JP4001218B2 - Image reading apparatus, image processing apparatus, and image signal processing characteristic adjusting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to adjustment of image signal processing characteristics performed as initialization processing in an image reading apparatus used in an image processing apparatus such as a DPPC (Digital Plane Paper Copy-machine, so-called digital copying machine), and more accurately in a short time. Adjustment method that allows easy adjustmentShortThe present invention relates to an image reading apparatus including means for performing more accurate adjustment in a long time, and an image processing apparatus including the image reading apparatus.
[0002]
[Prior art]
In the conventional DPPC, the apparatus is initialized when the power switch is turned on, or when starting up or returning from shutdown (power saving standby state in which the power supply other than the monitoring part is stopped). In the initialization process, homing and adjustment of read image processing characteristics are performed in an image reading apparatus provided in the apparatus.
In adjustment of read image processing characteristics, an analog signal processing unit in a signal processing system of an image sensor (usually a CCD linear image sensor) that performs photoelectric conversion of an image is corrected to make the output constant. This correction is performed in consideration of light source deterioration and environmental fluctuations, and is an essential requirement in the initialization process. The correction of the analog signal processing unit includes black level adjustment and white level adjustment. The black level adjustment is performed by adjusting the read black level signal (for example, the signal obtained by reading the OPB portion of the CCD) to the target value and adjusting the white level. Adjusts a white level signal (usually due to a peak value) obtained by reading a reference white plate illuminated by a light source to a target value. This adjustment is performed for each signal processing system even when image data read by the CCD is processed by a plurality of signal processing systems (for example, two systems of EVEN pixel signals and ODD pixel signals).
[0003]
[Problems to be solved by the invention]
By the way, although it is a user's need to start up from the power supply SW or from a shutdown in a short time, it is a ZESM standard (with low power consumption standby state and within a specified time) proposed for energy saving. Development is also progressing toward the goal of adapting to the purpose of If power consumption in the standby state is limited from the viewpoint of energy saving, it is difficult to shorten the startup time, and the ZESM standard sets a goal of returning from the standby state within 10 seconds. Until now, it took the longest time to warm up the fixing unit on the main body side for this target, so even if the time required for homing and initialization of the scanner is 10 seconds or more, there is a problem. However, the time required for warming up the fixing unit is becoming less than 10 seconds, and the initialization process of the scanner determines the rise time of DPPC. In other words, there is a situation where the time for which copying can be used is limited by the time required for homing and initialization on the scanner side. In order to overcome such a situation, the adjustment of the read image processing characteristics is also required to develop an effective solution for the purpose of shortening the processing time.
However, in the above-described apparatus having a plurality of read image data processing systems, the time required for adjustment is as long as the number of processing systems, and shortening is difficult. This is because the adjustment for each system is processed in series (see the description regarding FIG. 9 described later), and no effective solution for shortening the adjustment time is shown. In addition, each processing system is independent in terms of circuit configuration, and if there is sufficient margin in the CPU processing capacity to adjust, it is possible to shorten the time by parallel processing that adjusts each system simultaneously, but cost and circuit Such conditions may not be obtained depending on the scale, and there is no change in the need for shortening in serial processing.
The present invention has been made in view of the above-described problems of the prior art, and a first object thereof is an apparatus having a reading means for outputting a read image as a plurality of signals and a signal processing system for the plurality of read images. In order to reduce the cost and circuit scale, the read image processing characteristics of each system cannot be adjusted by parallel processing. When performing serial processing, accurate adjustment should be performed in a shorter time. The image processing operation can be started early.
[0004]
On the other hand, even if measures that can be adjusted in a short time are taken, there will be differences in the adjustment time depending on the deterioration of the light source and environmental fluctuations, and the reader can be started up within the specified time while waiting for the end of adjustment. It is necessary to execute the operation with the best adjustment value even in such a time constraint. This is another issue. It has been proposed to solve this problem by a method in which the adjustment that is being executed is terminated and control for setting a substitute value is performed in order to keep the prescribed time constraint. As a substitute value, a value obtained in the adjustment performed in the past is prepared as an initial value in advance, and the data is used or the data obtained by the adjustment performed immediately before is used. The adjustment result has not been obtained.
The second object of the present invention is made in view of the above-mentioned situation in the adjustment of the read image processing characteristics of the image reading apparatus, and as a substitute value used when the adjustment cannot be performed within a predetermined time, By using a more accurate and reliable value, the reading operation of the image reading apparatus can be started quickly without deteriorating.
[0005]
[Means for Solving the Problems]
  The invention of claim 1 is a scanned image.signalTheCorresponding to even and odd pixels respectivelyReading means for outputting as a signal of multiple systems,In the read image signalAccording to the processing characteristics according to the set valueBlack level and white level adjustmentAn image reading apparatus comprising: an image signal processing means having a plurality of processing systems for performing processing; an adjusting means for adjusting processing characteristics by changing a setting value of the image signal processing means; and a control means for controlling the adjusting means The control means adjusts the processing characteristics only in one processing system among the plurality of processing systems in the image signal processing means, and sets the setting value obtained as an adjustment result to another processing system.And means for changing the one processing system for adjusting the processing characteristics for each adjustment.An image reading apparatus comprising:
[0006]
  The invention of claim 2Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values Image signal processing means, adjustment means for adjusting processing characteristics by changing set values of the image signal processing means, and control means for controlling the adjustment meansIn the image reading apparatus, the control means includesMeans for adjusting the processing characteristics only in one processing system of the plurality of processing systems in the image signal processing means, and setting the set value obtained as an adjustment result in another processing system; andSet values obtained as an adjustment result after adjusting the processing characteristics of all the multiple processing systems during the first adjustment.The one processing system for executing the adjustment is selected by selecting a smaller setting value from amongCharacterized by having meansImage reading deviceIt is.
[0007]
  The invention of claim 3 is claimed in claim 1.Or 2The image reading device described inPlaceIt is characterized by havingImage processing deviceIt is.
[0008]
  The invention of claim 4Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values A method for adjusting an image signal processing characteristic in an image signal processing means having an adjustment process result by changing a set value only in one processing system among a plurality of processing systems in the image signal processing means, and an adjustment result A step of setting the set value obtained in the other processing system, and a step of changing the one processing system for adjusting the processing characteristics for each adjustment.It is characterized byMethod for adjusting image signal processing characteristicsIt is.
[0009]
  The invention of claim 5Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values A method for adjusting image signal processing characteristics in an image signal processing means having a step of adjusting processing characteristics for all of a plurality of processing systems at the time of initial adjustment, and determining a set value obtained as an adjustment result according to a predetermined standard The step of specifying the one processing system for adjusting the processing characteristics, the step of adjusting the processing characteristics by changing the setting value only in the specified one processing system, and the setting obtained as the adjustment result Specifying the one processing system for performing adjustment by selecting a smaller set value among the values;It is characterized byMethod for adjusting image signal processing characteristicsIt is.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described based on the following examples shown with the accompanying drawings. The following embodiment is applied to a DPPC (Digital Plane Paper Copy-machine, so-called digital copying machine) which is one of image processing apparatuses provided with an image reading apparatus.
FIG. 1 is a schematic diagram showing the overall configuration of a DPPC according to an embodiment of the present invention.
As shown in FIG. 1, the DPPC of the present embodiment includes an auto sheet feeder (automatic document feeder) 1, a scanner unit 2, a writing unit 3, a process unit 4, a paper feeding unit I5, a paper feeding unit II6, and paper discharge. The unit 7 is provided.
An outline of the operation of the DPPC shown in FIG. 1 will be described.
When a start key of an operation unit (not shown) is pressed, a document placed on a document table provided in the auto sheet feeder 1 is predetermined on the contact glass of the scanner unit (image reading device) 2 by a feeding unit. , The image data is read by the scanner, and the document that has been read is discharged. When there is a next original, this original reading operation is automatically repeated one after another. The writing unit 3 controls the light emission of the laser in the writing unit based on the image forming data generated based on the image data read by the scanner unit 2, and creates a latent image by laser writing on the photosensitive member. Thereafter, a toner image is formed on the photosensitive member at the developing unit of the process unit 4, and the toner image on the photosensitive member is transferred to a copy sheet supplied from the paper feeding unit I5 and the paper feeding unit II6. Thereafter, the transfer paper fixes the image by the fixing unit of the process unit 4 and is discharged from the main body by the paper discharge unit 7.
[0027]
Here, the scanner unit (image reading device) 2 of the DPPC will be described in more detail.
FIG. 2 shows the configuration of the scanner unit 2 shown in FIG. 1 in detail.
As shown in FIG. 2, the scanner unit 2 according to the present embodiment includes a document conveying belt 11, a contact glass 12, a reference white plate 13, a lamp 14, a lens 15, an HPS (home position sensor) 16, and an APS (document size detection sensor). I17, APSII18, sensor board 19, scanner control board 20, scanner motor 21, heater 22, and fan 23 are provided.
The operation of the scanner unit 2 will be described. The document conveyed by the document conveying belt 11 and placed on the contact glass 12 is irradiated by the lamp 14, and the reflected light is reflected by the three mirrors and passes through the lens 15. An image is formed on the CCD line sensor on the sensor board 19. The CCD line sensor converts the imaged original image into an electric signal while performing main scanning (in FIG. 2, the direction perpendicular to the drawing is the main scanning direction) by sensor pixels arranged in the line direction, and outputs it as an image signal. To do.
The lamp 14 and the mirror group travel on a carriage driven by a wire by the scanner motor 21 while sub-scanning the document surface (in FIG. 2, the direction parallel to the drawing is the sub-scanning direction) The image is transmitted to a CCD line sensor provided in a reading unit (described later) on the sensor board 19, and the above-described main scanning of the CCD line sensor is applied to obtain a read image signal on the entire surface of the original, and analog processing is performed on the obtained image signal. After A / D conversion, the image data is sent to an image processing unit (described later) of the scanner control board 20. Initialization processing such as adjustment of homing and read image processing characteristics, control of the scanner motor 21 for performing normal document scanning, and the like are controlled by a main body controller (not shown) that controls the image forming sequence and the overall system relationship. A scheme can be adopted. The reference white plate 13 provides a reference for the reading density, and is used for adjusting the reading image processing characteristics. The document size is detected by APS (document size detection sensor) I17 and APSII18. Further, a heater 22 is provided for preventing condensation of the scanner, and a fan 23 is provided for cooling, and the scanner control plate 20 performs the control thereof.
[0028]
  Here, the image data processing of the scanner unit 2 of the above-described DPPC (FIGS. 1 and 2) will be described along the data flow.
  FIG. 3 shows a schematic block diagram of a processing unit related to image data processing of the scanner unit 2 and its control unit. Here, a reading unit 30 on the scanner unit 2 side, an image processing unit 40, and a control unit 50 on the DPPC main body side that controls these units are shown.
  As shown in FIG. 3, the reading unit 30 mainly includes a CCD 31, analog processing circuits 321 and 322, AD converters (ADC) 331 and 332, and a timing generation circuit (timing processing IC) 36. The reading unit 30 performs processing such as clamping and gain correction on the original image signal read by the CCD 31 by the analog processing circuits 321 and 322 and converts the analog signal to the digital signal by the ADCs 331 and 332, and then the image processing unit 40. To send.
  The image processing unit 40 mainly includes a sampling circuit 41, an image correction circuit 42, and a register 43. Here, the writing unit that performs image output processing such as shading processing, gamma correction processing, scaling processing, and filter processing necessary for performing output processing such as drawing processing on the sent image data, and performs print output processing 3 (plotter unit). On the other hand, the sampling circuit 41 samples black level and white level data necessary for obtaining adjustment values for performing clamp and gain correction in the analog processing circuits 321 and 322 of the reading unit 30 from the sent digital image data. The sampled value is written to the register 43 to perform a feedback operation. Since the basic technique for adjusting the black level and white level of the image data to the target value by acquiring black level and white level data and performing clamp / gain correction can be applied to the conventional technique, It is not detailed here.
  The feedback operation for adjusting the black level and the white level is controlled by the CPU 51 of the control unit 50 on the main body side that controls the entire unit constituting the DPPC. At this time, the CPU 51 sets adjustment values for performing clamp level (black level adjustment) and gain correction (white level adjustment) in the analog processing circuits 321 and 322 via the timing generation circuit 36 and the DA converter DAC 34. In addition, the CPU 51 controls the memory52And store data necessary for the control operation.
  In the example of FIG. 3, the CCD output has two channels, and there are two systems of analog processing circuits 321 and 322 to ADCs 331 and 332 for each channel. Parallel processing using a plurality of channels can be performed with two channels as in this example, and each channel is associated with an even (EVEN) pixel signal and an odd (ODD) pixel signal. Also, in the case of 4 channels, it can be carried out in the same manner as 2 channels.
[0029]
Next, the DPPC initialization process described above will be described.
When the power supply SW is turned on or started up from shutdown, power supply is resumed to the scanner unit (image reading device) 2 that has stopped supplying power simultaneously with the initialization process of the main body, and the initialization process is performed at that time. Execute. In addition to homing, the initialization processing of the scanner unit 2 includes adjustment of read image processing characteristics, which is an object of the present invention.
Before showing an embodiment of scanner adjustment according to the present invention, a sequence of scanner adjustment control conventionally performed as initialization processing will be described below with reference to a flowchart shown in FIG.
In the example shown in FIG. 9, the control unit 50 is turned on when the power of the reading unit 30 is turned off, such as when the power of the reading unit 30 is turned off in the energy saving mode such as the main SW ON of the DPPC or the ZESM mode, and then the power is restored. This is performed based on the sequence of the scanner adjustment control operation performed by the CPU 51.
Accordingly, the flow is started by turning on the power of the reading unit 30 (S101). First, homing and initial setting of the reading unit 30 are performed (S102). The homing is an operation for positioning the carriage on which the reading unit is mounted at a home position that is a reference for scan control, and the initial setting is an initial value necessary for the operation of the analog processing circuits 321 and 322 and the ADCs 331 and 332 of the reading unit 30. Is an operation to set. The initial values to be set include initial setting values necessary for black level and white level adjustment.
[0030]
Thereafter, an operation for adjusting the black level and the white level is started. First, the lamp 14 is turned on (S103), and the carriage is moved to read the reference white plate 13 from the home position. Since the CCD 31 always photoelectrically converts the read image and outputs an image signal, the OPB (Optical Black) portion provided in a part of the CCD 31, that is, outside, at an appropriate time until the reference white plate 13 is read. The black level is detected by reading the image signal output from the pixel portion where the light is blocked, and the black level is adjusted (S104, 105). In the black level adjustment, an adjustment value for setting the black level to the target value is determined from the detected black level image signal, and the value is set as a value for adjusting the clamp level of the analog processing circuits 321 and 322. This process is performed by repeatedly performing a feedback operation such as detecting the output level again and driving the target value to obtain the final adjustment value. In this flow, since there are two signal processing systems, adjustment of each system is performed sequentially as steps S104 → S105.
After the carriage is moved to a position for reading the reference white plate 13, white level adjustment is performed (S106, 107). In the white level adjustment, an adjustment value for setting the white level to the target value is determined from the white level image signal read from the reference white plate 13, and the value is set as a value for adjusting the gain of the amplifiers of the analog processing circuits 321 and 322. To do. Also at this time, like the black level, the feedback loop operation is repeated to obtain the adjustment value. In this flow, since there are two signal processing systems, adjustment of each system is sequentially performed as steps S106 → S107.
The black level and white level adjustment of each system is processed in series, and after the processing is completed, the lamp is turned off (S108), and the adjustment data set as the adjustment value is stored in the memory 52, and the data is managed ( S109), the sequence is terminated.
[0031]
In the conventional method of FIG. 9 in which black level and white level adjustment of each system is performed by serial processing, the adjustment time is increased by the number of systems as described above. In the present invention, it is an object to reduce the adjustment time while basically maintaining the serial processing method. For this purpose, adjustment is performed only in one system, and the other systems use the adjusted value as a substitute value. As a result, the adjustment time is shortened.
For example, when adjusting the white level, only the white level of system 1 is adjusted, the value determined as the adjustment value is set in system 1, and the same adjustment value is substituted for the adjustment value of system 2 The same set value is used in the system 1 and the system 2. By doing so, the processing time required for white level adjustment can be reduced to the time of approximately one system. Similarly, for black level adjustment, only one system for actually obtaining an adjustment value is used, and the obtained value is substituted for another system.
[0032]
In addition, when the method of substituting the adjustment value of one system for another system is applied to the white level adjustment, the white level of the system that actually calculates the adjustment value (here, system 1) is always high. It is better to make such conditioning. This can also be realized by a mechanism in which the white level is always increased in the system that is intentionally adjusted, for example, by making a difference in circuit constants.
If the white level of system 1 that is conditioned as described above is actually adjusted, and the value obtained as a result of the adjustment is set as the adjustment value of system 2, the gain becomes excessive and adjustment becomes impossible. There is no. This is because if the adjustment system is reversed, the gain becomes too high and the circuit output is saturated, and the shading correction processing in the subsequent stage does not make correction, so only the data on one side of the image is whitish. This is because there is a fear of the possibility of becoming.
Note that the mechanism for constantly increasing the white level is not limited to a method of making a difference between circuit constants, but depending on conditions such as a gain curve, a value obtained as an adjustment result such as “adjustment setting value-1”. This can also be realized by setting a small value (such as subtracting a certain value) to a fixed system that always uses a substitute value.
[0033]
FIG. 4 is a flowchart showing a scanner adjustment control sequence in which the adjustment value of one system described above is substituted for another system.
Referring to FIG. 4, each process of steps S41 to S43 from the start of the flow to the lighting of the lamp is the same as the conventional example shown in FIG. 9, so the description of FIG. 9 is referred to. .
In this embodiment, adjustment is performed using only one signal system (in this example, system 1). Therefore, only the image signal of the system that is actually adjusted is sampled and output as the processing target. Black level detection is performed and black level adjustment is performed (S44). The black level adjustment itself is not different from step S104 shown in the flow of FIG. Since adjustment is actually performed only by the system 1, there is no need to store the image signal of the system 2 in a memory or perform a process of calculating an adjustment value.
After the black level adjustment is performed for the system 1, the value set as the adjustment value in the system 1 adjustment is substituted for the system 2 and set as a set value (S45).
Next, white level adjustment is performed (S46). Similarly to the black level adjustment performed previously, the white level adjustment is actually performed only in the system 1 and the adjustment value obtained in the system 1 is set as a set value instead of the system 2 (S47).
In this way, the black level and white level adjustment of each system is serially processed. After the processing is completed, the lamp is turned off (S48), the adjustment data set as the adjustment value is stored in the memory 52, and the data is managed. (S49) and the sequence is terminated.
[0034]
Next, still another embodiment in scanner adjustment of a system in which the adjustment value of one system is substituted for another system will be shown.
In the embodiment shown in FIG. 4, it is assumed that one system for actually adjusting and a system for setting other substitute values are designated in advance, and the circuit conditions of a specific system are set on the assumption that the designation is not changed. By fixing, proper operation was ensured. In this embodiment, the above assumptions and conditions are not added, and all systems are identical in terms of circuit, and only at the time of initial adjustment (for example, at the time of factory shipment, replacement of parts that affect the adjustment, etc.) A system is adopted in which all the systems are adjusted, a system for performing the adjustment is designated from the next time onward according to the adjustment result, and a substitute value is set for the other system. In this way, all the systems are adjusted at the time of the first adjustment, and by determining which system processing circuit will be the system to execute the adjustment from the adjustment result, there is a variation in the circuit for each system. In addition, an appropriate system can be selected as an adjustment value so that adjustment can be performed. When performing such an operation, if the operation is controlled by a sequence in which a predetermined time limit is provided for the adjustment time, it is necessary to exclude or loosen the time regulation at the first adjustment. Would.
[0035]
For example, in the case of two systems, the white level adjustment of both systems is performed for the first time, and the obtained adjustment values are compared. Then, a smaller value is selected, that is, a circuit having a larger gain is selected and designated as a system for performing adjustment. This is because if a circuit having a large value, that is, a circuit having a small gain is selected, saturation of output in the circuit cannot be prevented. In other words, if saturation occurs, the correction will not be effective even in the subsequent shading correction process, and there is a concern that only the data on one side of the image may become whitish.
From the viewpoint of shortening the adjustment time, in this embodiment, the adjustment time cannot be shortened only for the first time, but the first time adjustment can be considered at the time of factory shipment or replacement of parts that affect the adjustment. There are few problems in actual operation.
[0036]
FIG. 5 is a flowchart showing a sequence of scanner adjustment control executed at the time of the first adjustment described above. This flow includes a step of selecting a system for executing adjustment after the second time. Since this flow is performed as a part of the scanner adjustment, basically, the scanner adjustment is replaced with the steps related to the black level and white level adjustment in the scanner adjustment control sequence of FIG. 4 (steps S44 to 47 in FIG. 4). Run as part.
Referring to FIG. 5, in this adjustment sequence, black level and white level adjustment are performed for system 1 (S51, S54), and then system 2 is performed (S52, S55). From the adjustment values obtained as the adjustment results, For each of the black level and the white level, a determination is made based on the selection criteria as to which system is the adjustment execution system to be adopted after the second time (S53, S56). At this time, the selected system is stored in the memory 52 as data for designating the system for actual adjustment in steps S44 and S46 in FIG. 4, and this flow is finished.
[0037]
Next, still another embodiment in scanner adjustment of a system in which the adjustment value of one system is substituted for another system will be shown.
In the embodiment shown in FIGS. 4 and 5, only a fixed system without changing a predetermined system is determined by defining a system for which adjustment is performed once by some method, such as planning from the design stage or selecting at the time of initial adjustment. To make adjustments. In this case, it is essential that the condition for selecting the adjustment system is continuously established. For example, as described above, when the circuit having the larger gain is selected as the system for executing the adjustment, the selected system is selected. If the gain is always larger than the others, the intended purpose cannot be achieved. However, in reality, the circuit conditions are not constant and may be reversed due to changes over time. When the rotation is reversed, there arises a problem that only the data on one side as described above becomes whitish.
In such a case, it is necessary to avoid making adjustments with a fixed system at all times, and it is necessary to avoid this. For this purpose, the system to be adjusted is changed for each adjustment, and the adjustment is performed to some extent even if the circuit conditions change. To be able to. In this way, the time required for adjustment is shortened by using one system for executing the adjustment control, and the adjustment value itself is also updated every time adjustment is performed, so that the system for executing the adjustment control is fixed. This also makes it possible to maintain accuracy.
The flow shown in FIG. 4 can basically be applied to the scanner adjustment sequence of this embodiment. However, at the time of application, it is necessary to control so that the system for performing the adjustment in steps S44, 45 and S46, 47 in FIG. 4 and the system for setting the substitute value are changed every time the adjustment is performed. When the two systems shown in FIG. 4 are used, the system 1 and the system 2 are alternately designated as systems for executing the adjustment.
[0038]
Next, still another embodiment in scanner adjustment of a system in which the adjustment value of one system is substituted for another system will be shown.
When adopting a method of performing control to change the circuit system to be adjusted for each adjustment as in the above-described embodiment, if the variation in characteristics between the circuits of each system is large, the value obtained by actually adjusting and Since the variation affects the substitute value, it is necessary to reduce the variation.
For this reason, in this embodiment, for the system that was adjusted last time, the set value of the previous adjustment result is set, and for the system that is adjusted this time, the previous adjustment result is By performing adjustment using the set system reflection result as an adjustment target value, variation can be suppressed. According to this method, the adjustment data is updated in any system, so although the control man-hours increase slightly, the target value is unified with the value that was actually adjusted last time to reduce the variation between each system. There is a merit that can be.
However, setting the actual result to the target value means that even if the actual value deviates from a desired value, there is a possibility that all systems may match the value. For this reason, a process for avoiding following the abnormal value is prepared. In this process, the result adjusted with the setting value of the previous adjustment result is compared with the standard value (a value that has been standardized in advance as a value that should be originally) to check the validity of the setting value. The set adjustment value is changed to, for example, the previous value or the initial value, and the adjustment is performed using the standard value as the target value for the person who performs the adjustment.
[0039]
FIG. 6 is a flowchart showing a sequence of scanner adjustment control executed at the time of adjustment when a method for performing control for changing the circuit system to be adjusted for each adjustment is used. Including a step of avoiding tracking. Since this sequence is performed as part of the scanner adjustment, the scanner adjustment is basically replaced with the steps related to the black level and white level adjustment in the scanner adjustment control sequence in FIG. 4 (steps S44 to S47 in FIG. 4). Run as part. However, the sequence of FIG. 6 is performed at the second and subsequent adjustments when the system for performing the adjustment and the system for setting the substitute value are changed every time the adjustment is performed.
Referring to FIG. 6, in this adjustment sequence, the black level and the white level adjustment are performed for the system 2 each time before the current adjustment is started. First, the previous black level adjustment value performed in the system 2 is set in the system 2 (S61), the black level is detected based on the set adjustment value, the detection result is fetched from the image processing unit 40, and stored in the memory 52. Save (S62).
Next, it is checked whether the detection result of the black level is within a predetermined allowable value range, that is, whether it is a normal value (S63). Here, when a predetermined allowable value is determined, it can be determined based on a standard value (a value that is standardized in advance as a value that should be originally).
When it is determined that the detection result is normal by the check in step S63, the detection result of system 2 (the black level value detected in S62) is adjusted as the target value for black level adjustment of system 1 (S64).
On the other hand, if the detection result is not normal as a result of the check in step S63, for system 2, the value set for system 2 is changed from the previous adjustment value to the previous set value, and the setting is performed again (S65). Further, the system 1 is adjusted using the standard value as the adjustment target value (S66).
After finishing black level adjustment, white level adjustment is performed. The white level adjustment control process can be executed by the same sequence as the process performed for the black level in the black level adjustment. In other words, the white level including the step of avoiding the follow-up to the abnormal value by the steps S67 to 72 similar to the steps S61 to 66 of the black level is basically different only in the black level or the white level. The adjustment is executed and this flow is finished.
[0040]
Next, an embodiment of the invention relating to a method of setting a substitute value for an adjustment value when adjustments such as black level and white level adjustment are not completed within the time limit will be described.
When the power supply SW is turned on or when starting up from the shutdown, power supply is resumed to the scanner unit 2 which has been stopped. At that time, the initialization process is performed as described above, but the reading device can be scanned. Therefore, it is required to perform the processing within the time limit specified until a certain state is reached. In many cases, such a time regulation is set in order to prevent the apparatus from moving to an operable state unless the adjustment is completed. There is also a standard that clearly states the return time, such as ZESM.
The black level and white level adjustment included in the initialization process is also limited by this time, and if the adjustment is not completed within the time, the adjustment is stopped and the substitute value is set to comply with the regulations, To be able to finish.
Conventionally, an initial setting value (default value) or a previous adjustment value obtained by adjustment is set as a value to be substituted when adjustment cannot be completed within a predetermined time, and the adjustment sequence is completed. Control was taking place.
In the embodiment of the present invention, the substitute value is not simply the default value or the previous set value, but the set value obtained by the adjustment performed in the past is recorded, and the priority for selecting a value with higher reliability. And a setting value is selected according to the priority.
Specifically, the CPU 51 stores a record of past adjustment results in the memory 52 in the control unit 50. Since the frequency at which each adjustment value is used as a set value is known from the stored record, first, the use frequency Select the setting value based on.
When selecting a setting value according to the frequency of use, it is determined whether or not a setting value used in the past exists in the recorded data. If there is no setting value, a default value is used. If there is only one record, the value, that is, the set value obtained by the previous adjustment is used. Further, when there are a plurality of records, the adjustment value with the highest frequency is adopted as the set value. At this time, when there are a plurality of setting values having the same frequency, the latest adjustment value is adopted as the setting value.
[0041]
FIGS. 7 and 8 are flowcharts showing a sequence of scanner adjustment control executed during adjustment when a method of setting a substitute value for the adjustment value when adjustment is not completed within the time limit is employed. The sequence shown in FIG. 7 includes a step of setting a substitute value, and an adjustment value is selected according to the priority described above in that step. FIG. 8 shows a detailed sequence of a process for setting a substitute value. Since this sequence is performed as part of the scanner adjustment, the scanner adjustment is basically replaced with the steps related to the black level and white level adjustment in the scanner adjustment control sequence of FIG. 4 (steps S43 to S47 in FIG. 4). Run as part. 7 and 8 show the white level adjustment, but the same can be applied to the black level.
The flow in FIG. 7 is white level adjustment control. First, the carriage on which the reading optical system is mounted is moved to the position of the reference white plate 13 (S81), the lamp 14 is turned on (S82), and then the adjustment initial value is set. The white level is detected based on the adjustment value set at this time (S83).
By comparing the detected white level with the target value, it is determined whether or not the white level is appropriate (S84). If it is appropriate, this sequence is terminated without setting a substitute value.
On the other hand, if the detected white level is not appropriate, control is performed to change the set value to bring the white level closer to the target value, but when the control is performed to change the set value and drive to the target value, the adjustment time is a predetermined time. Is checked (S85). If not, the process returns to step S83 to continue the control.
If the adjustment time exceeds the predetermined time, the control for adjusting the white level that has been performed is stopped, and a substitute value is set as the adjustment value (S86).
[0042]
In the sequence for setting a substitute value, as shown in FIG. 8, first, it is checked whether or not recording data exists in the past adjustment record stored in the memory 52 of the control unit 50 (S91). When there is no recording (for example, when adjustment is performed for the first time), setting using an initial setting value (default value) is performed (S92).
If there is a record in step S91, frequency information indicating how many times the adjustment value has been used is added to each adjustment value as the past adjustment record stored in the memory 52. In addition, the adjustment value with the highest frequency is preferentially selected. At that time, if there are multiple adjustment values with the highest frequency, the adjustment value that has been adjusted most recently is selected with priority.
In order to perform this sequence, it is checked whether or not there is one of the most frequently used adjustment values in the record (S93). If there is not one, that is, there are a plurality of adjustment values, the latest adjustment value is selected from them. This adjustment value is set as a substitute value (S94). On the other hand, if it is determined in step S93 that the most frequently used adjustment value exists in the record, this adjustment value is set as a substitute value (S95). Therefore, in this step, when there is only one record, the value, that is, the set value obtained by the previous adjustment is used.
Further, when there are a plurality of adjustment values having the highest frequency, another criterion can be used to select an adjustment value to be prioritized. In the above description, the adjustment value that has been adjusted most recently is prioritized, but the magnitude relationship of the adjustment values can be used as another reference. For example, when priority is given to taking a smaller value, output saturation in the circuit can be prevented, and shading correction processing in the subsequent stage can be used effectively, and selection according to circuit characteristics becomes possible.
[0043]
Next, another embodiment of the invention relating to a method of setting a substitute value for an adjustment value when adjustments such as black level and white level adjustment are not completed within the time limit will be described.
The above-described embodiment (see FIGS. 7 and 8) employs a method of recording past adjustment results and selecting and setting adjustment values according to the situation, but the memory capacity for recording the results is limited. If there is, data support is insufficient (if it is necessary to record as raw data, it is difficult to secure a capacity to store all data), and it is difficult to make a sufficient judgment There was a problem.
In this embodiment, the problem is solved by calculating the average value of past adjustment values and using the average value data. The adjustment control sequence for carrying out this example is basically the following average value as a substitute value in the step of setting the substitute value of the above-described embodiment shown in FIG. 7 (step S86 in FIG. 7). Execute by using value data. Further, the sequence of FIG. 7 shows the white level adjustment, but the black level can be similarly implemented.
In order to obtain an average value to be used as a substitute value, the CPU 51 stores the number of adjustments that have been normally completed by performing an adjustment control operation in the past in the memory 52, and calculates the average value of the adjustment values that are set each time adjustment is performed. The obtained value is also stored in the memory 52.
The average value is, for example, the following formula:
Average value = (Average value up to previous time x Adjustment count + Current adjustment result) / (Adjustment count + 1)
Every time adjustment is performed, the obtained average value is updated and stored.
Therefore, only the data of the average value and the number of adjustments needs to be stored, and the memory occupancy can be reduced as compared with the case of storing all raw data.
According to this method, only the information on the number of adjustments is increased, which increases the data storage capacity. However, a control that is cleared a certain number of times or when the main SW is turned OFF / ON is performed, or when returning from the energy saving mode. It is possible to further limit the capacity by incrementing only.
Here, if the adjustment is not completed for the first time, there is no past recording data, and the average value processing is impossible, so an initial set value or the like is set.
Further, although the above average value calculation formula takes a simple average, this may be performed by a multiple addition average, and at this time, it is not necessary to record data of the number of adjustments.
For example, the multiple addition average value
Multiple addition average value = {(n−1) × average value up to previous time + current adjustment result} ÷ n
Here, n in the above formula is an arbitrary number of n ≧ 2.
Can be calculated.
In this manner, by obtaining the average value of past adjustment values, it is possible to calculate a substitute value that is set with a smaller memory capacity.
[0044]
In the present invention, the above-described embodiment is used as a processing program for an image signal processing characteristic adjustment method such as adjustment of the analog processing devices 321 and 322 for making the output level of the reading unit executed by the CPU 51 of the control unit 50 constant. By preparing a processing program that describes the procedure for executing the operation shown in (1) and executing the prepared program on a computer, the target operation can be realized. This program is recorded on a known computer-readable recording medium, used as a recording medium under the control of the CPU 51 of the control unit 50 or installed in a storage means, and a control operation is executed by the program read from the recording medium. .
[0045]
【The invention's effect】
  (1) Claim 1,4Inventionofeffect
  According to the present invention, the processing characteristics are adjusted (adjustment to the target value is performed by feedback control) in only one processing system among the plurality of processing systems in the image signal processing means, and the setting value obtained as the adjustment result is changed to other values. By setting the processing system as well, the time required to adjust other processing systems can be reduced. Can raiseIn addition, by changing one processing system that actually adjusts processing characteristics for each adjustment, it becomes possible to cope with changes in characteristics over time that cannot be covered by adjustment of only a fixed processing system. Can keep the adjustment more accurateThe
(2) Claim 2,5Inventionofeffect
  In addition to the effect of (1) above, by adjusting the processing characteristics for all of the plurality of processing systems at the time of the first adjustment, and specifying the one processing system to be actually adjusted from the next time onward, Even if there are variations in processing circuits for each system, it is possible to select and adjust a more appropriate processing system.CanThe
(3) ClaimThreeinventionofeffect
  Effect of (1) aboveCan be realized in an image processing apparatus such as a copying machine, a facsimile machine, a scanner, and a complex machine thereof, or a filing apparatus for storing image data, thereby improving the performance of the image processing apparatus.be able to.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of a DPPC according to an embodiment of the present invention.
FIG. 2 shows the configuration of the scanner unit in FIG. 1 in more detail.
FIG. 3 is a schematic block diagram of a processing unit related to image data processing of a scanner unit and its control unit.
FIG. 4 shows a scanner adjustment control sequence of a system in which an adjustment value of one system is substituted for another system.
FIG. 5 shows a part of a sequence of scanner adjustment control executed at the first adjustment.
FIG. 6 shows a part of a scanner adjustment control sequence in which a circuit system to be adjusted is changed for each adjustment.
FIG. 7 shows a scanner adjustment control sequence in which a substitute value is set as an adjustment value when adjustment is not completed within the time limit.
FIG. 8 shows a detailed sequence of a process of setting a substitute value in the sequence of FIG.
FIG. 9 shows a conventional example of a sequence of scanner adjustment control executed as initialization processing.
[Explanation of symbols]
2 ... Scanner part, 4 ... Process part,
13 ... Standard white board, 19 ... Sensor board,
20 ... Scanner control board, 30 ... Reading unit,
31 ... CCD, 321 ... analog processing circuit (system 1),
322: Analog processing circuit (system 2), 40: Image processing unit,
50 ... Control unit 51 ... CPU,
52 ... Memory.

Claims (5)

A plurality of processing lines read means performs adjustment processing of the black level and white level in accordance with the process characteristics according to the setting value to the read image signal to be output as signals of a plurality of lines corresponding to the read image signal to even-numbered pixels and odd pixels, respectively An image reading apparatus comprising: an image signal processing unit having: an adjustment unit that adjusts processing characteristics by changing a setting value of the image signal processing unit; and a control unit that controls the adjustment unit.
The control means adjusts the processing characteristics in only one processing system among the plurality of processing systems in the image signal processing means, and sets the setting value obtained as an adjustment result in another processing system , and the processing characteristics An image reading apparatus comprising: means for changing the one processing system for performing adjustment every adjustment . Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values An image reading apparatus comprising: an image signal processing unit having: an adjustment unit that adjusts processing characteristics by changing a setting value of the image signal processing unit; and a control unit that controls the adjustment unit .
The control means adjusts the processing characteristics in only one processing system among the plurality of processing systems in the image signal processing means, and sets the setting value obtained as an adjustment result in another processing system, and the first time At the time of adjustment, adjust the processing characteristics of all the multiple processing systems,
An image reading apparatus comprising: means for designating the one processing system for executing adjustment by selecting a smaller set value among set values obtained as an adjustment result. The image processing apparatus characterized by comprising an image reading equipment according to claim 1 or 2. Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values An image signal processing characteristic adjusting method in an image signal processing means having:
A step of adjusting the processing characteristics by changing the set value in only one processing system of the plurality of processing systems in the image signal processing means, a step of setting the setting value obtained as an adjustment result in another processing system, and A method for adjusting an image signal processing characteristic , comprising: changing the one processing system for adjusting a processing characteristic for each adjustment . Reading means for outputting read image signals as a plurality of systems corresponding to even pixels and odd pixels, and a plurality of processing systems for performing black level and white level adjustment processing on the read image signals according to processing characteristics according to set values An image signal processing characteristic adjusting method in an image signal processing means having:
A step of adjusting the processing characteristics for all of the plurality of processing systems at the time of the first adjustment, and a step of specifying the one processing system for adjusting the processing characteristics by determining a set value obtained as an adjustment result according to a predetermined standard The step of adjusting the processing characteristics by changing the set value only in the specified one processing system, and the adjustment is executed by selecting a small set value from the set values obtained as the adjustment result. A method for adjusting image signal processing characteristics , comprising a step of designating a processing system .

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