JP2005184641A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus for storing an imaged image by allowing noise reduction processing to be operated in a moving picture mode and allowing the noise reduction processing not to be operated in a still picture mode. <P>SOLUTION: The imaging apparatus for outputting an image signal imaged by a CCD is provided with: signal processing sections (47, 49, 63, 64, 65, 66) for reducing noise included in the image signal; a SW (51) for switching whether or not the image signal is to pass through the signal processing sections (47, 49, 63, 64, 65, 66); and an image memory (46) for storing the image signal obtained by switching operation by the SW (51). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solid-state imaging device, and more particularly to a noise reduction method for a solid-state imaging device suitable for a microscope camera or the like.

  In recent years, a subject image optically photographed by a photographing optical system such as a photographing lens is photoelectrically converted by an image pickup means such as an image pickup device, and an image signal as an electric signal obtained by photoelectric conversion is electronically recorded. Electronic imaging devices such as electronic cameras (hereinafter referred to as electronic cameras) are widely used. In such an electronic camera, a CCD or the like is generally used as an imaging means.

Usually, the image signal as an electrical signal obtained by photoelectric conversion by a CCD includes fixed pattern noise due to defects such as white spot scratches caused by various factors during the manufacturing process of the CCD, shot noise, etc. Random noise.
Therefore, in order to display a better image on the display means or the like, various signal processing for suppressing or removing noise or the like from the image signal is performed. In addition, in order to faithfully display the subject image as an image, various signal processes for performing various corrections on the image signal are performed.

  As a noise reduction method for performing noise reduction of the image signal in real time, a noise compression device using a noise coring method as shown in FIG. 26 is known (for example, Patent Document 1, Patent Document 2, and Patent Document 3). This method is a method for removing small amplitude component noise in the high frequency component of the video signal.

  In FIG. 26, a low-pass filter (hereinafter referred to as “LPF”) 47 that extracts a low-frequency signal component that is equal to or lower than a predetermined frequency of an input signal, and a high-pass filter (hereinafter referred to as “LPF”) that extracts a high-frequency signal component that is higher than a predetermined frequency of the input signal 64), a coring circuit 65 for limiting the signal passed through the HPF 64 at a predetermined coring level, and an adder 52 for adding the output signal of the coring circuit 65 and the output signal of the LPF 47 And are sequentially connected.

  FIG. 27 shows input / output characteristics of coring processing by the coring unit in a general electronic imaging apparatus. As shown in the figure, in the normal coring process, a coring level K (dead band) is provided to the output corresponding to the input A2 of the edge signal extracted from the A2 signal of the image signal by the HPF unit 64. The noise component of the output of the edge signal is suppressed. In other words, the input P1 point of the coring circuit 65 and the output P2 point of the coring circuit 65 are limited by the coring level K as shown in FIG.

  In such coring processing, the S / N ratio is improved as shown in FIG. 28 as the noise level to be suppressed is increased by increasing the coring level K, that is, as the coring level is increased. If the coring level is set low, the S / N ratio tends to deteriorate.

  FIG. 29 is a diagram for explaining the operation of the noise compression apparatus according to the noise coring method of FIG. For example, a captured image signal including noise as shown in FIG. 29A is input to the noise compression apparatus as an input signal. The LPF 47 extracts low-frequency signal components including only low-frequency components as shown in FIG. 29B from this signal. In the HPF 64, a high frequency signal component in the captured image signal as shown in FIG. 29C is obtained from this signal. A small amplitude component in the high frequency signal component is a noise component.

  Therefore, in the coring circuit 65, the limiter level is set by the coring level K, the noise component having an amplitude smaller than the limiter level is removed, and the high frequency signal component from which the noise component is removed as shown in FIG. can get. Finally, the low-frequency signal component extracted by the LPF 47 and the high-frequency signal component from which noise is removed by the coring circuit 65 are mixed by the adder 52, and noise is removed as shown in FIG. Main signal is output.

  In the above-described conventional electronic camera, control circuits such as AE (auto exposure) and AF (auto focus) for automatically performing operations such as exposure adjustment and focus adjustment necessary for photographing a subject image. It is common to provide a camera to facilitate the operation of the camera. Further, it can be classified into a moving image mode when performing AE, AF, framing for adjusting the angle of view, and the like, and a still image mode for recording a still image on a recording medium or the like.

On the other hand, in a field that handles weak light, such as a fluorescence observation method that is one of the observation methods of a microscope, a numerical analysis is required, so that raw data without image processing is required.
FIG. 30 is a timing chart when this weak light is taken into a still image. The synchronization signal VD in units of one frame, the operation mode of the CCD image sensor, the transfer pulse TG from the charge accumulation region to the vertical transfer path in order from the top. , Substrate applied high voltage pulse VSUB for forcibly discharging charges in the charge storage region to the semiconductor substrate (substrate = vertical overflow drain VOFD), circuit gain state, signal output SIG signals, memory recording operation, liquid crystal and monitor The image output to output is shown.

Since the subject is faint light, increase the gain (four times that in still image mode) to increase the frame rate in the movie mode to adjust the focus and angle of view, and expose for a long time during still image shooting. And shooting. Then, noise is superimposed on the image output in order to increase the gain during moving images.
JP 7-16288 A JP-A-11-112837 JP 11-1113012 A

However, image data measured / measured by a microscope, etc., may be used depending on the purpose of testing / research, etc., even when raw data (raw data) that has not undergone image processing is required. Must be stored separately.
However, such data need only be still images, and even moving images need not be raw data, so image data is stored as raw data in still image mode, and image processing such as noise removal is performed in moving image mode. It is possible to do. However, since the frame rate increases in the moving image mode, the exposure time is correspondingly shortened and the level of the output image signal is reduced. Therefore, the gain is increased to increase the image signal level, but noise is also increased accordingly. Therefore, since the gain is increased in this way, the S / N is poor and there is a case where the image signal cannot be confirmed unless a still image is taken (because noise is superimposed, the image signal is Because it is buried in noise).

  In view of the above-described problems, the present invention provides an imaging apparatus that stores a captured image without operating noise reduction processing in the moving image mode and without performing noise reduction processing operation in the still image mode. In video mode (rec view), noise reduction processing is performed while increasing the gain by shortening the exposure time, and when capturing still images, the exposure time is increased and the gain is decreased, and recording is performed without performing the noise reduction processing operation. Thus, an imaging apparatus capable of obtaining a still image with a high frame rate and a high S / N and without image processing is provided.

  According to the first aspect of the present invention, in the imaging device that outputs an image signal captured by an imaging device, the noise reduction unit that reduces noise included in the image signal, and Storage control means for performing control for storing either an image signal or an image signal with reduced noise, wherein the noise reduction means extracts a low frequency component of the image signal. Among the high frequency components extracted by the high frequency component extraction means, the high frequency component extraction means for extracting the high frequency component of the image signal, and the high frequency component extraction means, an amplitude greater than a predetermined value is extracted. By providing an imaging device, comprising: an amplitude extracting unit configured to perform synthesis; and a synthesizing unit configured to combine the low frequency component and the high frequency component having an amplitude greater than or equal to the predetermined value. It can be achieved.

With this configuration, the captured image can be stored as an image signal (raw data) that has not been subjected to noise reduction or as an image signal that has undergone noise reduction processing.
According to the second aspect of the present invention, the storage control unit reduces the noise by the noise reduction unit when the moving image is captured by the imaging device. 2. The imaging apparatus according to claim 1, wherein when the image signal is stored and a still image is captured by the imaging apparatus, the image signal that is captured by the imaging element is stored. Can be achieved.

With this configuration, a still image can be stored as an image signal (raw data) that has not been subjected to noise reduction, and a moving image can be stored as an image signal that has undergone noise reduction processing.
According to the third aspect of the present invention, when a moving image is acquired, the image signal is amplified to increase the level of the image signal, and 2. The imaging apparatus according to claim 1, wherein when an exposure time is shortened and a still image is acquired, the level of the image signal is decreased and the exposure time of the imaging element is increased. Can be achieved.

  By configuring in this way, the noise reduction process is operated while increasing the gain by shortening the exposure time in the moving image mode (REC view), and the gain is decreased by increasing the exposure time when capturing a still image. By recording without performing the processing operation, it is possible to obtain a still image with a high frame rate and a high S / N and without image processing.

  According to a fourth aspect of the present invention, the imaging device further includes a first storage unit and a second storage unit, and the storage control unit includes the imaging device. When shooting a moving image, the image signal with the noise reduced by the noise reduction unit is stored in the first storage unit, and when shooting a still image with the imaging device, the imaging It can achieve by providing the image pick-up device according to claim 1, wherein the image signal which has been picked up by an element is stored in the second storage means.

With this configuration, a storage device that stores a moving image and a still image can be provided separately.
According to the invention described in claim 5, the storage control means reduces the noise by the noise reduction means when the moving image is captured by the imaging device. When storing an image signal and capturing a still image with the imaging device, storing the image signal as captured by the imaging device and the image signal with noise reduced by the noise reduction means This can be achieved by providing the imaging device according to claim 1.

With this configuration, a still image with and without noise reduction can be instantaneously recorded on a storage medium.
According to a sixth aspect of the present invention, the amplitude extracting unit is configured to set the predetermined value in accordance with the image signal. This can be achieved by providing an imaging device.

With this configuration, the coring level can be varied according to the signal level, so that noise reduction according to the level correction is possible.
According to the seventh aspect of the present invention, the image pickup device includes an in-element signal adding unit that adds the picked-up image signal inside the image pickup device, and the amplitude extracting unit. Can be achieved by providing the imaging apparatus according to claim 1, wherein the predetermined value is set according to a result of the addition.

By configuring in this way, the coring level can be varied according to the number of binning, so that optimum noise reduction is possible.
According to the invention described in claim 8, the above-described problem further includes low-frequency component extraction range control means for controlling the range of the frequency component extracted by the low-frequency component extraction means. This can be achieved by providing the imaging device according to claim 1.

With this configuration, it is possible to vary the noise reduction effect.
According to the ninth aspect of the present invention, the frequency component range is controlled by the size of a filter matrix and the weighting of elements of the matrix. This can be achieved by providing the imaging device according to 8.

With this configuration, it is possible to vary the noise reduction effect.
According to the invention described in claim 10, the above-mentioned problem further includes high frequency component extraction range control means for controlling the range of the frequency component extracted by the high frequency component extraction means. This can be achieved by providing the imaging device according to claim 1.

With this configuration, it is possible to vary the noise reduction effect.
According to the eleventh aspect of the present invention, the frequency component range is controlled by the size of a filter matrix and the weighting of elements of the matrix. 10 can be achieved.

With this configuration, it is possible to vary the noise reduction effect.
According to the invention described in claim 12, the above object can be achieved by providing a microscope system provided with the imaging device described in any one of claims 1-11.

By configuring in this way, a microscope system using an electronic imaging device having a good S / N by setting an LPF and a coring level suitable for changing the resolution by exchanging an objective lens or the like. Can be provided.
According to the invention described in claim 13 of the invention, the object is a method of controlling an image pickup apparatus that outputs an image signal picked up by an image pickup device, wherein the image signal and noise are reduced. One of the signals is stored, and the noise reduction is performed by extracting a low frequency component of the image signal, extracting a high frequency component of the image signal, An imaging apparatus comprising: extracting an amplitude greater than or equal to a predetermined value from frequency components, and combining the low frequency component and a high frequency component having an amplitude greater than or equal to the predetermined value. This can be achieved by providing a control method.

With this configuration, the captured image can be stored as an image signal (raw data) that has not been subjected to noise reduction or as an image signal that has undergone noise reduction processing.
According to the invention described in claim 14, when the moving image is captured by the imaging device, the noise of the image signal is reduced and stored, and the imaging device 14. When taking a still image, the image signal that has been picked up by the image pickup device is stored, and this can be achieved by providing a control method for an image pickup apparatus according to claim 13.

With this configuration, a still image can be stored as an image signal (raw data) that has not been subjected to noise reduction, and a moving image can be stored as an image signal that has undergone noise reduction processing.
According to the fifteenth aspect of the present invention, when a moving image is acquired, the image signal is amplified to increase the level of the image signal, and 14. The method of controlling an imaging apparatus according to claim 13, wherein when the exposure time is shortened and a still image is acquired, the level of the image signal is decreased and the exposure time of the imaging element is increased. Can be achieved by providing.

  By configuring in this way, the noise reduction process is operated while increasing the gain by shortening the exposure time in the moving image mode (REC view), and the gain is decreased by increasing the exposure time when capturing a still image. By recording without performing the processing operation, it is possible to obtain a still image with a high frame rate and a high S / N and without image processing.

  According to the invention described in claim 16, when the moving image is captured by the imaging device, the image signal in which the noise is reduced is stored, and the imaging device 14. When capturing a still image, the image signal that has been picked up by the image pickup device and the image signal in which noise has been reduced by the noise reduction means are stored. This can be achieved by providing a method for controlling the imaging apparatus.

With this configuration, a still image with and without noise reduction can be instantaneously recorded on a storage medium.
According to the invention described in claim 17 of the scope of the invention, the predetermined value is set in accordance with the image signal in the extraction of the amplitude greater than or equal to the predetermined value. This can be achieved by providing the control method of the image pickup apparatus according to 13.

With this configuration, the coring level can be varied according to the signal level, so that noise reduction according to the level correction is possible.
According to the invention described in claim 18, the image pickup device includes an in-element signal adding means for adding the picked-up image signal inside the image pickup device, and is equal to or greater than the predetermined value. The amplitude can be extracted by setting the predetermined value according to the result of the addition, by providing the method for controlling the imaging apparatus according to claim 13.

By configuring in this way, the coring level can be varied according to the number of binning, so that optimum noise reduction is possible.
According to the invention described in claim 19 of the claim, the object is to control the range of the frequency component in extracting the low frequency component of the image signal. This can be achieved by providing the control method of the described imaging apparatus.

With this configuration, it is possible to vary the noise reduction effect.
According to the invention described in claim 20 of the claim, the range of the frequency component is controlled by the size of a filter matrix and the weighting of elements of the matrix. 19 can be achieved by providing the control method of the imaging apparatus according to 19.

With this configuration, it is possible to vary the noise reduction effect.
According to the invention described in claim 21 of the scope of claim, the range of the frequency component is controlled in the extraction of the high frequency component of the image signal. This can be achieved by providing the control method of the described imaging apparatus.

With this configuration, it is possible to vary the noise reduction effect.
According to the invention described in claim 22 of the claim, the range of the frequency component is controlled by the size of the filter matrix and the weighting of the elements of the matrix. This can be achieved by providing the control method of the image pickup apparatus according to 21.

  With this configuration, it is possible to vary the noise reduction effect.

  By using the present invention, it is possible to store a captured image without operating the noise reduction processing in the moving image mode and without performing the noise reduction processing operation in the still image mode. In video mode (rec view), noise reduction processing is performed while increasing the gain by shortening the exposure time, and when capturing still images, the exposure time is increased and the gain is decreased, and recording is performed without performing the noise reduction processing operation. By doing so, it is possible to obtain a still image that has a high frame rate and a high S / N and that is not subjected to image processing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a microscope system according to an embodiment of the present invention. In the drawing, an objective lens 27 facing the sample 3 on the stage 26 is arranged in the microscope body 1. On the observation optical axis via the objective lens 27, an eyepiece lens unit 6 is disposed via the trinocular tube unit 5, and an electronic camera 36 is disposed via the imaging lens unit 100. Yes.

  FIG. 2 is a diagram showing a detailed configuration of the microscope system. This figure shows a configuration in which various spectroscopic methods such as transmitted bright field observation, dark field observation, phase difference observation, differential interference observation, and fluorescence observation can be selected as appropriate. The microscope system shown in FIG. 2 includes a transmission illumination optical system 11 and an epi-illumination optical system 12 as an illumination system.

  The transmission illumination optical system 11 is provided with a transmission illumination light source 13, a rectifier lens 14 for condensing the transmission illumination light on the optical path of the transmission illumination light emitted from the transmission illumination light source 13, and a transmission filter unit. 15, a transmission field stop 16, a transmission shutter 161, a bending mirror 17, a transmission aperture stop 18, a condenser optical element unit 19, and a top lens unit 20 are disposed.

The epi-illumination optical system 12 includes an epi-illumination light source 21, and the epi-illumination filter unit 22, the epi-illumination shutter 23, and the epi-illumination field stop are arranged on the optical path of the epi-illumination light emitted from the epi-illumination light source 21. 24 and an epi-illumination aperture stop 25 are arranged.
On the observation optical path S where the optical axes of the transmitted illumination optical system 11 and the epi-illumination optical system 12 overlap each other, a plurality of sample stages 26 and objective lenses 27 on which a specimen to be observed is placed are mounted. Is selected by rotation and positioned on the observation optical path S, an objective lens side optical element unit 29, for example, a dichroic mirror on the observation optical path S according to various spectroscopic methods such as transmitted bright field observation or fluorescence observation. And a beam splitter 31 that branches the observation optical path S into an observation optical path Sa and an observation optical path Sb.

  The beam splitter 31 is disposed in the trinocular tube unit 5. An eyepiece 6a is arranged on the observation optical path Sa bent forward by the beam splitter 31. Further, on the observation optical path Sb that has passed through the beam splitter 31, an intermediate variable power optical system (zoom lens barrel) 33, an imaging lens unit 100 including an autofocus (AF) unit 371 and a photographic eyepiece unit 35, and an electron Camera 36 is arranged.

  The intermediate variable magnification optical system (zoom lens barrel) 33 incorporates a variable magnification zoom lens 33 a for changing the magnification of an image picked up by the electronic camera 36. If intermediate zooming is not required, the intermediate zooming optical system (zoom lens barrel) 33 can be removed. An image sensor 42 is disposed in the electronic camera 36.

  The light image from the objective lens 27 is imaged on the imaging surface of the image sensor 42 by the photographic eyepiece lens 35 a in the photographic eyepiece unit 35. A beam splitter 34 is disposed in the autofocus (AF) unit 371, and an AF light receiving element 34a is disposed on the optical path branched from the observation optical path Sb.

The autofocus unit 371 detects focus based on the output signal from the light receiving element 34a, and can be removed as a unit when the AF function is unnecessary. A transmission filter unit 15 in the transmission illumination optical system 11, a transmission field stop 16, a transmission shutter 161, a transmission aperture stop 18, a condenser optical element unit 19, and a top lens unit 20; an incident light filter unit 22 in the incident illumination optical system 12; The epi-illumination shutter 23, the epi-illumination field stop 24, the epi-illumination aperture stop 25, the revolver 28, the objective lens side optical element unit 29, the cube unit 30, the beam splitter 31, and the intermediate variable magnification optical system (zoom lens barrel) 33 are respectively motorized. It is driven by each motor (not shown) according to each drive signal from the drive circuit unit 37.

  On the other hand, the revolver 28 is provided with an objective lens detector 38 that detects the type of the objective lens 27 positioned on the observation optical path S, and the objective lens side optical element unit 29 has a retardation adjustment that detects a retardation adjustment operation. An operation detection unit 39 is arranged, and the photographic eyepiece lens unit 35 is arranged with a photographic eyepiece lens detection unit 40 for detecting the type of the photographic eyepiece.

  The microscope control unit 41 controls the operation of the entire microscope. The transmission illumination light source 13, the epi-illumination light source 21, the drive circuit unit 37, the objective lens detection unit 38, the retardation adjustment operation detection unit 39, and the photographic eyepiece detection The unit 40 and the electronic camera 36 are connected. The microscope control unit 41 performs light control of the transmitted illumination light source 13 and the epi-illumination light source 21 and gives a control instruction to the drive circuit unit 37 in accordance with the CPU 60 that determines the imaging conditions of the electronic camera 36.

  Further, the microscope control unit 41 starts a control state for the transmission illumination light source 13 and the epi-illumination light source 21 and a control state for the drive circuit unit 37, an objective lens detection unit 38, a retardation adjustment operation detection unit 39, and a photographic eyepiece lens detection unit. Detection information from 40 is fed back to the electronic camera 36.

<First Embodiment>
FIG. 3 is a system configuration diagram according to the present embodiment. FIG. 2 is a block diagram showing a conceptual configuration of an electronic camera used in the microscope system. In the figure, an electronic camera 36 includes an image pickup device (CCD) 42, a CDS circuit 43, an amplifier (AMP) 44, an A / D converter 45, an image memory 46, a memory controller 55, a low frequency signal processing unit 200, a high frequency signal. Signal processing unit 201, adder 52, switch (SW) 51, liquid crystal display (LCD) 59, DRAM 56, compression / decompression circuit 57, recording medium 58, operation unit 61, timing generator (TG) 53, and signal generator ( SG) 54. Furthermore, a CPU 60 that controls the microscope control unit 41 is also included.

The low frequency signal processing unit 200 includes a low pass filter (LPF) 47 and a low frequency γ correction circuit 49. The high-frequency signal processing unit 201 includes an edge γ correction circuit 63, an HPF 64, a coring unit 65, and an edge enhancement circuit 66.
The image pickup device (CCD) 42 picks up a color or black-and-white image, and is disposed on the observation optical path Sb together with the above-described microscope photographic eyepiece unit 35. A solid-state image sensor (hereinafter simply referred to as a CCD) 42 such as a CCD captures and photoelectrically converts an observation image of a specimen magnified by a microscope.

  A CDS circuit (correlated double sampling circuit) 43 extracts an image signal component from the output signal of the CCD 42. The amplifier (AMP) 44 is gain control means including an AGC circuit for adjusting the output signal level of the CDS circuit 43 to a predetermined gain value.

  The A / D converter 45 converts the analog signal output from the AMP 44 into a digital signal. The image memory 46 stores the digital signal output from the A / D converter 45. The memory controller 55 controls the image memory 46. The low-pass filter (LPF) 47 extracts a low-frequency signal component having a frequency equal to or lower than a predetermined frequency of the low-frequency input signal from the image signal read from the image memory 46.

  The low frequency γ correction circuit 49 performs gamma (γ) correction of the main signal. The high frequency γ correction circuit 63 performs gamma (γ) correction of the signal read from the image memory 46. The high pass filter (HPF) unit 64 removes the low frequency component of the signal output from the high frequency γ correction circuit 63 and extracts a contour signal (hereinafter referred to as an edge signal).

  The coring unit 65 performs coring processing for suppressing the noise component of the edge signal generated by the HPF 64 and improving the S / N ratio. The edge enhancement circuit 66 includes an accumulator that multiplies a high-frequency signal subjected to coring processing by the coring unit 65 by a predetermined coefficient, and performs edge enhancement processing.

  The adder 52 adds the edge-enhanced high-frequency signal output from the edge enhancement circuit 66 to the signal output from the low-frequency γ correction circuit 49. A switch (SW) 51 switches between a signal output from the adder 52 and a signal read from the image memory 46. A liquid crystal display (LCD) 59 is a display unit including a signal processing circuit that processes an image signal into a displayable form.

The DRAM 56 is a camera built-in storage unit including a memory or the like that temporarily stores an image signal. The compression / decompression circuit 57 performs compression processing and decompression processing on the image signal. The recording medium 58 is a storage medium such as a memory card that stores image signals.
The operation unit 61 includes a plurality of switches such as a trigger switch, an objective lens operation switch, and an aperture stop control switch that can start an AF operation during shooting and generate a trigger signal for starting an exposure operation. A timing generator (TG) 53 generates a synchronization signal such as a drive pulse for the CCD 42. The signal generator (SG) 54 supplies a synchronization signal to the TG 53.

  The constituent members are electrically connected to a CPU 60 that is a control means, and the entire electronic imaging apparatus of the present embodiment is comprehensively controlled by the CPU 60. The CCD 42 has an electronic shutter function (means) by means of a SUB voltage conversion circuit or the like so that the exposure time can be controlled.

Next, the operation of the microscope system configured as described above will be described. Here, only the portion related to the present invention is described among the actions performed at the time of photographing.
In the fluorescence observation spectroscopic method, the light emitted from the epi-illumination optical system 12 passes through the epi-illumination aperture stop 25 in the cube unit 30, is dispersed by the fluorescent cube in the cube unit 30, is reduced through the objective lens 27, and is sampled. 3 is irradiated. The specimen 3 emits excitation light that is weaker than the irradiated light, the emitted light is enlarged through the objective lens 27, and is spectrally separated by the fluorescent cube in the cube unit 30 at a wavelength different from that of the spectrum. Irradiate.

  An image signal component is extracted from the image signal obtained by the CCD 42 in the CDS circuit 43, the output signal level is adjusted to a predetermined gain value in the AMP 44, and converted into a digital signal in the A / D converter 45. The image signal converted into the digital signal is temporarily stored in the image memory 46.

  The signal stored in the image memory 46 can be a low frequency signal from which the high frequency has been removed by the LPF 47. Further, the high frequency signal from which the low frequency band is removed can be obtained by the HPF 64, the signal from which the high frequency noise component is eliminated by the coring circuit 65, the gain of the high frequency signal from which the noise is eliminated by the edge enhancement circuit 66 is applied, and the edge Is emphasized. By adding this signal and the low-frequency signal, a signal from which high-frequency noise components have been removed can be obtained.

The signal b from which the noise is removed and the raw signal a stored in the image memory 46 can be switched by the SW 51.
Here, the γ correction circuit 49 for low frequency and the γ correction circuit 63 for high frequency have a γ curve = 1 as shown in FIG. 4 and the same linearity as the raw signal stored in the image memory 46. Normally, the image signal is γ-corrected at γ = 0.45 (to correct the γ value of the display monitor), but in this embodiment, γ is corrected at γ = 1 to obtain the same linearity as the raw signal. Yes. Usually, when used in a measurement application such as a microscope, a raw signal is often created linearly (γ = 1).

  FIG. 5 is a diagram showing the timing when the exposure time at the time of still image shooting in this embodiment is four times longer than the exposure time at the time of moving image shooting. The synchronization signal VD in units of one frame from the top, the CCD image sensor operation mode, the transfer pulse TG from the charge accumulation region to the vertical transfer path, and the charge in the charge accumulation region are forced to the semiconductor substrate (substrate = vertical overflow drain VOFD). Each signal of substrate applied high voltage pulse VSUB for discharging, circuit gain state, signal output SIG, recording operation of memory 46, image output for liquid crystal and monitor output, and operation of SW51 (H / L) are shown. Yes.

  At this time, noise is generated in the A / D input signal because the gain in the moving image mode is four times higher than that in the still image mode. The difference from the conventional example is that SW51 is set to H (signal b is input) in the moving image mode, a signal from which the high frequency component noise component is removed is output, and SW51 is set to L (signal a in the still image mode). And an unprocessed signal that does not remove noise components is being output.

  FIG. 6 is a modification of the timing diagram of FIG. In the figure, what is different from FIG. 5 is the switching timing of the SW 51. In order to record two frames of still images, raw data is output for both frames in FIG. 5, but in FIG. 6, one frame is recorded with a noise reduction output (via the output of signal b of SW51), The other frame is recorded by raw data output (via the output of signal a of SW51).

As described above, an image with a good S / N can be output while increasing the frame rate by noise reduction for a moving image, and an image with a good S / N can be obtained by exposing raw data without image processing for a long time to a still image. .
Further, since an image at the time of a still image is temporarily stored in the image memory 46, it is also possible to store both raw data and data through noise reduction for the image stored in the recording medium 58 ( (See FIG. 6).

<Second Embodiment>
Noise is usually classified into light shot noise Na and dark noise Nb such as CCD dark current and circuit noise. The noise N (overall) can be expressed by the following equations of these two types of noise components.

N = SQRT (Na ² + Nb ² )
FIG. 7 is a graph illustrating an example of a noise component at a noise level with respect to an input signal. The horizontal axis is the input signal level (256 levels represented by 8 bits), and the vertical axis is the noise level. In this case, noise removal by coring cannot cover the entire area. For example, as shown in the figure, even when the coring level = 8 is selected, the noise removal effect becomes weaker as the input level increases from about 80 level to the high luminance part (near 256 level).

On the other hand, electronic cameras that capture weak fluorescence often perform so-called level correction in which gain is increased after recording without changing gain. This will be described with reference to FIG.
FIG. 8 shows the 4th gain of FIG. For example, if the coring level = 8 is selected in FIG. 7, the coring level = 32 in FIG. 8, so that obviously the necessary high frequency components other than noise are also removed due to excessive coring. That is, the image has no high frequency component. Therefore, if the coring level is varied according to the input signal level, any signal level can be supported. This will be described with reference to FIG.

FIG. 9 shows a system configuration diagram in the present embodiment. Unlike the system configuration of FIG. 3, in FIG. 9, an LPF 62 and a multiplier and adder 50 are mounted. Here, the coring coefficient is changed by the multiplier 50 in accordance with the signal obtained by cutting the high band by the LPF 62.
FIG. 10 shows coring coefficients when the system configuration of FIG. 9 is used. In FIG.
When signal level <32, coring coefficient = K × signal level / 8 + 2
When 32 ≦ signal level <128, coring coefficient = K × signal level / 16 + 4
When 128 ≦ signal level, coring coefficient = K × signal level / 32 + 8
(K = 1). These are realized by the LPF 62 and the coring coefficient by the multiplier / adder 50. In the figure, coring and noise (overall) level are almost overlapped in any input signal, and coring is not applied more than necessary. Thus, an appropriate coring value can be taken for every signal.

FIG. 11 shows the four times gain of FIG. In the figure, even if the gain is quadrupled by level correction, the coring value determined in FIG. 10 is an appropriate value.
In the noise removal according to the present embodiment, level correction can be performed for each portion of each screen, that is, for each signal that has passed through the LPF 62.

As described above, since the coring level can be varied according to the signal level, noise reduction according to the level correction becomes possible.
<Third Embodiment>
In the second embodiment, since the coring amount differs depending on the signal, the S / N is good, but since the degree of enhancement differs between a bright edge and a dark edge, an unnatural image may occur.

However, if the coring amount is fixed, an image having no sharpness is obtained by the level correction as described above. Therefore, the system of FIG. 12 is used.
FIG. 12 is a diagram illustrating a configuration of a system in the present embodiment. The difference from FIG. 3 is that the LPF 62 is mounted. In FIG. 12, the signal output from the image memory 46 is input to the CPU through the LPF 62, the image is analyzed based on the signal that has passed through the LPF 62, the histogram and peak detection are performed, and then the coring amount is determined.

  In this way, the coring amount can be determined after the histogram and peak detection for each image. Thus, noise can be removed with a coring amount suitable for each image. When level correction is performed automatically, the gain value is determined based on normal peak detection or a histogram. Therefore, the coring amount may be determined so as to predict this gain value.

As described above, since the coring level can be varied according to the signal level, noise reduction according to the level correction becomes possible.
<Fourth Embodiment>
In the present embodiment, a case will be described in which the noise reduction coefficient is changed when signals are added in the CCD element.

  FIG. 13 shows a system configuration diagram in the present embodiment. In FIG. 13, the binning mode (coring coefficient 1 or coring coefficient 2) can be switched according to the operation of the operation unit 61. Here, “binning” means adding an image signal in the CCD element. First, the operation of the CCD will be briefly described.

  FIG. 14 shows an element structure of an interline CCD. Signal charges accumulated in the photodiode 206 are transferred to a vertical transfer path (V transfer path) 202. The charges on the vertical transfer path 202 are sequentially transferred to the horizontal transfer path 203. The charge transferred to the horizontal transfer path 203 is output as a signal through the charge detector 204 and the amplifier 205.

  FIG. 15 is a timing chart in the CCD image sensor when there is no binning. In the figure, a reset pulse RST, pulses H1 and H2 (driven by two layers) for driving the horizontal transfer path 203, an image output signal, and pulses SHP and SHD output from the TG 53 are shown from the top. .

As shown in FIG. 15, the charge detector 204 normally outputs a black level and a signal level within one pixel after being reset by a reset pulse RST. This signal is output by the CDS circuit at the timing of pulses SHP and SHD output from the TG 53.
Next, the intra-element addition of the CCD will be described. There are two types of addition in the CCD element: vertical addition and horizontal addition.

  FIG. 16 is a timing chart in the CCD image pickup device during binning. First, the in-element addition in the horizontal direction will be described. In order to perform intra-element addition in the horizontal direction, as shown in FIG. 16, the reset pulse RST may be eliminated. For example, if the reset pulse RST is issued once for two pixels, the charge is added in the charge detector 204, and the output signal can be doubled as shown in FIG. If the frequency and phase of the SHP and SHD pulses are adjusted so that the doubled signal can be taken out, it becomes possible to add horizontally adjacent signals.

Next, in-element addition in the vertical direction will be described. In order to add the vertical direction, when transferring from the vertical transfer path 202 to the horizontal transfer path 203, it is only necessary to transfer continuously and add charges inside the horizontal transfer path 203.
FIG. 17 is a timing chart at the time of intra-element addition in the vertical direction. Here, the difference from normal reading is that the number of V transfer pulses has doubled during intra-element addition (in the figure, during binning). That is, the number of times of transfer from the vertical transfer path 202 to the horizontal transfer path 203 is doubled to perform vertical addition.

In FIG. 17, binning is performed including intra-element addition in the horizontal direction, and the signal output is a quadruple signal.
Thus, the signal level is quadrupled during binning. Here, when the level correction as described above is used, the gain value becomes ¼, so that an increase in noise amount due to the level correction is reduced. As the amount of noise is reduced, the amount of coring can be reduced, resulting in noise reduction with no unnaturalness.

In FIG. 13, since the coring coefficient 1 or the coring coefficient 2 can be set, the coring amount can be adjusted during binning. In the present embodiment, the number of coring coefficients that can be selected is two. However, the present invention is not limited to this, and a plurality of coring coefficients may exist.
As described above, since the coring level can be varied according to the number of binning, optimal noise reduction is possible.

<Fifth Embodiment>
FIG. 18 shows a system configuration diagram in the present embodiment. In the present embodiment, unlike FIG. 3, the settings of the LPF 47, HPF 64, and coring circuit 65 can be changed by the operation unit 61.

  In the present embodiment, the LPF 47 can switch the filter matrix to three stages (LPF1, LPF2, and LPF3 in the figure) as will be described later, thereby effectively reducing noise. In addition, the filter matrix for HPF 64 can be switched to three stages (HPF1, HPF2, HPF3 in the figure). Similarly, the coring coefficient of the coring circuit 65 can be switched to three levels (coring coefficient 1, coring coefficient 2, and coring coefficient 3).

As described above, in the present embodiment, the LPF 47, the HPF 64, and the coring circuit 65 can be switched in three stages, but the present invention is not limited to this, and there may be a plurality of stages.
FIG. 19 is a diagram showing the relationship between the LPF, HPF, and noise in this embodiment. The right column (column C) in FIG. 19 represents LPFs of 2 × 2 (C1), 4 × 4 (C2), and 6 × 6 (C3) as filter matrices in order from the top. A weighting value is shown in the matrix element of each filter matrix.

  The diagram in the left column (column A) of FIG. 19 is a diagram showing MTF (Modulation Transfer Function) and frequency, and the hatched portion above the LPF is a high-frequency component. MTF is an abbreviation for contrast transfer function and is one of performance evaluation methods for optical systems. This figure shows the modulation of a sinusoidal object image with an increase in spatial frequency. When an object with a sinusoidal intensity distribution is imaged by the test lens, the intensity distribution on the image side is the same as the intensity distribution on the object side. Come different.

  A1 indicates raw data and data processed by 2 × 2 LPF. The data processed by the 2 × 2 LPF is data having a low frequency component without a high frequency component indicated by an oblique line A1. A2 indicates raw data and data processed by 4 × 4 LPF. The data processed by the 4 × 4 LPF has no high frequency component indicated by the hatched line A2, and is data of a low frequency component. A3 indicates raw data and data processed by 6 × 6 LPF. The data processed by the 6 × 6 LPF is data having a low frequency component without a high frequency component indicated by an oblique line A1.

  The diagram in the center row (B row) in FIG. 19 shows the frequency and the noise reduction ratio (gain) (when coring is effective). Since the processing is performed by the LPF, the noise is reduced as the frequency becomes higher. From the figure, the noise reduction effect can be confirmed. B1 shows the noise reduction effect when processed by 2 × 2 LPF. B2 shows the noise reduction effect when processed by 4 × 4 LPF. B3 shows the noise reduction effect when processed by 6 × 6 LPF.

  It can be seen that the 6 × 6 LPF has a smaller noise reduction ratio, that is, noise reduction. That is, as the size of the filter matrix increases, the frequency region that is removed as a high-frequency component increases. For example, when comparing the vicinity of the frequency 0.50 of B1 and B3, the noise reduction ratio in B1 is about 0.70, whereas in B3 it is about 0.2. However, since the resolution is reduced by that amount, it is necessary to set the subject or lens.

  FIG. 20 shows a timing chart in the present embodiment. When the lens magnification, lens type, and data are analyzed after frequency analysis, and when it is determined that there is no high frequency component in the output image signal, noise can be further reduced by selecting a 6 × 6 filter for the still image. It becomes possible. This is because there is no high frequency component in the output image signal, but noise exists at a high frequency, and according to this embodiment, the noise can be removed.

  Also, HPF is the same as LPF. In other words, the HPF simply extracts a high-frequency component (shaded portion) from which the low-frequency component in the column A is removed and removes noise from the HPF as shown in FIG. The idea about the reduction effect is the same as that of the LPF, and the larger the filter matrix size, the larger the frequency region that is removed as the low frequency component.

As described above, in the present embodiment, a 2 × 2, 4 × 4, and 6 × 6 filter matrix is used. However, the present invention is not limited to this, and an n × n (n is a positive number) filter matrix may be used.
As described above, it is possible to vary the noise reduction effect.
<Sixth Embodiment>
FIG. 21 is a block diagram when the fifth embodiment is applied to a microscope. It is known that when the magnification 27 of the objective lens is increased or the epi-illumination aperture stop 25 is reduced, the limit resolution is lowered or the MTF is fluctuated. This will be described with reference to FIGS.

FIG. 22 is a diagram illustrating the relationship between the magnification of the objective lens and the limit resolution. As shown in the figure, the limit resolution decreases as the lens magnification increases.
FIG. 23 is a diagram illustrating the relationship between the aperture stop of the objective lens and the limit resolution. As shown in the figure, when the aperture stop is reduced (depth becomes deeper), the limit resolution decreases.

Therefore, the LPF and HPF or the coring level may be changed according to the change in the magnification of the objective lens.
For example, when the resolution becomes low, an image with good S / N can be obtained by increasing the LPF coefficient or increasing the coring level. At this time, since the resolution is originally low, there is almost no influence. FIG. 24 and FIG. 25 show the flow charts.

  FIG. 24 shows a flow for switching ON / OFF the noise reduction processing in accordance with the switching of the aperture stop in the present embodiment. In the figure, first. The power supply of the microscope system is turned on (step S1, hereinafter, step is abbreviated as S). Next, the sample 3 is set on the sample stage 26 (S2).

  Next, the electronic camera 36 is turned on (S3). Next, the sample is imaged with the electronic camera in the moving image mode through the microscope 1 (moving image REC view) (S4). Next, the operation unit 61 is set (S5). Here, the aperture stop is switched using the operation unit 61. Next, when the still image capturing trigger of the operation unit 61 is turned on (S6), the still image is recorded in the image memory 46 (S7).

  Next, it is determined whether or not the aperture stop has been switched (S8). If the aperture stop has not been switched, the process proceeds to S14. If the aperture stop has been switched, whether to perform noise reduction processing (ON / OFF) is determined by operating the operation unit 61. (S9). Next, as described above, the LPF is determined using the operation unit 61 (S10), the HPF is determined (S11), and the coring value is determined (S12). The information determined in S10-S12 is transferred to the signal processing unit (low frequency signal processing unit 200 and high frequency signal processing unit 201) (S13), and the captured image is written (stored) in a storage medium 58 such as a memory card. ), The process returns to S4.

By doing so, when the aperture stop is narrowed, the limit resolution is lowered, so that the high-frequency component included in the image is eliminated, but since the high-frequency noise exists, the noise can be removed.
FIG. 25 shows a flow for switching ON / OFF the noise reduction process in accordance with the switching of the objective lens in the present embodiment. In the figure, first. The microscope system is turned on (S21). Next, the sample 3 is set on the sample stage 26 (S22).

  Next, the electronic camera 36 is turned on (S23). Next, the sample is imaged with the electronic camera in the moving image mode through the microscope 1 (moving image REC view) (S24). Next, the operation unit 61 is set (S25). Here, the objective lens is switched using the operation unit 61. Next, when the still image capturing trigger of the operation unit 61 is turned on (S26), the still image is recorded in the image memory 46 (S27).

  Next, it is determined whether or not the lens magnification has been switched (S8). If the lens magnification has not been switched, the process proceeds to S14. If the lens magnification has been switched, whether to perform noise reduction processing (ON / OFF) is determined by operating the operation unit 61. Determine (S9). Next, as described above, the LPF is determined using the operation unit 61 (S10), the HPF is determined (S11), and the coring value is determined (S12). The information determined in S10-S12 is transferred to the signal processing unit (low frequency signal processing unit 200 and high frequency signal processing unit 201) (S13), and the captured image is written (stored) in a storage medium 58 such as a memory card. ), The process returns to S4.

In this way, when the magnification of the lens is increased, the limit resolution is lowered, so that the high-frequency component contained in the image is eliminated, but since the high-frequency noise exists, the noise can be removed.
As described above, according to the present embodiment, an electronic imaging device having a good S / N is used by setting an LPF and a coring level suitable for a case where the resolution changes, for example, by changing an objective lens. A microscope system can be provided.

It is a figure which shows the structure of the microscope system which concerns on embodiment of this invention. It is a figure which shows the detailed structure of the microscope system of FIG. It is a figure which shows the structure of the system in 1st Embodiment. It is a figure which shows the graph of the switching of (gamma) curve in 1st Embodiment. It is the figure which showed the timing when the exposure time at the time of still image photography in a 1st embodiment is 4 times longer than the exposure time at the time of animation photography. 6 is a modification of the timing diagram of FIG. It is a figure which shows the relationship between the conventional coring coefficient and a noise level. FIG. 8 is a diagram showing a gain obtained by multiplying FIG. 7 by four times. It is a figure which shows the structure of the system in 2nd Embodiment. It is a figure which shows the relationship between the coring coefficient and noise level in 2nd Embodiment. It is a figure which shows what obtained FIG. 10 4 times gain. It is a figure which shows the structure of the system in 3rd Embodiment. It is a figure which shows the structure of the system in 4th Embodiment. It is a figure which shows the element structure of the CCD image pick-up element in 4th Embodiment. It is a figure which shows the timing when there is no binning in 4th Embodiment. It is a figure which shows the timing when there exists binning in 4th Embodiment. It is a timing chart at the time of vertical intra-element addition in the fourth embodiment. It is a figure which shows the structure of the system in 5th Embodiment. It is the figure which showed the relationship between LPF, HPF, and noise in 5th Embodiment. It is a figure which shows the timing chart in 5th Embodiment. It is a block diagram when applying 5th Embodiment to a microscope in 6th Embodiment. It is a figure which shows the relationship between the magnification of the objective lens and limit resolution in 6th Embodiment. It is a figure which shows the relationship between the aperture stop of the objective lens in 6th Embodiment, and limit resolution. It is a figure which shows the flow of aperture stop switching in 6th Embodiment. It is a figure which shows the flow of the objective lens switching in 6th Embodiment. It is a figure which shows the noise compression apparatus by the conventional noise coring system. It is a figure which shows the input / output characteristic of the coring process by the coring part in a general electronic imaging device. It is a figure which shows the relationship between the coring level at the time of imaging | photography in a general electronic imaging device, and S / N ratio of an image signal. It is a figure explaining operation | movement of the noise compression apparatus by the noise coring system of FIG. It is a timing chart when taking in the weak light in the past in a still picture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microscope main body 3 Sample 5 Trinocular tube unit 6 Eyepiece unit 11 Transmission illumination optical system 12 Epi-illumination optical system 13 Transmission illumination light source 14 Collector lens 15 Transmission filter unit 16 Transmission field stop 161 Transmission shutter 17 Bending mirror 18 Transmission Aperture stop 19 Condenser optical element unit 20 Top lens unit 21 Epi-illumination light source 22 Epi-illumination filter unit 23 Epi-illumination shutter 24 Epi-illumination field stop 25 Epi-illumination aperture stop 26 Sample stage 27 Objective lens 28 Revolver 29 Objective lens-side optical element unit 30 Cube unit 31 Beam splitter 33 Intermediate zoom optical system (zoom lens barrel)
34 beam splitter 35 photographic eyepiece unit 36 electronic camera 37 drive circuit unit 38 objective lens detection unit 39 retardation adjustment operation detection unit 40 photographic eyepiece lens detection unit 41 microscope control unit 42 imaging device (CCD)
43 CDS circuit 44 Amplifier (AMP)
45 A / D converter 46 Image memory 55 Memory controller 52 Adder 51 Switch (SW)
53 Timing Generator (TG)
54 Signal Generator (SG)
56 DRAM56
57 Compression / decompression circuit 58 Recording medium 59 Liquid crystal display (LCD)
60 CPU
61 Operation Unit 200 Low Frequency Signal Processing Unit 201 High Frequency Signal Processing Unit 202 V Transfer Path 202 Vertical Transfer Path 203 Horizontal Transfer Path 203
204 Charge detector 205 Amplifier 206 Photodiode

Claims (22)

In an imaging apparatus that outputs an image signal captured by an imaging element,
Noise reduction means for reducing noise contained in the image signal;
Storage control means for performing control for storing either the image signal or the image signal with reduced noise;
The noise reduction means is
Low-frequency component extracting means for extracting a low-frequency component of the image signal;
High-frequency component extracting means for extracting a high-frequency component of the image signal;
Amplitude extraction means for extracting an amplitude greater than or equal to a predetermined value from the high frequency components extracted by the high frequency component extraction means;
A synthesizing unit that synthesizes the low-frequency component and the high-frequency component having an amplitude greater than or equal to the predetermined value;
An imaging apparatus comprising: The storage control means
When capturing a moving image with the imaging device, the image signal with noise reduced by the noise reduction means is stored,
The imaging apparatus according to claim 1, wherein when the still image is captured by the imaging apparatus, the image signal that is captured by the imaging element is stored. When acquiring a moving image, the image signal is amplified to increase the level of the image signal, and the exposure time of the image sensor is shortened.
The imaging apparatus according to claim 1, wherein when a still image is acquired, the level of the image signal is reduced and the exposure time of the imaging element is increased. The imaging apparatus further includes a first storage unit and a second storage unit,
The storage control means
When shooting a moving image with the imaging device, the image signal reduced in noise by the noise reduction means is stored in the first storage means,
The imaging apparatus according to claim 1, wherein when taking a still image with the imaging apparatus, the image signal that has been captured by the imaging element is stored in the second storage unit. The storage control means
When capturing a moving image with the imaging device, the image signal with noise reduced by the noise reduction means is stored,
When the still image is captured by the imaging device, the image signal that has been captured by the imaging device and the image signal in which noise is reduced by the noise reduction unit are stored. The imaging apparatus according to 1.   The imaging apparatus according to claim 1, wherein the predetermined value is set in the amplitude extraction unit according to the image signal. The image sensor includes an in-element signal adding means for adding the captured image signal inside the image sensor,
The imaging apparatus according to claim 1, wherein the predetermined value is set in the amplitude extraction unit according to the result of the addition.   The imaging apparatus according to claim 1, further comprising a low-frequency component extraction range control unit that controls a range of the frequency component extracted by the low-frequency component extraction unit.   The imaging apparatus according to claim 8, wherein the range of the frequency component is controlled by a size of a filter matrix and weighting of elements of the matrix.   The imaging apparatus according to claim 1, further comprising high-frequency component extraction range control means for controlling a range of the frequency component extracted by the high-frequency component extraction means.   The imaging apparatus according to claim 10, wherein the range of the frequency component is controlled by a size of a filter matrix and weighting of elements of the matrix.   The microscope system provided with the imaging device of any one of Claims 1-11. An image pickup apparatus control method for outputting an image signal picked up by an image pickup element,
Performing control to store either the image signal or the image signal with reduced noise;
The noise reduction is
Extracting the low frequency component of the image signal,
Extract high frequency components of the image signal,
Of the high frequency components, extract an amplitude greater than a predetermined value,
A method for controlling an imaging apparatus, comprising: combining a low-frequency component with a high-frequency component having an amplitude greater than or equal to the predetermined value. When shooting a moving image with the imaging device, the noise of the image signal is reduced and stored,
The method of controlling an imaging apparatus according to claim 13, wherein when the imaging apparatus captures a still image, the image signal that has been captured by the imaging element is stored. When acquiring a moving image, the image signal is amplified to increase the level of the image signal, and the exposure time of the image sensor is shortened.
The method for controlling an image pickup apparatus according to claim 13, wherein when a still image is acquired, the level of the image signal is reduced and the exposure time of the image pickup element is increased. When shooting a moving image with the imaging device, the image signal with reduced noise is stored,
When the still image is captured by the imaging device, the image signal that has been captured by the imaging device and the image signal in which noise is reduced by the noise reduction unit are stored. 14. A method for controlling the imaging apparatus according to 13. In extracting an amplitude greater than or equal to the predetermined value,
The method according to claim 13, wherein the predetermined value is set according to the image signal. The image sensor includes an in-element signal adding means for adding the captured image signal inside the image sensor,
14. The method of controlling an imaging apparatus according to claim 13, wherein the extraction of an amplitude greater than or equal to the predetermined value sets the predetermined value according to the result of the addition. In extracting the low frequency component of the image signal,
The method of controlling an imaging apparatus according to claim 13, wherein the range of the frequency component is controlled.   The method of controlling an imaging apparatus according to claim 19, wherein the range of the frequency component is controlled by the size of a filter matrix and the weighting of elements of the matrix. In extracting the high frequency component of the image signal,
The method of controlling an imaging apparatus according to claim 13, wherein the range of the frequency component is controlled. The method of controlling an imaging apparatus according to claim 21, wherein the range of the frequency component is controlled by a size of a filter matrix and weighting of elements of the matrix.

Images