JP2007013458A - Image pickup reference signal correction device and image pickup reference signal correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct the abnormal image pickup reference signal in a black level in a region where an image pickup reference signal is detected, for example, an optical black(OB) region to a proper value by a simple and quick processing method. <P>SOLUTION: Whether or not a detection signal (image pickup reference signal) in a black level in an OB region deviates from a normal range is judged (S4, S5), and when the detection signal of the OB region deviates from the normal range, the detection signal is replaced with the latest normal detection signal in the OB region and/or the normal detection signal in an OB region near the detection signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, when an imaging reference signal such as a black level of an image detection apparatus using an imaging device (or an imaging sensor) such as a CCD or CMOS sensor used in an imaging apparatus such as a camera deviates from a normal range, the imaging reference signal is The present invention relates to an imaging reference signal correction method and an imaging reference signal correction apparatus that perform correction.

An imaging device using a CCD, CMOS sensor, or the like used in an imaging apparatus such as a camera is provided with an imaging part for imaging a subject and an area for detecting an imaging reference signal around the imaging part.
Usually, a black level reference signal is used as the imaging reference signal. For this reason, an area for detecting the imaging reference signal is formed as an area called a “optical black (OB) area” where a light-shielding film is provided on the imaging element.
The imaging signal (imaging reference signal) in the OB area is a “0” level signal with a voltage of 0 V indicating black. Of course, there are some signal variations. Even if a light-shielding film is provided on the image sensor, there is some light (stray light) that circulates from the periphery of the image sensor, and the imaging reference signal indicating the black level is always at a voltage of 0 V indicating completely black. Although there is no such value, the voltage is almost 0V within such an error range.

In this way, the OB area provides an imaging reference signal of a black (reference) level that serves as a reference for the level of the imaging signal of the imaging part.
In an imaging apparatus such as a camera, the imaging signal detected in the imaging part of the imaging device is subtracted from the imaging reference signal detected in the OB region, and the level of the imaging signal of the imaging unit is corrected.

  Patent Document 1 discloses a signal in an OB region by light transmitted through the OB region or light strayed from the imaging unit into the OB region by diffuse reflection when strong highlight light such as sunlight enters the OB region. If the reference level of the imaging signal is corrected using the black level signal of the OB area when the voltage deviates from 0V, the level of the imaging signal is relatively lowered (the luminance is reduced). For example, when the corrected video signal is displayed on a display, for example, a measure for improving the problem that a darkened image (black sun phenomenon) due to a decrease in luminance is proposed.

As a countermeasure, one dummy luminance level is provided, and the dummy luminance level is compared with the luminance level of the black level signal in the OB area, so that the luminance level of the black level signal in the OB area is far from the dummy luminance level. If the black level signal is abnormal, the dummy luminance signal is clamped and output as a black level signal in the OB area.
JP-A-2005-57608

In the optical black area (OB area), for example, there are black level signals detected by a plurality of image sensors in the horizontal direction even in one OB area defined at four locations around the imaging unit, and the vertical direction In addition, there is a black level signal corresponding to the horizontal scanning line.
However, the technique proposed in Patent Document 1 always replaces the black level signal with one fixed dummy luminance level regardless of which part of any OB region is abnormal. Therefore, the luminance level of the black level signal when an abnormality occurs is always constant.
Actually, since the level of the black level signal varies depending on the position of the OB area or the state of the imaging device, a certain dummy luminance level does not accurately indicate the black level signal of the OB area.

  It is an object of the present invention to provide a method and apparatus for correcting an imaging reference signal such as a black level signal to an appropriate value with a simple and quick processing method.

According to the first aspect of the present invention, the means for inputting the detection signal of the imaging element in the area for detecting the imaging reference signal of the imaging device provided with the imaging part and the area for detecting the imaging reference signal around the imaging part. And means for determining whether or not the input imaging reference signal is out of a normal range, and when the imaging reference signal is out of a normal range, the imaging reference signal is detected from the imaging reference signal An imaging reference signal correction device is provided, characterized by comprising imaging reference signal correction means for replacing a latest imaging reference signal that is normally detected in a region or a previous normal imaging reference signal.
According to the present invention, the step of inputting the detection signal of the imaging element in the area for detecting the imaging reference signal of the imaging device provided with the imaging part and the area for detecting the imaging reference signal around the imaging part; A step of determining whether or not an input imaging reference signal is out of a normal range; and when the imaging reference signal is out of a normal range, the imaging reference signal is An imaging reference signal correction method is provided, comprising: an imaging reference signal correction step that replaces a normally detected latest imaging reference signal or a previous normal imaging reference signal.

According to the second aspect of the present invention, the means for inputting the detection signal of the imaging element in the area for detecting the imaging reference signal of the imaging device provided with the imaging part and the area for detecting the imaging reference signal around the imaging part. And means for determining whether or not the imaging reference signal deviates from the normal range, and when the imaging reference signal deviates from the normal range, the imaging reference signal that deviates from the normal range is imaged. An imaging reference signal correction device comprising: an imaging reference signal correction unit that replaces a normally detected imaging reference signal at an adjacent position or a nearby position in the same area as the area in which the reference signal is detected is provided Is done.
According to the invention, the step of inputting the detection signal of the imaging element in the region for detecting the imaging reference signal of the imaging device provided with the imaging part and the region for detecting the imaging reference signal around the imaging portion, and the imaging A step of determining whether or not a reference signal deviates from a normal range; and when the imaging reference signal deviates from the normal range, an imaging reference signal that has deviated from the normal range is detected. An imaging reference signal correction method is provided, comprising: an imaging reference signal correction step that replaces with a normally detected imaging reference signal at an adjacent position or a nearby position in the same area as the area.

According to the third aspect of the present invention, the means for inputting the detection signal of the imaging element in the area for detecting the imaging reference signal of the imaging device provided with the imaging part and the area for detecting the imaging reference signal around the imaging part. And means for determining whether or not the imaging reference signal deviates from the normal range, and when the imaging reference signal deviates from the normal range, the imaging reference signal that deviates from the normal range is imaged. An imaging reference signal correcting unit that replaces an area where the reference signal is detected and a normally detected imaging reference signal at a corresponding position in the area where the imaging reference signal on the opposite side across the imaging part is detected; An imaging reference signal correction device is provided.
According to the invention, the step of inputting the detection signal of the imaging element in the region for detecting the imaging reference signal of the imaging device provided with the imaging part and the region for detecting the imaging reference signal around the imaging portion, and the imaging A step of determining whether or not a reference signal deviates from a normal range; and when the imaging reference signal deviates from the normal range, an imaging reference signal that has deviated from the normal range is detected. An imaging reference signal correction step comprising: a region and an imaging reference signal correcting step for replacing with a normally detected imaging reference signal at a corresponding position in a region where an imaging reference signal on the opposite side across the imaging part is detected A correction method is provided.

It is usually transient that, for example, sunlight or the like enters an area where an imaging reference signal is detected, for example, an optical black area.
According to the present invention, when an imaging detection signal in an area for detecting an imaging reference signal such as an optical black area deviates from the normal range, the imaging reference signal is updated to the latest normal in the area for detecting the imaging reference signal. Since it is replaced with the detected imaging reference signal or the previous normal imaging reference signal, such transient highlight light can be corrected in accordance with the situation of the imaging device.

  According to the present invention, when an imaging detection signal in an area for detecting an imaging reference signal such as an optical black area deviates from a normal range, the imaging reference signal is converted into an imaging reference in the vicinity of the area of the imaging detection signal. Since it is replaced with the imaging reference signal normally detected in the signal detection region, for example, it is possible to correct a transient abnormality such as sunlight incident according to the situation of the imaging device.

  Further, according to the present invention, when the imaging detection signal of the area for detecting the imaging reference signal such as the optical black area deviates from the normal range, the imaging reference signal is converted into the area for detecting the imaging reference signal on the opposite side. Since it is replaced with the imaging reference signal that is normally detected, for example, it is possible to correct a transient abnormality such as sunlight incident in accordance with the situation of the imaging device.

  Embodiments of an imaging reference signal correction method and an imaging reference signal correction apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing a device configuration of an imaging reference signal correction device according to an embodiment of the present invention.
The imaging reference signal correction apparatus 1 is used for an imaging apparatus such as a camera, and includes an imaging device unit 10 and a signal processing unit 20.

The imaging device unit 10 includes an imaging sensor (or imaging device) 11 and a sampling circuit 12.
In an imaging apparatus such as a camera, an optical system composed of various lenses such as a focus lens is usually disposed in front of the imaging sensor 11, but illustration of the optical system is omitted.

In the imaging sensor 11, for example, a plurality of elements that convert an image into an electronic signal, such as a CCD sensor or a CMOS sensor, are arranged two-dimensionally in a vertical direction and a horizontal direction.
The imaging sensor 11 detects an imaging signal from the imaging unit 11a, for example, as shown in a plan view in FIG.
The imaging sensor 11 is provided with an optical black (OB) region around the imaging unit 11a. The OB area includes an upper horizontal optical black (OB) area OB-HU, a lower horizontal OB area OB-HL, a left vertical OB area OB-VL, and a right vertical OB area OB-VR. From these OB areas, a detection signal indicating a black level is extracted using an image sensor. The detection signal is called an imaging reference signal.

The above description exemplifies an OB area that provides an imaging reference signal of a black level as an area for detecting an imaging reference signal. However, even when a reference level such as a white level is used as an imaging reference signal instead of a black level. It is the same.
Hereinafter, the OB region will be described as an example of the region for detecting the black level imaging reference signal.

The sampling circuit 12 outputs a plurality of imaging signals arranged in the imaging unit 11a and the surrounding OB areas at a predetermined scanning cycle, for example, an NTSC scanning cycle, based on detection signals from a plurality of sensor elements of the imaging sensor 11. The detection signal of the element is scanned (sampled) in the horizontal direction from the top to the bottom in the vertical direction, and the result is stored in a register in the sampling circuit 12.
The imaging signal sampled by the sampling circuit 12 and stored in the register in the sampling circuit 12 is output to the signal processing unit 20.

As illustrated in FIG. 3, for example, the signal processing unit 20 is preferably a processor 21 having a signal processing function, a bus 22, a clock generator 23, a ROM 24, a RAM 25, a signal output unit 26, An interface unit 27 and an imaging signal input unit 28 are provided.
The configuration of the signal processing unit 20 shown in FIG. 3 is conceptually illustrated, and the signal processing unit 20 is not limited to the configuration illustrated in FIG.
When the signal processing unit 20 is used in an imaging device such as a camera, a video signal processing device or the like is connected to the subsequent stage of the signal output unit 26, but the illustration is omitted.

The processor 21 includes a register REG that holds various data when performing various processes. This is called a built-in register REG. The built-in register REG has a plurality of registers.
The clock generator 23 generates a clock signal that serves as a reference for the operation of the processor 21.
The ROM 24 stores various programs processed by the processor 21. Various signal processing of the processor 21 described below is executed by a program stored in the ROM 24 operating in the processor 21.
The RAM 25 stores the processing result of the processor 21. For example, the imaging reference of each optical black area, that is, the upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB-VR. Hold the signal.
The interface unit 27 is connected to the sampling circuit 12, and signals for performing control processing of the processor 21, timing adjustment of operation with the processor 21, and operation confirmation are exchanged via the interface unit 27.
The imaging signal input unit 28 is used to take in the signal processing unit 20 an imaging signal (including an imaging reference signal in the OB area) obtained by scanning the detection signal of the imaging element in the sampling circuit 12.

  4 shows an example of the planar shape of the image sensor 11 illustrated in FIG. 2, there are horizontal lines LN <b> 2 to LN <b> 5 of the imaging unit 11 a part in the vertical scanning direction, and the upper horizontal OB region OB above and below the imaging unit 11 a part. It is assumed that −HU and the lower horizontal OB area OB-HL exist as horizontal lines LN1 and LN6, respectively.

FIG. 5 is a diagram illustrating a sampling result of the sampling circuit 12 in each horizontal line.
In FIG. 4, when strong sunlight is incident on the right vertical OB region OB-VR of the lines LN4 to LN6 and the image pickup unit in the vicinity thereof, or the left vertical OB region OB-VL (region of the lines LN5 to LN6) Z1) and the right vertical OB region OB-VR (region Z2) and the case where sunlight is incident in the vicinity of these regions are illustrated. Of course, in practice, sunlight is not normally incident on the two locations of the imaging unit 11a at the same time. However, in order to describe the signal processing method according to the embodiment of the present invention, it is assumed that such sunlight has entered. To say.

The upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB-VR are each made of a light-shielding material, such as an aluminum foil. In general, no light is incident on the image sensor in the OB area of the image sensor 11. In that case, the signal level of the image sensor in the OB region shows a value close to a voltage of approximately 0V.
Hereinafter, the state of the scanning imaging signal of each line illustrated in FIG. 5 will be described.

(1) The scanning imaging signal of the line LN1 and the line LN1 of the upper horizontal OB area OB-HU is substantially 0 V between the left vertical OB area OB-VL and the right vertical OB area OB-VR, and is normal. A black level signal (imaging reference signal) is shown.
(2) The scanning imaging signal is substantially 0 V in the lines LN2 to LN3 and the left vertical OB area OB-VL, indicating a normal black level signal. Similarly, the scanning imaging signal is almost 0 V in the right vertical OB region OB-VR, indicating a normal black level signal. Between the left vertical OB area OB-VL and the right vertical OB area OB-VR, the level of the video signal by the imaging device of the imaging unit 11a is shown.
(3) In the portion of the line LN4 and the left vertical OB area OB-VL, the scanning imaging signal is almost 0 V, indicating a normal black level signal.

  However, when strong highlight light, for example, sunlight is incident, the image sensor in the OB region part transmits light through the light-shielding film or the strong reflection of strong light that has passed through the image pickup unit near the OB region. May be detected. In that case, the detection signal of the image sensor in the OB region is considerably higher than the voltage 0V.

(4) The portion of the line LN4 and the right vertical OB region OB-VR (region Z2) is affected by sunlight, and the scanning image pickup signal of that portion shows a value considerably higher than the voltage 0V.
(5) The portion of the line LN5 and the left vertical direction OB region OB-VL (region Z1) is affected by sunlight, and the scanning imaging signal of that portion shows a value considerably higher than the voltage 0V. Similarly, the right vertical OB area OB-VR portion (area Z2) is affected by sunlight, and the scanning image pickup signal of that portion shows a value considerably higher than the voltage 0V. The scanning image pickup signal of the image pickup element of the image pickup unit that is not affected by sunlight between the region Z1 and the region Z2 shows a level corresponding to the image.
(6) Line LN6, lower horizontal OB area OB-HL, and like line LN1 (upper horizontal OB area OB-HU), all of them should be imaging reference signals with a voltage of 0 V, but sunlight The scanning image pickup signal of the part (regions Z1 and Z2) affected by the above has a value considerably higher than the voltage 0V. The scanning imaging signal of the imaging device in the lower horizontal OB region OB-HL that is not affected by sunlight shows a voltage of approximately 0 V, that is, a normal black level signal.

  For example, when the scanning imaging signal (curve CV1) of the line LN5 is output as it is from the signal processing unit 20 to the subsequent signal processing circuit and corrected with the imaging reference signal by the circuit, or by the processor 21 of the signal processing unit 20 When the imaging reference signal is corrected, the luminance of the entire level of the imaging signal of the signal of the line LN5 is lowered as indicated by the dashed curve CV2. When the result is displayed on the display device, there is a possibility that a black sun phenomenon occurs in which the luminance of the portion is reduced and displayed black.

Signal Processing Method According to First Embodiment In order to prevent such a phenomenon, in the embodiment of the present invention, the following processing described with reference to FIG. Do.
FIG. 6 is a flowchart showing the first imaging reference signal correction method according to the embodiment of the present invention performed by the processor 21.

Steps 1 and 2 : The processor 21 operates in synchronization with the clock from the clock generator 23. In step 1, the processor 21 monitors the scanning timing of the sampling circuit 12 via the interface unit 27. In the processor 21, the sampling circuit 12 It is detected that the scanning imaging signal can be input. If it is not time to input the scanning imaging signal, the processor 21 waits in step 2 with a delay.

Step 3 : When the timing at which the processor 21 can input the scanning imaging signal from the sampling circuit 12 is reached, the processor 21 continuously inputs a plurality of scanning imaging signals from the sampling circuit 12 for each horizontal scanning direction.
The input scanning imaging signal can be temporarily stored in the RAM 25 and the following processing can be performed, or the following processing can be performed in real time in the input order without being stored in the RAM 25.

Step 4 : The processor 21 performs the upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB-VR for the input scanning imaging signal. It is determined (checked) whether or not there is a scanning imaging signal of the region in any of the above.

Step 5 : In the case of a scanning image pickup signal in any one of the OB areas, it is checked whether or not the signal detected by the image pickup device is in a normal range.
The normal range is, for example, a relative normal range within several percent of the maximum luminance signal level (maximum amplitude) detected by the image sensor, or above and below the voltage 0 V, which is the original level of the black level signal. The limit value can be set as appropriate, for example, within the absolute normal range of several tens of mV.
Such upper and lower limit values are set in, for example, the built-in register REG (first and second built-in registers REG) of the processor 21.

Step 6 : When the detection signal (scanning imaging signal) by the imaging device in the OB area is in a normal range, the value is held in the third built-in register REG of the processor 21. In this way, the latest normal OB area scanning imaging signal (detection signal) is held in the third internal register REG.

Step 7 : When the scanning imaging signal of the OB area is not in the normal range, the processor 21 holds the detection signal in the third normal register REG of the processor 21 and the latest normal OB area black level signal. Replace with.
Thereby, for example, the black level signal of the right vertical OB region OB-VR of the line LN4 in FIG. 5 is replaced with the black level signal of the left vertical OB region OB-VL of the same line LN4.

Step 8 : The processor 21 obtains the scanning imaging signal (detection signal of the imaging device) in Step 6 or the normal scanning imaging signal replaced in Step 7, or the scanning imaging signal of the imaging unit 11a in Step 4 The signal is output to the subsequent signal processing circuit via the signal output unit 26.

When the signal processing described above is performed, the example described with reference to FIGS. 4 and 5 is as follows.
The black level signal of the line LN4 and the right vertical OB area OB-VR (area Z2) is the left vertical direction of the same line LN4 which is the latest normal imaging reference signal stored in the third internal register REG. It is replaced with a black level signal (scanning imaging signal) in the OB area OB-VL.
The scanning imaging signal of the line LN5 and the left vertical OB area OB-VL is also the latest normal imaging reference signal stored in the third built-in register REG, and is the left vertical OB area OB of the previous line LN4. Replaced by a black level signal of -VL. Note that the scanning imaging signal of the imaging unit 11a is not replaced even in the region Z1 where the luminance is high due to the influence of sunlight.
Similarly, the scanning imaging signal of the right vertical OB area OB-VR is also the latest normal black level signal stored in the third built-in register REG, which is the left vertical OB area OB-VL of the line LN4. Replaced with black level signal. Note that the scanning image pickup signal of the image pickup unit 11a remains unchanged even in the region Z2 affected by sunlight.
Line LN6 : The latest normal black level stored in the third built-in register REG is the scanning imaging signal of the part (area Z1) affected by sunlight in the lower horizontal OB area OB-HL. The signal is replaced with the black level signal of the left vertical OB region OB-VL of the line LN4.

As described above, in this example, from the right vertical OB area OB-VR of the line LN4 to the area Z1 of the line LN6, the latest normal black level signal is in the left vertical OB area OB-VL of the line LN4. This is a black level signal.
In the line LN6, the scanning image pickup signal in the portion beyond the region Z1 is normal, and these normal black level signals are sequentially updated and held in the third built-in register REG.
In the lower horizontal direction OB area OB-HL, the scanning imaging signal of the part (area Z2) affected by sunlight is the latest normal black level signal in the area beyond the area Z1, Is replaced with a black level signal stored in the internal register REG.

For example, it is temporary (temporary) to perform imaging in a state where sunlight or the like is incident on the imaging sensor 11. Alternatively, it is usually instantaneous or transient that sunlight or the like enters the image sensor 11.
When the black level signal in the OB area deviates from the normal range as described above, the latest black that has been normally detected in the OB area held in the third built-in register REG is detected when the abnormality is detected. Since the level signal is used for replacement, it is possible to correct the imaging reference signal in accordance with the situation of the imaging device with respect to such transient highlight light.

The imaging reference signal correction apparatus 1 has an advantage that only one built-in register REG is used to hold the latest normal black level signal in the OB region, and two built-in registers REG are used to hold the limit value. There is.
Signal processing is also simple. Therefore, the configuration of the signal processing unit 20 illustrated in FIG. 3 can be realized by a hardware circuit without using a computer having the processor 21, the clock generator 23, the ROM 24, and the like. In that case, a timing adjustment circuit that performs the processing in steps 1 and 2, an imaging data input circuit that performs the processing in step 3, a first comparison circuit that performs the processing in step 4, and a second comparison circuit that performs the processing in step 5 And a register for performing the process of step 6, a replacement circuit for performing the process of step 7, and a data output circuit for performing the process of step 8.

The above process is simple. Therefore, the processing speed is rapid, the above processing can be performed in accordance with the input timing of the signal input from the sampling circuit 12, and the signal can be processed without causing a signal processing delay in the scanning imaging signal input from the sampling circuit 12. There is an advantage that the signal can be continuously output to the subsequent signal processing circuit via the output unit 26.
For example, when the signal processing circuit in the subsequent stage corrects (subtracts) the level of the imaging signal of the imaging unit using the imaging reference signal corrected with the black level signal, and displays the result on the display device in real time Real time can be satisfied.

Imaging Reference Signal Correction Processing Method According to Second Embodiment An imaging reference signal correction method and imaging reference signal correction apparatus according to the second embodiment of the present invention will be described with reference to FIGS.
In the second embodiment, instead of storing one normal scanning image pickup signal in the built-in register REG as in the first embodiment, for example, in the RAM 25, for example, as illustrated in FIG. A part for storing normal data in the upper horizontal OB area OB-HU, a part for storing normal data in the lower horizontal OB area OB-HL, and a normal data in the left vertical OB area OB-VL, respectively. A portion for storing normal data in the right vertical OB area OB-VR is secured.
For example, the normal data storage amount in the upper horizontal OB area OB-HU requires a memory of (number of scanning points of the OB area in each horizontal line). Similarly, the amount of normal data stored in the left vertical OB area OB-VL requires (number of scanning points of the OB area area in each horizontal line) × (number of lines in the vertical direction).

Thus, the memory storage area is secured in the RAM 25, and the processor 21 performs the processing shown in the flowchart of FIG.
In FIG. 8, the same steps as those in FIG. 6 are given the same step numbers.

Steps 1 and 2 : The processor 21 operates in synchronization with the clock from the clock generator 23, and can input the scanning imaging signal of the sampling circuit 12 in the same manner as the operations in Steps 1 and 2 described with reference to FIG. Detect that become.

Step 3 : Similarly to the operation in Step 3, the processor 21 continuously collects a plurality of scanning imaging signals from the sampling circuit 12 in one horizontal scanning direction at a timing when the scanning imaging signals can be input from the sampling circuit 12. And input.
Saving of the input scanning imaging signal is the same as the method described with reference to FIG.

Step 4 : The processor 21 includes the upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB- It is determined (checked) whether or not there is a scanning imaging signal in an area in any of the VRs.

Step 5 : It is checked whether or not the signal detected by the image sensor is within the normal range for the scanning image pickup signal in any one of the OB areas.
Such upper and lower limit values may be set in the internal register REG (first and second internal registers REG) of the processor 21 or may be set in the RAM 25, for example.

Step 16 : When the detection signal (black level signal) from the image sensor in the OB area is in a normal range, the value is stored in the corresponding part of the normal data storage area of the RAM 25 described above.

Step 17 : When the detection signal (black level signal) of the OB area is not within the normal range, the processor 21 uses the detection signal as a normal black level signal at the corresponding position of the corresponding OB area stored in the RAM 25. Replace with.
Accordingly, for example, the black level signal of the right vertical OB region OB-VR of the line LN4 in FIG. 5 is a normal black level signal at the same position that is stored in the RAM 25 and is not affected by sunlight. Replaced.
The influence of sunlight or the like is transient. For example, the black level signal in the right vertical OB area OB-VR of the line LN4 in FIG. Replaced by signal.

Step 8 : The processor 21 outputs the scanning imaging signal (detection signal of the imaging device) in Step 16 or the normal scanning imaging signal replaced in Step 17 or the scanning imaging signal of the imaging unit 11a to the signal output unit 26. To the subsequent signal processing circuit.

As described above, for example, it is temporary to perform imaging in a state where sunlight or the like is incident on the imaging sensor 11. Alternatively, it is usually instantaneous or transient that sunlight or the like enters the image sensor 11.
Since the black level signal affected by sunlight or the like is replaced with a normal black level signal stored in the RAM 25 and not affected by sunlight or the like at the same position, the image sensor 11 actually It is possible to correct the imaging reference signal according to the situation and the black level signal at the same position in the OB area.

The above process is simple. Therefore, the processing speed is rapid, the above processing can be performed in accordance with the input timing of the signal input from the sampling circuit 12, and the signal can be processed without causing a signal processing delay in the scanning imaging signal input from the sampling circuit 12. There is an advantage that the signal can be continuously output to the subsequent signal processing circuit via the output unit 26.
For example, when the signal processing circuit in the subsequent stage corrects (subtracts) the level of the imaging signal of the imaging unit using the imaging reference signal corrected with the black level signal, and displays the result on the display device in real time Real time can be satisfied.

Imaging Reference Signal Correction Processing Method of Third Embodiment With reference to FIGS. 7 and 9, an imaging reference signal correction method and an imaging reference signal correction device of the third embodiment will be described.
In the imaging reference signal correction method and imaging reference signal correction apparatus of the third embodiment, one normal scanning imaging signal is stored in the built-in register REG as in the first embodiment. As in the imaging reference signal correction method of the embodiment, the RAM 25 stores, for example, the normal data in the upper horizontal OB area OB-HU and the lower horizontal OB area OB as illustrated in FIG. A part for storing normal data of HL, a part for storing normal data in the left vertical OB area OB-VL, and a part for storing normal data in the right vertical OB area OB-VR are secured.

The processor 21 performs the processing shown in the flowchart in FIG.
In FIG. 9, the same step numbers as in FIGS. 6 and 8 indicate the same operations (processes).

Steps 1 and 2 : The processor 21 operates in synchronization with the clock from the clock generator 23 and detects that the scanning imaging signal of the sampling circuit 12 can be input.

Step 3 : When the timing at which the scanning imaging signal can be input from the sampling circuit 12 is reached, the processor 21 continuously inputs a plurality of scanning imaging signals from the sampling circuit 12 for each horizontal scanning direction.
Saving of the input scanning imaging signal is the same as the method described with reference to FIG.

Step 4 : The processor 21 includes the upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB- It is determined (checked) whether or not there is a scanning imaging signal in an area in any of the VRs.

Step 5 : In the case of a scanning image pickup signal in any one of the OB areas, it is checked whether or not the signal detected by the image pickup device is in a normal range.

Step 16 : When the detection signal (scanning imaging signal) by the image sensor in the OB area is in a normal range, the processor 21 sets the value of the normal black level signal in the corresponding part of the normal data storage area of the RAM 25 described above. Save to.
Step 21 : The processor 21 further stores the value of the normal black level signal in the internal register REG of the processor 21 as the latest normal black level signal.

Step 22 : The processor 21 stores the black level signal in an abnormal state by the image sensor in the OB area as it is in the corresponding portion of the normal data storage area of the RAM 25 described above. Therefore, the stored black level signal is in an abnormal state.

Step 23 : The processor 21 determines whether or not a normal black level signal exists in the same OB area, for example, in the same upper horizontal OB area OB-HU, at a position adjacent to the detection signal or at a nearby position. Check by referring to the black level signal stored in.
The position in the vicinity is, for example, about several lines in the vertical direction of the image sensor 11 and about several digits in the horizontal direction. This is because if it is too far from the target position, there is a possibility that it is deviated from the black level signal at that position.

Step 24 : If there is a normal black level signal at an adjacent position or a nearby position, the processor 21 replaces the abnormal black level signal with the normal black level signal.
As described above, in this embodiment, when an abnormality is detected, correction is performed with a normal black level signal at a position adjacent to or adjacent to the position.

Step 25 : If there is no normal black level signal at the adjacent position or a nearby position, the processor 21 uses the latest normal black level signal stored in the step 21 to store the abnormal black level signal. Replace level signal.
Since the latest normal black level signal of the image sensor 11 is stored in the built-in register REG, even if there is no normal black level signal at an adjacent position or a nearby position, the latest normal black level signal is stored. Can be corrected by signal.

Step 8 : The processor 21 processes the black level signal in Step 16 or the black level signal replaced in Step 24 or Step 25 or the scanning imaging signal of the imaging unit 11a via the signal output unit 26 in the subsequent stage. Output to the circuit.

  In this embodiment, when an abnormality is detected, (1) first, correction is performed with a normal black level signal at a position adjacent to or near the position, and (2) when the correction is difficult, Correction is performed with the latest normal black level signal stored in the internal register REG.

Imaging Reference Signal Correction Processing Method According to Fourth Embodiment An imaging reference signal correction method and imaging reference signal correction apparatus according to a third embodiment will be described with reference to FIGS.
In the imaging reference signal correction method and imaging reference signal correction apparatus of the fourth embodiment, in addition to storing one normal scanning imaging signal in the built-in register REG as in the first and third embodiments, for example, Similar to the imaging reference signal correction methods of the second and third embodiments, the RAM 25 stores, for example, normal horizontal data in the upper horizontal OB area OB-HU, respectively, as illustrated in FIG. A portion for storing normal data in the direction OB area OB-HL, a portion for storing normal data in the left vertical OB area OB-VL, and a portion for storing normal data in the right vertical OB area OB-VR are secured. To do.

The processor 21 performs the processing shown in the flowchart in FIG.
In FIG. 10, the same step numbers as those in FIGS. 6, 8, and 9 indicate the same operations (processes).

Steps 1 and 2 : The processor 21 operates in synchronization with the clock from the clock generator 23 and detects that the scanning imaging signal of the sampling circuit 12 can be input.

Step 3 : When the timing at which the scanning imaging signal can be input from the sampling circuit 12 is reached, the processor 21 continuously inputs a plurality of scanning imaging signals from the sampling circuit 12 for each horizontal scanning direction.
Saving of the input scanning imaging signal is the same as the method described with reference to FIG.

Step 4 : The processor 21 includes the upper horizontal OB area OB-HU, the lower horizontal OB area OB-HL, the left vertical OB area OB-VL, and the right vertical OB area OB- It is determined (checked) whether or not there is a scanning imaging signal in an area in any of the VRs.

Step 5 : In the case of a scanning image pickup signal in any one of the OB areas, it is checked whether or not the signal detected by the image pickup device is in a normal range.

Step 16 : When the detection signal (scanning imaging signal) by the image sensor in the OB area is in a normal range, the processor 21 sets the value of the normal black level signal in the corresponding part of the normal data storage area of the RAM 25 described above. Save to.
Step 21 : The processor 21 further stores the value of the normal black level signal in the internal register REG of the processor 21 as the latest normal black level signal.

Step 22 : The processor 21 stores the black level signal in an abnormal state by the image sensor in the OB area as it is in the corresponding portion of the normal data storage area of the RAM 25 described above. Therefore, the stored black level signal is in an abnormal state.

Step 31 : The processor 21 is the OB area opposite to the OB area in which the image pickup device that has obtained the detection signal is disposed, for example, the lower horizontal OB area OB- with respect to the upper horizontal OB area OB-HU. Whether or not a normal black level signal is present at a corresponding position in the OB or its reverse OB area, or in the right vertical OB area OB-VR or its reverse OB area with respect to the left vertical OB area OB-VL Is checked with reference to the black level signal stored in the RAM 25.
The corresponding position is, for example, the same horizontal scanning position of the lower horizontal OB area OB-HL for the upper horizontal OB area OB-HU, and the right vertical direction for the left vertical OB area OB-VL. This is the position of the horizontal scanning line in the same vertical direction of the OB area OB-VR.

Step 32 : If there is a normal black level signal at the corresponding position in the opposite OB area, the processor 21 replaces the abnormal black level signal with the normal black level signal.
As described above, in the present embodiment, when an abnormality is detected, correction is performed with a normal black level signal at a corresponding position in the OB area opposite to the position of the OB area.

  Such a correction method is particularly suitable for the lower horizontal OB when, for example, almost the entire upper horizontal OB area OB-HU is affected by sunlight, as shown in FIG. Correct the normal black level signal in the region OB-HL, or correct the normal in the right vertical OB region OB-VR when almost the entire left vertical OB region OB-VL is affected by sunlight. It can be corrected with a black level signal and is effective.

Step 25 : If there is no normal black level signal at the corresponding position in the opposite OB area, the processor 21 uses the latest normal black level signal in the internal register REG stored in Step 21 to detect the abnormal black level signal. Replace level signal.
Since the latest normal black level signal of the image sensor 11 is stored in the built-in register REG, even if there is no normal black level signal at the corresponding position in the opposite OB area, the latest normal black level signal is stored. Can be corrected with a signal.

Step 8 : The processor 21 processes the black level signal in Step 16 or the black level signal replaced in Step 32 or Step 25, or the scanning imaging signal of the imaging unit 11a via the signal output unit 26 in the subsequent stage. Output to the circuit.

  In this embodiment, when an abnormality is detected, (1) first, correction is performed with a normal black level signal at a corresponding position opposite to the OB area, and (2) when correction is difficult. Then, the latest normal black level signal stored in the built-in register REG is used for correction.

Other Embodiments The implementation of the imaging reference signal correction method and imaging reference signal correction apparatus of the present invention is not limited to the above-described embodiment.
For example, the above-described first to fourth embodiments can be appropriately combined or selected for use.

  For example, first, when the processor 21 observes the imaging signal of the OB area as a whole and the 1OB area is totally affected by sunlight as shown in FIG. 11A or 11B. The imaging reference signal correction method according to the fourth embodiment described with reference to FIG. 10 is selected.

  Alternatively, first, when the processor 21 observes the entire image signal of the OB area and the 1OB area is partially influenced by sunlight, the processor 21 of the third embodiment described with reference to FIG. An imaging reference signal correction method is selected.

  First, when the processor 21 observes the entire image signal of the OB area and is not affected by sunlight until the previous time and is affected by sunlight during the current scan, FIG. The imaging reference signal correction method of the second embodiment described with reference is selected.

  When complicated processing is not desired, the imaging reference signal correction method of the first embodiment described with reference to FIG. 6 is selected.

  The above description exemplifies an OB area that provides an imaging reference signal of a black level as an area for detecting an imaging reference signal. However, even when a reference level such as a white level is used as an imaging reference signal instead of a black level. It is the same.

FIG. 1 is a diagram showing a device configuration of an imaging reference signal correction device as an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a plan view of the imaging sensor illustrated in FIG. 1. FIG. 3 is a diagram illustrating a configuration example of the signal processing unit illustrated in FIG. 1. FIG. 4 is a diagram illustrating an example of the planar shape of the imaging sensor illustrated in FIG. 2. In the vertical scanning direction, there are horizontal lines LN2 to LN5 of the imaging unit portion, and the upper horizontal direction OB region above and below the imaging unit portion. And the lower horizontal OB area are assumed to exist as horizontal lines LN1 and LN6, respectively. FIG. 5 is a diagram illustrating a sampling result of the sampling circuit for each horizontal line in the imaging sensor illustrated in FIG. FIG. 6 is a flowchart showing a first imaging reference signal correction method according to the embodiment of the present invention. FIG. 7 is a diagram for explaining storing normal data of each optical black region as the second imaging reference signal correction method according to the embodiment of the present invention. FIG. 8 is a flowchart showing a second imaging reference signal correction method according to the embodiment of the present invention. FIG. 9 is a flowchart showing a third imaging reference signal correction method according to the embodiment of the present invention. FIG. 10 is a flowchart showing a fourth imaging reference signal correction method according to the embodiment of the present invention. 11A and 11B are diagrams for explaining a fourth imaging reference signal correction method according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Imaging reference signal correction apparatus 10 ... Imaging device unit
11 ... Imaging sensor
11a ... Imaging unit
OB-HU: Upper horizontal optical black area
OB-HL: Lower horizontal optical black area
OB-VL: Left side vertical optical black area
OB-VR: right vertical optical black area
12 ... Sampling circuit 20 ... Signal processing unit
21 ... Processor 22 ... Bus, 23 ... Clock generator
24 ... ROM, 25 ... RAM, 26 ... signal output section
27: Interface unit, 28 ... Imaging signal input unit

Claims (14)

Means for inputting a detection signal of an imaging device in an area for detecting the imaging reference signal of an imaging device provided with an imaging part and an area for detecting an imaging reference signal around the imaging part;
Means for determining whether or not the input imaging reference signal deviates from a normal range;
When the imaging reference signal deviates from the normal range, the imaging reference signal is replaced with the latest detected imaging reference signal or the previous normal imaging reference signal that is normally detected in the region where the imaging reference signal is detected. An imaging reference signal correction device, comprising: an imaging reference signal correction unit. Holding means for holding the latest imaging reference signal detected normally in the region for detecting the imaging reference signal;
The imaging reference signal correcting means replaces the imaging reference signal with an imaging reference signal held in the holding means when the imaging reference signal is out of a normal range.
The imaging reference signal correction device according to claim 1, wherein The area for detecting the imaging reference signal around the imaging part is composed of four areas in the vertical and horizontal directions and the horizontal direction,
Holding means for holding imaging reference signals detected in the four areas;
The holding means holds imaging reference signals normally detected in the four areas,
The imaging reference signal correction means, when the imaging reference signal in any one of the four areas deviates from the normal range, the imaging reference signal is held in the holding means and the corresponding normal imaging Replace with the reference signal,
The imaging reference signal correction device according to claim 1, wherein Means for inputting a detection signal of an imaging element in an area for detecting the imaging reference signal of an imaging device provided with an imaging part and an area for detecting an imaging reference signal around the imaging part;
Means for determining whether or not the imaging reference signal deviates from a normal range;
When the imaging reference signal deviates from the normal range, the imaging reference signal that deviates from the normal range is normally detected at an adjacent position or a nearby position in the same area as the area where the imaging reference signal is detected. An imaging reference signal correction device, comprising: an imaging reference signal correction unit that replaces the acquired imaging reference signal. First holding means for holding the latest normal imaging reference signal that has been normally detected in the region where the imaging reference signal is detected;
When there is no normally detected imaging reference signal at an adjacent position or a nearby position in the same region, an imaging reference signal that deviates from the normal range is stored in the first normal means. Replace with a standard imaging reference signal,
The imaging reference signal correction apparatus according to claim 4, wherein The area for detecting the imaging reference signal around the imaging part is composed of four areas in the vertical and horizontal directions and the horizontal direction,
Second holding means for holding imaging reference signals detected in the four areas;
The second holding means holds imaging reference signals normally detected in the four areas.
The imaging reference signal correction apparatus according to claim 4, wherein Means for inputting a detection signal of an imaging element in an area for detecting the imaging reference signal of an imaging device provided with an imaging part and an area for detecting an imaging reference signal around the imaging part;
Means for determining whether or not the imaging reference signal deviates from a normal range;
When the imaging reference signal deviates from the normal range, an imaging reference signal that deviates from the normal range is detected, and an imaging reference signal on the opposite side across the area where the imaging reference signal is detected and the imaging portion is detected. An imaging reference signal correction device comprising: an imaging reference signal correction unit that replaces a normally detected imaging reference signal at a corresponding position in a region to be processed. First holding means for holding the latest normal imaging reference signal that has been normally detected in the region where the imaging reference signal is detected;
When there is no normally detected imaging reference signal at an adjacent position or a nearby position in the same region, an imaging reference signal that deviates from the normal range is stored in the first normal means. Replace with a standard imaging reference signal,
The imaging reference signal correction apparatus according to claim 7, wherein The area for detecting the imaging reference signal around the imaging part is composed of four areas in the vertical and horizontal directions and the horizontal direction,
Second holding means for holding imaging reference signals detected in the four areas;
The second holding means holds imaging reference signals normally detected in the four areas.
The imaging reference signal correction apparatus according to claim 7, wherein The area for detecting the imaging reference signal is an optical black area in which the imaging element is shielded by a light shielding film,
The imaging reference signal is a black reference level signal;
The imaging reference signal correction device according to claim 1. Inputting a detection signal of an imaging element in an area where the imaging reference signal is detected in an imaging device provided with an imaging part and an area where an imaging reference signal is detected around the imaging part;
Determining whether the input imaging reference signal deviates from the normal range; and
When the imaging reference signal deviates from the normal range, the imaging reference signal is replaced with the latest detected imaging reference signal or the previous normal imaging reference signal that is normally detected in the region where the imaging reference signal is detected. An imaging reference signal correction method comprising: an imaging reference signal correction step. Inputting a detection signal of an imaging element in an area where the imaging reference signal is detected in an imaging device provided with an imaging part and an area where an imaging reference signal is detected around the imaging part;
Determining whether the imaging reference signal deviates from a normal range;
When the imaging reference signal deviates from the normal range, the imaging reference signal that deviates from the normal range is normally detected at an adjacent position or a nearby position in the same area as the area where the imaging reference signal is detected. An imaging reference signal correction method comprising: an imaging reference signal correction step that replaces the acquired imaging reference signal. Inputting a detection signal of an imaging element in an area where the imaging reference signal is detected in an imaging device provided with an imaging part and an area where an imaging reference signal is detected around the imaging part;
Determining whether the imaging reference signal deviates from a normal range;
When the imaging reference signal deviates from the normal range, an imaging reference signal that deviates from the normal range is detected, and an imaging reference signal on the opposite side across the area where the imaging reference signal is detected and the imaging portion is detected. An imaging reference signal correction method comprising: an imaging reference signal correction step of replacing with a normally detected imaging reference signal at a corresponding position in a region to be performed. The area for detecting the imaging reference signal is an optical black area in which the imaging element is shielded by a light shielding film,
The imaging reference signal is a black reference level signal;
The imaging reference signal correction method according to claim 11.

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