Gain correction device, signal processing unit, imaging device, image reading device, imaging apparatus, and gain correction method

Abstract

The gain correction device (20) includes a plurality of gain correction units (31) and a plurality of gain reflection control units (44), the number of units of the plurality of gain correction units (31) corresponds to the number of the plurality of signal types input to the plurality of gain correction units, each gain correction unit (31) is configured to correct the gain value for amplifying the plurality of signals, the plurality of gain reflection control units (44) are configured to change the time of switching the gain value of the plurality of gain correction units (31), so that the gain value switching time of the signal that one of the plurality of signals affects the signal level of another signal is different from the gain value switching time of the another signal.

Description

Technical Field

[0001] Embodiments of the present invention relate to a gain correction device, a signal processing unit, an imaging device, an image reading device, an imaging equipment, and a gain correction method. Background Technology

[0002] In image reading devices known in the art, when multiple image signals of red, green and blue (RGB) obtained from photoelectric conversion elements are amplified by a variable gain amplifier (VGA), the gain value is corrected by a processing circuit with three channels to prevent color saturation, etc., so that each signal level is changed to a predetermined target value.

[0003] Currently, the known technology in this field is to correct the gain value of the image signal output by the photoelectric conversion element corresponding to each of the four channels of red, green and blue and black and white monochrome (BW) by using an analog front-end (AFE) controller (for example, see Patent Document 1).

[0004] Furthermore, currently known photoelectric conversion elements in the art have a set of pixels that receive infrared (IR) light as a fourth set of pixels and output invisible data in addition to visible data in red, green, and blue (RGB).

[0005] Citation List

[0006] Patent documents

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2004-040146 Summary of the Invention

[0008] Technical issues

[0009] However, in the gain correction methods known in the art, there is a problem that when the gain value is switched, the change between ground (GND) and power supply caused by the load change in the processing circuit often causes the level of the image signal on different channels to change through the common impedance of the processing circuit.

[0010] In particular, as mentioned above, the pixel group receiving infrared (IR) light has low sensitivity to the infrared region of silicon (Si), resulting in a tendency for the signal level to decrease and the gain value to increase. Therefore, when the gain value is switched, the impact of load changes on the other channel tends to increase.

[0011] The embodiments of the present invention are proposed in view of such circumstances. According to one aspect of the present invention, in a system having multiple processing system lines, the signal level variation caused by load changes when switching gain values ​​can be reduced.

[0012] Solution to the problem

[0013] The gain correction device includes a plurality of gain correction units, the number of which corresponds to the number of signal types input to the plurality of gain correction units, each of the plurality of gain correction units being configured to correct the gain value used to amplify the plurality of signals; and a plurality of gain response control units configured to change the timing of the switching gain values ​​of the plurality of gain correction units, such that the timing of the gain value switching of the signal that affects the signal level of one of the plurality of signals is different from the timing of the gain value switching of the other signal.

[0014] Effects of the present invention

[0015] According to one aspect of the invention, in a system having multiple processing system lines, the signal level variation caused by load changes when switching gain values ​​can be reduced. Attached Figure Description

[0016] The accompanying drawings are intended to illustrate exemplary embodiments of the invention and should not be construed as limiting its scope. Unless explicitly stated otherwise, the drawings should not be considered to be drawn to scale. Furthermore, the same or similar reference numerals denote the same or similar components in several views.

[0017] Figure 1 This is a diagram illustrating the configuration or structure of an imaging device according to an embodiment of the present invention.

[0018] Figure 2 This is a cross-sectional view of an example structure of an image reading unit according to an embodiment of the present invention.

[0019] Figure 3 This is a block diagram illustrating the electrical connections of the elements of an image reading unit according to an embodiment of the present invention.

[0020] Figure 4 This is a flowchart of the gain correction process according to an embodiment of the present invention.

[0021] Figure 5 This is a timing diagram illustrating how automatic gain control (AGC) is performed in the gain correction process according to an embodiment of the present invention.

[0022] Figure 6 This is a timing diagram illustrating how automatic gain control (AGC) is performed in the gain correction process according to an embodiment of the present invention.

[0023] Figure 7 This is a block diagram illustrating a variation of the configuration or structure of a gain correction device according to an embodiment of the present invention. Detailed Implementation

[0024] The embodiments of the gain correction device, signal processing unit, imaging device, image reading device, imaging equipment, and gain correction method of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] Figure 1 This is a diagram illustrating the configuration or structure of an imaging device 100 according to an embodiment of the present invention.

[0026] like Figure 1 The imaging device 100 shown has at least two of the following functions: copying, printing, scanning, and faxing (FAX), and is commonly referred to as a multifunction printer or multifunction peripheral device (MFP).

[0027] The imaging device 100 includes an image reading unit 101 and an automatic text feeder (ADF) 102, both serving as image reading devices, and an image forming unit 103 is also provided below. Figure 1 In the middle, the outer cover of the image forming unit 103 is removed to reveal the internal structure.

[0028] ADF 102 is a document support unit that places documents whose images are to be scanned at the scanning position. ADF 102 automatically transports documents placed on the placement table to the scanning position. Image reading unit 101 scans and reads the documents transported by ADF 102 at the predetermined scanning position. Furthermore, image reading unit 101 has a contact glass on its top surface and scans documents placed on the contact glass, which serves as the scanning position. The contact glass acts as a document support unit for placing the documents. More specifically, image reading unit 101 is an optical scanner internally equipped with photoelectric conversion elements such as a light source, an optical system, and a charge-coupled device (CCD), and uses the optical system to scan and read the light reflected after the document is illuminated by the light source.

[0029] Image forming unit 103 prints document images scanned and read by image reading unit 101. Image forming unit 103 has a manual paper feed roller 104 for manual paper feeding and a recording paper supply unit 107 for supplying recording paper. Recording paper supply unit 107 has a mechanism for supplying recording paper in multiple layers from multiple paper trays 107a. The supplied recording paper is conveyed to secondary transfer belt 112 via positioning roller pair 108.

[0030] The toner image on the intermediate transfer belt 113 is transferred by the transfer unit 114 onto the recording paper conveyed on the secondary transfer belt 112.

[0031] Furthermore, as described above, the image forming unit 103 includes, for example, an optical writing device 109, an imaging unit (Y, M, C, and K) 105 in a series system, an intermediate transfer belt 113, and a secondary transfer belt 112. In the imaging process performed by the imaging unit 105, the image drawn by the optical writing device 109 is formed as a toner image on the intermediate transfer belt 113.

[0032] More specifically, the imaging unit (Y, M, C, and K) 105 includes four rotatable photosensitive drums (Y, M, C, and K) and an imaging element 106 disposed around each photosensitive drum. The imaging element 106 includes a charging roller, a developing unit, a primary transfer roller, a cleaning unit, and a de-energizer. The imaging element 106 operates on each of the four photosensitive drums, and the image formed on each of the four photosensitive drums is transferred to an intermediate transfer belt 113 via a corresponding primary transfer roller.

[0033] An intermediate transfer belt 113, consisting of a drive roller and at least one driven roller, is positioned at a roller clamping section between multiple photosensitive drums and multiple primary transfer rollers. When the intermediate transfer belt 113 is in operation, the secondary transfer unit transfers the toner image transferred to the intermediate transfer belt 113 during the primary transfer process onto recording paper conveyed on the secondary transfer belt 112. When the secondary transfer belt 112 is in operation, the recording paper is conveyed to the fixing unit 110, where the toner image is fixed as a color image onto the recording paper. The recording paper is then discharged to an external paper tray. When duplex printing is to be performed, the flipping mechanism 111 flips the front and back sides of the recording paper and conveys the flipped recording paper onto the secondary transfer belt 112.

[0034] The image forming unit 103 is not limited to the unit that forms an image by electrophotography as described above, but may also be a unit that forms an image by inkjet printing system.

[0035] The image reading unit 101 will now be described.

[0036] Figure 2 This is a cross-sectional view of an example structure of the image reading unit 101 according to this embodiment.

[0037] like Figure 2 As shown, the image reading unit 101 has a main body 11, within which are a sensor plate 10 with a photoelectric conversion element 9, a lens unit 8, a first carriage 6, and a second carriage 7. The photoelectric conversion element 9 is, for example, a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor. The first carriage 6 includes a reflector 3 and a light-emitting diode (LED) as a light source 2. The second carriage 7 includes a pair of reflectors 4 and 5. The image reading unit 101 has a contact glass 1 and a reference white plate 13 on its top surface.

[0038] During the reading or scanning operation, the image reading unit 101 emits light upward using the light source 2, while simultaneously moving the first carriage 6 and the second carriage 7 from the standby position or the initial position along direction A, which is the sub-scanning direction. Then, the first carriage 6 and the second carriage 7 form an image of the light reflected by the document 12 on the photoelectric conversion element 9 through the lens unit 8.

[0039] For example, when the power is turned on, the image reading unit 101 reads or scans the light reflected by the reference white board 13 and sets a baseline. In other words, when the first carriage 6 is moved to a position directly below the reference white board 13, the image reading unit 101 turns on the light source 2 and forms an image of the light reflected by the reference white board 13 on the photoelectric conversion element 9 to change the gain.

[0040] Figure 3 This is a block diagram showing the electrical connections of the elements of the image reading unit 101 according to this embodiment.

[0041] like Figure 3 As shown, the image reading unit 101 is equipped with a light source 2, an imaging device 21, a controller 23, and a light source driving unit 24. The light source 2 is driven by the light source driving unit 24.

[0042] Light source 2 illuminates the document as the object with visible light of red, green, and blue wavelengths and invisible light of infrared (IR) wavelengths (i.e., infrared light).

[0043] The imaging device 21 has a photoelectric conversion element 9 and a signal processing unit 22.

[0044] The photoelectric conversion element 9 receives incident light according to wavelength. This incident light is decomposed by, for example, a color filter into visible light of red, green, and blue wavelengths, and invisible light of infrared (IR) wavelength. The received light is then converted into electrical signals of red, green, blue, or infrared light. When scanning and reading visible images, the photoelectric conversion element 9 simultaneously outputs red, green, or blue (RGB) image signals to the signal processing unit 22 in the subsequent stage via multiple independent lines. When scanning and reading invisible images, the photoelectric conversion element 9 simultaneously outputs infrared (IR) image signals to the signal processing unit 22 in the subsequent stage via separate lines.

[0045] In this embodiment, an infrared (IR) image is used as the invisible image. However, it is not limited to this; an ultraviolet (UV) image can also be used as the invisible image. Furthermore, there are no restrictions on the wavelength used for the invisible image. In another embodiment, only visible images can be used.

[0046] The controller 23 controls each of the light source driving unit 24, the photoelectric conversion element 9, and the signal processing unit 22.

[0047] The signal processing unit 22 performs various signal processing on the image signal output from the photoelectric conversion element 9.

[0048] Next, the signal processing unit 22 will be described in detail.

[0049] like Figure 3 As shown, the signal processing unit 22 has multiple gain correction units 31 and analog-to-digital (A / D) converters 32, and the number of gain correction units 31 and A / D converters 32 corresponds to the number of channels or the number of signal types. With this structure, gain control processing can be performed on multiple image signals independently. The signal processing unit 22 has a central processing unit (CPU) 33, registers 34, and a level detection unit 35. The CPU 33 controls the level detection unit 35 and the multiple gain correction units 31 corresponding to the number of channels or signal types to perform a series of gain control processes. In this embodiment, the gain correction device 20 is implemented by the CPU 33, registers 34, level detection unit 35, and multiple gain correction units 31 corresponding to the number of channels or signal types.

[0050] The level detection unit 35 detects the level of the digital data of the signals output from the multiple A / D converters 32.

[0051] Each gain correction unit 31 includes an amplification unit 41, a gain setting unit 42, a gain control unit 43, and a gain response control unit 44.

[0052] The gain setting unit 42 stores the gain value.

[0053] Amplification unit 41 amplifies the input signal using the gain value stored in gain setting unit 42, and outputs the amplified input signal as an output signal. Amplification unit 41 can be, for example, a switched capacitor. However, it is not limited to this; amplification unit 41 can be any other unit or device, as long as it is capable of amplifying signals.

[0054] The gain control unit 43 determines the gain value based on the level of the signal output from the multiple A / D converters 32 and detected by the level detection unit 35.

[0055] In other words, the level detection unit 35 and the multiple gain control units 43 are configured to implement automatic gain control (AGC) functionality, wherein optimized gain settings are implemented for the state of each input signal as appropriate.

[0056] More specifically, the level detection unit 35 detects the level of each input signal that has not yet been amplified by the amplification unit 41. Each gain control unit 43 determines a gain value based on the level detected by the level detection unit 35. Each gain setting unit 42 switches a corresponding gain value among the multiple amplification units 41.

[0057] Each gain control unit 43 has an arithmetic circuit that calculates the target gain value based on the detected level.

[0058] like Figure 3 As shown, the CPU 33 controls the level detection unit 35 and the number of gain correction units 31 corresponding to multiple channels or signal types to perform a series of gain control processes.

[0059] When each of the gain correction units 31 performs gain correction processing simultaneously, the input of an adjacent pair of gain correction units 31 may change due to the common impedance caused by the load change caused by the signal with a relatively large deterministic gain.

[0060] In this embodiment, the magnitude of the image signal can vary between visible and infrared light, and there are cases where the infrared image signal has a lower value. In fact, the amount of infrared image signal is as small as an integer multiple of the amount of visible image signal. This is because the quantum sensitivity in the invisible or infrared region of the silicon (Si) constituting the photoelectric conversion element 9 is lower than that in the visible region.

[0061] To address this situation, according to this embodiment, each gain correction unit 31 includes a gain response control unit 44. The gain response control unit 44 alters the timing of the switching gain value determined by the automatic gain control (AGC) function and sent from multiple gain control units 43. By doing so, the gain value of an image signal affecting the signal level of other image signals is switched at a different time than that of other image signals. More specifically, the gain response control unit 44 delays the timing at which the gain value of a specific image signal will be reflected, making it later than the timing at which the gain values ​​of other image signals will be reflected. Alternatively, the gain response control unit 44 determines whether to switch the gain value sent from the gain control unit 43. That is, the gain response control unit 44 determines whether to reflect the gain value sent from the gain control unit 43 to the gain setting unit 42. With this configuration, in each gain correction unit 31, the determined gain value is not simultaneously reflected to the gain setting unit 42, thereby preventing load changes due to gain value switching.

[0062] In other words, depending on whether there are channels that do not switch gain values ​​simultaneously, the gain response control unit 44 will delay the response time of the image signal for a predetermined duration for a signal level that may affect other image signals, thereby changing and updating the gain value at a time different from other image signals. Depending on the situation, the response time controlled by the gain response control unit 44 is stored in register 34 via CPU 33.

[0063] Alternatively, depending on whether there are channels that do not switch gain values ​​simultaneously, the gain response control unit 44 can be turned on and off. Depending on the situation, the switching control performed by the gain response control unit 44 is stored in register 34 via CPU 33.

[0064] The following describes the flow of the gain correction process performed by the signal processing unit 22.

[0065] Figure 4 This is a flowchart of the gain correction process according to this embodiment.

[0066] Figure 5 and Figure 6 This is a timing diagram illustrating how automatic gain control (AGC) is performed in the gain correction process according to this embodiment.

[0067] like Figure 5 and Figure 6 As shown in this embodiment, the level changes when automatic gain control (AGC) is performed on the outputs Dout1 to 4 of each of the four gain correction units 31 are plotted.

[0068] like Figure 4 As shown, firstly, in step S1, the signal processing unit 22 determines whether there are any image signals that may affect the signal level of another image signal. When it is determined that at least one image signal will affect the signal level of another image signal ("Yes" in step S1), the process proceeds to branch step S2. As described above, in step S2, the gain response control unit 44 of the signal processing unit 22 determines whether to perform on / off control to switch or to shift the response time to make them different. For example, the gain response control unit 44 can refer to a predetermined mode (e.g., a mode of performing on / off control or a mode of shifting the response time to make them different) to determine whether to perform on / off control or shift the response time to make them different.

[0069] When timing control is to be performed by the gain response control unit 44 (No in step S2), the light source 2 of the image reading unit 101 emits visible light and infrared light, and the signal processing unit 22 corrects the gain values ​​of the visible and invisible (red, green, blue, and infrared) regions. Then, in step S3, the gain response control unit 44 of the signal processing unit 22 presets the gain switching of the output Dout4 (infrared light) to "delay" via register 34, and sets the gain switching of the outputs Dout1 to 3 (visible light) to "normal".

[0070] like Figure 4 As shown, in step S4, once automatic gain control (AGC) starts, the signal processing unit 22 detects an image signal with an initial gain value. Then, in step S5, the multiple gain correction units 31 of the signal processing unit 22 determine the gain value (output Dout1~3) and switch the gain value (output Dout1~3) to change the gain value to a predetermined target value.

[0071] Because the gain response control unit 44 sets the gain switching of the output Dout4 (infrared light) to "delay", such as Figure 5 As shown, at this time, the signal processing unit 22 will not reflect the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to the output Dout4.

[0072] On the other hand, when the gain response control unit 44 sets the gain switching of output Dout1~3 (visible light) to "normal", such as Figure 5 As shown, at this time, the signal processing unit 22 will reflect the gain value sent from the gain control unit 43 to the gain correction unit 31 corresponding to the outputs Dout1 to 3.

[0073] As a result, in step S6, the signal processing unit 22 determines that only the gain values ​​of the visible area channels of red, green and blue (RGB) are corrected.

[0074] Then, the gain response control unit 44 sets the output Dout4 to "normal", and the signal processing unit 22 delays the reflection of the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to the output Dout4.

[0075] In other words, in step S7, one of the multiple gain correction units 31 of the signal processing unit 22 determines a gain value (output Dout4) and switches the gain value (output Dout4) so ​​as to change the gain value to a predetermined target value.

[0076] When the gain switching is set to "delay" by the gain response control unit 44, the delay duration is changed by the register 34 according to the duration of the load change.

[0077] As a result, signal processing unit 22 determines that only the gain value of the infrared invisible region channel is corrected. Since the reflection time moves between the infrared invisible region and the red, green and blue (RGB) visible regions, they are not synchronized. In step S8, signal processing unit 22 terminates automatic gain control (AGC) without being affected by noise from output Dout4.

[0078] This configuration enables precise automatic gain control (AGC) without being affected by noise in channels with higher gain values.

[0079] As described above, according to this embodiment, the gain switching of the signal with the relatively large gain value among multiple signal levels is delayed. With this configuration, the influence of noise on another signal when the gain value is switched can be effectively eliminated, and in a system with multiple processing system lines, the signal level change caused by load changes when switching gain values ​​can be reduced.

[0080] Furthermore, according to this embodiment, it is not necessary to consider the long wait time that is equal to or greater than the time for executing automatic gain control (AGC) due to the change in the convergence time of the load change when the load change occurs.

[0081] When the gain response control unit 44 performs on / off control ("Yes" in step S2), the signal processing unit 22 instructs the light source 2 of the image reading unit 101 to emit visible light and infrared light as a first automatic gain control (AGC) (1), and corrects the gain values ​​of the visible areas of red, green, and blue (RGB) colors. Thus, in step S9, the signal processing unit 22 presets the gain switching of output Dout4 (infrared light) to "invalid" and sets the gain switching of outputs Dout1 to 3 (visible light) to "valid".

[0082] like Figure 4 As shown, in step S10, once the first automatic gain control (AGC) (1) is started, the signal processing unit 22 detects an image signal with an initial gain value. Then, in step S11, the multiple gain correction units 31 of the signal processing unit 22 determine the gain value so as to change the gain value to a predetermined target value and switch the gain value at once.

[0083] like Figure 6 As shown, since the gain response control unit 44 sets the gain switching of output Dout4 (infrared light) to "invalid", the switching is turned off, so the signal processing unit 22 does not reflect the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to output Dout4.

[0084] On the other hand, such as Figure 6 As shown, when the gain response control unit 44 sets the gain switching of output Dout1 to 3 (visible light) to "enabled", and the switching is turned on, the signal processing unit 22 reflects the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to output Dout1 to 3.

[0085] As a result, in step S12, the signal processing unit 22 determines that only the gain values ​​of the visible area channels of red, green and blue (RGB) are corrected, and then terminates the first automatic gain control AGC (1) without being affected by the noise from the output Dout4.

[0086] Subsequently, in step S13, the signal processing unit 22 sets the gain switching of output Dout1~3 (red, green and blue (RGB) visible light) to "invalid", sets the gain switching of output Dout4 (infrared light) to "valid", and starts the processing of the second automatic gain control AGC (2).

[0087] like Figure 4 As shown, in step S14, once the second automatic gain control (AGC) (2) is started, the signal processing unit 22 detects the image signal with an initial gain value. Then, in step S15, the multiple gain correction units 31 of the signal processing unit 22 determine the gain value so as to change the gain value to a predetermined target value and switch the gain value at once.

[0088] like Figure 6 As shown, since the gain response control unit 44 sets the gain switching of outputs Dout1 to 3 (visible light) to "invalid", the switching is turned off, so the signal processing unit 22 does not reflect the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to outputs Dout1 to 3.

[0089] On the other hand, such as Figure 6 As shown, when the gain response control unit 44 sets the gain switching of the output Dout4 (infrared light) to "enabled", and the switching is turned on, the signal processing unit 22 reflects the gain value sent from the corresponding gain control unit 43 to the gain correction unit 31 corresponding to the output Dout4.

[0090] As a result, in step S16, the signal processing unit 22 determines that only the gain value of the infrared invisible area channel is corrected, and then terminates the second automatic gain control AGC (2) without being affected by the noise of the output Dout1 to 3.

[0091] This configuration enables precise automatic gain control (AGC) without being affected by noise in channels with higher gain values.

[0092] As described above, according to this embodiment, the gain switching of the signal with the relatively large gain value among multiple signal levels is delayed. With this configuration, the influence of noise on another signal when the gain value is switched can be effectively eliminated, and in a system with multiple processing system lines, the signal level change caused by load changes when the gain value is switched can be reduced.

[0093] Furthermore, according to this embodiment, automatic gain control (AGC) is performed twice. It is unnecessary to consider the long wait time, equal to or greater than the duration of the automatic gain control (AGC), that occurs due to variations in the convergence time of load changes when they happen. For example, when another control is to be performed on a scanner, the timing of the second automatic gain control (AGC) can be determined based on the sequence and system configuration around the imaging device.

[0094] For example, when the radiation intensity of the incident light is high enough and the gain value in the optical system being processed is not too high, and the influence of noise between multiple channels is determined to be minimal, the signal processing unit 22 can determine that the gain switching in all channels is "effective", and automatic gain control (AGC) can be performed simultaneously.

[0095] In such a setting, such as Figure 4 As shown, firstly, it is determined that there is no image signal that affects the signal level of other image signals ("No" in step S1). Similar to the above embodiment, in step S17, once the first automatic gain control (AGC) starts, the signal processing unit 22 detects an image signal with an initial gain value. Then, in step S18, the multiple gain correction units 31 of the signal processing unit 22 determine the gain value (outputs Dout1 to 4) to change the gain value to a predetermined target value and switch the gain value all at once. After determining that the gain values ​​of all channels have been corrected, in step S19, the automatic gain control (AGC) is terminated.

[0096] Figure 7 This is a block diagram illustrating a modification to the configuration or structure of the gain correction device 20 according to this embodiment. For example... Figure 7 As shown, the gain correction device 20 may include a level detection unit 35 in each gain correction unit 31. In this configuration, the level detection unit 35 detects the level of the image signal that has not yet been amplified by the plurality of amplification units 41.

[0097] In the embodiments described above, the imaging device according to embodiments of the present invention is applied to a multifunction printer or multifunction peripheral device (MFP) having at least two of the following functions: copying, printing, scanning, and faxing (FAX). However, it is not limited thereto; the imaging device according to embodiments of the present invention can also be applied to any imaging device such as a copier, printer, scanner, and fax machine (FAX).

[0098] As stated above, many additional modifications and variations are possible. Therefore, it should be understood that the disclosure of this invention can be practiced outside the specific description herein, within the scope of the appended claims. For example, elements and / or features of different illustrative embodiments can be combined and / or substituted for each other within the scope of this invention and the appended claims. For example, some elements described in the above embodiments can be removed. Furthermore, elements can be appropriately combined according to different embodiments or modifications.

[0099] Any of the operations described above can be performed in various other ways, for example, in a different order than those described above. Each function of the embodiments can be implemented by one or more processing lines or circuits. The processing circuitry includes a programmable processor, just as a processor includes circuitry. The processing circuitry also includes devices such as application-specific integrated circuits (ASICs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), and conventional circuit elements for performing the functions.

[0100] This patent application is based on and claims priority to Japanese Patent Application No. 2020-012778, filed on January 29, 2020, and Japanese Patent Application No. 2020-157309, filed on September 18, 2020, the entire disclosure of which is incorporated herein by reference.

[0101] List of reference numerals

[0102] 2. Light source

[0103] 9. Photoelectric conversion element

[0104] 20. Gain modification device

[0105] 21 Imaging Device

[0106] 22 Signal Processing Unit

[0107] 31 Gain Correction Unit

[0108] 32 A / D Converter

[0109] 44. Gain Reflection Control Unit

[0110] 100 Imaging Equipment

[0111] 101 Image Reading Unit

[0112] 103 Image forming units

Claims

1.A gain correction apparatus comprising: a plurality of gain correction units, a number of units of which corresponds to a number of kinds of a plurality of signals input to the plurality of gain correction units, each of the plurality of gain correction units being configured to correct a gain value for amplifying the plurality of signals acquired at the same time; and a plurality of gain reflection control units configured to change a timing of switching a gain value of the plurality of gain correction units such that a timing of switching the gain value of a signal of the plurality of signals that affects a signal level of another signal of the plurality of signals is different from a timing of switching the gain value of the other signal of the plurality of signals; wherein each of the gain reflection control units is further configured to set a degree of delay of the gain switching that varies depending on a length of time during which a load changes at the time of switching the gain value. 2.The gain correction apparatus according to claim 1, the plurality of gain reflection control units determine that the gain value of a signal of the plurality of signals that affects a signal level of another signal of the plurality of signals is not switched by the plurality of gain correction units. wherein, 3.The gain correction apparatus according to claim 1, the plurality of gain reflection control units delay the timing of switching the gain value of a signal of the plurality of signals that affects a signal level of another signal of the plurality of signals by the plurality of gain correction units. wherein 4.A signal processing unit comprising: the gain correction apparatus according to any one of claims 1 to 3, wherein each of the plurality of signals is an image signal input for each of a plurality of processing systems. 5.An imaging apparatus comprising: a photoelectric conversion element configured to convert incident light into a signal and output the signal; and the signal processing unit according to claim 4, wherein the signal output from the photoelectric conversion element is an image signal of each color. 6.The imaging apparatus according to claim 5, the image signal of each color includes an image signal output when visible light is received and an image signal output when invisible light is received. 7.An image reading apparatus comprising: wherein a light source configured to emit light; and the imaging apparatus according to claim 5 or 6. 8.An image forming apparatus comprising: an image forming unit; and the image reading apparatus according to claim 7. 9.A gain correction method comprising: correcting a gain value for amplifying a plurality of signals acquired at the same time; and when correcting the gain value for amplifying the plurality of signals, changing a timing of switching the gain value such that a timing of switching the gain value of a signal of the plurality of signals that affects a signal level of another signal of the plurality of signals is different from a timing of switching the gain value of the other signal of the plurality of signals; wherein a degree of delay of the gain switching varies depending on a length of time during which a load changes at the time of switching the gain value. ​ ​ ​ ​ ​

Images