JPH02294169A - Camera with solid-state image pickup element - Google Patents

Abstract

PURPOSE:To shorten a focusing time by exhausting an electrical signal generated in an area other than the prescribed area of an image pickup element at high speed, and detecting the state of incident light by outputting only the electrical signal generated in the prescribed area sequentially. CONSTITUTION:The extraction of an image pickup charge is performed only from an AF(automatic focusing function) where the focus area 41 of a solid-state image pickup element 15 exists with, for example, a scan timing of 63.5mu s per horizontal scan corresponding to an NTSC television signal. In another AF unrequired charge areas 42a and 42b, an accumulated charge is quickly swept from a drain 35 by reversely transferring at high speed, for example, with a scan timing of 800kHz, In such a way, it is possible to more quickly extract the image pickup charge corresponding to the focus area 41, and to shorten a time required for automatic focusing.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a camera having a solid-state image sensor.

[Prior art and its problems] Conventionally, in cameras using solid-state imaging elements, such as electronic still cameras, automatic focus (AF) or automatic exposure (AE) functions have been activated. AF sensor or A
The E-sensor is provided as a dedicated component.

In contrast, electronic still cameras such as those described above are being considered that perform automatic focus control or automatic exposure control using the output of a solid-state image sensor without using an AF sensor or AE sensor. If you configure
This results in the following drawbacks.

In other words, an electronic still camera or video camera is
For example, the image signal obtained from the solid-state image sensor is
In order to output the signal at a timing that corresponds to the television shooting signal of the system, at least 1/2
An imaging signal for focus detection or automatic exposure control can only be obtained every 60 seconds. Here, HD in FIG. 6 is a horizontal synchronizing signal, BLK is a planking signal,
V l +TG is a vertical transfer clock (1, Ov) plus a read clock (tllgh).

In other words, the AF is performed by the solid-state imaging device that captures the subject image.
If a sensor is used instead, the focus detection signal will be generated only at the timing of 1/60 sec, regardless of the area to be focused on or not, so if the dedicated AF sensor is installed, In comparison, there is a problem in that it takes time to actually match the focus.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems.
Even when used as an E-sensor, a camera with a solid-state image sensor that makes it possible to shorten the focus time or exposure control time without obtaining an imaging signal for detecting incident light due to the sampling timing according to the TV signal. The purpose is to offer the following.

[Summary of the Invention] In other words, a camera using a solid-state image sensor according to the present invention includes a lens, an image sensor that generates an electric signal according to the amount of light incident through the lens, and an electric signal generated by the image sensor. imaging signal output means for sequentially outputting electric signals generated in the image as still image signals; The device is configured to include a region-based output means for outputting the light, and a detection means for detecting the state of incident light based on the electrical signal outputted by the region-based output means.

[Embodiment 1 of the invention An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the focus 1 is adjusted using the output signal of the solid-state image sensor.
Figure 1 shows the configuration of the electronic circuit. In the figure, 11 is a main control section, and the operation of each section of the circuit is controlled by this main control section 11. A release switch 11 that is operated when photographing a subject is connected to the main control section 10.

On the other hand, 12 is an imaging lens, 13 is a zoom lens, and 14 is an iris (aperture).
3, and a solid-state image sensor (CCD) through the iris 14.
15. The imaging lens 12 is driven by a focus motor 16, and the zoom lens 13 is driven by a zoom motor 17. Both the focus motor 16 and the zoom motor 17 are driven and controlled by a lens control section 18.

An autofocus control signal for obtaining the optimum focal length corresponding to the focus area is input to the lens control section 18 from the autofocus control section 19 . Further, the iris 14 is connected to the iris motor 2.
This iris motor 20 is driven by an iris control section 21. An iris control signal indicating the aperture opening corresponding to the optimum exposure value is inputted to the iris control section 21 from the exposure control section 22 .

The solid-state image sensing device 15 has a large number of pixels made up of photodiodes arranged horizontally and vertically, and converts image information formed into an image into an electrical signal at a level corresponding to the amount of light of the image and outputs it. , a large number of pixels of this solid-state image sensor are horizontally scanned by the H driver 23 and vertically scanned by the {circle around (2)} driver 24 . The horizontal scanning timing of each pixel of the image sensor for the H driver 23 and the vertical scanning timing for the ■ driver 24 are output in synchronization with the timing signal from the timing signal generator 25.

Further, the electric signal outputted for each pixel of the solid-state image sensor 15 is sampled and held in a sample hold circuit 26 in synchronization with a timing signal from a timing signal generating section 25, and sequentially sent from an exposure control section 22 to an AGC (automatic The signal is output to the image signal processing circuit via the gain control) circuit 37. Here, the exposure control unit 22 calculates an optimum exposure value according to the total amount of incident light to the solid-state image sensor 15 based on the image output signal from the solid-state image sensor 15, and calculates an aperture opening according to this optimum exposure value. An iris control signal for obtaining the iris control signal is output to the iris control section 21.

On the other hand, the output signal for each pixel according to horizontal scanning from the solid-state sensor 15 is also given to the switching circuit 28 via the sample hold circuit 26, the exposure control section 22, and the AGC circuit 27. This switching circuit 28 is
Only the output signal from the solid-state image sensor 15 corresponding to the focus area for automatic focusing determined in advance at the center of the imaging area is given to the autofocus control unit 19, and the on/off operation of the switching gate in this switching circuit 28 is performed. (For example, the timing signal generator 2
This is performed by detecting the scan timing of a preset focus area based on the timing signal indicating the solid-state sensor scan timing from 5.

FIG. 2 shows the internal configuration of the solid-state image sensor 15, which includes a large number of pixels (photodiodes) 30, 302, .
. . , 30m is read out to the V-CCD 31 in accordance with the read clock, and sequentially corresponds to the storage areas 321, 322 . . . 30 m in accordance with the scanning signal φVn. ..., 32n. And this storage area 32. , 322.
. . 32n to the H-CCD 33, and is sequentially output through the output amplifier 34 in synchronization with the scanning signal φHn. Here, when the scanning signal φVI1 is applied at a timing opposite to that of normal scanning, each image signal read out to the V-CCD 31 is swept out via the drain 35. In this case, when reading out the charge of each pixel, the scanning signal φVn is applied at a timing of 63.5 μS per horizontal scan corresponding to the TV signal, but the scanning signal φVn is applied at a timing of 63.5 μS per horizontal scan in accordance with the television signal. The scanning signal Vφn is applied in reverse scanning at a high-speed timing of 0 k Ilz.

FIG. 3 shows AF unnecessary charge areas 42a, 42b and AF charge area 43 for the focus area 41 within the imaging area 40. In the solid-state image sensor 15 in FIG. The charges in the corresponding horizontal pixel columns are sequentially swept out at high speed via the drain 35 by the 800 kHz timing signal, and the charges in the horizontal pixel columns corresponding to the AF direction area 43 are The charge is read out using a timing signal of .5 μs, and only the charge corresponding to the focus area 41 at each horizontal scanning timing is provided to the autofocus control unit 19 via the switching circuit 28. In addition,
44 is a camera shake warning lamp, 45 is a focus matching lamp, and 46 is a flash lamp.

Next, the photographing operation of the camera equipped with the autofocus function configured as described above will be explained with reference to the timing chart shown in FIG.

In FIG. 4, AFS is an autofocus start clock, V1+TG is a vertical transfer clock+readout clock, and AFE is an autofocus end signal.

FIG. 5 is a flowchart showing the photographing operation. First, the user looks through the finder 13, captures the subject in the focus area 41, and sets the composition of the photographing area. Then, in order to perform AF control, the release switch 11 is pressed halfway. Then, an AFS pulse signal is generated and outputted from the main control section 10, and the aperture of the iris 14 is opened by the iris motor 2o via the exposure control section 22 and the iris control section 21 (step Sl).

Then, the timing signal generator 25 and the H driver 23
and the V driver 24, the accumulated charge in all pixels of the solid-state image sensor 15 in FIG.
By performing the Hz reverse transfer, the data is swept out and cleared from the drain 35 side at high speed (step S2). In this way, when all accumulated charges in the solid-state imaging element 15 are cleared, charges are accumulated according to the incident light on the solid-state imaging element 15 at a sampling timing of 1/250 seconds (step S3). . Each pixel 301, 302, . . . 30m of the solid-state image sensor 15
On the other hand, when charges corresponding to each subject image are uniformly accumulated, they are accumulated in the AF unnecessary charge area 42a in front of the AF charge area 43 where the focus area 41 shown in FIG. 3 exists, that is, in front of the focus frame. The charges of each pixel are swept out from the drain 35 side in FIG. 2 by high-speed reverse transfer processing at 800 kHz, and are made into invalid data (step S4). Subsequently, the focus frame of the AF charge area 43 where the focus area 41 exists is transferred to the storage areas 32, . 3 22 , ・, 3
2n, H-CCD 33 and output amplifier 34
The signal is output to the sample and hold circuit 26 via. At this time, in each horizontal scanning period in the AF charge area 43, an area corresponding to the focus area 41 is captured'
Only N 6Cj is given to the autofocus control section 19 through the switching circuit 28 . That is, the switching circuit 28 has a predetermined 6" of focus area 41 in advance.
Since the L position data is given, the scanning brightness corresponding to the focus area 41 is detected based on the horizontal scanning timing of the solid-state image sensor 15 obtained from the timing signal generating section 25, and the AF charge area is detected only in that focus frame. By sequentially turning on the gate of the switching circuit 28 for each horizontal scanning period of 43, the focus area 4
Only one imaging voltage l1 is given to the autofocus control section 19. After this, focus area 4
The charge of each pixel accumulated in the AF unnecessary charge region 42b from the focus frame to the final frame beyond the AFfi charge region 43 where 1 exists, that is, from the focus frame to the final frame, is The data is swept out from the drain 35 side at high speed and becomes invalid data (step S6). In this case, only the AF charge region 43 in which the focus area 41 exists is photographed for 1 g at a scan timing of 63.5 μs per horizontal scan according to, for example, an NTSC television signal. The charges are extracted and the accumulated charges are reduced to 80 in the other AF unnecessary charge regions 42a and 42b.
Since the charge is reversely transferred at high speed and swept out from the drain 35 at the scanning timing of 0 1c txz, the imaging charge corresponding to the focus area 41 can be extracted more quickly.

In this way, when the autofocus control unit 19 is given an imaging charge signal corresponding to the focus area 41 of the solid-state image sensor 15, the autofocus control unit 19 calculates the optimum focal length based on the focus area 41. 1, the focus motor 16 and the zoom motor 17 are driven and adjusted through the lens control unit 18, and the focal positions of the imaging lens 12 and the zoom lens 13 are controlled to move in accordance with the optimum focal length. When the movement control corresponding to the optimum focal length of the imaging lens 12 and zoom lens 13 is completed, an AFE (autofocus end) signal indicating that the focus is in focus is sent from the autofocus 1 rearrangement section 19 to the main control section 10. It is output (step S7).

In this case, the autofocus control unit 19 determines the point at which the contrast of the subject image in the focus area 41 of the solid-state image sensor 15 is maximum, that is, the high frequency component of the imaging signal in the focus area 41 obtained via the switching circuit 28 is at its maximum. It detects a point where the image is in focus, determines that it is in focus, and outputs an AFE signal.

Then, the timing signal generator 2 is output from the main controller 10.
5, by controlling the H driver 23 and the V driver 24, all charges on the solid-state imaging probe 15 are swept out to the drain 35 side by the high-speed reverse transfer process and cleared (step S8).

Then, the exposure 1, 18 section 22 drives and adjusts the iris motor 20 through the iris control section 21, and the opening/closing degree of the aperture in the iris 14 is controlled in accordance with the optimum exposure value. After that, when the release switch 11 is fully pressed, the solid-state image sensor 15 is exposed to accumulate charges according to the subject image by normal vertical/horizontal scanning processing (step S
9). As a result, the effective image data imaged and accumulated on the solid-state imaging probe 15 is transferred to the storage area 32 in FIG. 2 at the normal sampling timing of 63.5 μs per horizontal scan. , 322. ..., H-C via 32n
The data is sequentially transferred and output from the CD 33 (Step S 1 0
). This valid image data is stored in the sample hold circuit 26.
, the exposure control section 22, and the AGC circuit 27, the image signal is sent to the image signal processing circuit, and after being subjected to A/D conversion processing, binarization processing, etc., it is stored in a memory as digital image data.

Therefore, according to the camera having the solid-state image sensor configured as described above, the AF charge IJ where the focus area 41 exists is
Imaging charges are extracted only in the 4-area 43 at a scanning timing of 63.5 It s per horizontal scan according to, for example, an NTSC television signal, and in the other AF-unnecessary charge areas 42a and 42b, the accumulated charges are extracted at 800 k
The drain 35 is transferred at high speed with Hz scanning timing.
The above focus area 41
The imaging charge corresponding to the image can be extracted more quickly, and the time required for automatic focusing can be significantly reduced.

[Effects of the Invention] As described above, according to the present invention, there is a lens, an image sensor that generates an electric signal according to the amount of light incident through the lens, and a static image sensor that generates an electric signal generated by the image sensor. Imaging signal output means for sequentially outputting as an image signal; and area-compatible output for outputting electrical signals generated in a region other than a predetermined region of the imaging cord at high speed υr and sequentially outputting only electrical signals generated in the predetermined region. and a detection means for detecting the state of the incident light based on the electrical signal outputted by the area-based output means, so that, for example, a solid-state image sensor for capturing an image of a subject can be used as an AF sensor. Even in this case, it is possible to provide a camera with a solid-state m-image element that makes it possible to shorten the focusing time without obtaining an imaging signal for focus detection due to the sampling timing according to the television signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an electronic circuit of a camera having a solid-state image sensor according to an embodiment of the present invention, FIG. 3 is a diagram showing the AF unnecessary charge area and the AF electric rjj area for the focus area within the imaging area by the camera having the solid-state image sensor, and FIG. 4 is the extraction of focus area data by the camera having the solid-state image sensor. FIG. 5 is a flowchart showing the photographing operation by the camera having the solid-state imaging device, and FIG. 6 is a timing chart showing the conventional focus data extraction operation. DESCRIPTION OF SYMBOLS 10... Main control part, 11... Release switch, 12... Imaging lens, 13... Zoom lens, 1
4...Iris, 15...Solid-state image sensor, 16...
・Focus motor, 17...Zoom motor, 18・
... Lens control section, 19... Auto focus control section, 20... Iris motor, 21... Iris control section, 22... Exposure 1.11 control section,
23...H driver, 24...V driver, 25.
...Timing signal generation section, 26...Sample hold circuit, 27...AGC circuit, 28...Switching circuit, 30l to 30-...Pixel (photodiode)
31...V-CCD, 32l-3211...Storage area, 33,. H-CCD, 34... Output amplifier, 35... Drain, 41... Focus area, 42a. 42b...AF unnecessary charge area, 43...
・AF electric field 61 area, 44... Camera shake warning lamp, 45
... Focus matching lamp, 46... Flash lamp. Applicant's representative Patent attorney Takehiko Suzue

Claims (1)

[Claims] A lens, an imaging device that generates an electrical signal according to the amount of light incident through the lens, and an imaging signal output that sequentially outputs the electrical signals generated by the imaging device as a still image signal. means, region-based output means for discharging electrical signals generated in a region outside a predetermined region of the image sensor at high speed, and sequentially outputting only the electrical signals generated in the predetermined region; and output by the region-based output means. 1. A camera having a solid-state image sensor, comprising: a detection means for detecting a state of incident light based on an electrical signal generated by the sensor.