JPH02174471A - Image pickup device - Google Patents

Abstract

PURPOSE:To always adjust a level in an excellent way by adjusting a signal level to be a proper level based on a video signal of a set effective pattern. CONSTITUTION:A picture signal obtained from an image pickup element 2 is once A/D-converted by an A/D converter 6, the result is stored in a RAM 7 as a digital signal and a readout address is controlled in the case of reading picture information by a timing generating circuit 8 from the RAM 7 to output a picture subject to zooming to a display element 13. The brightness of a picture displayed on the display element 13 is detected again by a 2nd AGC detection circuit 11 receiving an analog output of a D/A converter 10 and the gain for display picture information is controlled by controlling a 2nd AGC amplifier 12 so as to obtain a proper brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and particularly to a device for adjusting the output level of an imaging element to a proper level.

[Conventional technology]

2. Description of the Related Art Conventionally, solid-state imaging devices called, for example, MO3 type solid-state imaging devices have been considered to have a so-called electronic zoom function that performs zooming by changing the readout area.

[Problem to be solved by the invention]

In general, in imaging devices, the aperture is generally changed so that the output level of the imaging element is at an appropriate level.
The shutter speed is changed.

Therefore, when using an element having the above-mentioned electronic zoom function, various inconveniences occur if the above-mentioned aperture and shutter speed control is performed using the overall signal regardless of zooming even when zooming. For example, due to such zooming, there is a problem in that when a bright center area is enlarged, the entire screen becomes bright, and conversely, when a dark center area is enlarged, the entire screen becomes dark.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an imaging apparatus that can solve these problems and always control the level of a signal output from an image sensor in a good manner regardless of changes in the readout area of the image sensor.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention includes an image sensor, a means for setting an effective screen of the image sensor, and a system for adjusting the signal level to an appropriate level based on a video signal of the effective screen set by the means. and means for adjusting.

[Effect]

In the above configuration, the level of the signal is adjusted based on the video signal of the effective screen set by the setting means.

〔Example〕

Next, examples of the present invention will be described.

In the embodiment described below, the effective screen of the image sensor is set by first A/D converting the output of the image sensor into a digital signal, storing this in a frame memory, and setting the readout area from the frame memory. Although an apparatus configured to do this is disclosed, the present invention is not limited to such an apparatus, and it goes without saying that the present invention may be applied to an apparatus using an element having an electronic zoom in the image pickup element itself.

The present invention will be explained in detail below using the drawings.

FIG. 1 is a block diagram showing an example of the circuit configuration of a camera according to an embodiment of the present invention. In FIG. 1, reference numeral 2 denotes an image sensor that captures an image, and is of the CCD MOS type, for example.

1 is an aperture mechanism that controls the exposure amount so that the amount of light entering the image sensor 2 is appropriate, that is, the level of the video signal output from the image sensor is appropriate; 3 is a first AG that can control gain;
A first AGC detection circuit outputs a signal to control the aperture control circuit 4 that controls the gain of the C amplifier 5 and the aperture.The AGC amplifier 5 has an amplification degree that is determined based on a signal input to the control voltage input terminal C0NT. Change. Reference numeral 6 denotes an A/D conversion circuit that converts the image signal output of the AGC amplifier 5 from an analog value to a digital value, and 7 stores the output of the A/D conversion circuit 6 according to an address output from a timing generation circuit 8, which will be described later. RAM, which is a memory, 8 is an image sensor 2. RAM
7. latch circuit 99; a timing generation circuit for controlling the drive timing of the display element 13, etc.; although the order of the symbols is different, 14 is a zoom ratio selection switch that constitutes a setting means for setting the effective screen of the image sensor in the present invention; 15. 16
9 is a switch linked to the release button that controls exposure to the silver halide film loaded in the camera of this embodiment; 9 is a latch circuit that temporarily stores signals read out from the RAM 7; 10 is a latch circuit of the latch circuit 9; A D/A conversion circuit 11 converts the output into an analog value, and outputs a signal controlling the gain of the second AGC amplifier 12 according to the specific power level from the output terminal shown as OUT. The second AGC detection circuit 13 is a display element that reproduces and displays the output of the second AGC amplifier 12 as a visible image, and uses an LCD panel, for example.

FIG. 3 is a perspective view showing the external appearance of the imaging device whose configuration is shown in FIG. 1. In FIG. 3, elements having the same functions as in FIG. 1 are labeled with the same numbers. In FIG. 3, 31 is a camera body, 32 is a lens for forming a subject image on a silver halide film loaded in the camera, and 33 is a lens for forming a subject image on the image sensor 2. Reference numeral 34 designates a release button of the camera, and when pressed with the first stroke, the switch 15 shown in FIG. 1 is turned on, and when it is pressed further, the switch 16 shown in FIG. 1 is turned on when pressed with the second stroke.

Next, the operation of the embodiment shown in FIGS. 1 and 3 will be explained.

When the photographer presses the first stroke of the release button 34, the switch 15 shown in FIG. 1 is turned on, the timing generating circuit 8 starts operating, and the image sensor 2. R.A.
M7. The data latch 91 display element 13 is driven, and the image pickup element 2 converts the image formed on the element into an electrical signal via the aperture mechanism l and lens 33, and sequentially captures the image data as the AGC detection circuit 1. 3 and 1st AG
Output to C amplifier 5. This image signal is output as luminance information of the entire image by the first AGC detection circuit 3, which has an internal function of integrating the image signal for one screen. By this information output, if it is too bright, the aperture control circuit 4
controls the aperture mechanism 1 to reduce the amount of light entering the image sensor 2. Further, by outputting this information, the first AGC amplifier 5 lowers the gain and outputs it to the A/D conversion circuit 6 as an image signal corresponding to appropriate brightness, and the digital value is stored in the RAM 7. On the other hand, when the amount of incident light on the image sensor 2 is small, the level of the image signal is also low, and the first AGC detection circuit 3 outputs a signal indicating that the amount of incident light is insufficient, and this signal causes the aperture control circuit 4 to The aperture of the diaphragm mechanism is controlled to be large, and the amount of light entering the image sensor 2 is increased. Further, the first AGC amplifier 5 increases the gain and outputs an image signal corresponding to appropriate brightness.

In the RAM 7, the output of each pixel of the image sensor 2 is recorded by a timing generation circuit 8 at a memory location (address) corresponding to each pixel, as will be described later.

Further, between recordings, image data is read from the memory location (address) corresponding to each display pixel of the display element 13, latched by the latch circuit 9, and image information is converted into an analog signal by the D/A conversion circuit 10. 2 A
It is output to the GC detection circuit 11. In this example, R
A zoomed image is output to the display element 13 by controlling the read address when reading image information from the AM7.

The zoom ratio can be set using the zoom ratio selection switch 14, for example, so that the image displayed on the display element 13 changes as shown in FIG. 5 each time the switch 14 is turned on.

In the method shown in FIG. 5, each time the zoom ratio selection switch 14 is turned on, three images are displayed on the display element 13.
The image will change to become an image equivalent to 5 mm, 50 mm, or 80 mm.

For example, if a lens equivalent to 35 mm is used as the lens 33 for the image sensor, the method of incrementing the read address of the RAM 7 when retrieving data from the RAM 7 is set to 3/3 for the pixels of the display element 13.
By incrementing by 4 or 215, the display element 13 has a length of about 50 mm or 80 m.
This means that you can get the same results as if you were shooting with an m-equivalent lens. Of course, in this case, it is necessary to set the start address and end address for reading in advance in the central bone of the screen. The operation of the read address for zooming is controlled by the timing generation circuit 8 according to information set by the zoom ratio selection button 14. Furthermore, when the photographer presses the release button 34 even further, the switch 16 is turned on with a second stroke.
is turned on, a shutter provided between the lens 32 and the film operates, the silver halide film is exposed, and a photograph is taken. At the same time, the timing generation circuit 8 stops writing for recording into the RAM 7, and one image of the same screen is always output to the display element 13, so that a still image is obtained. Furthermore, in this embodiment, a still image is selected by the timing generation circuit 8 by using the zoom ratio selection button 14 in the same manner as described above.
display element]3 by manipulating the readout address of
Zooming is now possible.

Here, the first AGC detection circuit 3 performs detection by, for example, integrating all the image data obtained by the image sensor 2, so in some cases, the exposure of the zoomed image on the display element 13 may be inappropriate. occurs. For example, if the center is dark compared to the background, such as in a backlit scene, zooming to the center will make the whole thing darker; conversely, if the center is brighter than the background, zooming will make the whole thing brighter, making it very It may become unpleasant to look at.

Therefore, in order to solve this problem, in this embodiment,
The second AGC detection circuit 11 to which the analog output of the D/A conversion circuit 10 is input detects the brightness of the image displayed on the display element 13 again, and the second AGC amplifier 12 detects the brightness of the image displayed on the display element 13 so that the brightness is appropriate. By controlling the voltage of the control voltage input terminal C0NT, the gain of the image information for display is controlled. As a result, the display element 13 displays the correct brightness regardless of zooming.

Further, although not shown, pseudo zooming is possible by recording trimming information on exposed frames of the silver halide film.

Next, the configuration and operation of the timing generation circuit 8 in FIG. 1 will be explained using FIG. 2.

In FIG. 2, 21 is a circuit that generates drive pulses for the CCD of the image sensor 2, and generates vertical transfer pulses φv1, horizontal transfer pulses φH, and the like. 22 is a controller which synchronizes each circuit and controls switches 15.
16 has been detected. 24 is a zoom ratio selection circuit, which sets the end address and start address of the read address generation circuit 25 to the preset terminal PR, or sets the output address of the address generation circuit in accordance with the zooming instruction inputted by the switch 14. The increment timing of the pulse for incrementing is controlled as described above, and the RA is displayed on the LCD display element 13.
It is provided to enlarge and display the data of the zoomed portion of the image data in M7. 26 is an RA corresponding to the pixels of image information from the CCD which is the image sensor 2;
This is a write address generation circuit of M7. 27 and 28 are path transceivers, from the controller 22 to the RA
The output address of either path transceiver 27 or 28 is selected according to the line 1 enable signal WE outputted to M7. That is, for example, when the signal WE is output as a high level from the controller 22, the write address from the write address generation circuit 26 is sent to the RAM 7, the output of the A/D converter 6 is written to the RAM 7, and the The gate 29 prevents the read address from the read address generation circuit 25 from being sent to the RAM 7.

The readout of image information from the RAM 7 performed by the readout address generation circuit as described above will be described with reference to FIG.

FIG. 4 is a diagram showing an area where an image signal is read out from the RAM 7 by operating the view angle conversion button 9.
is FF (hexadecimal) horizontally and FF (hexadecimal) vertically
A pixel in RAMT is indicated by a four-digit address (the upper two digits correspond to the vertical address and the lower two digits correspond to the horizontal address).

In Figure 4, the numbers shown in squares indicate the address of each point,
The arrow numbers outside the area indicated by are X and Y, respectively.

Indicates the size of the area indicated by Z. The area indicated by X 35 mm is an area read out when no zooming instruction is given by operating the zoom ratio selection switch 14, and the area indicated Y 50 mm is an area read out when a zooming instruction is given to an angle of view equivalent to 50 mm. The area indicated by 280 mm is the area read out when a zooming instruction with an angle of view equivalent to 80 mm is given. Further, each area is separated by addresses shown in brackets [ ] in the figure.

That is, for example, when a zooming instruction equivalent to 35 mm is given, the zoom ratio selection circuit 24 sets the start address of the read address generation circuit 25 to [0000] so that all addresses are read out, and the zoom ratio selection circuit 24 sets the start address of the read address generation circuit 25 to [0000].
When a zooming instruction equivalent to m is given, [2626
] is set to [4949] when a zooming instruction equivalent to 80 mm is given.

Similarly, when the end address is a zooming instruction equivalent to 35 mm, the zoom ratio selection circuit 24 selects [FFFF
], for zooming instructions equivalent to 50mm [D9D9]
, in the case of a zooming instruction equivalent to 80 mm, [ClCl] is preset in the read address generation circuit 25.

Note that the read address generation circuit 25 resets the horizontal address when the horizontal address generated by the circuit 25 matches the horizontal address indicated by the lower two digits of the set end address. It is configured to increment the address in the vertical direction.

FIG. 6 is a block diagram showing the configuration of another embodiment of the present invention, and is an example in which the configuration is simplified compared to FIG. 1, although trimming of still images cannot be performed. In this example, 4
It is characterized by providing a sample circuit shown as 1. That is, the sample circuit 41 outputs the video signal of only a predetermined area on the screen, that is, the area to be zoomed, according to the output of the timing generation circuit 8' to the AGC detection circuit 3'.
By providing such a circuit, the AGC detection circuit 11 shown in FIG. The level of the video signal can be adjusted by changing the state of the aperture mechanism 1 or the AGC amplifier 5' only in accordance with the video signal corresponding to the area to be displayed on the display element 13 without providing the AGC amplifier 12. You can. In FIG. 6, circuits similar to those in FIG. 1 are denoted by the same reference numerals and their explanations are omitted. Depending on the degree of zooming, it may be better to slightly change the time constant.

Among the embodiments described above, in the embodiment shown in FIG. 1, the image signal obtained from the image sensor is temporarily stored in the RAM 7, and an area to be read out from the RAM is designated in accordance with a zooming instruction, and the read out image is Although AGC is applied to the signal, the present invention is not limited to this, and the amount of light incident on the image sensor may be controlled using the electronic shutter function of the image sensor itself, and both of these may be used. Only one of them may be used, or both may be used in combination.

Further, the method of changing the exposure amount is not limited to the method using a shutter as described above, and various methods can be applied.

Furthermore, it goes without saying that the present invention may be applied to an image sensor having a zoom function in itself as described above.

Further, although an LCD is used as a monitor in this embodiment, the present invention is not limited to this, and other display elements may be used.

〔Effect of the invention〕

As explained above, according to the present invention, the level of the video signal obtained from the effective screen is adjusted to an appropriate level according to the designation of the effective screen of the image sensor. Regardless of the situation, the level can always be adjusted well.

[Brief explanation of the drawing]

1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the timing generation circuit 8 shown in FIG. 1, and FIG. 3 is a block diagram showing the configuration of the timing generation circuit 8 shown in FIG. 1. FIG. 4 is a perspective view showing the external appearance of the device of the embodiment; FIG. 4 is a view showing the readout area when a zooming instruction is given on the RAM 7 shown in FIGS. 1 and 2; FIG. 5 is a diagram showing the zoom ratio selection switch. Display element 1 by operation
FIG. 6 is a block diagram showing the configuration of another embodiment of the present invention. 2・・・・・・・・・・・・・・・・・・Song・・Curved surface・Surface curve・Song・Song Imaging device 3・・・・・・・・・・・・
...Song...Curved surface/Curved surface first AGC detection circuit 5...
・・・・・・・・・ Song・・・・・・Curved Curved Piece 1st A
GC7 pump 12...Curved surface Curved surface curve 2nd AGC7 pump 11...
...Curved surface curved second AGC detection circuit ('itomyn of O1θ0---(θOFF)

Claims (5)

[Claims] (1) It has an image sensor, a means for setting an effective screen of the image sensor, and a means for adjusting the level of the signal to an appropriate level based on the video signal of the effective screen set by the means. An imaging device characterized by: (2) The imaging device according to claim (1), wherein the effective screen is an area displayed on a monitor. (3) The imaging apparatus according to any one of claims (1) and (2), wherein the adjusting means is a means for adjusting the exposure state of the image sensor based on the video signal. (4) The imaging apparatus according to claim 3, wherein the adjusting means is a means for adjusting the exposure state of the image sensor based on the level of the luminance signal of the video signal. (5) Claim (5) characterized in that the means for adjusting the exposure state is means for controlling the accumulation time of the image sensor.
3) and the imaging device described in (4).