JPH07154676A - Camera - Google Patents

Abstract

PURPOSE:To read data correctly even when read times are overlapped by obtaining a photoelectric conversion output to represent picture information relating to setting of image pickup condition corresponding to effectively equal exposure time in the same field for plural number of times. CONSTITUTION:An object light received via a focusing lens 1 is converted into an electric signal and written in a 2nd memory 5 and a 1st memory 6 storing picture data respectively. The a recording picture exposure control circuit 11 obtains an optimum exposure condition to read recording picture data of an image pickup pattern of a succeeding field based on the picture data written in the 2nd memory 5 and reading of the picture data of a CMD 2 is executed. Furthermore, an AF area exposure control circuit 10 obtains an optimum exposure condition to read an AF picture data in an AF area of a succeeding field based on the AF picture data stored in the 1st memory 6 and a read control circuit 12 is used to execute read of the picture data of CMD 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly, to a camera that sets shooting conditions based on image information.

[0002]

2. Description of the Related Art A conventional high-frequency component of an image pickup signal is used as a detection process of a focus position of a photographing lens, which is one photographing condition of a video movie, an electronic still camera, etc., so that a screen contrast is maximized. The so-called hill-climbing AF (autofocus), in which the focusing lens is driven and controlled to obtain the in-focus point, has been the mainstream.

[0003] Further, it is a usual way for a user to position a subject in the center of the screen for photographing. With this in mind, there has been a camera that has an AF area in the center of the screen and uses the video signal in that area to perform the hill-climbing AF process.

In these cameras, CC is used as an image sensor.
Since D is used, the recording image and A
It was necessary to make the timing of reading the F evaluation value image the same. Therefore, the exposure times of both the recording screen and the AF evaluation value imaging screen were the same. Also, A between 1 fields
The F image was read once.

[0005]

However, there is a problem that the data cannot be read correctly when the reading times overlap with each other in order to read the data a plurality of times in one field.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a camera capable of correctly reading data even when the reading times overlap.

[0007]

The camera according to the present invention is provided with image information for setting photographing conditions, which correspond to exposure times which are substantially equal to each other within the same field or frame period from the non-destructive readout type solid-state image pickup device. Is a camera provided with means for obtaining a photoelectric conversion output for representing a plurality of times.

[0008]

According to the present invention, the photoelectric conversion output for representing the image information relating to the setting of the photographing condition corresponding to the effectively equal exposure times is obtained plural times within the same field or frame period.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

A camera showing a first embodiment of the present invention will be described with reference to FIGS.

In the camera of this embodiment, the information sampling rate for AF is substantially increased by devising the method of reading the image data from the image sensor, and the AF speed is increased.

FIG. 14 is a block diagram of this embodiment.
The first memory 22, the AF area exposure control circuit 20, and the recording image exposure control circuit 21 have portions that perform operations peculiar to this embodiment.

In the camera of this embodiment, the camera shown in FIG.
As shown in FIG. 3, the subject light taken in through the focusing lens 1 is a solid-state image sensor similar to a MOS FET described later, which is a CMD (CHARGE MODEL).
An image is formed as a subject image on the image forming plane of the (ANISION DEVICE). Then, it is converted into an electric signal, amplified and sampled by the image pickup processing circuit 3, and inputted to the A / D conversion circuit 4 as an image pickup signal. The A / D conversion output is output by a read control circuit 12 which will be described later.
A second memory 5 which is controlled by the memory controller 8 and stores the image data, and a first memory 22 which stores the image data for obtaining information for setting shooting conditions based on the image data on the AF area GAF And written respectively.

The image data written in the second memory 5 is output to a recording system (not shown). At the same time, the D / A conversion circuit 7 converts the image data into analog data and the EVF system (electronics). It is also output to a viewfinder system (not shown).

The image data in the first and second memories 22 and 5 are respectively the AF area exposure control circuit 20 and the recording image exposure control circuit 21 for obtaining the information for setting the photographing conditions.
Entered in and.

The AF control circuit 9 drives the focusing lens 1 to the in-focus position via the focusing motor 13 based on the output data of the first memory 22.

The iris (optical diaphragm) 31 is driven by an iris driver 32 via an actuator (not shown). The iris driver 32 is controlled by the recording image exposure control circuit 21 to set the iris 31 in a predetermined state.

In this example, the sampling rate of the image data for AF is substantially doubled as compared with the conventional one. Therefore, as shown in FIG. 15, one field period (hereinafter, T
2) AF area reading "Kou", "Otsu"
Are performed at equal time intervals.

In the first case described below (hereinafter referred to as case (1)), the exposure time of the recording image, that is, the charge storage time is the most general one field, for example, the NTSC system. Then, since it is set to 1/60 sec, the reading of the recording image is performed at the same time as the reset. However, in terms of each pixel, it is actually performed immediately before the reset. At this time, as can be seen from FIG. 15, the reading "AF" of the AF area overlaps a part of the reading of the recording image, but this is a predetermined area corresponding to the AF area when reading the recording image. At the timing, it is shown that the same read signal is simultaneously taken into the second memory 5 and the first memory 22, respectively.

Since the exposure time is fixed when the case (1) is driven as described above, the exposure amount is adjusted by the iris 31 in this embodiment. That is, the recording image signal temporarily stored in the second memory 5 is output to each system in a timely manner, but the recording image exposure control circuit 21 detects the output signal and adjusts the signal level to be appropriate / excessive / excessive. In accordance with the above, the current state of the iris 31 is maintained / narrowed down / opened open is controlled. This constitutes a well-known feedback type auto iris control, and the recording image is always kept in a proper exposure state.

On the other hand, with respect to the image data of the AF area, read data is obtained twice in one field and stored in the first memory 22, respectively. The read "Kou" is the exposure time Tv / 2, and the read "B". Is 1 × Tv. Here, the data of the read “Kou” (hereinafter, referred to as data (Kou)) is used as it is, but the data of the read “Otsu” (hereinafter, described as data (Otsu)) is not used as it is. As a result of subtracting the data (A) captured immediately before, this is used as a data (H), and this data is used.

That is, with respect to each pixel data, data (H) = data (B) -data (K) are calculated, and AF image data are sequentially, that is, alternately (K). , Use the data "丙". However, as the above data (A), the data read immediately before the data (B) is used.

At this time, since the read-out "Kou" and "Otsu" were images having the same reset timing, that is, the same exposure start timing and an exposure time of 1 × Tv, data (Kou) and data (Kou) ) Is equivalent to "equal exposure time T with exposure timing shifted by Tv / 2.
Sequential exposure image data having v / 2 ”. That is, since the field rate of this image data for AF is equivalently doubled, the sampling rate of AF information can be doubled and used for control.

Specifically, the AF control circuit 9 analyzes the contents of the above-mentioned sequential exposure image data (step A) and (step A) each time it is obtained. For example, it is determined whether the contrast value has increased or decreased compared to the previous time, and a control signal is sent to the motor 13 according to the result to drive the focus lens 1. Needless to say, conventionally known techniques can be applied to the data analysis and the lens drive control algorithm itself.

In the above example, the exposure time for AF is Tv / 2 as described above, which is 1 / of that of the recording image.
Since it is 2, there is a slight tendency toward underexposure, but when performing imager AF on an ordinary subject using an image pickup system having a normal S / N ratio, such an underexposure is practical. The present inventor has confirmed that the above is not a problem both theoretically and experimentally. Of course, if the brightness of the subject in the AF area is brighter than that of the entire screen, it may be more convenient than the case of the same exposure time.

Next, a case where the circuit image reading shown in FIG. 15 is the third case (hereinafter referred to as case (3)) will be described.

The AF-related processing in case (3) is exactly the same as in case (1) above, including the driving of the image pickup device, but the read timing of the recording image is different, and it overlaps with the AF read "A". ing. At this time, since the time from the reset is Tv / 2, the equivalent exposure time of the recording image is Tv / 2, which is half the case (1). In other words, it is the same as the exposure time for AF. At this time as well, the auto iris operation continues to work effectively, so that proper exposure is maintained. Therefore, there is a great advantage that underexposure of the AF area does not occur as compared with the case (1).

By the way, in this case (3), since the exposure time of the recording image is 1/2 of that in case (1), it is more disadvantageous than case (1) from the viewpoint of sensitivity related to imaging of a low-illuminance subject. However, if the subject brightness is bright, this problem does not occur.

In case (3), since the image data corresponding to the double exposure of the proper exposure is processed in the AF area reading "B", the dynamic range of the signal processing system including the image sensor and the memory is processed. However, the problem due to signal saturation is more likely to occur than in case (1), but this can be solved by careful design.

As described above, the cases (1) and (3) of this embodiment are both extremely effective examples. However, since the cases (1) and (3) have their respective advantages and disadvantages, The second case (hereinafter referred to as case (2)) will be described below as an intermediate one.

This is an example in which the recording image exposure time is set to an intermediate value between cases (1) and (3). Figure 15
This reading cannot be overlapped with the AF area reading "Kou" or "Otsu", as shown in
The exposure time cannot be completely arbitrary, but is set to 0.7 Tv, for example. The above value 0.7
Is an approximation of the reciprocal of the square root of 2.

At this time, the mutual disadvantages described in the cases (1) and (3) are gradually alleviated. Specifically, the degree of underexposure or overexposure is within ± 0.5 EV.

The above cases (1), (2) and (3) are
While considering the dynamic range and S / N of the system,
Automatically switch according to the situation of the subject at that time, especially the overall brightness and the brightness of the AF area.
It is configured to perform F.

In the camera of the first embodiment, an example has been shown in which the AF sampling rate is twice the field rate, but it is equivalent by performing the signal reading a plurality of times during one field and performing the calculation between the data. It is clear that the basic idea of the present example of obtaining image data of a relatively high field rate and thereby increasing the sampling rate of AF information can be extended and applied in the same manner even in the case of arbitrary n-fold sampling. Is.

Regarding the operation between data, the image data is treated as being linear with respect to the input as an implicit assumption in the above description. If you want to handle data that has undergone non-linear processing such as γ (gamma) correction, either linearize it by inverse transformation such as degamma correction, or handle it, or introduce an arithmetic expression that has an equivalent effect. It should be processed.

Further, the present technology can be applied to other information processing systems other than AF, for example, AE (automatic exposure), AWB (auto white balance), AGC (automatic gain control), and the like. It is easily understood by the engineers of. Here, as another example, it is also possible to use a configuration in which only any one of the processes related to the AFs in cases (1), (2), and (3) described above is executed. Then, if the user such as photographing of backlit subject is taken with extreme exposure conditions, when the AF area or when a bright extremely dark compared to the overall image, the exposure set by the entire imaging screen condition However, the exposure conditions are not always good for the AF area, and there are cases where it is not possible to capture the optimum image data for obtaining the AF evaluation value such as contrast information.
Further, there is a problem that AF image data having different exposure conditions cannot be obtained within one field period.

In order to solve the above-mentioned problems, even if the user takes an image under extreme exposure conditions, optimum data can be obtained as image data for setting the imaging conditions.
Further, an example of a camera capable of shooting without deterioration of image quality will be described.

FIG. 1 is a block diagram of a camera showing an example thereof. This camera has a focusing lens 1
This is a camera capable of automatically focusing by driving the. The focusing drive is performed by image data on the AF area GAF provided in the central portion of the image pickup screen GK of FIG. 7, which will be described later. It is assumed that control is performed based on the detected AF evaluation value, for example, contrast information.

In the camera of this example, as shown in FIG. 1, the subject light taken in through the focusing lens 1 is a CMD (CHARGE MODULATI) which is a solid-state image sensor similar to a MOS FET described later.
An image is formed as a subject image on the image forming surface of (ON DEVICE). Then, the image pickup processing circuit 3 is converted into an electric signal.
At, the signal is amplified and sampled, and is input to the A / D conversion circuit 4 as an image pickup signal. The A / D conversion output is controlled by the memory controller 8 according to an instruction from the read control circuit 12 described later, and is output to the second memory 5 for storing the image data and the first memory 6 for storing the image data. Each is written.

The image data written in the second memory 5 is output to a recording system (not shown). At the same time, the image data is converted into analog data by the D / A conversion circuit 7 and the EVF system (electronics). It is also output to a viewfinder system (not shown).

The image data of the first and second memories 6 and 5 includes an AF area exposure control circuit 10 for obtaining information for setting photographing conditions and a recording image exposure control for obtaining image information for recording. It is input to the circuit 11 and.

Then, the recording image exposure control circuit 11 is used.
Determines the optimum exposure condition for reading the image data for recording of the image pickup screen GK in the next field based on the image data written in the second memory 5, and the read control circuit 1
The reading of the image data of the CMD2 is executed via the step 2. In addition, the AF area exposure control circuit 10 is
The optimum exposure condition for reading out the AF image data of the AF area GAF of the next field is obtained from the AF image data fetched in the memory 6, and similarly the read control circuit 12
The image data of the CMD2 is read out via the.

The AF control circuit 9 drives the focusing lens 1 to the in-focus position via the focusing motor 13 based on the output data of the first memory 6.

Next, the structure of the CMD2 is shown in FIG.
~ It demonstrates by FIG.

2 and 3 are an enlarged plan view and a sectional view of the CMD 2, and the structure of this CMD is similar to that of a MOS type FET. And the gate is a donut type POLY-S
i and the source are formed by the inner n + diffusion layer, and the drain is formed by the outer n + diffusion layer. In addition, since the gate is surrounded by the drain, an electrical and optical isolation region is unnecessary, and one CMD element formed by one transistor constitutes one pixel. Suitable for high pixel density and high density.

In the light receiving operation of the CMD, when the source is set to the ground side, the drain is set to the positive bias, the substrate is set to the negative bias, and the gate is set to the negative bias, light is emitted with the gate generated under the gate electrode. It is accumulated as an inversion layer electrode at the Si-SiO2 interface. Due to this hole accumulation, the potential barrier between the source and drain for electrons is lowered, a source current corresponding to the amount of incident light flows, and is output to the outside as a signal current.

As described above, since the CMD does not directly output the photo-generated charges, it can be said that it has an analog memory function in the pixel.

Next, the reading operation of the pixel signal when the CMD is used as an actual imager will be described.

As for the gates and sources of the CMDs arranged in an array on the light receiving portion, if one pixel is focused, as shown in FIG. 4, the vertical scanning signal line and the horizontal scanning signal line are horizontal selection MOS transistors. Are respectively connected via. Further, vertical and horizontal scanning circuits are commonly connected to the CMD as shown in FIG.

To read the pixel data, first,
A CMD having a common row is brought into a read state by a read pulse from the vertical scanning circuit. Next, the horizontal selection MOS transistors are sequentially turned on by the horizontal scanning pulse to read out the signal current of each pixel.

After reading, a reset pulse is applied from the vertical scanning circuit to reset the accumulated charge in each pixel. If the reset is not performed, the same pixel signal can be accessed and read any number of times, that is, nondestructive reading can be performed. Further, since the pixel data of an arbitrary portion on the screen can be partially read by the configuration of the horizontal and vertical scanning circuits, the exposure condition of each designated imaging area can be changed by controlling the read timing after reset. Can be made.

Next, the image data reading operation in the camera of this example configured as described above will be described with reference to the time chart of FIG. 6 and the drawing showing the image pickup screen of FIG.

As described above, in this apparatus, the AF area GAF is set at the center of the image pickup screen GK of FIG.

As described above, the CMD2 is capable of non-destructive read-out and is capable of partial read-out of pixel data of an arbitrary portion on the image pickup screen. Therefore, image pickup is performed within one field period. The recording image data on the screen GK and the image data on the AF area GAF can be read under different exposure conditions, that is, under different exposure times. Therefore, the AF image data of the AF area GAF can be read out under the exposure condition matched with the brightness of the AF area GAF regardless of the exposure condition of the imaging screen GK. After resetting CMD2,
Since the exposure is started immediately, the exposure time is determined by the read timing after the reset.

Therefore, in the case of this example, the recording image of the imaging screen GK one field before and the AF area GA.
Based on the photometric data of the F image for AF, the exposure timing for each of the imaging screen GK of the next field or the AF area GAF, that is, the read timing for giving the exposure time which is the second or first timing is set. It will be decided. The optimum exposure time is calculated for the recording image data of the imaging screen GK by calculating the brightness by multi-area photometry by a calculation method with various corrections. For the AF image data in the AF area GAF, the brightness is obtained by average photometry to obtain the optimum exposure time.

As the resetting and reading processing of the CMD2, as shown in FIG.
The horizontal scanning line LK is reset in units, and at the same time, exposure is started. Then, the reading of the recording image data is executed at the designated second timing. At that time, the recording image data for the entire imaging screen including the AF area GAF is read. On the other hand, with respect to the AF image on the AF area GAF, the reset is performed in units of horizontal scanning lines without being distinguished within the reset processing time of the imaging screen GK. Similarly, the exposure is started immediately after the reset. The AF image data is read by the AF area GA at the read timing which is the first timing after the elapse of an appropriate exposure time for the AF area GAF detected in the previous field.
It is read from the left side of F in pixel units.

The time chart of FIG. 6 is a time chart showing each of the above read timings. In this case, an example in which the brightness of the AF area GAF is brighter than a predetermined range with respect to the brightness of the image pickup screen GK is shown. Shows.

The contents of the time T indicating each timing used in FIG. 6 are shown as follows: TV = the cycle of the vertical synchronizing signal VD TR = the reset time of CMD2 (this reset is synchronized with the rise of the time TV). TK = optimum exposure time of the recording image on the imaging screen GK (second
Timing) T2 = time for reading the recording image data of the imaging screen GK TRA = time for resetting the AF area GAF during the reset time TR T3 = time for starting resetting the AF area GAF after starting the exposure of the recording image TAF = Optimum exposure time of AF area GAF T1 = Reading time of AF area GAF

The image data of the AF area GAF is read at the read timing which is the first timing. In the case of FIG. 6, however, since the AF area is brighter than the image pickup screen GK which is the other area, the AF area GAF is read. The reading of the image data is started after the reading timing time T3 + TAF has elapsed, prior to the reading of the imaging screen GK. If the AF area GAF is darker,
Since it requires a long exposure time, although not shown, the image data of the AF area GAF is read after the reading of the imaging screen GK.

When the brightness of the AF area GAF is the same as the brightness (luminance information) within a predetermined range with respect to the image pickup screen GK, the recording image data of the image pickup screen GK is read at a predetermined timing. The AF image data is drawn from the data. The image data for imaging or for the AF read out at the respective readout times is used as data for obtaining the optimum exposure time of the next field. Furthermore, the image data for imaging is E
At the time of VF display or image recording, it is converted into an analog signal by the D / A conversion circuit 7 and output to the EVF system and the recording system, respectively. The image data for AF is AF
The focusing lens 1 is fetched by the control circuit 9 and is used as original data for extracting the focus position information, and the focusing lens 1 is driven by the focusing motor 13 based on the information.

Next, the CMD reading process will be described with reference to FIGS.
This will be described with reference to the flowchart of.

When it is necessary to read the image data of CMD2, the subroutine "CMD read control" in FIG. 8 is called in synchronization with the vertical synchronizing signal VD. There, in step S100, resetting of CMD2 is performed. Then, in step S101, it is determined whether or not this read processing is the first processing. If it is the first time, since the brightness information of the imaging screen in the previous field is not obtained, the standard value is set as the exposure time and the reading is performed.
Jump to. If it is the second time or later, since the exposure condition in the next field has been set, the process proceeds to step S105 and subsequent steps in FIG. 9 to be described later via the connection portion J1.

In step S102, the standard time is set as the exposure time TK of the recording image. Step S1
In 03 and 104, the reading of the recording image data is executed at the timing corresponding to the exposure time TK. Then, the image data of the portion corresponding to the AF area GAF in the recording image data is taken in as the AF image data. After that, the process proceeds to step S116, the exposure time TK for the recording image in the next field is calculated based on the photometric processing, and this routine is finished. Usually, thereafter, the processing of the subroutine "CMD read control" is subsequently performed. In that case, step S101
Since it is not the first processing in the determination of No., the process proceeds to step S105 and subsequent steps in FIG. 9 as described above.

In step S105 of FIG. 9, the AF area GAF is calculated from the captured AF image data.
It is determined whether the brightness of is within a specified range, brighter or darker than that range. If it is within the specified range, step S106.
If it is very bright, the process jumps to step S108, and if it is very dark, the process jumps to step S112.

When jumping to step S106, the recording image data is read at the read timing corresponding to the exposure time TK that has already been obtained. Then, in step S107, the AF image data is extracted from the recording image data. After that, the process proceeds to the step S116 of FIG. 8 via the connection portion J2.

If the process jumps to step S108, A
The optimum exposure time TAF of the F area GAF is calculated. In step S109, whether the AF area read timing calculated by the exposure time TAF calculated in step S108 is temporally different from the recording image read timing calculated by the exposure time TK, that is, whether it overlaps. To determine. If they do overlap, the process jumps to step S106, and if they do not overlap, the process proceeds to step S110. Whether or not the read timings overlap is determined by comparing the times described in the time chart of FIG. 6, and if the following expression is satisfied, it corresponds to the above overlap.

T3 + TAF + T1 ≧ TK When the process proceeds to step S110, first, the image data of only the AF area GAF is read at the timing corresponding to the optimum exposure time TAF. Then, in step S111, the recording image data of the imaging screen is read at a timing corresponding to the optimum exposure time TK.
Then, the process returns to step S116 of FIG.

On the other hand, by the determination in step S105, A
If the F area is darker than the specified range, step S11
Although it jumps to 2, the optimum exposure time TAF of the AF area is calculated also in this case. Then, in step S113,
It is determined whether or not the readout timing of the AF area GAF by the exposure time TAF calculated in step S112 described above overlaps with the already-obtained recording image readout timing by the exposure time TK. If they do overlap, the process jumps to step S106. If they do not overlap, the process proceeds to step S114. Whether or not the read timings overlap with each other is determined by comparing based on the times TAF and TK described in FIG. Equivalent to.

T3 + TAF ≧ TK + T2 When the processing proceeds to step S114, first, the recording image data of the image pickup screen is read at the timing corresponding to the optimum exposure time TK. Then, step S115.
Then, the process reads out image data of only the AF area GAF at a timing corresponding to the optimum exposure time TAF. Then, the process returns to step S116 of FIG.

The example of the time chart of FIG. 6 is as follows.
From the state of the brightness of the AF area, in the flowchart of FIG. 9, in the determination processing of step S105, step S10 is performed.
8 and then steps S109, 110,
You will proceed to 111.

As described above, steps S107 and S11
The image data of the AF area GAF read at 0 and 115 is used for calculating the optimum exposure time of the AF area GAF of the next field. Then, it becomes possible to obtain AF image data under an appropriate exposure condition for each field, and finally, focus information based on the AF image data under the optimum exposure condition can be obtained, so that highly accurate focusing can be achieved. Focusing drive of the lens 1 is performed.

As described above, in the camera of this example, in the process of reading the image data of CMD2,
Only the AF area GAF is very bright, or
Even if it is dark, since the image data is read at a timing different from the reading timing of the recording image data, the AF image data is read under the exposure condition that matches the brightness of the AF area GAF, and A good focus evaluation value can be obtained.

Regarding the AF image data reading process in the above-mentioned camera, referring to the flowchart of FIG.
Since the brightness of the AF area has changed, step S
When the process proceeds to step S108 or 112 up to the previous field in the determination of 105, but suddenly jumps to step S106 due to the change in the brightness of the AF area, the captured AF image data is also included. There is a risk that it will change abruptly and an accurate AF evaluation value may not be obtained.

As one of the countermeasures, it is possible to propose a modification in which the focus speed is controlled by using the reliability coefficient by fuzzy reasoning or the like. That is, in the modification, as described above, A
When the F evaluation value changes significantly, the focus drive is prohibited during the first few fields. Alternatively, as another modified example, the reliability may be lowered at the beginning when the above change occurs, and the reliability may be increased with the passage of time. Alternatively, it is possible to propose a modified example of the method in which the reliability is determined by the correlation before and after the change.

In the case where the read timings of the recording image data and the AF image data are in conflict with each other,
The AF evaluation value may be obtained based on both image data. In addition, the AF evaluation value before and after the change may be corrected by calculation.

Next, a camera of a modified example of the above example will be described.

The camera of this modification is different from the camera of FIG. 1 in that the second memory 5 which is a recording image memory, the first memory 6 which is an AF image memory, a memory controller 8 and an EVF ( The electronic viewfinder device is not required, and instead, the optical finder 14 is applied as shown in the block diagram of FIG. The configuration of the apparatus other than the above is the same as that in FIG.

In the camera of this modification, the recording image data of the image pickup screen GK captured by the CMD2 and the AF image data of the AF area GAF are both A /
After the D conversion, it is directly taken into the recording image exposure control circuit 11 for obtaining the recorded image information or the AF area exposure control circuit 10 for obtaining the shooting condition setting information. Then, as in the case of the above example, the optimum exposure time is calculated based on the captured image data for recording and the image data for AF, and the reading of the next field is executed.

In this modification, the memories 5, 6,
Further, it is possible to obtain image data of a good AF area required for high-precision AF processing similar to that of the camera of the above example, by using a device having a simplified configuration without requiring a memory controller.

As described above, the camera of the present invention sets the photographing condition based on the output read out at the first timing from the photoelectric conversion output of the nondestructive read-out type solid-state image pickup device, and the second timing different from the first timing is set. Since the recorded image information is obtained based on the output read at the timing of, even if the user takes an image under extreme exposure conditions,
Optimal data can be obtained as image data for setting the shooting conditions, and further image pickup with little deterioration in image quality becomes possible.

Regarding the camera showing the second example of the present invention,
This will be described with reference to FIGS. 11 to 13.

The camera of this example has the same block configuration as that shown in FIG. 1 except that the camera of FIG.
The difference is that the F area is composed of a plurality of areas. That is, the AF area GAFL is located on the left side inside the imaging screen GK for recording images, and the AF area GA is located in the center.
FC, three AF areas of AF area GAFR on the right side are provided. Therefore, in the first memory 6, the AF area G
It is assumed that the AF image data of each of AFL, GAFC, and GAFR is written. Further, the AF area exposure control circuit 10 calculates each optimum exposure time based on each of the AF image data, and controls the reading of the data of the AF area. Further, the AF control circuit 9 carries out AF control regarding the multi-area based on each of the AF image data.

FIG. 11 is a time chart of the reset / read processing of the CMD2 of the camera of this example. Reference numerals in this figure are the same as those shown in the time chart of FIG. However, the exposure time TAF1, TAF2, TA
F3 indicates the optimum exposure time for each corresponding AF area. The reset time of each AF area is performed in units of horizontal scanning lines as described above, and as shown in FIG. 11, the reset of the three AF areas is performed at the reset time T3 at the same time.

The exposure time TAF1, TAF2, TAF3
Shows the shortest exposure time in the three AF areas.
, The intermediate exposure time is TAF2, and the longest exposure time is TAF3. In the example of FIG. 11, the left AF area GAFL is brighter than the imaging screen GK, the central AF area GAFC has a brightness within a predetermined range with respect to the brightness of the imaging screen GK, and The case where the AF area GAFR is darker than the imaging screen GK is shown. Therefore, the exposure time of the left AF area GAFL corresponds to the above time TAF1, and the exposure time of the center AF area GAF
The exposure time of C corresponds to the above time TAF2, and the right AF
The time TAF3 corresponds to the exposure time of the area GAFR.

Then, the reading of the AF image data of the AF area GAFL is started at time T3 + TAF1 earlier than the reading of the recording image data of the imaging screen GK.
Further, the reading of the AF image data of the AF area GAFR is delayed from the reading of the imaging screen GK at time T3 +.
It starts in TAF3. Further, regarding the AF area GAFC, in the case of this example, the optimum reading time of the AF image data overlaps with the reading time of the recording image data of the imaging screen GK.
The image data for AF is not read, and the imaging screen GK
The image data for AF is taken in from the image data for recording.

Next, the CMD reading process will be described with reference to the flowchart of FIG.

When it is necessary to read out the image data of CMD2, in synchronization with the vertical synchronizing signal VD, the above-mentioned FIG.
The "CMD read control" sub-routine is called, but the processes of steps S201 to S205 of FIG. 13 and step S209 are the same as those of the example of FIG. 8, and the description thereof will be omitted. However, step S2
In the present example, the processing for capturing the AF image data in 05 is performed in the three AF areas GAFL and GAF.
Image data for C and GAFR will be captured.

The read process is performed for the second time, and step S
If the process proceeds to step S206 by the determination of 202, the three captured AF areas GAFL, GAFC,
Optimal exposure time TA from the image data of GAFR
Calculate F. In step S207, the optimum exposure time T
The exposure time is registered as the value TAF1 for the AF area that gives the shortest exposure time of the AF. Furthermore,
Next, the value TAF2 is registered as the exposure time of the AF area which gives the shortest exposure time. Further, the value TAF3 is registered as the exposure time of the AF area which gives the longest exposure time.

Next, in step S208, a subroutine "reading process" is executed. In this process, exposure and reading of the corresponding AF areas are sequentially performed from the shortest exposure time TAF1 of the exposure times set in step S207. In this process, if there is an exposure time that overlaps with the reading timing of the recording image data, the overlapping AF area is not read out intentionally, and the corresponding AF area is read from the recording image data.
Import area data.

When the three AF areas have the same brightness, the reading timings of the AF areas may overlap. In this case, the AF image is exposed with the average exposure time of the exposure times of the overlapping areas. Data shall be captured. Further, when the AF area is very bright, the read timing overlaps the reset timing, which is acceptable. However, it is prohibited that the AF area is very dark and the read timing overlaps the reset time of the next field.

As described above, in the camera of this embodiment, it is possible to set an appropriate exposure time for each of a plurality of AF areas. Therefore, a highly accurate focus evaluation value for the plurality of AF areas can be set. Can be obtained.

It should be noted that the present technology can be applied to information processing systems other than AF, for example, AE (automatic exposure), AWB (auto white balance), AGC (automatic gain control), and other related fields. It is easily understood by the engineers of.

[0093]

As is apparent from the above description, the present invention has an advantage that data can be correctly read even when the read times overlap.

[Brief description of drawings]

FIG. 1 is a block diagram of a camera showing an example of the present invention.

FIG. 2 is an enlarged plan view of a CMD applied to the camera shown in FIG.

FIG. 3 is an enlarged cross-sectional view of a CMD applied to the camera shown in FIG.

4 is a circuit configuration diagram of one pixel element of CMD applied to the camera of FIG.

5 is a circuit diagram of a CMD applied to the camera shown in FIG.

6 is a time chart of CMD reading processing of the camera of FIG.

7 is a diagram showing an image pickup screen of the camera shown in FIG.

8 is a part of a flowchart of CMD read control of the camera shown in FIG.

9 is a part of a flow chart of CMD read control of the camera of FIG.

FIG. 10 is a block configuration diagram of a camera showing a modified example of the camera of the above example.

FIG. 11 is a time chart of CMD reading processing of the camera of the second example of the present invention.

12 is a diagram showing an image pickup screen of the camera shown in FIG.

13 is a flowchart of CMD read control of the camera shown in FIG.

FIG. 14 is a block diagram of a camera showing the first embodiment of the present invention.

15 is a time chart of CMD reading processing of the camera of FIG.

[Explanation of symbols]

5 Second memory 6,22 First memory 10,20 AF area exposure control circuit 11,21 Recording image exposure control circuit T3 + TAF, T3 + TAF1, T3 + TAF3AF Read timing (first timing) TK Recorded image read timing (second timing) )

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Yoshida 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Kazuya Kobayashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd.

Claims (1)

[Claims] 1. A non-destructive read-out type solid-state imaging device is provided with a plurality of photoelectric conversion outputs for representing image information for setting a photographing condition, which correspond to effectively equal exposure times in the same field or frame period. A camera provided with means for obtaining.