JP2002333569A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate checking of focusing by a monitor image. SOLUTION: This imaging device has an image data signal forming section which includes an imaging lens and an image sensor, an autofocus mechanism which defects the focusing to a subject and automatically focuses the imaging lens to the subject in accordance with the detected result, an image data signal processing section which processes the image data signals outputted from the image data forming section and a monitor image display section which displays the image based on at least a portion of the image data processed by the image data signal processing section. The image data signal processing section has a low-pass filter processing circuit to cut the high-frequency component of the image data signals, a bypass signal path which bypasses the same and a selector which selects at least either of the low-pass filter processing circuit and the bypass signal path and sends the image data to the monitor image display section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device,
In particular, the present invention relates to an imaging apparatus provided with an autofocus mechanism capable of automatically adjusting the focus and an image monitor (moving image monitor) for checking a composition before photographing.

[0002]

2. Description of the Related Art Recently, an autofocus (AF) mechanism capable of automatically adjusting a focus has been incorporated in many image pickup apparatuses.

[0003] In a digital still camera, in particular, among image pickup apparatuses, low-pass filter processing is generally performed for the purpose of improving image quality. When the low-pass filter processing is performed, aliasing distortion of the high-frequency component of the image data signal due to sampling is removed. Therefore, generation of false colors can be prevented.

[0004]

In a digital still camera provided with an auto-focus mechanism, whether or not the object to be shot is in focus is confirmed by a monitor image displayed on a liquid crystal display device or the like. However, it has been difficult in some cases to confirm from a monitor image whether or not an object to be focused is in focus.

An object of the present invention is to provide an image pickup apparatus such as a digital still camera having an autofocus mechanism.
An object of the present invention is to allow a monitor image to easily confirm whether or not a target to be focused is actually focused.

[0006]

According to one aspect of the present invention, there is provided an image data signal generating section including an image pickup lens and an image sensor, an in-focus state of an object is detected, and the image pickup lens is detected based on a detection result. An auto focus mechanism that can automatically focus on the subject,
An image data signal processing unit for performing signal processing on an image data signal output from the image data signal generation unit; and displaying, as a monitor, an image based on at least a part of the image data processed by the image data signal processing unit. A monitor image display unit for the, the image data signal processing unit, a low-pass filter processing circuit that performs a low-pass filter processing to cut high-frequency components of the image data signal, a bypass signal path that bypasses the low-pass filter processing circuit, An image pickup apparatus is provided which has a selector for selecting at least one of the low-pass filter processing circuit and the bypass signal path and sending image data to the monitor image display unit.

According to another aspect of the present invention, there is provided an imaging lens and an image sensor, and an optical low-pass filter provided so as to be inserted between the imaging lens and the image sensor for removing a high-frequency component of an optical image. An image data signal generation unit including: an advancing / retracting mechanism that allows the optical low-pass filter to retreat from between the imaging lens and the image sensor; and detects an in-focus state of a subject, and based on the detection result, An auto-focus mechanism capable of automatically focusing an imaging lens on a subject; an image data signal processing unit for performing signal processing on an image data signal output from the image data signal generation unit; Displaying an image based on at least a part of the processed image data processed by the signal processing unit as a monitor An imaging device and a monitor image display unit is provided.

According to the above-described imaging apparatus, it is possible to obtain an image data signal from which high-frequency components have been cut by low-pass filtering and an image data signal containing high-frequency components which have not been subjected to low-pass filtering. By displaying an image data signal that has not been subjected to the low-pass filter processing on the monitor image, it is easy to confirm the in-focus state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing an embodiment of the present invention, considerations made by the inventor will be described with reference to FIG. Representative examples of auto-focus mechanism is a type of passive TCL (T hrough the C ame
( raLens) system. In this method, the high-frequency component of the image signal is maximized at the in-focus position in a focused state.

As a low-pass filter (LPF), an optical LPF and a digital LPF are used. For example, an optical LPF is an imaging lens of a digital still camera and a CCD.
It is provided between a solid-state imaging device and is designed to remove, from high-frequency components of an optical image, components equal to or more than の of the sampling frequency. The digital LPF removes high-frequency components at the stage of signal processing of image data. Usually, it is provided in the image processing circuit.

There is a case where it is difficult to confirm from a monitor image whether or not the object to be focused is actually focused. The inventor thought that this is because the low-pass filter processing is performed not only on a still image actually captured but also on image data for displaying a monitor image. When checking on the monitor image whether or not the subject that you want to focus on is actually focused, you realize that low-pass filtering is not necessary to improve image quality. Was.

When confirming the focus by looking at the monitor image, it is preferable not to perform the low-pass filter processing. When image data in a state where the low-pass filter processing is turned off is viewed as a monitor image, a high frequency component that should be eliminated in terms of image quality often returns in a still image. Since the high-frequency components of the image are not cut, it is easy to check whether or not the image is in focus on the monitor image. Therefore, the photographer can easily confirm from the monitor image whether or not the subject to be focused is actually focused.

In this case, the probability of occurrence of a false color in the monitor image increases, but this is only a false color that has occurred in the monitor image, and no false color appears in the still image. If many false colors occur in the background portion other than the subject on the monitor screen, it can be confirmed that the background is in focus. It's easy to see what needs to be fixed. By the time of actual imaging, the focus can be corrected so as to focus on a desired object. The occurrence of false colors on the monitor screen is useful even if it is unsightly. When actually photographing a necessary still image, false color hardly occurs in the still image if low-pass filter processing is performed.

Based on the above considerations, an image pickup apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a functional block diagram of the image pickup apparatus according to the first embodiment of the present invention. As shown in FIG.
The imaging device A includes an image data signal generation unit 1, an image data signal processing unit 3, and an image data output unit 5.

The image data signal generator 1 includes an imaging lens 1
1, an optical filter 17, and an image sensor 15. The optical filter 17 includes, for example, an infrared cut filter 17a. Further, the optical low-pass filter 1
7b. The image sensor 15 is, for example, a CCD solid-state imaging device. CCD solid-state imaging device
It has a large number of photoelectric conversion elements formed on a two-dimensional plane, and a charge transfer path for reading and transferring charges accumulated in the photoelectric conversion elements. An optical signal corresponding to the optical image is converted into an electric signal and output.

The image data signal processing unit 3 includes a correlated double sampling circuit (CDS) 21 and an automatic gain control circuit (A
GC) 23, an A / D conversion circuit 25, and a digital low-pass filter processing circuit 27. The image data output 5 has an image monitor 37 and an image data storage unit 41.

The imaging apparatus A further includes a motor driving circuit 4
An auto-focus mechanism 40 including a focus motor 3 and a focus motor 45 is provided.

FIG. 2 is a block diagram showing the configuration of the image pickup apparatus centered on the digital data processing circuit 27. FIG.
In the configuration (1), the low-pass filter processing is performed by digital low-pass filter processing. 2A and 2B, the selector 29 or 29 ′ for selecting whether or not to perform the low-pass filter processing is provided by the low-pass filter processing circuit 27.
It is different from the arrangement on the entrance side or the exit side.

As shown in FIG. 2, the image pickup apparatus A includes at least an image data signal generation unit 1, an image data signal processing unit 3, and an image data output unit 5. The image data signal generator 1 generates an image data signal based on an optical image of a target to be captured. Image data signal processing unit 3
Receives an image data signal generated by the image data signal generation unit 1 and performs predetermined signal processing. The image data signal processing unit 3 also includes a low-pass filter processing circuit 27 that performs low-pass filter processing. The image data processed by the image signal processing unit 3 is sent to the image data output unit 5. The image data output unit 5 is provided with an image monitor 37 such as a liquid crystal display device, and further provided with a storage unit (memory) for storing image data of a still image in a storage unit such as a memory card. Is also good.

As shown in FIGS. 2A and 2B,
The imaging device A is provided with a selector 29 or 29 ′. The selector 29 or 29 'selects a signal path 28a passing through the low-pass filter processing circuit 27 and a signal path 28b for bypassing the low-pass filter processing. When storing image data for a still image, which is the original purpose of the imaging apparatus, the image data after performing the low-pass filter processing circuit 27 is stored in an image data storage unit (memory) or the like in order to give top priority to image quality. Remember. At the time of preview by the image monitor 37 for confirming a state immediately before shooting, for example, a focused state, a bypass signal path for bypassing the low-pass filter processing circuit 27 in order to easily confirm whether or not the subject is in focus. The image signal passing through 28b is displayed on the image monitor 37.

FIG. 3 is a block diagram showing a detailed configuration focusing on the image data processing unit 3. The description of the imaging device A will be continued with reference to FIGS. 1 and 2. The structure shown in FIG. 3 is a structure corresponding to FIG. 2B, and illustrates a structure in which the selector 29 (29 ′) is arranged after the low-pass filter processing circuit.

As described above, the image data processing unit 3 includes:
A selective low-pass filter processing circuit 27a including a digital low-pass filter processing circuit 27 is included. The selector 29 is provided in the selective low-pass filter processing circuit 27a.
Is provided.

Selective low-pass filter processing circuit 27a
Includes a low-pass filter processing circuit 27, a selector 29 ', and a bypass signal path 28b. When the selector 29 'in the selective low-pass filter processing circuit 27a is used, an image data signal processed by the low-pass filter processing circuit or an image data signal bypassed by the low-pass filter processing is selectively monitored by the image monitor. 37.

The autofocus mechanism 40 includes a distance measuring sensor 31, a distance measuring circuit 35, a motor driving circuit 43, and a focus motor 45. A signal from the distance measuring sensor 31 for measuring a distance by detecting a phase difference is input to a distance measuring circuit 35. The distance is calculated by the distance measuring circuit 35, and a signal Sa based on this distance is output to the motor driving circuit 43.
Is output to

As shown by a broken line 32 in FIG. 3, based on an output signal from the image data signal processing unit 3, more specifically, an output signal from the AD conversion circuit 25, an automatic distance is calculated based only on the contrast. A focus mechanism may be used.

The image pickup device A is provided with a shutter 38. In addition to the stopped state ST0, the shutter 38 is in a state where it is pushed in about halfway, that is, a half-pressed state ST1, and a state where the shutter 38 is fully pushed in, that is, in a fully pressed state ST2.
And two states.

Next, the operation of the image pickup apparatus B will be described with reference to FIGS.

When the shutter 38 is switched from the stop state ST0 to the half-pressed state ST1, the autofocus mechanism 40 operates to perform an autofocus process, an automatic exposure process (AE), and the like. The distance to the subject can be measured by the distance measuring sensor 31 and the distance measuring circuit 35. An autofocus signal Sa based on the measured distance is sent to the motor drive circuit 43. The motor drive circuit 43 calculates in which direction and how much the imaging lens should be moved, and an autofocus signal Sa based on the calculation result.
To the focus motor 45. Upon receiving the autofocus signal Sa, the focus motor 45
Can be focused by moving.

While the subject is in focus, a monitor image data signal Sg2 is output to an image monitor (moving picture monitor) 37, and a monitor image is displayed on, for example, a liquid crystal display device based on the image data signal Sg2. Let it. In the case of displaying the image as a monitor image, thinning-out reading for thinning out a predetermined amount from image data of all pixels is performed. Therefore, an image based on image data of a smaller data amount than image data of all pixels is displayed.

In the shutter half-pressed state ST1, the selector 29 'sends a signal obtained by bypassing the digital low-pass filter processing circuit 27 to the monitor image 37 by the bypass signal path 28b. The image data signal Sg2 bypassing the digital low-pass filter processing circuit 27 is displayed on the image monitor 37. Since this monitor image is formed based on the image data Sg2 that does not pass through the digital low-pass filter processing circuit 27, the high-frequency component of the image data signal is not cut. Therefore, the photographer can easily confirm whether or not the object to be focused is actually in focus. In this case,
If a part other than the target to be focused is in focus, many false colors may occur in that part. In this case, moving the digital camera toward the object to be focused reduces false colors. Therefore, it is also an index when focusing on an object that is actually desired to be focused.

In the shutter fully pressed state ST2, an actual still image is captured. The processing by the digital low-pass filter processing circuit 27 is performed as shown by reference numeral 28b.
The processed image data Sg1 that has passed through the digital low-pass filter processing circuit 27 is stored in the image data storage unit 41 into which a memory card or the like is inserted. Based on the stored image data, for example, a personal computer (PC)
For example, an actual still image can be displayed.

Since the still image is formed based on the image data after the digital low-pass filter processing, high-frequency components are cut off. Therefore, a high-quality image with few false colors can be obtained.

In the shutter half-pressed state ST1, the image data signal output to the image monitor 37 is changed to data Sg2 bypassing the digital low-pass filter processing circuit 27 or data Sg1 passed through the digital low-pass filter processing circuit 27. If the selector 29 is selected, the photographer can arbitrarily select whether to focus using only the autofocus mechanism or to check the in-focus state by checking the in-focus state using the auto-focus mechanism and the monitor image. .

FIG. 4 shows the details of the processing in the digital low-pass filter processing circuit 27 shown in FIG.

In step S1, the A / D conversion circuit 2
5 (FIG. 3), processing for arranging image data on a two-dimensional plane, and the like. For example, image data of an RGB three-primary-color Bayer array is converted into full-color image data including a Y (luminance) signal and a C (color difference) signal (Cr and Cb). The low-pass filter processing and the correction processing are separately performed on the converted Y signal and the Cr and Cb signals. This is because the Y signal and the Cb and Cr signals have different frequency bands and need to be processed separately. Assuming that the sampling frequency is fs, the Y signal generally has a high frequency band of about ｆ × fs, and the C signal has a frequency band of about １ ／ × fs and lower than the Y signal. Therefore, the digital low-pass filter processing differs between the Y signal and the C signal.

With respect to the Y signal, it is determined in step S2-1 whether or not focus confirmation is to be performed by an image monitor. Yes when confirming the focus on the image monitor
To bypass the digital low-pass filter processing. If focus confirmation by the image monitor is not performed, digital low-pass filter processing is performed in step S2 to obtain target image data for a still image.

After selecting whether to bypass step S2 or to perform digital low-pass filtering, contour correction of the Y signal is performed in step S3. The contour correction processing is signal processing for enhancing the contour of an image. In the contour processing step S3, vertical contour correction processing for correcting a vertical contour and horizontal contour correction processing for correcting a horizontal contour are performed.

Also in the processing relating to the color difference signals Cb and Cr, it is determined in step S4-1 whether or not focus confirmation is to be performed by an image monitor. When the focus is confirmed by the image monitor, the digital low-pass filter processing is bypassed in the direction of Yes. If focus confirmation by the image monitor is not performed, digital low-pass filtering is performed in step S4 to obtain target image data for a still image. Next, a saturation correction process shown in step S5 is performed.

In step S4-1, it is selected whether or not to perform low-pass filtering on the Cb and Cr signals.
Cb signal and C that have been low-pass filtered
If the r signal is displayed on the monitor image together with the Y signal bypassing the low-pass filter processing, the in-focus state can be confirmed by the monitor image.

After the above-described image processing is completed, step S
In step 6, the Y signal and the C signal are added to form image data for displaying either a monitor image or a still image. Y with low-pass filtering bypassed
When an image is displayed on the image monitor based on the signals and the Cb and Cr signals, it is easy to confirm the in-focus state. On the other hand, if image data is formed based on the Cb signal and the Cr signal subjected to the low-pass filter processing and the Y signal subjected to the low-pass filter processing, a high-quality still image can be obtained.

An example of the digital low-pass filter processing will be described with reference to FIGS.

FIG. 5 is a diagram in which image data is two-dimensionally arranged. FIG. 5A shows an example of arrangement of image data of a still image, and FIG. 5B shows an example of arrangement of image data of a monitor image. Is shown.

In the arrangement example shown in FIG. 5A, the horizontal direction (x
Image data from 0 to _{xmax in} the vertical direction (y direction) and 0 to _{ymax in the} vertical direction (y direction). In the case of the still image shown in FIG. 5A, for example, in the x direction, x = 0 to x _max = 1599, and in the y direction, y = 0 to y _max =
Up to 1199 are lined up. In the case of the monitor image shown in FIG. 5B, for example, x _max is 639 and y _max is 479. In the case of a monitor image, since thinning-out reading is performed, the amount of image data is reduced.

In the actual image processing, the image processing shown in FIG. 4 is performed on each image data, and the image processing is sequentially performed in the horizontal direction (x direction). When scanning in the x direction is completed for one row, image processing in the x direction is performed on the next row. By performing image processing for each row in the y direction (column direction), image data processing for all images can be performed. For a still image, the low-pass filter processing circuit shown in FIG. 4 is used, and for a monitor image, the low-pass filter processing circuit may be bypassed.

FIG. 6 is a flowchart showing the procedure of the actual digital low-pass filter processing. The digital low-pass filter processing will be described with reference to FIG.

First, in step S11, digital low-pass filter processing is started. In step S12, 0 is substituted for y. In step S13, 0
It is determined whether or not ≦ y ≦ y _max . Since y = 0, the flow advances to the Yes direction, that is, to step S14. In step S14, 0 is substituted for x. In step S15,
It is determined whether or not 1 ≦ x ≦ x _max . Since x = 0, the process proceeds to the direction of No, that is, step S18. In step S18, it is determined whether x = 0 or x = x _max −1. If x = 0, the direction of Yes,
That is, the process proceeds to step S19. In step S19, lpf [x] [y] = data [x] [y] (lpf [x,
y] = data [x, y]), that is, no interpolation processing is performed. This is because, at the position of x = 0, pixel data adjacent in the row direction (x direction) exists on only one side, and it is not possible to perform a low-pass filter process of interpolating using adjacent pixel data.

In step S17, 1 is added to the current value of x. x = 1. Returning to step S13, low-pass filter processing is performed at the position of x = 1. In step S14, x = 1, that is, 1 ≦ x
Since ≦ x _max −1, the process proceeds to the direction of YES, that is, to step S16. Here, actual low-pass filter processing is performed. That is, lpf [x] [y] = ｛(data
[x-1] [y] + 2 × data [x] [y] + data [x +
1] [y]) Perform an operation of｝ / 4. By performing an interpolation process using data of adjacent left and right positions, the characteristics of the actual low-pass filter are made as close as possible. However, the above expression shows an example in which the number of taps in the low-pass filter processing is set to 3 (tap coefficient: 1, 2, 1) for simplicity. Actually, processing based on a calculation formula of about five taps is performed as described later. When the calculation based on the expression of step S16 is performed by increasing the number of taps, high frequency components can be sharply cut.

Proceeding to step S17, 1 is added to x.
X = 2. Further, returning to step S15, the next
The processing at the position of x = 2 is performed. Finally x_max-1of
Continue low-pass filtering to the position. Next,
In step S17, x = x _max, The position on the right
No longer exists. Step from step S15
Proceed to step S18. x = x_maxRelationship,
As shown in step S19, low-pass filter processing (interpolation processing)
Do not do X = x in step S17_{max + 1}become
No in step S15 and No in step S18
No, and the process proceeds to step S20. Where y = y + 1
As a result, y = 1 (the processing shifts to the data processing in the second row). S
Returning to step S12, x = 0 to x = x again_maxuntil
The same low-pass filter processing is performed.

By repeating the above steps, y = y _{max + 1}
Becomes, according to the arrow of No from step S13,
Proceeding to step S21, the low-pass filter processing ends.

Through the above steps, low-pass filtering can be performed on all image data. Brightness Y
And the color difference C (Cr and Cb). Of course, when the digital low-pass filter processing is bypassed, the above processing is not performed.

FIGS. 7 and 8 are program lists showing the contents of the actual digital low-pass filter processing. FIG. 7 shows processing contents regarding the luminance signal Y. The first half of the program list shows a process of averaging in the horizontal direction (x direction), and the second half of the program list shows a process of averaging in the vertical direction (y direction).

FIG. 8 shows Y for the color difference signals Cb and Cr.
9 is a program list showing the same processing contents as in FIG. Here, the number of taps used in the digital low-pass filter processing is 5 in both the x and y directions, and the tap coefficient is −
43, 64, 214, 64, and -43 are used. Regarding the color difference signals Cb and Cr, 42,
Five taps of 51, 70, 51, and 42 are used. still,
The processing shown in FIGS. 7 and 8 is basically the same as the processing flow shown in FIG. 6 except that the tap coefficients are different, and thus detailed description of FIGS. 7 and 8 is omitted.

As described above, according to the imaging apparatus according to the first embodiment of the present invention, it is determined whether or not the autofocus is operating correctly as intended by the photographer, that is, whether or not the object is in focus. Can be easily confirmed on the monitor screen.

Next, an imaging device according to a second embodiment of the present invention will be described with reference to FIG. 9 is a diagram corresponding to the image data signal generation unit 1 in FIG. In the present embodiment, an example is shown in which low-pass filter processing is performed using an optical low-pass filter.

As shown in FIG. 9, the image data signal generating section 1 of the image pickup apparatus includes an image pickup lens 11 and an optical filter 17.
And a CCD solid-state imaging device 15.

The optical filter 17 has an infrared cut filter 17a and an optical low-pass filter 17b. Further, the image data signal generating section 1 is capable of retracting the optical low-pass filter 17 b from between the imaging lens 11 and the CCD solid-state imaging device 15.
A PF moving mechanism (hereinafter, referred to as a first moving mechanism) 51 and a second optical LPF moving mechanism (hereinafter, referred to as a second moving mechanism) 61 are provided.

The first advance / retreat mechanism 51 is, for example, a cylinder 5
3 and a piston 55. The second advance / retreat mechanism 61 also includes, for example, a cylinder 63 and a piston 65. The piston 55 is configured to be able to advance and retreat from within the cylinder 53. The piston 65 is configured to be able to advance and retreat from within the cylinder 63. The first advance / retreat mechanism 51 and the second advance / retreat mechanism 61 are connected to the optical LPF 17b from opposite sides.
To extrude.

At the time of the half shutter, the first moving mechanism 5
1 receives the signal ST1 of the half shutter and
The piston 55 jumps out of the inside 3. The optical low-pass filter 17b is connected to the imaging lens 11 and the CCD by the piston 55.
It is retracted from between the solid-state imaging device 15. Piston 55
Optical low-pass filter 1
If the retracted state of 7b can be maintained, the optical low-pass filter processing is not performed during the half shutter.

At the time of full shutter, the second advance / retreat mechanism 61
Receives the full shutter signal ST1, the piston 65 jumps out of the cylinder 63. The piston 65 returns the optical low-pass filter 17 b between the imaging lens 11 and the CCD solid-state imaging device 15. Piston 65 into cylinder 63
If the optical low-pass filter 17b is configured to be able to hold the state even when the
An optical low-pass filter process is performed. The optical low-pass filter 17B can be retracted from the optical axis by rotating the optical low-pass filter 17B.

When a monitor image is displayed based on image data on which low-pass filtering has not been performed, high-frequency components of the image data are not cut off. Therefore, the photographer can easily confirm whether or not the actual focus is focused on the object by the operation of the autofocus mechanism.

The actual still image is formed based on the image data after the low-pass filter processing. Therefore, high frequency components are cut. Therefore, a high-quality image with few false colors can be obtained.

As described above, also in the imaging apparatus according to the second embodiment of the present invention, it is determined whether or not the autofocus is operating correctly as intended by the photographer, that is, whether or not the object is in focus. It is easy to check on the monitor screen.

It should be noted that whether to perform the low-pass filter processing or to bypass this processing is to automatically bypass the low-pass filter processing when forming an image data signal for a monitor image, May be configured to always perform the low-pass filter processing when forming the image data. Alternatively, when forming the image data signal for the monitor image, the manual switching may be performed to switch between performing the low-pass filter processing and bypassing the image data signal. A switch may be provided.

In the first and second embodiments, an example has been described in which the technique of checking the in-focus state by the auto-focus mechanism of the digital still camera on the liquid crystal monitor screen.
In addition, it goes without saying that the technology of the present invention can be applied to a film camera having an autofocus mechanism and having a monitor screen.

In short, the imaging technique according to the present invention can be applied to various imaging apparatuses for displaying an image data signal on an image monitor.

For example, a personal computer (PC) having an image pickup device, a so-called PC camera,
The in-focus state is confirmed using the liquid crystal display described above, and the actual image can be stored in a storage device (memory or hard disk) of the PC. Furthermore, the present invention can be similarly applied to a mobile phone having a liquid crystal screen and an imaging mechanism.

Incidentally, some recent digital still cameras can store moving images in addition to still images. In this case, when a moving image is displayed as a monitor image for capturing a photo opportunity of a still image, the low-pass filter processing may be bypassed, and when the moving image is actually stored, the low-pass filter processing may be performed. .

[0069] Some digital movie cameras, which mainly shoot moving images, have a mode for shooting still images. Also in this case, when displaying a moving image with a monitor image when capturing a photo opportunity for capturing a still image, the monitor image may be displayed by bypassing the low-pass filter processing. At the time of capturing a moving image, low-pass filter processing may be performed.

Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0071]

According to the present invention, in an image pickup apparatus having an autofocus mechanism, whether or not the autofocus mechanism is operating on an object as intended by the photographer, that is, whether or not the object is in focus It is easy to confirm whether or not.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a structure of an imaging device according to a first embodiment of the present invention.

FIGS. 2A and 2B show a first embodiment of the present invention.
FIG. 10 is a block diagram showing a structure focusing on low-pass filter processing in the structure of the imaging device according to the embodiment.

FIG. 3 is a block diagram showing a more detailed structure of FIG. 2;

FIG. 4 is a block diagram illustrating a flow of low-pass filter processing and contour correction processing of the imaging device according to the first embodiment of the present invention.

5A is a conceptual diagram showing a configuration of image data in a plan view. FIG. 5A shows a configuration of still image data in FIG.
(B) is a diagram showing a data configuration of a monitor image.

FIG. 6 is a flowchart illustrating the flow of a low-pass filter process in detail.

FIG. 7 is a program list showing an example of actual low-pass filter processing on a luminance signal.

FIG. 8 is a program list showing an example of actual low-pass filter processing on a color difference signal.

FIG. 9 is a diagram illustrating a structure of an image data signal generation unit in an imaging device according to a second embodiment of the present invention.

[Explanation of symbols]

 A, B imaging device 1 image data signal generation unit 3 image data signal processing circuit 3a low-pass filter processing unit 5 image data output unit 11 imaging lens 15 image sensor (CCD solid-state imaging device) 17 optical filter 17a infrared cut filter 17a 17b optical low-pass Filter 17b 21 Correlated double sampling circuit (CDS) 23 Automatic gain control circuit (AGC) 25 A / D conversion circuit 27 Image data signal processing circuit 28a Low-pass filter processing signal path 28b Bypass signal path 29a, 29a 'Selector 31 Distance measuring sensor 33 Photometry Sensor 35 Distance Measurement Circuit 37 Image Monitor 38 Shutter 41 Image Data Storage 43 Motor Drive Circuit 45 Focus Motor ST0 Stopped State ST1 Shutter Half-Pressed State ST2 Shutter Fully-Pressed State Sa Auto Focus Signal 43 motor drive circuit 45 focus motor 51 first advance / retreat mechanism 53, 63 cylinder 55, 65 piston 61 second advance / retreat mechanism

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/232 G02B 7/11 D // H04N 101: 00 G03B 3/00 A F-term (Reference) 2H011 AA03 BA31 BB04 DA02 DA05 2H051 AA00 BA47 CE09 CE14 EA14 EA26 EB09 GA03 GA10 GA13 GB12 2H083 AA09 AA26 AA28 AA32 AA34 AA35 AA36 AA51 AA52 2H102 AA33 BA12 BA21 BB01 5C022 AA13 AB24 AC69 AC11 AC11

Claims (4)

[Claims] An image data signal generation unit including an imaging lens and an image sensor; detecting an in-focus state with respect to a subject;
An autofocus mechanism capable of automatically focusing the imaging lens on a subject; an image data signal processing unit for performing signal processing on an image data signal output from the image data signal generation unit; A monitor image display unit for displaying, as a monitor, an image based on at least a part of the image data processed by the data signal processing unit, wherein the image data signal processing unit cuts a high frequency component of the image data signal. A low-pass filter processing circuit that performs a filtering process; a bypass signal path that bypasses the low-pass filter processing circuit; and at least one of the low-pass filter processing circuit and the bypass signal path is selected and an image is displayed on the monitor image display unit. An imaging device having a selector for sending data. 2. An image data storage unit for storing image data processed by the image data signal processing circuit; a stop position; and a shutter having a first position and a second position different from the stop position. And operating the autofocus mechanism at the first position, selecting the bypass signal path by the selector, outputting image data passing through the bypass signal path to the monitor image display unit, The image pickup apparatus according to claim 1, further comprising a control circuit that outputs the image data processed by the low-pass filter processing signal circuit to the image data storage unit at the position (1). 3. An image data signal generating unit, comprising: an imaging lens and an image sensor; and an optical low-pass filter provided between the imaging lens and the image sensor so as to be insertable and for removing a high frequency component of an optical image. An advancing / retracting mechanism that allows the optical low-pass filter to retreat from between the imaging lens and the image sensor; and detects an in-focus state with respect to a subject, and based on the detection result,
An autofocus mechanism capable of automatically focusing the imaging lens on a subject; an image data signal processing unit for performing signal processing on an image data signal output from the image data signal generation unit; An imaging apparatus comprising: a monitor image display unit for displaying, as a monitor, an image based on at least a part of the processed image data processed by the data signal processing unit. 4. An image data storage unit for storing an image data signal processed by the signal processing circuit; a stop position; a shutter having a first position and a second position different from the stop position; In the first position, the autofocus mechanism is operated, and the image data obtained in a state where the optical low-pass filter is retracted from between the imaging lens and the image sensor by the advance / retreat mechanism is monitored by the monitor. Output to the image display unit, and at the second position,
4. The image processing apparatus according to claim 3, further comprising a control circuit configured to output image data obtained in a state where the optical low-pass filter is disposed between the imaging lens and the image sensor by the advance / retreat mechanism to the image data storage unit. Imaging device.