each month, such as “temperate climate”, “subarctic climate”, and “cold climate”. In the case of classifying and maintaining in detail, a method using a network system is more effective in consideration of the amount of information data and climate change. Use of a network system has an advantage that necessary information can be freely set when necessary.

  For example, in the correction calculation data example using the Köppen climate classification shown in FIG. 9, the correction data number (for each region such as temperate, subarctic, tropical, etc.) can be corrected monthly. Table data is created in association with Data 1 to 20 in FIG. Further, using the division positions A and B and the correction amounts A, B, and C shown in FIG. 10A, Data 1 to 20 are specified by correction calculation as shown in FIG. 10B.

  As described above, in the second embodiment, since the problem of gradation correction caused by environmental factors is solved, not only machine differences but also image quality fluctuations and deterioration caused by environmental fluctuations can be suppressed. become able to.

  For example, as described above, in product development, various data are collected and analyzed by environmental tests. Gradation fluctuation due to the usage environment is also grasped at this time, and the difference calculation data is held inside the aircraft, the above-mentioned reference gradation correction parameter is corrected and calculated, and image processing is performed. Regardless, good image quality can be obtained without bothering the user. At this time, the accuracy can be further improved by adding control in consideration of the internal fluctuation data of the machine body by the number of continuous outputs.

  For example, a low-function device such as a black and white multifunction device does not have a gradation correction function or dedicated hardware itself with the highest priority on cost, and does not consider environmental fluctuations or deterioration due to temperature, humidity, or machine differences. On the other hand, the gradation correction system used in color multifunction peripherals, for example, calculates the correction curve by matching the gradation correction curve to the base gradation correction curve. This is a function for correcting the state itself (corresponding to the image output unit 30 in this example).

  Even if there is a gradation correction function, for example, in the mechanisms described in Patent Documents 1 to 3, since the reference gradation correction curve is a correction curve calculation that is adjusted to the base gradation correction curve, the quantization is similarly performed. In response to material changes that often occur due to errors or minor changes, or differences in consumables between production lots, the larger the difference from the standard, the greater the quantization error, which increases accuracy and costs. Get higher. Further, as a cost, a dedicated density (gradation) detection sensor or the like is required, and the user performs correction work, so that image quality deterioration due to an operation error may occur.

  On the other hand, in the present embodiment, a new reference correction curve can be automatically designed according to environmental fluctuations and the state of consumables, so that flexible and accurate gradation correction processing can be performed. If a system that provides correction data via a network line is used, correction data can be acquired and processed using the network line even if there is no large storage capacity in the device, thus providing good image quality at low cost. can do. In particular, even when correction data is large like a color machine, the storage capacity can be greatly reduced, and its utility is great.

  For example, by substituting substitute parts at the time of discontinuation of production and building a re-download service via the web (Web) at the time of replacement, good gradation reproduction without quantization error can be achieved for a long time until the life of the aircraft body. Can be guaranteed. As a result, user follow-up that is more thorough than at present can be realized, and the storage stock itself can be reduced.

  In addition, these days, medium and high-end and high-end black-and-white multifunction printers are equipped with a color scanner as a standard feature, so the through-tone gradation of each machine discharged from the image output unit 30 using the scanner at the time of shipment from the factory. Data can be read and tone correction parameters can be automatically generated and set in the storage holding unit, or regenerated and changed after market installation. By using this, it is possible to construct a system that can flexibly cope with changes in various installation environments around the world, large aging changes, and member changes.

  Also, by providing the machine administrator with a gradation parameter automatic design download tool using a measuring device and a client PC, image quality management can be performed at a document center or the like.

  By performing automatic correction using the reference correction data table based on regional information, timer information (date), and test data at the time of product development, even if there is no advanced machine control system, the level according to the state of the aircraft Since the tone correction parameter can be applied, good image quality can be provided at low cost.

  In addition, in network connected devices, model information, regional information, and calendar information are always set for communication, so that the optimal reference tone correction curve data can be automatically downloaded from a security-managed server. It is also possible to build a system that can be adapted to the situation.

  As measures such as seasonal variations, image quality can be improved based on the climatic information of the product provision area and the gradation variation data of the output device obtained in the system test in an environment that is zoned into temperature and humidity at the product development stage. As the table data to search from the region and date (year / month / day) according to the affected range, the variation coefficient is held internally, and the variation coefficient is based on the difference from the region and date on which the reference gradation correction curve data was created. By calculating the above, it is also possible to construct an automatic gradation correction system that automatically corrects the gradation correction curve so as to conform to actual environmental conditions.

  By using these, it is possible to always apply a good gradation correction parameter for each season or for each installation area environment. In addition, by utilizing these, when there are not enough consumables that are unit parts, if there is a replaceable member, even if the characteristics change, the normal calibration and automatic gradation correction system Since it is possible to cope with gradation correction curve data with a small quantization error, the need for mechanical replacement is alleviated, which is a great merit for the user.

  In addition, by utilizing these, it becomes possible to reduce the number of steps for designing the tone correction curve at the product development stage, so the development cost can be reduced and the cost of the product itself can be suppressed. Products can be supplied to users at low cost.

  In addition, based on data obtained during various tests in advance in product development, the standard correction data is stored internally from the internal timer and regional information on the standard gradation variation for each season (month and day) and region In addition, the machine automatically corrects the generated reference tone correction parameter information (month, day, region, etc.), so that an output result without significant image quality degradation can be obtained even in an expensive system. Obtainable.

  FIG. 11 is a diagram for explaining gradation correction parameters used in the above embodiments. Here, FIG. 11A is a diagram showing characteristics of an ideal output gradation, and the output gradation level (OUT on the vertical axis) is different from the input gradation level (IN on the horizontal axis). It is designed to change linearly.

  On the other hand, FIG. 11B is a diagram showing the characteristics of the output gradation of the actual image output unit 30 (output device), and the linearity between the input gradation level and the output gradation level is lost. ing. Therefore, in order to correct this collapse of linearity, as shown in FIG. 11C, a tone correction parameter is created so that the tone correction curve has a characteristic opposite to the output tone characteristic of the output device. By correcting the image data using the gradation correction parameter, the final output changes linearly with respect to the input gradation level, as shown in FIG. 11A. Like that.

  12-14 is a figure explaining an example of the operation screen used by said each embodiment. Here, FIG. 12 shows an example of the operation screen of the main control and the sub-control. In this example, as shown in FIG. 12A, a button for selecting one of reference pattern output, data acquisition, and parameter creation is prepared on the main control screen.

  When data acquisition is instructed by the user on the screen shown in FIG. 12A, the correction data generation unit 400 presents the sub-control screen shown in FIG. 12B to the user. In this sub-control screen, data acquisition using a measurement device connected to a client PC (PC: Personal Computer) that forms the main part of the server device, or data acquisition using the image acquisition unit 10 as its own scanner is not performed. The user can select whether or not.

  FIG. 13 is a diagram showing an example of a measurement condition setting screen corresponding to each data acquisition method selected on the sub-control screen shown in FIG. When data acquisition using the measuring device is selected on the sub-control screen shown in FIG. 12B, the correction data generating unit 400 presents the setting screen for the measuring device shown in FIG. 13A to the user. . In this example, the user is provided with a radio button capable of selecting a measurement mode of Lab measurement or density measurement, an input field for designating an output data file, and buttons for starting and saving measurement.

  The user starts measurement by designating the measurement mode and then clicking the measurement start button. Further, by clicking the save button after the measurement is completed, the measured data is saved with the designated output data file name.

  It should be noted that a button for calibrating the measuring device (measuring device calibration) is prepared as necessary so as not to be affected by the machine difference of the measuring device to be used. At the time of calibration work, the measurement is started by clicking the measurement device calibration button.

  On the other hand, when data acquisition using a scanner is selected on the sub-control screen shown in FIG. 12B, the correction data generation unit 400 displays the setting screen for the scanner (document reading apparatus) shown in FIG. To the user. In this example, the user is provided with a radio button that can select a measurement mode of Lab measurement or Density measurement, an input field for designating an output data file, and buttons for reading and saving.

  When the user designates the measurement mode and clicks the measurement start button, reading of the image (reference pattern image output from the image output unit 30) using the image acquisition unit 10 is started. The gradation characteristic measurement processing unit 300 performs data processing in the own apparatus using the reference pattern image to acquire gradation data. Also, by clicking the save button after the completion of this process, the gradation data based on the read image data is saved with the designated output data file name.

  Note that a button for calibrating (scanner calibration) the image acquisition unit 10 as a scanner is prepared as necessary so as not to be affected by machine differences of the image acquisition unit 10 to be used. At the time of this calibration work, the calibration measurement is started by clicking the scanner calibration button.

  FIG. 14 is a diagram illustrating an example of an operation screen for automatically creating a gradation correction curve. Here, FIG. 14A is an example of a standard operation screen, and FIG. 14B is an example of a simple operation screen. For example, in the standard operation screen shown in FIG. 14A, input fields for specifying a target data file, a measurement data file, and an output data file, and buttons for creation, setting, and confirmation display are prepared. .

  The user designates a file representing ideal output gradation characteristics as shown in FIG. 11A as the target data file. The correction data generation unit 400 presents the output gradation characteristics indicated by the designated target data file on the screen (right side of the figure).

  Further, the user is a file designated to be saved in FIG. 12A or 12B as a measurement data file, and an actual image output unit 30 (output) as shown in FIG. Specifies the file that represents the characteristics of the output gradation of the device.

  The user clicks a creation button after designating a target data file and a measurement data file. Then, the correction data generation unit 400 can automatically correct the gradation characteristic indicated by the measurement data file, which is opposite to the output gradation characteristic of the output device as shown in FIG. The tone correction parameter representing the tone correction curve of the characteristic is calculated and saved as a designated output data file.

  Here, when the user clicks the confirmation button, the correction data generation unit 400 presents the gradation correction curve on the screen (right side of the figure). When the user clicks the setting button, the correction data generation unit 400 accepts manual fine adjustment for the automatically generated gradation correction parameter (or the gradation correction curve based thereon), and the gradation after fine adjustment. Save the correction parameters to the specified output data file.

  On the other hand, in the simple operation screen shown in FIG. 14B, the target data file designation column and the output gradation characteristics according to the target data file are displayed from the standard operation screen shown in FIG. The screen shown and the confirmation display button are omitted, and a standard target data file stored in advance in the own apparatus is used.

1 is a mechanism diagram of a color copying apparatus as an embodiment of an image forming apparatus according to the present invention. FIG. 3 is a functional block diagram of a color copying apparatus focusing on an image quality correction function in an internal controller unit. FIG. 3 is a block diagram illustrating an example of a hardware configuration when image quality correction processing is realized by software using a computer function. It is a figure which shows an example of the reference | standard pattern for an inspection. It is a flowchart which shows the example of an outline | summary of the process sequence of 1st Embodiment which produces | generates a gradation correction parameter. It is a flowchart which shows the detailed example of the process which calculates | requires the gradation correction curve in step S20 shown in FIG. It is a flowchart of the detailed example of step S30-S50 shown in FIG. It is a flowchart which shows the example of an outline | summary of the process sequence of 2nd Embodiment which produces | generates a gradation correction parameter. It is FIG. (1) which shows the structural example of a correction calculation data table. FIG. 10 is a diagram illustrating a configuration example of a correction calculation data table (part 2); It is a figure explaining the gradation correction parameter used by each embodiment. It is a figure of an example of the operation screen of a main control and a sub control. It is a figure which shows an example of the setting screen of the measurement conditions corresponding to each data acquisition method selected on a sub-control screen. It is a figure which shows an example of the operation screen which produces a gradation correction curve automatically.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Color copying apparatus, 8 ... Server apparatus, 10 ... Image acquisition part, 15 ... User interface apparatus, 20 ... Internal controller part, 22 ... Tone correction function part, 30 ... Image output part, 31 ... Image formation part, 84 ... operating temperature detection unit, 86 ... operating humidity detection unit, 300 ... gradation characteristic measurement processing unit, 400 ... correction data generation unit, 412 ... component state information acquisition unit, 413 ... history information acquisition management unit, 414 ... environment information acquisition , 415 ... Consumable material information acquisition unit, 416 ... Specification information acquisition unit, 420 ... Communication control unit, 500 ... Tone correction unit, 830 ... Tone characteristic measurement processing unit, 840 ... Correction data generation unit, 860 ... Communication control Part

Claims (14)

An image processing method for correcting gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device becomes predetermined characteristics based on the processing target image having gradation characteristics. And
Without correcting the gradation characteristics, the output device outputs a test image for measuring the gradation characteristics on a predetermined recording medium,
Specifying the gradation characteristics of the output device by measuring the output test image with a measuring device provided outside the output device,
An image processing method characterized in that a gradation correction parameter for correcting gradation characteristics is electronically generated by electronically analyzing the specified gradation characteristics of the output device. The gradation correction parameter is stored in association with the environmental condition of the output device in the generation process,
A gradation correction parameter for correcting the gradation characteristics is electronically generated based on an environmental condition of the output device in actual use and an environmental condition of the output device in a generation process of the gradation correction parameter. The image processing method according to claim 1, wherein: An image processing method for correcting gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device becomes predetermined characteristics based on the processing target image having gradation characteristics. And
Based on predetermined gradation data specifying the gradation characteristics of the output device, the gradation correction parameters for correcting the gradation characteristics are electronically generated, and the environmental conditions of the output device in the generation process Saved in association with
A gradation correction parameter for correcting the gradation characteristics is electronically generated based on an environmental condition of the output device in actual use and an environmental condition of the output device in a generation process of the gradation correction parameter. An image processing method characterized by: An image processing method for correcting gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device becomes predetermined characteristics based on the processing target image having gradation characteristics. And
Environmental conditions of the output device in the generation process when the gradation correction parameter for correcting the gradation characteristic is electronically generated based on predetermined gradation data specifying the gradation characteristic of the output device And notifies the predetermined server device of the environmental conditions of the output device during actual use,
In response to this notification, the tone correction parameter returned from the external device is received,
An image processing method comprising correcting the gradation characteristics of the processing target image using the received gradation correction parameter. An image processing apparatus that corrects gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device have predetermined characteristics based on the processing target image having gradation characteristics. And
The gradation characteristic of the output device specified by measuring the gradation characteristic measurement test image output on the predetermined recording medium by the output device without correcting the gradation characteristic is electronically determined. An image processing apparatus comprising: a correction data generation unit that electronically generates a gradation correction parameter for correcting gradation characteristics of the output device by performing data analysis. The correction data generation unit stores the gradation correction parameter in association with the environmental condition of the output device in the generation process, and stores the environmental condition of the output device and the gradation correction parameter in actual use. The image processing apparatus according to claim 5, wherein a gradation correction parameter for correcting the gradation characteristic is electronically generated based on an environmental condition of the output device in a generation process. An image processing apparatus that corrects gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device have predetermined characteristics based on the processing target image having gradation characteristics. And
Based on predetermined gradation data specifying the gradation characteristics of the output device, the gradation correction parameters for correcting the gradation characteristics are electronically generated, and the environmental conditions of the output device in the generation process And a level for correcting the gradation characteristics based on the environmental conditions of the output device during actual use and the environmental conditions of the output device in the generation process of the gradation correction parameter. An image processing apparatus comprising: a correction data generation unit that electronically generates a tone correction parameter. The gradation characteristic of the output device is determined based on gradation data obtained based on a test image for gradation characteristic measurement output on a predetermined recording medium by the output device without correcting the gradation characteristic. The image processing apparatus according to claim 5, further comprising a gradation characteristic measurement processing unit to be specified. An image processing apparatus that corrects gradation characteristics of an image to be processed so that the gradation characteristics of an output image formed by a predetermined output device have predetermined characteristics based on the processing target image having gradation characteristics. And
Environmental conditions of the output device in the generation process when the gradation correction parameter for correcting the gradation characteristic is electronically generated based on predetermined gradation data specifying the gradation characteristic of the output device The environmental condition of the output device at the time of actual use is notified to a predetermined server device, and the gradation correction parameter returned from the external device is received in response to the notification, and the received gradation correction parameter is used. An image processing apparatus comprising: a gradation correction unit that corrects gradation characteristics of the processing target image. An image processing apparatus that corrects the gradation characteristics of the processing target image so that the gradation characteristics of the output image formed by the predetermined output device become predetermined characteristics based on the processing target image having gradation characteristics A server device used in combination,
A measurement unit for measuring a test image for measuring the gradation characteristic output on a predetermined recording medium by the output device without correcting the gradation characteristic;
A server apparatus comprising: a communication control unit that transmits measurement data measured by the measurement unit to the image processing apparatus. An image processing apparatus that corrects the gradation characteristics of the processing target image so that the gradation characteristics of the output image formed by the predetermined output device become predetermined characteristics based on the processing target image having gradation characteristics A server device used in combination,
A measurement unit for measuring a test image for measuring the gradation characteristic output on a predetermined recording medium by the output device without correcting the gradation characteristic;
A gradation characteristic measurement processing unit that specifies the gradation characteristic of the output device by electronically analyzing the measurement data measured by the measurement unit;
A server apparatus comprising: a communication control unit configured to transmit to the image processing apparatus gradation data indicating the gradation characteristic of the output device specified by the gradation characteristic measurement processing unit. An image processing apparatus that corrects the gradation characteristics of the processing target image so that the gradation characteristics of the output image formed by the predetermined output device become predetermined characteristics based on the processing target image having gradation characteristics A server device used in combination,
A measurement unit for measuring a test image for measuring the gradation characteristic output on a predetermined recording medium by the output device without correcting the gradation characteristic;
A gradation characteristic measurement processing unit that specifies the gradation characteristic of the output device by electronically analyzing the measurement data measured by the measurement unit;
Correction that electronically generates gradation correction parameters for correcting the gradation characteristics of the output device by electronically analyzing the gradation characteristics of the output device specified by the gradation characteristic measurement processing unit A data generator;
A communication control unit configured to transmit the gradation correction parameter generated by the correction data generation unit to the image processing apparatus; The correction data generation unit stores the gradation correction parameter in association with the environmental condition of the output device in the generation process, and stores the environmental condition of the output device and the gradation correction parameter in actual use. The server apparatus according to claim 12, wherein a gradation correction parameter for correcting the gradation characteristic is electronically generated based on an environmental condition of the output device in a generation process. An image processing apparatus that corrects the gradation characteristics of the processing target image so that the gradation characteristics of the output image formed by the predetermined output device become predetermined characteristics based on the processing target image having gradation characteristics A server device used in combination,
A tone correction parameter for correcting the tone characteristics acquired based on a test image for measuring tone characteristics output on a predetermined recording medium by the output device without correcting the tone characteristics. And gradation correction for correcting the gradation characteristics based on the environmental condition of the output device in the process of electronically generating the gradation correction parameter and the environmental condition of the output device during actual use A correction data generator for electronically generating parameters;
A communication control unit configured to transmit the gradation correction parameter generated by the correction data generation unit to the image processing apparatus;

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