JP4422401B2 - Imaging apparatus and exposure control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a video camera with a monitor having a monitor unit and a camera unit, wherein the camera unit includes an imaging unit, and a recording / reproducing and grip unit (recording unit) that can rotate relative to the imaging unit. It is related with the exposure control technique of the imaging device comprised by these.
[0002]
[Prior art]
In a video camera with a liquid crystal monitor (camera-integrated VTR), a liquid crystal monitor unit and a camera unit are attached so as to be relatively rotatable by a rotation mechanism. Further, there is an imaging apparatus of a type in which the camera unit includes an imaging unit and a recording / reproducing and grip unit that can rotate relative to the imaging unit. This type of imaging device is referred to as a rotary imaging device in this specification.
[0003]
The outline of the configuration of the rotary imaging apparatus will be described below with reference to FIG. FIG. 6A is a front view of the rotary imaging device (video camera), and FIG. 6B is a rear view of the rotary imaging device (viewed from the photographer side). As shown in FIGS. 6A and 6B, the rotary imaging device 100 can be rotated by a main body having a recording / reproducing unit 101 and an imaging unit 102 and a swing member 123 relative to the main body. And a monitor (for example, a monitor having a liquid crystal display screen 104) 103 attached thereto. The imaging unit 102 is provided with a lens 105 for photographing a subject and a viewfinder 106.
[0004]
The monitor rotating video camera 100 shown in FIGS. 6A and 6B reverses the monitor unit 103 having the LCD display screen 104 so that the lens 105 faces the photographer himself and monitors the photographer himself / herself. It is possible to take a picture while checking with the unit 103. In this case, in order to hold the lens 105 in an upright state, the monitor unit 103 is rotated without turning the main body units 101 and 102 upside down, so that an image having a correct positional relationship in the vertical direction can be taken. it can.
[0005]
On the other hand, in a camera having an automatic exposure (so-called AE) function, photometry is required to determine exposure conditions. In an imaging apparatus that includes a solid-state image sensor (CCD or the like) and obtains a video signal representing a subject image, a method for obtaining a photometric value by dividing a video signal output from a solid-state image sensor into an appropriate photometric area and integrating it Is considered. By electrically processing the video signal obtained from the solid-state image sensor, variations such as average photometry, partial photometry, and split photometry are possible, and it is possible to set exposure conditions for various shooting environments. It is.
[0006]
For example, partial photometry is performed on the basis of video signals obtained from substantially the central and lower areas of the imaging area where the possibility that the main subject is present is relatively high. Such partial photometry has the advantage that the main subject can always be properly exposed.
[0007]
FIG. 3 shows a composition in which the upper part is empty and a person is present in the lower part, and it can be seen that there is important information in the central part and the lower part. In this way, many subjects have important information at the center and bottom, and by performing metering with emphasis on the center and bottom rather than average metering of the entire screen, Appropriate exposure.
[0008]
[Patent Document 1]
JP-A-6-98210 [0009]
[Problems to be solved by the invention]
However, in the rotary imaging apparatus 100 shown in FIG. 6, it is necessary to change the hand holding the grip or the like in order to hold the lens 105 in the normal position. In order to emphasize the ease of use, it is preferable that the grip that is held is left as it is. As a configuration for that purpose, as shown in FIG. 7, the main body is configured by an imaging unit 101 and a recording / reproducing unit 102, and the imaging unit 101 and the recording / reproducing unit 102 are connected to each other so as to be rotatable. The relative rotation is possible. With this configuration, the lens unit 105 attached to the imaging unit 102 is directed toward the photographer by relatively rotating and moving the imaging unit 101 and the recording / reproducing unit 102 constituting the main body unit. You can shoot yourself. In this case, the monitor unit 103 is rotated so that the photographer himself can see and confirm the display screen 104.
[0010]
When the photographer himself / herself is photographed in the rotary imaging apparatus 100 capable of face-to-face photography, the imaging unit 101 is turned upside down as shown in FIG. In the case of face-to-face shooting in which the imaging unit 101 is reversed (upside down), the video recorded in the recording unit 102 is also reversed (upside down) and unsightly, and it has been found that there is a problem with exposure correction. .
An object of the present invention is to provide an imaging apparatus capable of performing appropriate photometry (exposure correction) even during face-to-face photography and capable of performing better photography, and an exposure control method thereof.
[0011]
[Means for Solving the Problems]
According to an aspect of the present invention, there is provided an imaging apparatus having a recording unit and an imaging unit provided so as to be rotatable relative to the recording unit, wherein the first electrical signal output from the imaging unit is received. An image generated by an output signal from the signal processing unit based on a signal processing unit to be processed, an upside-down inversion detector for detecting upside-down inversion of the imaging unit, and a detection result of the upside-down inversion by the upside-down inversion detector There is provided an imaging apparatus having an upside down circuit that performs processing so that data is displayed upside down.
According to the above imaging device, when the upside down of the imaging unit is detected, the image data processing is performed so that the upside down is performed. Therefore, even when the imaging unit is rotated, the image data can be output in a correct state. it can.
[0012]
According to an imaging apparatus according to another aspect of the present invention, a recording unit; provided so as to be relatively rotatable with respect to the recording unit, and between an imaging lens, an imaging element, and the imaging lens and the imaging element. An imaging unit comprising: an iris that is provided and driven by an iris driving circuit; and an upside-down inversion detector that detects upside-down inversion of the imaging unit, and a first output from the imaging unit A signal processing unit that processes one electrical signal, and an upside-down inversion that performs processing for displaying the image data generated based on the first electrical signal upside down based on the detection result of the upside down detector A divided photometric detection circuit that divides the image data into a plurality of photometric areas, and the divided image data in the vertically inverted image data based on the detection result of the upside down detection by the upside down detector. Calculating a weighting of the photometric per light area, an imaging device and a control unit for controlling the iris driving circuit based on the weight degree is provided.
According to the imaging apparatus, even when the imaging unit is turned upside down, weighting can be performed in accordance with a subject important for auto iris control, so that exposure can be appropriately performed even in inverted photography.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In this specification, the subject generally refers to an important part that is the center of an image, such as a person, and is used as a term corresponding to the background existing in the peripheral part.
An imaging apparatus and an exposure control method thereof according to the present invention will be described with reference to the drawings. The inventor considered as follows the cause of the problem in the exposure correction in the case of face-to-face shooting in which the imaging unit is reversed (upside down). As described above, FIG. 3 is a diagram illustrating an example of a composition in a general video during normal shooting. FIG. 4 is a composition of a video in the case of face-to-face shooting, and shows a composition when a subject corresponding to FIG. 3 is shot. As can be seen from a comparison between FIG. 3 and FIG. 4, when exposure correction is performed based on an upside down image, the person and the sky are reversed and the exposure correction for an important subject such as a person is not performed correctly. Is likely. That is, as shown in FIG. 4, the captured image is also turned upside down. In this case, if metering is performed in the same way as before, the sky and the person are upside down, so there are cases where the sky is metered during exposure and the person is not metered. Metering is not possible.
[0014]
Considering the above points, the imaging technique according to the first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram illustrating a configuration example of the imaging apparatus according to the present embodiment. The basic appearance configuration is the same as that of the image pickup apparatus described with reference to FIGS. 6 and 7, and will be described below with reference to FIGS. 6 and 7 as appropriate.
[0015]
As shown in FIG. 1, a rotary imaging apparatus A according to the present embodiment includes a lens 3 that captures an image of a subject, an iris 31, a CCD (solid-state imaging device) 5 that converts an optical signal into an electrical signal, and a CCD 5 A CDS / AGC circuit 7 that amplifies and samples the electrical signal output from the signal, an AD converter (ADC) 11 that samples the output electrical signal from the CCD as a digital signal, and a camera signal process that processes the digitized video A memory 15 for an even field (hereinafter referred to as “even field memory”) 17, a memory for odd field (hereinafter referred to as “even field memory”) 21, and these memories 17 and 21. An upside-down inversion circuit including an upside-down inversion memory reading circuit 23 that reads out an image by using upside-down inversion using a stored signal 5, a recording circuit 27 that records the output from the vertical inversion circuit 25 as video data, and a vertical inversion detector 33 that detects whether the imaging unit 101 (FIG. 6) is upside down. Yes.
[0016]
In the imaging apparatus A, the optical signal captured by the lens 3 enters the CCD 5 and is converted into an electrical signal when the iris 31 is open. This electric signal is converted into a digital signal by the CDS / AGC circuit 7 that performs amplification and sampling and the AD converter 15 that digitally samples the CCD signal, and is input to the camera signal processing unit 15. In this state, the video signal remains reversed and is not a normal video. This signal is converted into normal video data up and down by an up / down inversion circuit 25 including an even field memory 17 and an even field memory 21 and an up / down inversion memory reading circuit 23.
[0017]
The upside down circuit 25 operates as described below, for example. First, in order to reverse both the horizontal direction and the vertical direction, the upside-down video is stored in the memories 17 and 21 as it is. Next, the address is counted down and read out, and an upside down video is output. In the case of the imaging device according to the present embodiment, the even field video is stored in the even field memory 17. Next, the odd field image is stored in the odd field memory 21. During that time, if the even field memory 17 reads out the address by the reverse address to that at the time of writing, the image to be displayed based on the video signal is reversed upside down and output. can do. If the writing to the even field memory 17 and the odd field memory 21 and the reverse reading are performed for each field, it is possible to output a continuous video by vertically inverting it. Whether the imaging unit 101 is inverted upside down is detected by the upside down detector 33. After detecting whether the imaging unit 101 is upside down by the upside down detector 33, a signal notifying that it is upside down is output to the upside down memory reading circuit 23. When the camera is not turned upside down, signals may be read in the order of addresses by a normal writing operation.
[0018]
Next, an imaging device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a functional block diagram illustrating a configuration example of the imaging apparatus according to the present embodiment. The appearance configuration is the same as the configuration shown in FIGS.
The rotary imaging apparatus B according to the present embodiment includes a lens 53 that captures an image of a subject, a CCD (solid-state imaging device) 55 that converts an optical signal into an electrical signal, and a CDS that performs amplification and sampling of a signal transferred from the CCD 55. / AGC circuit 57, AD converter (ADC) 61 that converts a CCD signal into a digital signal, a camera signal processing unit 65 that processes digitized video, and a microcomputer 73 that detects the upside down of the imaging unit 101 and that will be described later. A vertical inversion detector 81 for notifying the camera, a vertical inversion circuit 67 that can invert and output the signal from the camera signal processing unit 65, an iris 83 for controlling the optical signal from the lens 53, An iris driving circuit 75 that controls the iris of the iris 83, a lens driving circuit 77 that drives the lens 53, and a camera signal processing unit 65 Composed photometric / distance measuring circuit 71 for performing photometric / distance measurement based on the signal et detected, the microcomputer 73 capable of controlling the iris driving circuit 75 and a lens driving circuit 77, it contains.
[0019]
The operation of the image pickup apparatus B having the above configuration, particularly, auto iris control and auto focus control will be described below. Reference is also made to FIGS. For the auto iris control, a combination of dual pattern photometry and peak sensing is generally used. In the dual pattern photometry method, a weighted average value with an emphasis on the central portion and the lower portion is obtained from a video signal, and this is compared with a reference luminance and fed back to the iris to control the iris. Since there are many cases where the subject is present at the center and lower part of the screen, according to this method, the brightness of the subject is controlled to match the reference brightness, and the exposure is appropriately controlled in the case of weak backlight. The
[0020]
The peak sensing method is a method in which the maximum value of the video signal is obtained and feedback control is performed on the iris so that the maximum value matches the reference luminance. According to this method, since the maximum luminance in the image does not saturate, the whiteout phenomenon can be prevented even under an over-ordered light condition. However, in practice, when the operation is performed only based on the peak sensing method, the image may be underexposed. Therefore, by combining the peak sensing method and the above-described dual pattern photometry method, the effect of peak sensing (the image is underexposed) is weakened.
[0021]
On the other hand, for autofocus control, the video AF method is generally adopted. In the video AF method, the lens 53 is controlled and focused based on the size of the high frequency component included in the video signal obtained through the lens 53 and the CCD (imaging device) 55. When the focus lens is moved back and forth, the magnitude of the high frequency component included in the video signal draws a mountain shape having a peak at the in-focus position. The basic principle of video AF is to detect the direction of this mountain, climb up the mountain and focus on the top.
[0022]
In the image pickup apparatus adopting the video AF method, when the image pickup unit 101 is not turned upside down, a weighted average is given with emphasis on the central portion and the lower portion as shown in FIG. And auto iris control is performed by combining the maximum brightness in the image.
[0023]
Regions (1) to (4) in FIGS. 3 to 5 are regions obtained by dividing the photometric area in the image. FIG. 3 is a diagram showing an example of the weighting of photometry in each divided area on the screen during normal shooting, where the area (1) is 10%, the area (2) is 40%, and the area (3) is 30%. , Region (4) represents a state where weighting of 20% is performed. Here, when the imaging unit 101 is rotated and turned upside down, the upside down detector 81 is turned on and notifies the microcomputer 73 that the imaging unit 101 is turned upside down. At this time, the microcomputer 73 recognizes that the photometry data input from the photometry / ranging circuit 71 is upside down, and as shown in FIG. 4, a weighted average value obtained by weighting upside down from FIG. And auto iris control by combining the maximum brightness in the screen. The weighting in each photometric area in FIG. 4 is, for example, that region (1) is 30% as in region (3) in FIG. 3, and region (2) is 40% as in region (2) in FIG. 3, region (3). Is 10%, which is the same as the region (1) in FIG. 3, and the region (4) is 20%, which is the same as the region (4) in FIG. Thereby, an important subject such as a person can be photographed under appropriate exposure conditions.
[0024]
When photometric data is detected from the image that has been inverted upside down, the video for a certain period of time while being inverted by the memory is retained, and the photometric data is delayed information. In exposure control where it is necessary to optimize the exposure at high speed, this delay time becomes a factor of performance deterioration, so it is necessary to detect it before performing memory processing.
[0025]
Furthermore, as a result of the microcomputer 73 performing autofocus control based on the distance measurement data input from the photometry / ranging circuit 71 with the imaging unit 101 rotated and turned upside down, the distance to the subject is within 10 cm to 1 m. If there is, it is determined that the shooting is face-to-face. Face-to-face shooting is shooting in a state where the subject is a person and the person who is the subject is a photographer, and the distance between the imaging device and the subject is generally about 10 cm to 1 m. . When the microcomputer 73 determines that the face-to-face shooting is performed, as shown in FIG. 5, the weighted average is obtained by weighting so that the person who is the subject is photometrically focused, and the auto iris control is performed. In this case, the maximum luminance on the screen is not reflected in the photometric data because it is affected by other than the person who is the subject. Therefore, as a weighting example in each photometric area in FIG. 5, the area is 40%, the area (2) is 60%, the area (3) is 0%, and the area (4) is also 0%. By using the weighting as shown in FIG. 5, the person who is the subject can be photographed with appropriate exposure during the face-to-face photographing.
As mentioned above, although demonstrated along this Embodiment, it cannot be overemphasized that this invention is not limited to these examples, and various deformation | transformation are possible.
[0026]
According to the imaging device according to each embodiment of the present invention, even when the imaging unit is rotated upside down, an image recorded on a recording medium or the like can be recorded in a normal state. Even when the image pickup unit is turned upside down, an appropriate subject such as a person can be photographed under proper exposure conditions by appropriately adjusting the weighted average weighting of the auto iris control. Furthermore, when it is determined that the face-to-face shooting is based on the autofocus control information, the person who is the subject can be shot under an appropriate exposure condition.
[0027]
【The invention's effect】
The imaging apparatus according to the present invention can record an image in a normal state on a recording medium even when the imaging unit is rotated upside down. Even when the imaging unit is turned upside down, the weight of the weighted average of the auto iris control can be changed appropriately, so that an important subject can be shot with appropriate exposure. Furthermore, when it is determined that the face-to-face shooting is based on the autofocus control information, the subject can be shot with an appropriate exposure.
[Brief description of the drawings]
FIG. 1 is a functional block diagram illustrating a configuration example of an imaging apparatus according to a first embodiment of the present invention.
FIG. 2 is a functional block diagram illustrating a configuration example of an imaging apparatus according to a second embodiment of the present invention.
FIG. 3 is a diagram showing a distribution of auto iris control weights for each region during normal shooting.
FIG. 4 is a diagram illustrating weight distribution for auto iris control when the imaging unit is inverted.
FIG. 5 is a diagram illustrating auto iris control weighting when face-to-face shooting is performed when the imaging unit is reversed;
6A and 6B are schematic diagrams illustrating an external configuration example of a camera unit rotation type imaging apparatus, in which FIG. 6A is a perspective view when viewed obliquely from the front, and FIG. It is a perspective view at the time of seeing.
FIG. 7 is a schematic diagram illustrating an example of an external configuration of a camera unit rotation type imaging apparatus, and is a perspective view when viewed obliquely from the front in the face-to-face shooting mode, and is a diagram illustrating a configuration after rotating a liquid crystal monitor is there.
[Explanation of symbols]
3, 53 ... lens, 5, 55 ... CCD image sensor, 7, 57 ... CDS / AGC, 11, 61 ... A / D converter, 15, 65 ... camera signal processing unit, 17 ... memory (for even field), 21 ... Memory (for odd field), 23... Upside down memory reading circuit, 25... Upside down circuit, 27... Recording circuit, 83, Iris, 71 .. Photometry / ranging circuit, 73. , 77... Lens driving circuit, 33, 81.

Claims (2)

A recording unit; an imaging lens which is provided so as to be rotatable relative to the recording unit and has an autofocus function; an imaging device; and is driven by an iris driving circuit provided between the imaging lens and the imaging device. An imaging device comprising: an iris; and an imaging unit comprising:
An upside down detector for detecting upside down of the imaging unit;
A signal processing unit for processing a first electrical signal output from the imaging unit;
Based on the detection result of the up / down inversion detector, an up / down inversion device for performing a process for displaying the image data generated based on the first electric signal upside down,
A divided photometric detection circuit for performing photometry by dividing the image data into a plurality of photometric areas;
Said upper and lower reversing detector based on the vertical inversion of the detection result of, sets the weighting of the vertical inverted divided in the image data photometric said each photometric area, the iris on the basis of the photometric data by the weighting degree A control unit for controlling the drive circuit;
An auto iris control unit that automatically adjusts an aperture of the imaging lens by driving an iris driving circuit based on a maximum luminance level of image data by the first electrical signal;
An autofocus control unit that performs focusing control,
Wherein the upper and lower reversal detector is detected upside down, based on the focusing distance, determines that the mirror mode when the distance to the subject was within 1m from 10 cm, determined to face shooting a subject person An image pickup apparatus that performs auto iris control with weighting that more dimmes light than when it is not performed. In the automatic iris control, the maximum brightness level of the screen, the image pickup apparatus according to claim 1, characterized in that not reflected in the photometric data.

Images