JP2000032345A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device capable of shortening a release time lag and performing proper AE control or AWB control through simple processing. SOLUTION: Concerning the image pickup device having an imaging device 1 capable of reading out pixel information through charge transfer, this device has a read control means 8 for reading the pixel information while selectively controlling an addition thinning read mode for thinning, adding and reading the pixel information from the imaging device 1 and a non-addition thinning read mode for thinning and reading the pixel information without adding it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup apparatus that extracts a pixel signal from an image pickup device to record a still image or performs a moving image process.

[0002]

2. Description of the Related Art Conventionally, various types of image pickup devices used for this type of image pickup apparatus have been proposed.
As schematically shown in FIG. 1, there is known an interline CCD solid-state imaging device having a vertical overflow drain structure. The CCD is two-dimensionally arranged in a horizontal direction and a vertical direction, and receives a charge accumulated in the photodiode 21 via a transfer gate 22 after receiving a charge through a photodiode 21. Vertical transfer path 23 for sequentially transferring data in the vertical direction
A horizontal transfer path 24 for sequentially transferring charges transferred by the vertical transfer path 23 in the horizontal direction; and a horizontal transfer path 2
And a signal detector 25 that amplifies and outputs the output signal of No.4.

[0003] Since the number of pixels of such a CCD has been increasing in accordance with recent advances in microfabrication technology, various image pickup devices incorporating a CCD having a high number of pixels have recently been proposed. However, for example, in a portable imaging device such as an electronic still camera, a high pixel count CC
Even if D is used, from the viewpoint of power consumption and cost, CCD
Drive frequency can not be too high, generally 20MHz
It is driven below. So, for example,
When a CCD equivalent to 1 million pixels is used, 10
Only about 15 frames can be obtained.

However, with this number of frames, for example,
When an image pickup device is provided with a liquid crystal display device for displaying a moving image picked up by a CCD, an auto focus control (AF), an automatic exposure control (A) using moving image data from the CCD.
E), when performing automatic white balance control (AWB) or the like, inconvenience occurs.

That is, when a moving image is displayed on a liquid crystal display device, a good moving image cannot be displayed unless image data of about 60 frames per second is supplied. Therefore,
Conventionally, a memory for storing image data from a CCD is provided, and data of the same frame stored in this memory is
For example, the data is repeatedly read out a plurality of times at a frame cycle of 1/60 second, supplied to the liquid crystal display device, and displayed. Therefore, in this case, if image data is obtained from the CCD at a rate of 10 frames per second, an image of the same frame is repeatedly displayed six times. However, providing an expensive memory only for adjusting the number of frames for display in this way is disadvantageous in terms of cost.

[0006] When taking a still image as in an electronic still camera, it is important not to miss a photo opportunity. For that purpose, the AF, AE,
It is necessary to obtain control data used for processing such as AWB at a high speed. However, if only about 10 frames of image data can be obtained per second, for example, in AF, focusing cannot always be performed using image data of one frame, and AF operation is performed using a plurality of frames. To be done,
If processing such as AF, AE, and AWB is performed sequentially, it takes a long time to perform the processing, and the release time lag becomes longer.
There is a case where a shutter chance or the like is missed. Therefore, conventionally, these processes are performed in parallel at the same time, or these processes are sequentially performed by storing image data by providing a memory as described above. However, when the processes such as AF, AE, and AWB are performed simultaneously in parallel as in the former, the circuit scale becomes large and the cost becomes disadvantageous, and a memory is provided for the processing as in the latter. This is disadvantageous in terms of cost.

As a method of solving such a problem,
Displaying a moving image on the liquid crystal display device as described above,
In a moving image processing mode for obtaining control data such as F, AE, and AWB, it has been proposed to read out by thinning out horizontal pixel lines of a CCD. However, in the case of a CCD that reads out all pixels and obtains a color image signal, generally,
As shown in FIG. 13, the odd-numbered lines are, for example, a repeating pattern of red (R) and green (G), and the even-numbered lines are, for example, a color difference line-sequential form of a Bayer array including a repeating pattern of G and blue (B). For example, when only the odd lines are read out, the B color signal is lost, and when only the even lines are read out, the R color signal is lost. For this reason, especially when displaying on a liquid crystal display device, there arises a problem that an accurate color image cannot be displayed.

Accordingly, the present applicant has solved the above-mentioned various problems, and has developed an imaging method capable of obtaining a large number of frames of image data per unit time from an imaging device in a moving image processing mode without using a high driving frequency. An apparatus has already been proposed (Japanese Patent Application No. 9-7831). In this image pickup apparatus, assuming that the CCD has a horizontal line of pixels from the first line to the Lth line in the vertical direction as a readout mode of pixel information from the CCD in the moving image processing mode, for example, As shown in FIG. 14 (A), n (m ≧ 3, m is an integer) for all lines
(N ≧ 2, n is an integer) n-line addition thinning-out readout mode in which lines are added and taken out, and k (k ≧ 6, k is an integer) partially continuous in the vertical direction as shown in FIG.
As for the lines, as in FIG. 14A, a k-line n-line addition thinning-out readout mode is set by adding n lines for m lines, and these modes are selected based on the operation of the release button to select a moving image. I try to get data. Here, it is assumed that m = 3 and n = 2, and the first line and the third line are added in each line group of m = 3.

That is, in the n-line addition thinning-out reading mode shown in FIG. 14A, of all the lines from the first line to the L-th line, of the three lines from the first line to the third line, Reading is performed by adding the first and third lines, and reading is performed by adding the fourth and sixth lines of the subsequent three lines from the fourth line to the sixth line. Thereafter, similar addition thinning-out reading is performed by L-2, L- including the last L-th line.
The processing is performed until the L-2 line and the L line are added to and read from the three lines 1 and L. Therefore, the number of lines read in the n-line addition thinning-out reading mode is L / m.

In addition, in the k-line and n-line addition thinning-out reading mode shown in FIG. 14B, k lines continuous in the vertical direction are set in advance, and the set k lines are compared with those in FIG. In the same manner, addition thinning-out reading of n lines is performed for m lines. Therefore, the number of lines read in this case is k / m.

FIG. 12 shows an n-line addition thinning-out reading operation in which two lines (n = 2) are added to three lines (m = 3) to obtain one line of pixel information.
FIG. 1 shows an example of the interline CCD shown in FIG.
This will be described with reference to FIG. In FIG. 15, GA, G
B, GC, BA, BB, BC, RA, RB, and RC denote photodiodes 21 corresponding to the Bayer array color filters shown in FIG. 13, respectively, and a vertical line located to the right of these photodiodes 21. Indicates a vertical transfer path 23, and a line located in the horizontal direction at the lower end side of the vertical transfer path 23 indicates a horizontal transfer path 24.

First, at the end of the exposure, GA,
Of the photodiodes 21 of GB, GC, BA, BB, BC, RA, RB, and RC, charges from the photodiodes 21 of suffixes A and C are transferred to the corresponding vertical transfer paths 23 as shown by ellipses in the figure. I do. After that, in each vertical transfer path 23, charges are transferred toward the horizontal transfer path 24. Since the vertical transfer operation in this case is m = 3, three transfers are performed as one unit, whereby the charge from the photodiode 21 with the suffix A and the charge from the photodiode 21 with the suffix C are obtained. Add the charge.

[0013] For example, in FIG.
In the portion 3, the charge of the photodiodes 21 of RA and RC among the three photodiodes 21 of RA, GB, and RC is transferred to the vertical transfer path 23, and the first transfer is performed in the vertical direction. And transfer the charge from the photodiode 21 of RA to a position in the vertical transfer path 23 adjacent to the photodiode 21 of GB. Next, a second transfer is performed in the vertical direction, and while the charge from the photodiode 21 of RC is held in the horizontal transfer path 24, the charge from the photodiode 21 of RA is transferred to RC.
Is transferred to a position in the vertical transfer path 23 adjacent to the photodiode 21 of FIG. Thereafter, the third transfer is performed in the vertical direction, and the charge from the photodiode 21 of RA is transferred into the horizontal transfer path 24 while the charge from the photodiode 21 of RC is held in the horizontal transfer path 24. Then, the charges from the photodiodes 21 of RA and RC are added in the horizontal transfer path 24.

The charges thus added are sequentially read out from the horizontal transfer path 24 to obtain one line of pixel information. Thereafter, in the same manner, one readout of the horizontal transfer path 24 is performed every three vertical transfers to obtain pixel information obtained by adding the charges of two of the three lines.

By performing the addition thinning-out reading as described above,
If a Bayer array color filter is provided,
As shown in FIG. 16, the first line and the third line, which are the lines (CR) including the information of R, are added and output,
Next, the fourth line and the sixth line, which are the lines (CB) containing the information of B, are added and output, and thereafter, R
And the line output including the information of B are repeatedly obtained, so that the color signals can be obtained in a line-sequential manner.

In the imaging apparatus proposed earlier by the present applicant, by operating the release button, the photographer wants to take a still image, and presses the release button lightly to generate a first trigger in a preparation stage of recording. The second trigger is generated by further pressing the release button in order to start recording the still image from the state, and as shown in FIG. 17, until the first trigger is generated, as shown in FIG. The selected n-line addition thinning-out reading mode is selected, thereby performing n-line addition thinning-out reading in synchronization with, for example, a 1/60 second vertical synchronization signal (VD), and supplying the moving image data to the liquid crystal display device for display. At the same time, AE control and AWB control are alternately repeated for each frame by using the data as control data.

In this state, when the first trigger is generated, the k-line and n-line addition thinning-out reading mode shown in FIG. 14B is selected from the next frame, whereby two frames are synchronized with VD in one frame period. The k-line and n-line addition thinning-out reading is performed a number of times, and AF control is performed using image data obtained by each reading operation as control data for AF. Thereafter, when the second trigger is generated, the main exposure is performed based on the result of the AE control performed until the first trigger is generated.
For example, scanning is sequentially performed at a rate of 10 frames per second, which is equivalent to six VD frames, and the still image is recorded on a recording medium (not shown). After the recording of the still image is completed, in order to prepare for the next shooting, the n-line addition thinning-out reading mode is selected again, the n-line addition thinning-out reading is performed in synchronization with VD, and the moving image data is transferred to the liquid crystal display device. The AE control and the AWB control are alternately repeated for each frame while being supplied and displayed and used as control data.

[0018]

According to the imaging apparatus according to the earlier proposal of the present applicant, in the moving image processing mode,
Compared with the case where pixel information is read out by sequentially scanning all lines of the CCD at a predetermined reading frequency, the frame rate can be improved m times in the n-line addition thinning-out reading mode shown in FIG. In the k-line and n-line addition thinning-out reading mode shown in B), since the frame rate can be improved to m × (L / k) times, a large number of signals can be output from the CCD per unit time without using a high driving frequency. Image data of the number of frames can be obtained.
Therefore, a favorable moving image can be displayed on the liquid crystal display device without using an expensive memory for display as in the related art, which is advantageous in cost. Further, even when processing such as AF, AE, and AWB is performed using moving image data, the processing can be performed without using a memory, which is advantageous in terms of circuit scale and cost. Further, when the first trigger is issued,
During the period from the first trigger to the second trigger after AE and AWB have already been completed, only AF is performed in the k-line and n-line addition thinning-out reading mode having a high frame rate, so that this period can be shortened, and the release time lag can be reduced. Can be shortened.

In addition, in the n-line addition thinning-out reading mode, assuming that m = 3 and n = 2, the pixel information of the first line and the pixel information of the third line in each line group of m = 3 are added. By doing so, when a color filter having a Bayer array is provided, as shown in FIG.
Since color signals can be obtained line-sequentially, when displaying on a liquid crystal display device, when interpolating line information by synchronizing a line including R information and a line including B information, for example, The third line including the R information and the fourth line including the B information are adjacent to each other on the CCD, so that highly correlated data can be obtained. Therefore, an image with good image quality can be displayed even if the number of readout lines is small.

However, according to various studies by the present inventor, it has been found that the imaging apparatus according to the earlier proposal of the present applicant has the following points to be improved. That is, in the above-described imaging apparatus, the AE and AW
B is controlled based on a control result using image data read in the n-line addition thinning-out reading mode until the first trigger is issued. In this case, n =
In the case of 2, in the case of AE control or AWB control, it is necessary to obtain the pixel information of one pixel by halving the read pixel information, so that the processing becomes complicated.

The pixel information that is added and read is:
Theoretically, this is the sum of the charge amounts of two pixels. However, in a charge transfer type imaging device such as a CCD, generally, a potential design is not made corresponding to the added charge amount because In the addition thinning-out reading, the transfer efficiency is deteriorated, and is actually smaller than the sum of the electric charges for two pixels. For example, as in the case of recording a still image, q is the charge amount of one pixel when addition thinning-out reading is not performed, ε is transfer efficiency in that case, and ε ′ is transfer efficiency in two-pixel addition thinning-out reading. In the case of the two-pixel addition thinning-out reading, ε ′ <ε, and the charge amount (pixel information) Q to be read becomes Q = 2ε′q. Therefore, A
In the case of E control or AWB control, the read charge amount Q
Is obtained, and the charge amount qx of one pixel is obtained.
ε′q, and (ε−ε ′) between the time of still image recording and
An exposure error of q occurs, and proper AE control and AWB control cannot be performed.

The present invention has been made in view of the above points, and provides an imaging apparatus which can shorten a release time lag and which is appropriately configured to perform appropriate AE control and AWB control with simple processing. It is the purpose.

[0023]

In order to achieve the above object, the present invention provides an image pickup apparatus having an image pickup device capable of reading out pixel information by charge transfer, wherein pixel information is thinned out from the image pickup device and added. There is provided a reading control means for selectively controlling the addition thinning-out reading mode for reading and the non-addition thinning-out reading mode for thinning out and reading out non-addition, and for reading out pixel information.

In one embodiment of the present invention, the read control means includes:
Pixel information obtained by adding n (n ≧ 2, n is an integer) lines for every m (m ≧ 3, m is an integer) lines in the vertical direction of the image sensor is read.

Further, in one embodiment of the present invention, in the non-addition thinning-out read mode, the read control means reads one line of pixel information for every m lines in the vertical direction.

Further, in one embodiment of the present invention, m lines in the vertical direction of the image sensor are set to m = 2α + 1 (α is a positive integer).

Further, in one embodiment of the present invention, m lines in the vertical direction of the image sensor are defined as m = 2p (p ≧ 2,
p is an integer).

Further, in one embodiment of the present invention, a color filter is provided in the image pickup device, and the readout control means reads out color pixel information line-sequentially in the addition thinning-out reading mode and the non-addition thinning-out reading mode. To do.

Further, in one embodiment of the present invention, the color filters are constituted by line-sequential filters.

Further, in one embodiment of the present invention, there is provided an exposure calculating means for performing an exposure calculation for controlling the exposure of the image pickup device based on the pixel information read by the reading control means, and a still image is recorded. Then, the pixel information is read in the non-addition thinning-out reading mode by the reading control means.

Further, in one embodiment of the present invention, a strobe means for illuminating a subject and a flash memory for recording a still image based on pixel information read by the read control means while the strobe means emits light are provided. And a light emission amount calculating means for calculating the light emission amount of the strobe means. When recording a still image, the read control means reads out pixel information in the non-addition thinning-out reading mode.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are diagrams for explaining a first embodiment of the present invention. This imaging apparatus is basically intended to capture and record a still image, and as shown in a block diagram in FIG. 1, converts a subject image incident through a lens and an aperture 17 into an electric signal. The CCD 1 having the configuration shown in FIG.
A correlated double sampling circuit (CDS) 2 for removing reset noise and the like from the output of D1, and a gain control amplifier (AM) for adjusting the gain of the output of CDS2.
P) 3, an analog-to-digital converter (A / D) 4 for converting the output signal of the AMP 3 into a digital signal, a process processing circuit 5 for performing various processes on the image signal converted into the digital signal, and the CCD 1 A drive signal such as various transfer pulses for driving is output, and a pulse for sample hold in the CDS is output.
A timing generator (TG) 6 for outputting a timing pulse for performing / D conversion, a signal generator (SG) 7 for generating a signal for synchronizing the TG 6 with a CPU 8 described later, and a read control means for the CCD 1 And a CPU 8 composed of, for example, a microcomputer for performing various controls including timing and the like for the entire image pickup apparatus; pixel data of the CCD 1 output from the process processing circuit 5; A DRAM 9 that constitutes a memory for storing image data supplied through the camera, an autofocus circuit (AF) 10 for controlling autofocus by a lens and an aperture 17, and performs photometry of a subject image formed on the CCD 1. Exposure control circuit (AE) 1 for
1, an automatic white balance circuit (AWB) 12 for automatically controlling the white balance, a liquid crystal display device 13 which is a monitor built in the imaging device, and an image signal etc. on a display device such as an external monitor. And an external display terminal 14 for outputting the image data, and compressing the image data of one frame stored in the DRAM 9 in order to reduce the amount of data to be recorded on a recording medium 16 to be described later.
And a recording medium 16 for recording still image data.

The CPU 8 has a first release switch (1RSW) 18 for generating a first trigger by pressing a release button (not shown) to the first stage.
a, in addition to a second release switch (2RSW) 18b that generates a second trigger by pushing the switch to the second stage,
When the subject has low brightness, a strobe device 19 that illuminates the subject at the time of shooting a still image is connected.

In such an image pickup apparatus, when an image is recorded on the recording medium 16, the CCD 1, CDS 2, AM
Image data output via the P3, the A / D 4 and the process processing circuit 5 is supplied to, for example, the liquid crystal display device 13 and displayed. Thus, the photographer can determine the composition and the like of the subject while looking at the liquid crystal display device 13. In this state, when the release button is pressed, the compression / expansion circuit 15 is sent from the process processing circuit 5 through the DRAM 9.
The image data supplied to the recording medium 16 is compressed.
Will be recorded.

When reproducing the image data recorded on the recording medium 16, the compressed data read from the recording medium 16 is expanded by the compression / expansion circuit 15 and is subjected to DR processing.
The image data written in the AM 9 and written in the DRAM 9 is transmitted to the liquid crystal display 1 via the process processing circuit 5.
3, and supplied to the external display device via the external display terminal 14 and reproduced as a still image.

Next, a read operation for driving the CCD 1 to obtain image data will be described. In addition, CCD
Reference numeral 1 denotes a horizontal line of pixels in a two-dimensional pixel array as a line, and this line is vertically arranged from the first line to the L-th line.

In this embodiment, in the still image recording mode for recording a still image, as shown in FIG.
1 is sequentially scanned from the first first line to the last L line, and pixel information relating to all pixels is sequentially read. This readout operation is so-called progressive scanning, and sequentially scans the full screen area and outputs information on all pixels, so that a high-resolution image can be obtained as a still image.

In a moving image processing mode in which image data picked up by the CCD 1 is displayed on the liquid crystal display device 13 and AF, AE, AWB, etc. are performed using the image data as control data, FIG. The n-line addition thinning-out reading mode shown and the k-line n shown in FIG.
In addition to the line addition thinning-out reading mode, FIG.
Are selected based on the operation of the release button to obtain moving image data.

In the non-addition thinning-out reading mode shown in FIG.
(M ≧ 3, m is an integer) One line of pixel information is extracted for each line. Therefore, in this read mode, the number of lines to be read is L / m, so that the frame rate is m times higher than when all pixels are read.

In this embodiment, in the moving image processing mode, m = 3 and n = 2, and in the n-line addition thinning-out reading mode and the k-line n-line addition thinning-out reading mode, the first among the line groups of m = 3 Line and 3
In the non-addition thinning-out reading mode, the pixel information of the third line of each group of m = 3 is extracted. The area of the continuous k lines in the k-line n-line addition thinning-out reading mode is preferably
At the center of the full screen area. In other words, the image data of the effective output area read in this mode is used in, for example, processing in the AF 10 as described later.
This is because, in this AF processing, center emphasis processing using image data in the center of the full image area is often performed.

FIG. 3 is a diagram for explaining a read operation in the non-addition thinning-out read mode shown in FIG. 2B. In FIG. 3, GA, GB, GC, BA, BB, B
C, RA, RB, and RC denote photodiodes 21 corresponding to the Bayer array color filter shown in FIG. 13 similarly to the case of FIG. 15, and a vertical line located to the right of these photodiodes 21 is a vertical line. The transfer path 23 is shown, and a line located at the lower end side of the vertical transfer path 23 in the horizontal direction indicates the horizontal transfer path 24.

In this non-addition thinning-out reading mode, GA, GB, GC, BA, B
Among the photodiodes 21 of B, BC, RA, RB, and RC, charges as indicated by an ellipse in the figure are transferred from the photodiode 21 of the suffix C to the corresponding vertical transfer path 23. Thereafter, every three vertical transfers, the horizontal transfer path 24 is read out after the first vertical transfer to obtain pixel information of one of the three lines.

When such non-addition thinning-out reading is performed, if a color filter having a Bayer array is provided, as shown in FIG.
An output and a line (CB) output including B information can be obtained in a line-sequential manner.

FIG. 5 is a diagram for explaining the operation of the first embodiment. In this embodiment, until the first trigger is generated, the n-line addition thinning-out reading mode shown in FIG. 14A is selected, thereby synchronizing with the vertical synchronization signal (VD) of, for example, 1/60 second. The n-line addition thinning-out read is performed, and the pixel information is stored in CDS2, AMP3, A
The data is supplied to the liquid crystal display device 13 via the / D4 and the process processing circuit 5 to display a moving image, and is supplied as control data to the AE 11 and the AWB 12 to alternately repeat the AE control and the AWB control for each frame.

In this state, when the 1RSW 18a is turned on and the first trigger occurs, the next one frame is
The non-addition thinning-out reading mode shown in (B) is selected, whereby one line of pixel information is extracted for every three lines for all lines, and CDS2, AMP3 and A / D4 are extracted.
Is supplied to the process processing circuit 5 and the image data is supplied to the AE 11 as AE control data to perform AE control. Thereafter, the k-line / n-line addition thinning-out reading mode shown in FIG.
In this case, k-line and n-line addition thinning-out reading are performed twice in one frame period, and in each reading operation, image data obtained from the process processing circuit 5 is supplied to the AF 10 as AF control data to repeat the AF control. Do.

If the 2RSW 18b is turned on and the second trigger occurs during the above processing, the main exposure is performed based on the AE control based on the image data read out in the non-addition thinning-out readout mode after the generation of the first trigger. 2A, all the lines of the entire screen are sequentially scanned as shown in FIG. 2A, and the still image data obtained from the process processing circuit 5 is compressed via the DRAM 9 and the compression / expansion circuit 15 and is recorded on the recording medium 16. Record.

After the recording of the still image is completed, in order to prepare for the next photographing, the n-line addition thinning-out reading mode is selected again, the n-line addition thinning-out reading is performed in synchronization with VD, and the moving image data is displayed on the liquid crystal display. It is supplied to the display device 13 for display, and is used as control data for AE.
The control and the AWB control are alternately repeated for each frame. In this embodiment, the read mode of the CCD 1 changes from non-addition thinning-out reading, k-line n-line addition thinning-out reading, and sequential scanning from the generation of the first trigger to the end of still image recording. During this time, the display on the liquid crystal display device 13 is temporarily stopped.

According to this embodiment, the frame rate is set to 3 in the n-line addition thinning-out reading mode in the moving image processing mode as compared with the case where all lines of the CCD 1 are sequentially scanned at a predetermined reading frequency to read out pixel information. / 2
2 times, 3 times in the non-addition thinning-out reading mode, and 3L / 2k in the k-line n-line adding thinning-out reading mode.
Since the number of frames can be doubled, it is possible to obtain image data of a large number of frames per unit time from the CCD 1 without using a high driving frequency.

Therefore, similarly to the imaging apparatus proposed by the present applicant, a good moving image can be displayed on the liquid crystal display device 13 without using an expensive memory for display, and AF, AE, Even when processing such as AWB is performed, such processing can be performed without using a memory, which is advantageous in terms of circuit scale and cost. In addition, during the period from the first trigger to the second trigger, non-addition thinning-out reading and k-line n-line addition thinning-out reading with a high frame rate are performed, so that this period can be shortened, and thus the release time lag can be shortened. .

In addition, in the next frame after the first trigger is generated, the non-addition thinning-out reading mode is selected, and AE control is performed based on the image data obtained by the selection.
Since the main exposure at the time of recording a still image is controlled based on the result of the AE control, the CCD 1 is used as in the case where the AE control is performed based on the image data in the n-line addition thinning-out reading mode as described above. In addition, no exposure error occurs due to a decrease in transfer efficiency, and a process of halving the read pixel information becomes unnecessary. Therefore, AE at the time of still image recording can be appropriately controlled by simple processing.

In the non-addition thinning-out reading mode, the pixel information of the third line of each line group of m = 3 is taken out, so that, as described above, when the color filter of the Bayer arrangement is provided, Since signals can be obtained line-sequentially, more appropriate AE control can be performed by interpolating the line information by performing the synchronization processing on the line containing the information of R and the line containing the information of B. become.

FIGS. 6 and 7 are views for explaining the second embodiment of the present invention. The main configuration of the imaging apparatus of this embodiment is the same as that of FIG.
The differences from the embodiment will be described. In this embodiment, as the moving image processing mode, the n-line addition thinning-out reading mode shown in FIG.
A line non-addition thinning-out reading mode is set, and these reading modes are selected based on the operation of the release button to obtain moving image data.

In this case, the k-line non-addition thinning-out reading mode shown in FIG. 6 is applied to m (m ≧ 3, k ≧ 3, k ≧ 6, k is an integer) lines that are partially continuous in the vertical direction of the CCD 1.
(m is an integer) One line of pixel information is extracted for each line.
Therefore, in this read mode, the number of lines to be read is k / m, so that the frame rate is mL / k times as compared with the case where all pixels are read.

In this embodiment, in the moving image processing mode, m = 3 and n = 2. In the n-line addition thinning-out reading mode, the first line and the third line of each line group of m = 3 are set. Add and extract pixel information, k
In the line non-addition thinning-out reading mode, it is assumed that pixel information of the third line in each line group of m = 3 is extracted. The area of continuous k lines in the k-line non-addition thinning-out reading mode is preferably
D1 is the center of the full screen area.

FIG. 7 is a diagram for explaining the operation of the second embodiment. In this embodiment, like the first embodiment, the n-line addition thinning-out reading mode shown in FIG. 14A is selected until the first trigger occurs, thereby synchronizing with the vertical synchronization signal (VD). And performs n-line addition thinning-out reading, and stores the pixel information in CDS2 and AMP.
3, supply to the liquid crystal display device 13 via the A / D 4 and the process processing circuit 5 to display a moving image, and supply as control data to the AE 11 and the AWB 12 to alternately perform the AE control and the AWB control for each frame. Repeat.

In this state, when the 1RSW 18a is turned on and the first trigger is generated, the next frame is started as shown in FIG.
, The k-line non-addition thinning-out readout mode is selected, whereby the k-line non-additional thinning-out reading is performed twice in one frame period in synchronization with VD. In this embodiment, in this k-line non-addition thinning-out reading mode, AE1 is used by using k / m-line image data obtained from the process processing circuit 5 first as AE control data.
In step 1, AE control is performed by center-weighted photometry, and image data of k / m lines obtained by subsequent k-line non-addition thinning-out reading is used as AF control data.
, The AF control is repeatedly performed.

During the above processing, if the 2RSW 18b is turned on and the second trigger is generated, then k after the first trigger is generated
The main exposure is performed based on the AE control based on the image data read in the line non-addition thinning-out reading mode, and all the lines of the entire screen are sequentially scanned from the next frame as shown in FIG. 5 is stored in the DRAM 9 and the compression / expansion circuit 15
Then, the data is compressed and recorded on the recording medium 16.

After the recording of the still image is completed, in order to prepare for the next photographing, the n-line addition thinning-out reading mode is selected again, the n-line addition thinning-out reading is performed in synchronization with VD, and the moving image data is displayed on the liquid crystal display. It is supplied to the display device 13 for display, and is used as control data for AE.
The control and the AWB control are alternately repeated for each frame. In the k-line non-addition thinning-out reading mode, only the thinned image data of the central k / m line can be obtained. Therefore, the first execution is performed from the generation of the first trigger to the end of the still image recording. As in the embodiment, the display of the moving image on the liquid crystal display device 13 is temporarily stopped.

According to this embodiment, during the period from the first trigger to the second trigger, only the k-line non-addition thinning-out reading with a high frame rate is performed, and the AE control and the AF control for the main exposure are performed. So,
This period can be shorter than in the first embodiment. Accordingly, in addition to the effects of the first embodiment, there is an advantage that the release time lag can be further reduced.

In the k-line non-addition thinning-out reading mode, the pixel information of the third line of each line group of m = 3 is taken out, so that a k-line portion is provided when a Bayer color filter is provided. In the same manner as shown in FIG. 4, a line (CR) output containing R information and B
The line (CB) output including the information of (B) can be obtained in a line-sequential manner, and the line information including the information of R and the line including the information of B are subjected to the synchronization processing to interpolate the line information, so that It is also possible to perform appropriate AE control.

FIG. 8 is a diagram for explaining a third embodiment of the present invention. The main configuration of the imaging apparatus of this embodiment is the same as that of FIG. 1, and therefore, the points that are different from the first embodiment will be mainly described. In this embodiment, when the subject has a low brightness and the strobe device 19 automatically emits a strobe to compensate for the amount of light to record a still image, or a strobe emission mode is selected and the strobe is forcibly emitted. When a still image is recorded, the amount of strobe light emission for obtaining an appropriate exposure is obtained.

For this reason, in this embodiment, as in the first embodiment, the reading mode of the CCD 1 in the moving image processing mode is the n-line addition thinning-out reading mode, the non-addition thinning-out reading mode, and the k-line n-line addition thinning-out mode. The read mode is set, and these read modes are selected based on the operation of the release button.

That is, until the first trigger occurs,
The n-line addition thinning-out reading mode shown in FIG. 14A is selected, whereby the n-line addition thinning-out reading is performed in synchronization with, for example, a vertical synchronization signal (VD) of 1/60 second. Is supplied to the liquid crystal display device 13 to display a moving image, and is supplied as control data to the AE 11 and the AWB 12 to alternately repeat the AE control and the AWB control for each frame.

In this state, when the 1RSW 18a is turned on and the first trigger is generated, the AE control results up to that time are:
Alternatively, a flash device 1 based on the flash mode
The strobe is pre-emitted by 9 to cause the CCD 1 to perform an accumulation operation, and the pixel information after the accumulation is read out in the next one frame in the non-addition thinning-out reading mode shown in FIG. As a result, the image data obtained from the process processing circuit 5 is supplied to the AE 11, and the AE calculation at the time of the main exposure is performed based on the image data to calculate the light amount of the main flash emission and the like. Thereafter, the k-line and n-line addition thinning-out reading mode shown in FIG. 14B is selected, whereby the k-line and n-line addition thinning-out reading is performed twice in one frame period in synchronization with VD. In operation, image data obtained from the process processing circuit 5 is supplied to the AF 10 as AF control data, and the AF control is repeatedly performed.

If the 2RSW 18b is turned on and the second trigger is generated during the above processing, the flash unit 19 causes the flash unit to emit main light with the flash main light emission amount based on the AE operation result in the non-addition thinning-out reading mode. , The accumulation operation of the CCD 1 is executed, and the pixel information after the accumulation is read from the next frame by sequentially scanning all the lines of the entire screen as shown in FIG. Is compressed via the DRAM 9 and the compression / expansion circuit 15 and recorded on the recording medium 16.

When the recording of the still image is completed, n is again set in preparation for the next photographing, similarly to the above-described embodiment.
The line addition thinning-out reading mode is selected, n-line addition thinning-out reading is performed in synchronization with VD, the moving image data is supplied to the liquid crystal display device 13 for display, and AE control and AWB control are performed using the data as control data. 1
It is repeated alternately for each frame.

As described above, in the third embodiment,
When a strobe is fired and a still image is recorded, the strobe is pre-emitted by the generation of a first trigger, and pixel information due to the pre-flash is read out in a non-addition thinning-out reading mode.
The AE calculation at the time of main exposure is performed based on the pixel information, thereby calculating the amount of main flash light emission at the time of recording a still image. Therefore, in addition to the effect of the first embodiment, the AE calculation at the time of recording a still image is performed. The amount of main flash light emission can be accurately controlled so as to obtain an appropriate exposure.

FIG. 9 is a diagram for explaining a fourth embodiment of the present invention. The main configuration of the imaging apparatus of this embodiment is the same as that of FIG. 1, and therefore, the points that are different from the first embodiment will be mainly described. In this embodiment, in the first embodiment, the n-line addition thinning-out reading mode, the non-addition thinning-out reading mode,
And k-line and n-line addition thinning-out reading mode,
Performed with m = 4 and n = 2.

That is, in the n-line addition thinning-out reading mode, as shown in FIG.
In four lines from the first line to the fourth line with respect to all the lines up to the line, for example, the first and third lines, which are the odd-numbered lines, are added and pixels for one line are added. Information is obtained, and in the next four lines from the fifth line to the eighth line, the sixth and eighth lines, which are even-numbered lines, are added to obtain pixel information for one line. Similarly, for the sequential line group of m = 4, the addition of odd-numbered lines and the addition of even-numbered lines in the line group are performed alternately.
Each line of pixel information is obtained. Therefore, in this case, the number of lines to be read is L / 4.
The frame rate can be improved four times as compared with the case where all pixels are read.

By performing the addition thinning-out reading as described above,
If a Bayer array color filter is provided,
Since a line output including information of R and a line output including information of B are repeatedly obtained, color signals can be obtained in a line-sequential manner.

In the non-addition thinning-out reading mode,
As shown in FIG. 9B, of the four lines from the first line to the fourth line with respect to all the lines from the first line to the L line, for example, an odd-numbered line among them, for example, 3 Read the line, and from the next 5th line to 8
In the four lines up to the line, an even-numbered line, for example, the eighth line is read out. Similarly, 4
For each line, one odd-numbered line and one even-numbered line are alternately read. Therefore,
In this case, the number of lines to be read is L / 4, so that the frame rate is 4 compared to the case where all pixels are read.
Can be doubled.

By performing such non-addition thinning-out reading, when a Bayer array color filter is provided, a line (CR) output including R information and a line (CB) output including B information are output. Can be obtained line-sequentially.

In the k-line and n-line addition thinning-out reading mode, although not shown, the k-line (preferably, the center portion of the screen) which is partially continuous in the vertical direction is shown in FIG.
Pixel information is read in the n-line addition thinning-out reading mode shown in FIG. Therefore, in this case, the number of lines to be read is k / 4, so that the frame rate can be improved to 4 L / k times as compared with the case where all pixels are read.

As described above, similarly to the first embodiment,
Until the first trigger is generated, pixel information is read in the n-line addition thinning-out reading mode shown in FIG.
A moving image is displayed on the liquid crystal display device 13 and AE control and AWB control are performed based on the read pixel information.
It repeats alternately for each frame, and when the first trigger is generated, in the next one frame, the non-addition thinning-out reading mode shown in FIG. 9B is selected and AE control is performed, and in the subsequent frames, k lines and n lines are added. The thinning-out reading mode is selected and the AF control is repeatedly performed.

After that, when the second trigger is generated, the main exposure is performed based on the AE control in the non-addition thinning-out reading mode after the generation of the first trigger, and FIG.
Are sequentially scanned for all the lines shown in (1), and the still image data is compressed and recorded on the recording medium 16.

In this embodiment, the n-line addition thinning-out reading mode, the non-addition thinning-out reading mode, and the k-line n-line addition thinning-out reading mode in the moving image processing mode are different from those of the first embodiment in that m = 4 and n = Since it is performed as 2, the frame rate in the moving image processing mode can be improved as compared with the first embodiment, and the release time lag can be reduced.

In this embodiment, FIG.
As shown in (A), in the n-line addition thinning-out reading mode, when a Bayer array color filter is provided, a line (CR) output including R information and a line (CB) output including B information are output. Can be obtained line-sequentially. By interpolating the line information by performing the synchronization process on the CR line and the CB line, an image with good image quality can be displayed on the liquid crystal display device 13 even if the number of readout lines is small. can do. Similarly, even in the non-addition thinning-out reading mode shown in FIG. 9B, when a Bayer array color filter is provided, CR lines and CB lines can be obtained line-sequentially. By interpolating the line information, more appropriate AE control can be performed.

FIGS. 10 and 11 are views for explaining a fifth embodiment of the present invention. The main configuration of the imaging apparatus of this embodiment is the same as that of FIG. 1, and therefore, the points that are different from the first embodiment will be mainly described. In this embodiment, in the first embodiment, the read mode of the CCD 1 for performing the AE control of the main exposure in the moving image processing mode is as follows. As shown in FIG. Addition and extraction mode and m = 3
An addition / non-addition thinning-out reading mode in which the mode for taking out one line for each line is mixed.

That is, with respect to all the lines from the first line to the L-th line, among the three lines from the first line to the third line, the first line, ie, the first line and the third line And the third line is added to obtain pixel information for one line. In the three lines from the fourth line to the sixth line, similarly, the first line, the fourth line and the third line, are obtained. The sixth line, which is a line, is added to obtain pixel information for one line. In the next three lines from the seventh line to the ninth line, pixel information of one line from the ninth line, which is the third line among them, is obtained without adding, and the tenth to twelfth lines are obtained. 3
In the line, pixel information for one line is obtained from the twelfth line, which is the third line, without addition. Thereafter, in the same manner, for each of two sequential line groups of m = 3, addition thinning-out reading of the first line and the third line and reading of only the third line are alternately performed. Pixel information for one line is obtained. Therefore, in this case, the number of lines to be read is L / 3, so that the frame rate can be tripled as compared with the case where all pixels are read. In performing the AE control for the main exposure based on the image data extracted in the addition / non-addition thinning-out reading mode, among the extracted data, the addition thinning-out reading data includes n
As in the case of performing the AE control in the line addition thinning-out reading mode, a process of halving the pixel data is performed.
Handle as one pixel data.

Thus, in this embodiment, FIG.
As shown in FIG. 1, until the first trigger occurs, FIG.
The pixel information is read out in the n-line addition thinning-out readout mode shown in (A), a moving image is displayed on the liquid crystal display device 13, and AE control and AWB control are alternately performed for each frame based on the read out pixel information. Repeatedly, when the first trigger occurs, the next one frame
The AE control is performed by selecting the addition / non-addition thinning-out reading mode shown in FIG. 0, and the AF control is repeatedly performed by selecting the k-line n-line addition thinning-out reading mode shown in FIG.

Thereafter, when the second trigger is generated, A in the addition / non-addition thinning-out reading mode after the first trigger is generated.
The main exposure is performed based on the E control, and FIG.
By sequentially scanning all the lines shown in (A), the still image data is compressed and recorded on the recording medium 16.

According to this embodiment, A for the main exposure
In the E control, among the data read in the addition / non-addition thinning-out reading mode, the data of the addition thinning-out reading part requires a process of halving, and the process is slightly more complicated than in the first embodiment. Since the data in this portion has a high correlation with the data read in the n-line addition thinning-out reading mode before the first trigger, it becomes effective information for processing such as flicker of the light source. Since the data is not affected by a decrease in the transfer efficiency of the CCD 1, a still image can be captured with a more appropriate AE as a whole.

Also in this embodiment, when a color filter having a Bayer array is provided, color signals can be obtained line-sequentially in the addition / non-addition thinning-out readout mode. By interpolating the line information by performing the synchronization processing in step (1) and (2), more appropriate AE control can be performed.

Note that the present invention is not limited to the above-described embodiment, and various modifications or changes can be made. For example, in the first to third embodiments and the fifth embodiment, a line group for addition thinning-out reading and non-addition thinning-out reading in the moving image processing mode is three lines (m =
Although 3) has been described, color signals may be taken out line-sequentially as arbitrary odd-numbered lines of m = 2α + 1 (α is a positive integer). Similarly, in the fourth embodiment, m
The color signal can be taken out line-sequentially as an arbitrary even line of m = 2p (p ≧ 2, p is an integer) without being limited to m = 2p. In addition, the addition / non-addition thinning-out reading mode in the fifth embodiment is not limited to the odd-numbered line group of m = 2α + 1, but m = 2p (p ≧ 2, p is an integer).
The color signals can be taken out line-sequentially as a line group of even-numbered lines.

Further, also in the second, fourth and fifth embodiments, when a still image is recorded by emitting a strobe light, the strobe main emission amount is set to an appropriate exposure similarly to the third embodiment. It can also be controlled.

In the first embodiment and the third to fifth embodiments, AF control after the first trigger is performed based on pixel information read in the k-line n-line addition thinning-out reading mode. Similar to the second embodiment, the AF control may be performed by reading out pixel information in the k-line non-addition thinning-out reading mode. By doing so, the frame rate can be further improved, so that the release time lag can be further reduced.

Further, in the first embodiment and the third to fifth embodiments, the AE control and the AF control are performed by sequentially switching the two read modes after the first trigger. However, as in the second embodiment, In the same readout mode, that is, in the first, third, and fourth embodiments, the non-additional thinning-out readout mode is used.
E control and AF control may be performed.

It is also possible to appropriately combine various reading modes in the moving image processing mode described in the first to fifth embodiments and the above-mentioned modified examples.

Further, as described above, after the first trigger is generated, non-addition thinning-out reading or addition / non-addition thinning-out reading is performed on all lines to perform A for the main exposure.
In the case of performing the E control, if the color signals are obtained in a line-sequential manner, image data including all the color signals can be obtained by performing the synchronizing process, and the image data is displayed on the liquid crystal display device 13. You can also.

In the above-described embodiments and modifications, the AE control for the main exposure is performed immediately after the first trigger is generated. However, the AE control is performed at any timing after the first trigger is generated. When the AF control is performed by one trigger, it may be performed immediately after the end of the AF control or immediately after the second trigger is generated.

Further, in the above description, the AE control for the main exposure is performed by the non-addition thinning-out reading, the k-line non-addition thinning-out reading, or the addition / non-additional thinning-out reading after the generation of the first trigger. AWB control may be performed instead of the AE control, or the AE control and the AWB control may be performed simultaneously or alternately.

[0092]

According to the present invention, it is possible to selectively control an addition thinning-out reading mode in which pixel information is thinned out from the image sensor and read out by adding, and a non-additional thinning-out reading mode in which thinning out is performed by non-addition. Since the pixel information is read, the release time lag can be shortened, and the AE control and the AWB control can be performed based on the pixel information in the non-addition thinning-out reading mode. It can be done properly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a sequential scanning read mode and a non-addition thinning-out read mode in the first embodiment.

FIG. 3 is a diagram for explaining a read operation in a non-addition thinning-out read mode in the first embodiment.

FIG. 4 is a diagram for explaining line-sequential color signals obtained in the non-addition thinning-out reading mode shown in FIG. 3;

FIG. 5 is a diagram for explaining the operation of the first embodiment.

FIG. 6 is a diagram for explaining a k-line non-addition thinning-out reading mode in a second embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of the second embodiment.

FIG. 8 is a diagram for explaining the operation of the third embodiment of the present invention.

FIG. 9 is a diagram for explaining an n-line addition thinning-out reading mode and a non-addition thinning-out reading mode in a fourth embodiment of the present invention.

FIG. 10 is a diagram for explaining an addition / non-addition thinning-out reading mode in a fifth embodiment of the present invention.

FIG. 11 is a diagram for explaining the operation of the fifth embodiment.

FIG. 12 is a diagram illustrating a configuration of an example of a CCD as an imaging device that can be used in the imaging device according to the present invention.

FIG. 13 is a diagram showing an example of a color filter used in the CCD shown in FIG.

FIG. 14 is a diagram for explaining an n-line addition thinning-out reading mode and a k-line n-line addition thinning-out reading mode applicable to the imaging apparatus according to the present invention.

FIG. 15 is a diagram for explaining a read operation in the addition thinning-out read mode shown in FIG. 14;

FIG. 16 is a diagram for explaining line-sequential color signals obtained in the addition thinning-out reading mode shown in FIG. 14;

FIG. 17 is a diagram for explaining the operation of the imaging device according to the earlier proposal of the present applicant.

[Explanation of symbols]

 Reference Signs List 1 CCD 2 correlated double sampling circuit (CDS) 3 gain control amplifier (AMP) 4 analog-to-digital converter (A / D) 5 process processing circuit 6 timing generator (TG) 7 signal generator (SG) 8 CPU 9 DRAM 10 auto Focus circuit (AF) 11 Automatic exposure control circuit (AE) 12 Auto white balance circuit (AWB) 13 Liquid crystal display device 14 External display terminal 15 Compression / expansion circuit 16 Recording medium 17 Lens and aperture 18a First release switch (1RSW) 18b Second Release switch (2RSW) 19 Strobe device 21 Photodiode 22 Transfer gate 23 Vertical shift register 24 Horizontal shift register 25 Signal detector

Claims (9)

[Claims] 1. An image pickup apparatus having an image pickup device capable of reading out pixel information by charge transfer, comprising: an addition thinning-out reading mode in which pixel information is thinned out and added and read out from the image pickup device; An imaging apparatus comprising: a readout control unit that selectively controls an addition thinning-out readout mode and reads out pixel information. 2. The image pickup device according to claim 1, wherein the read control unit is configured to set m (m ≧ 3, m ≧ 3)
An image pickup apparatus for reading pixel information obtained by adding n (n ≧ 2, n is an integer) lines for each line. 3. The image pickup apparatus according to claim 1, wherein the read control unit reads one line of pixel information for every m lines in the vertical direction in the non-addition thinning-out read mode. apparatus. 4. The imaging apparatus according to claim 2, wherein m = 2α + 1 (α is a positive integer). 5. The imaging apparatus according to claim 2, wherein m = 2p (p ≧ 2, p is an integer). 6. The image pickup device according to claim 1, wherein the image pickup device has a color filter, and the read-out control unit is configured to switch between the addition thinning-out reading mode and the non-addition thinning-out reading mode. An image pickup apparatus for reading out color pixel information in a line-sequential manner. 7. The imaging device according to claim 6, wherein the color filter is a line-sequential filter. 8. The exposure apparatus according to claim 1, wherein an exposure operation for controlling an exposure of the image sensor is performed based on pixel information read by the read control unit. An imaging apparatus, comprising: reading means for reading out pixel information in the non-addition thinning-out reading mode when recording a still image. 9. The image pickup apparatus according to claim 1, wherein: a strobe means for illuminating a subject; and pixel information read by the read control means during emission of the strobe means. A light emission amount calculating means for calculating a light emission amount of the strobe means at the time of recording a still image; An imaging device characterized by the above-mentioned.