JPH0738803A - Video camera - Google Patents

Abstract

(57) [Summary] [Structure] The video signal from the image sensor 4 is input to the motion detection circuit 10 and the light amount detection circuit 11. Motion detection circuit 1
At 0, the amount of movement is detected for each of the divided areas. The light amount detection circuit 11 detects the light amount for each of the divided areas of the screen, weights it according to the motion amount of the motion detection circuit 10 to calculate the total light amount, and outputs the detection result to the iris control circuit 8
Output to. The iris control circuit 8 outputs an iris control voltage on the basis of the light amount detection result, and the iris 3
To control. [Effect] Since the light amount detection is configured to divide the screen and increase the weighting of a moving area, there is an effect that an optimum iris adjustment can be performed even if the subject of interest is not fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to stores, factories, buildings,
The present invention relates to a video camera for video surveillance, which monitors stations, roads, etc. with video.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional video camera. In the figure, 1 is a video camera, 2 is a lens attached to the video camera 1, and 3 is an iris built in the lens 2. Reference numeral 4 is an image sensor for photoelectric conversion, 5 is a camera process circuit for processing a video signal from the image sensor 4,
A video signal 6 is output from the video camera 1. Reference numeral 7 is a light amount detection circuit that divides the screen into regions and detects the light amount for each region, and weights the region closer to the center of the screen to give a larger weight to calculate the total light amount. 8 is based on the detection result of the light amount detection circuit 7. It is an iris control circuit that controls the iris.

Next, the operation will be described. 7A and 7B are views for explaining the image pickup contents, and FIGS. 7A and 7B are images taken by the video camera 1, and the screen is divided into nine regions of alphabets A to I, respectively. .

The flow of the video signal will be described. The video signal photoelectrically converted by the image sensor 4 is subjected to processing such as gain control, shading correction, aperture correction, and gamma correction in the camera process circuit 5, and is output as a video signal 6. The video signal from the image sensor 4 is input to the light amount detection circuit 7. The light amount detection circuit 7 detects the light amount for each of the screen-divided areas, weights the area closer to the center to calculate the total light quantity, and outputs the detection result to the iris control circuit 8. The iris control circuit 8 outputs an iris control voltage based on the light amount detection result to control the iris 3.

The light amount detection will be described. The light amount is detected for each of the nine areas in FIG. And the central area E
Is weighted the most, and the light amounts of the nine areas are summed. When the light amount is detected in this manner, iris control suitable for the area E is performed. FIG. 7A shows a case where a person is the subject of interest. There is a bright sun in the background, and there is a person in it in the backlight condition. In such a case, if the light amount is detected without dividing the screen, the person becomes too dark. In the conventional video camera shown in FIG. 6,
Since the iris control suitable for the area E is performed, the person has appropriate brightness.

[0006]

Since the conventional video camera is constructed as described above, when the subject of interest is in a region other than the predetermined region E as shown in FIG. Since there is a fixed weighting for photometry, there is a problem that the iris cannot be controlled so that the subject of interest has an appropriate brightness.

The present invention has been made to solve the above problems, and an object thereof is to obtain a video camera capable of picking up an image of a subject of interest in an optimum state regardless of where it is on the screen.

[0008]

A video camera according to a first aspect of the present invention includes a motion detection circuit that divides an imaged screen to detect the motion of each area, and controls the imaging based on the motion detection result. It has a circuit.

A video camera according to a second aspect of the present invention includes a motion detection circuit that divides an imaged screen and detects a motion of each area, and includes a light amount detection circuit that calculates a light amount based on the motion detection result. An iris control circuit for controlling the iris of the lens based on the output of the detection circuit is provided.

A video camera according to a third aspect of the present invention includes a motion detection circuit that divides an imaged screen and detects a motion of each area, and a focus amount detection circuit that calculates a focus amount based on the motion detection result. And a focus control circuit that controls the focus of the lens based on the output of the focus amount detection circuit.

A video camera according to a fourth aspect of the present invention includes a motion detection circuit that divides an imaged screen to detect the motion of each area, and an average color detection circuit that calculates an average color based on the motion detection result. A white balance control circuit for controlling the white balance based on the output of the average color detection circuit is provided.

The video camera according to the fifth, sixth, and seventh inventions is characterized in that a region closer to the center of the screen is weighted more.

[0013]

The video camera according to the first aspect of the invention divides the imaged screen and detects the movement for each area. And
Since the image pickup is controlled according to the movement of each area, it is possible to pick up the image of the subject of interest in an optimum state no matter where it is on the screen.

The video camera according to the second aspect of the invention divides the imaged screen and detects the movement for each area. Then, the total amount of light is calculated from the amount of light weighted according to the movement of each area to control the iris.

The video camera according to the third aspect of the invention divides the imaged screen and detects the movement for each area. Then, the focus control circuit outputs a focus control voltage based on the total focus amount weighted according to the movement of each area to control the focus adjustment mechanism of the lens.

A video camera according to a fourth aspect of the present invention divides an imaged screen and detects a motion for each area. Then, the average color of the whole is calculated from the average color weighted according to the movement of each area, and the white balance control circuit is controlled.

In the video cameras according to the fifth, sixth, and seventh inventions, the closer to the center of the screen, the greater the weighting, so that the central area of the screen is kept in an optimum state.

[0018]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to FIG.
Will be described. In the figure, 9 is a video camera, 2
Is a lens attached to the video camera 9, 3 is an iris built in the lens 2, 4 is an image pickup device for photoelectric conversion, 5 is a camera process circuit for processing a video signal from the image pickup device 4, and 6 is a video camera 9 A video signal to be output, 10 is a motion detection circuit which is connected to the output of the image sensor 4 and divides the screen into regions to detect a motion for each region, and 11 is a screen which is connected to the output of the image sensor 4 and the output of the motion detection circuit 10. Is a light amount detection circuit that divides the region and weights each region according to the movement to calculate the total light amount, and 8 is an iris control circuit that controls the iris 3 based on the detection result of the light amount detection circuit 11.

Next, the operation will be described. The video signal photoelectrically converted by the image sensor 4 is subjected to processing such as gain control, shading correction, aperture correction, and gamma correction in the camera process circuit 5, and is output as a video signal 6. The video signal from the image sensor 4 is input to the motion detection circuit 10 and the light amount detection circuit 11. The motion detection circuit 10 detects a motion amount for each of the divided areas of the screen. The light amount detection circuit 11 detects the light amount for each of the divided areas of the screen, weights it according to the motion amount of the motion detection circuit 10 to calculate the total light amount, and outputs the detection result to the iris control circuit 8. The iris control circuit 8 outputs an iris control voltage based on the light amount detection result to control the iris 3.

The iris control will be described. Figure 7
When there is movement in the area E as shown in (a), the weight of the area E is increased to calculate the light amount, and when there is movement in the area D as shown in FIG. The weight of D is increased to calculate the amount of light to control the iris.
FIG. 2 is a diagram showing an example of changing weighting.
FIG. 2A shows that areas A to I each have a weight of 1, 2, or 3, respectively. FIG. 2B shows an initial value of weighting or a weighted state when there is no motion in the captured image or when there is motion in the entire captured image. In FIG. 2B, the area E is given a weight of 3 and the other areas are given a lower weight of 1. As shown in FIG. 7 (a), FIG. 2 (c) shows a case where the area E and the area H are moving when the area E is moved.
And a case where the weighting of the region H is increased.
As compared with FIG. 2B, in FIG. 2C, the area E has a weight of 3 and does not change, but the area H changes from weight 1 to weight 3. Next, FIG. 2D shows a case where the weights of the regions D and G are increased when the regions D and G are moving as shown in FIG. 7B. In the case of FIG. 2D, the weights of the areas D and G are set to 3. On the other hand, the weights of the areas E and H are set to 1. Next, FIG. 3 is a diagram showing another example of changing the weighting.

FIG. 3A shows the range of weights that can be taken by the areas A to I. For example, area A may have a weight of 1 or 2. Further, for example, the area D may have a weight of 2 or a weight of 3. FIG. 3B shows an initial value of weighting or a weighted state when there is no motion in the captured video or when there is motion in the entire captured video.
In FIG. 3B, the weight 3 is set in the area E, the weight 2 is set in the areas D, F, and H, and the weight 1 is set in the other areas. Figure 3 (c)
Shows the case where there is a movement in the areas E and H as shown in FIG. In this case, the area E and the area H
Takes the maximum weight 3 among the weights that can take. The other areas are the same as those shown in FIG. As shown in FIG. 7B, the area D and the area G in FIG.
It shows the case where there is movement. In this case, the weight of the area D and the area G is set to the maximum weight that the area can take as shown in FIG. In this way, in the case shown in FIG. 3, the range of weights that each area can take is set in advance, and the weights are assigned within the range. Particularly, in the case shown in FIG. 3, a case is shown in which a larger weight is set in the central portion or a portion near the central portion.

Example 2. FIG. 4 is a diagram for explaining an embodiment for controlling the focus, in which 12 is a video camera, 2
Is a lens attached to the video camera 12, 13 is a focus adjusting mechanism built in the lens 2, 4 is an image pickup device for photoelectric conversion, 5 is a camera process circuit for processing a video signal from the image pickup device 4, and 6 is a video camera A video signal output by 12 is connected to the output of the image sensor 4, 10 is a motion detection circuit that divides the screen into regions and detects the motion of each region, and 14 is connected to the output of the image sensor 4 and the output of the motion detection circuit 10. The focus adjustment mechanism 1 calculates the total focus amount by dividing the screen into regions and weighting each region according to the movement, and 15 the focus adjustment mechanism 1 based on the detection result of the focus amount detection circuit 14.
3 is a focus control circuit for controlling 3;

Next, the operation will be described. The video signal photoelectrically converted by the image sensor 4 is subjected to processing such as gain control, shading correction, aperture correction, and gamma correction in the camera process circuit 5, and is output as a video signal 6. The video signal from the image sensor 4 is input to the motion detection circuit 10 and the focus amount detection circuit 14. The motion detection circuit 10 detects a motion amount for each of the divided areas of the screen. The in-focus amount detection circuit 14 detects the in-focus amount for each of the screen-divided areas, weights it according to the motion amount of the motion detection circuit 10 to calculate the total in-focus amount, and performs focus control on the detection result. Output to the circuit 15. Focus control circuit 15
Then, the focus control voltage is output based on the result of the focus detection, and the focus adjusting mechanism 13 is controlled.

The focus point will be described. When the area E moves as shown in FIG. 7A, the weighting of the area E is increased to calculate the in-focus amount, and as shown in FIG. 7B, the area D moves. In this case, the weighting of the area D is increased to calculate the in-focus amount and control the focus.

Example 3. FIG. 5 is a diagram for explaining an embodiment for controlling the white balance. In the figure, 16 is a video camera, 2 is a lens attached to the video camera 16, 4 is an image sensor for performing photoelectric conversion, and 5 is an image sensor from the image sensor 4. A camera process circuit for processing a video signal, 17 a white balance circuit in the camera process circuit 5, 6 a video signal output from the video camera 16, 10 is connected to the output of the image sensor 4, and the screen is divided into areas. A motion detection circuit 18 for detecting the motion for each of them is connected to the output of the image sensor 4 and the output of the motion detection circuit 10 and divides the screen into regions, weights each region according to the motion, and averages the entire screen. Average color circuit to calculate
A white balance control circuit 19 controls the white balance based on the detection result of the average color circuit 18.

Next, the operation will be described. The video signal photoelectrically converted by the image sensor 4 is subjected to processing such as gain control, shading correction, aperture correction, gamma correction, and white balance in the camera process circuit 5, and the video signal 6
Is output as. The video signal from the image sensor 4 is input to the motion detection circuit 10 and the average color detection circuit 18. The motion detection circuit 10 detects a motion amount for each of the divided areas of the screen. The average color detection circuit 18 detects the average color for each of the divided areas of the screen, weights it according to the motion amount of the motion detection circuit 10, and calculates the average color of the entire screen.
The detection result is output to the white balance control circuit 19. The white balance control circuit 19 outputs the white balance control amount based on the average color detection result, and the white balance circuit 17 outputs the white balance control amount.
To control.

The white balance control will be described. Figure 7
When there is movement in the area E as shown in (a), the weighting of the area E is increased to calculate the average color.
When there is a movement in the area D as shown in (b), the weight of the area D is increased to calculate the light amount and control the white balance.

Example 4. The first embodiment is effective when one of the areas has the most movement when the screen is divided, but when there is no movement in the captured image, or
When there is movement in the entire captured image, the region closer to the center of the screen is weighted more heavily to calculate the total amount of light and control the iris.

Example 5. The second embodiment is effective when one of the areas has the most movement when the screen is divided, but when there is no movement in the captured image, or
When there is movement in the entire captured image, a region closer to the center of the screen is weighted more heavily to calculate the total in-focus amount and control the focus.

Example 6. The third embodiment is effective when one of the areas has the most movement when the screen is divided, but when there is no movement in the captured image, or
When there is movement in the entire captured image, the area closer to the center of the screen is weighted more heavily to calculate the average color and control the white balance.

Example 7. In the above embodiment, the screen is equally divided into nine, but the number of divisions such as 16 may be changed, or the division shape may be variously changed such as increasing the central portion of the division area.

Optimum iris adjustment, focus adjustment, and white balance adjustment can be performed by varying the number of divisions and their shapes.

Example 8. In the above embodiment, the screen is divided and the weight is added to the moving area. However, the weight is increased to some extent around the moving area, or each area is changed according to the size of the moving area. Areas may be weighted.

Optimum iris adjustment, focus adjustment and white balance adjustment can be performed by changing the weighting method.

Example 9. In the above embodiment, the screen area is divided by the motion detection circuit, the light amount detection circuit, the focusing amount detection circuit and the average color detection circuit, respectively. However, the area identification for generating a signal for identifying the divided area of the screen is performed. A signal generation circuit may be provided so that the motion detection circuit, the light amount detection circuit, and the focus amount detection circuit do not perform the area division of the screen by using the area identification signal.

The total hardware amount can be reduced by providing the area identification signal generating circuit for generating the signal for identifying the area into which the screen is divided.

[0037]

As described above, according to the first aspect of the present invention, since the subject of interest is recognized by the motion detection circuit, the video camera can be controlled so as to pick up the subject in an optimum state.

According to the second aspect of the invention, when the light amount is detected, the screen is divided so that the weighting of the moving area is increased, so that the optimum iris can be obtained even if the subject of interest is not fixed. There is an effect that can be adjusted.

According to the third aspect of the invention, when the in-focus amount is detected, the screen is divided so that the weighting of the moving area is increased, so that the object of interest is not necessarily fixed. This has the effect of enabling fine focus adjustment.

According to the fourth invention, when detecting the average color,
Since the screen is divided and the weighting of the moving area is increased, there is an effect that the optimum white balance adjustment can be performed even if the subject of interest is not a fixed place.

According to the fifth aspect of the invention, when the picked-up image does not move or when the picked-up image as a whole moves, a region closer to the center of the screen is weighted more to calculate the total light amount. Since it is configured to control the iris, there is an effect that an appropriate iris adjustment can be performed even when there is no movement in the captured image or when there is movement in the entire captured image.

According to the sixth aspect of the invention, when there is no motion in the picked-up image, or when there is motion in the whole picked-up image, a region closer to the center of the screen is given a greater weighting and the total focus point. Since the focus is controlled by calculating the amount, there is an effect that an appropriate focus adjustment can be performed even when there is no movement in the captured image or when there is movement in the entire captured image.

According to the seventh aspect, when there is no motion in the picked-up image, or when there is motion in the whole picked-up image, a region closer to the center of the screen is given a greater weighting and the average of the whole screen is averaged. Since it is configured to calculate the color and control the white balance, if there is no motion in the captured image,
Alternatively, there is an effect that an appropriate white balance adjustment can be performed even when there is movement in the entire captured image.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video camera according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in weighting according to an embodiment of the present invention.

FIG. 3 is a diagram showing a change in weighting according to an embodiment of the present invention.

FIG. 4 is a block diagram showing the configuration of a video camera for focus control according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a video camera for performing white balance control according to another embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional video camera.

FIG. 7 is a diagram illustrating a manner of dividing a screen, capturing an image, and performing photometry.

[Explanation of symbols]

 1,9,12,16 Video camera 2 Lens 3 Iris 4 Image sensor 5 Camera process circuit 6 Video signal 7,11 Light intensity detection circuit 8 Iris control circuit 10 Motion detection circuit 13 Focus adjustment mechanism 14 Focusing amount detection circuit 15 Focus control Circuit 17 White balance circuit 18 Average color detection circuit 19 White balance control circuit

Claims (7)

[Claims] 1. A motion detection circuit for detecting a motion for each area obtained by dividing an imaged screen, and a control circuit for controlling imaging according to the motion detected by the motion detection circuit. Video camera. 2. A motion detection circuit for detecting a motion for each area obtained by dividing an imaged screen into areas, detecting an amount of light in each area by dividing the imaged screen, and depending on the motion detected by the motion detection circuit. And a iris control circuit for controlling the iris of the lens based on the output of the light amount detection circuit. 3. A motion detection circuit for detecting a motion for each area obtained by dividing an imaged screen, and an operation for detecting an in-focus amount of each area by dividing the imaged screen and detecting a motion detected by the motion detection circuit. And a focus control circuit for controlling the focus of the lens based on the output of the in-focus point amount detection circuit. 4. A motion detection circuit that detects a motion for each area obtained by dividing the imaged screen, and an average color of each area is detected by dividing the imaged screen into areas and the motion detected by the motion detection circuit is detected. A video camera, comprising: an average color detection circuit for calculating an average color by weighting according to the weight; and a white balance control circuit for controlling white balance based on an output of the average color detection circuit. 5. When the picked-up image has no motion, or when the picked-up image has a whole motion, an area closer to the center of the screen is weighted more to calculate the total light amount. The video camera according to claim 2. 6. When the picked-up image has no motion or when the picked-up image as a whole is moving, an area closer to the center of the screen is weighted more to calculate the total focus amount. The video camera according to claim 3, wherein the video camera is a video camera. 7. When the picked-up image has no motion or when the picked-up image as a whole has a motion, a region closer to the center of the screen is weighted more to calculate the average color. The video camera according to claim 4.