JP2017118318A - Imaging apparatus and imaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately mask a subject to be masked by appropriate size in an imaging apparatus for monitoring.SOLUTION: In an imaging apparatus, a zoom lens 102 and a focus lens 103 are installed as imaging lenses. The imaging apparatus includes a mask control section 230 for acquiring setting information of a mask display position previously set in a specific focal distance and a mask signal addition section 113 for adding a mask signal for covering a specific range calculated on the basis of setting information of an imaging position including the zoom lens and the setting information of the mask display position to a video signal. The mask control section has two tables indicating correspondence between the focal distance of the zoom lens and the position of the zoom lens and having respectively different focal positions, calculates a present focal distance corresponding to a present focus lens position by operation using the two tables and makes a range for adding the mask signal coincide with a range indicated by the setting information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus and an imaging method.

  As surveillance cameras, cameras (hereinafter referred to as PTZ surveillance cameras) capable of pan (PAN: horizontal swing) rotation, tilt (TILT: vertical swing) rotation, and zoom (ZOOM) have been put into practical use. A PTZ surveillance camera uses a camera body fixed to a camera turntable that can freely rotate in a pan direction and a tilt direction. This PTZ monitoring camera is a system that can freely select an image projected by a camera by operating a camera turntable and a zoom of the camera by an external controller unit. A PTZ surveillance camera generally has a sequence control function that stores a plurality of video positions and sequentially displays the stored video positions at a predetermined time. In addition, a human sensor or the like is installed in the monitoring area, and when an abnormality is detected, an alarm function is provided that instantly pans, tilts, and zooms the camera and points the camera in the direction in which the abnormality is detected.

  When such a monitoring system is installed in a public place such as a street, there is a problem of processing in places where it is not desirable to take pictures for privacy protection, such as private houses and objects that are not allowed to be taken around the installation place. There is. In view of this, a masking method has been conventionally proposed in which an object that requires privacy protection is masked with another image so that the object is not visible on the image. For example, Patent Literature 1 describes a camera image masking method applied to a surveillance camera.

  The mask method described in Patent Document 1 is provided by a lens manufacturer, in which the camera indicates the correspondence between the f value, which is the distance between the lens and the image sensor (lens focal length), and the zoom lens position. Holds relationship table. Then, when the camera adds a mask, the f value indicated by the zoom lens position information at the time of mask setting and the f value indicated by the current zoom lens position information are obtained from the relation table. Then, by calculating the current zoom magnification using the two referenced f values, the camera links the size of the mask to be set to the zoom position.

Japanese Patent No. 5389879

As described in Patent Document 1, there are cases in which accurate mask setting cannot be performed simply by using a relationship table that shows correspondence between lens positions and f values.
For example, a case is assumed where the relationship table between the zoom lens position and the f value is only one table at infinity where the focus lens position is frequently used. In such a case, the f value is determined by the zoom lens position and the focus lens position. However, since the focus lens position can be considered only when the focus lens position is at infinity, the f value due to the difference in the focus lens position cannot be calculated correctly. Specifically, when the focus position moves from a position at infinity, the difference between the calculated zoom magnification and the actual zoom magnification increases, and the mask size that is variable in conjunction with the zoom magnification is It becomes impossible to accurately follow the change in size of the object. If the mask size cannot be followed correctly, there arises a problem that the mask object protrudes from the mask or masks other than the mask countermeasure object.

  An object of the present invention is to provide an imaging apparatus and an imaging method capable of accurately masking a subject to be masked with an appropriate size.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. For example, an imaging apparatus in which a zoom lens and a focus lens are mounted as imaging lenses.
A mask control unit for acquiring setting information of a mask display position set in advance at a specific focal length;
A mask signal adding unit that adds a mask signal for covering a specific range calculated based on the setting information of the imaging position including the zoom lens and the setting information of the mask display position to the video signal;
The mask control unit has two tables with different focus positions indicating the correspondence between the focal length of the zoom lens and the position of the zoom lens, and the current focus lens position is calculated using the two tables. And calculating a zoom magnification based on the calculated current focal distance, and a range in which the mask signal adding unit adds a mask signal based on the calculated zoom magnification, Processing to match the range indicated by the mask display position setting information is performed.

According to the present invention, an accurate zoom magnification can be obtained, a mask size and a mask position can be accurately set at any zoom magnification, and an image in which a mask object is reliably masked can be obtained. Has an effect.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a system configuration diagram according to an embodiment of the present invention. It is explanatory drawing which shows the example of the relationship table by one embodiment of this invention. It is explanatory drawing which shows three area | regions of the relationship table by the example of 1 embodiment of this invention. It is explanatory drawing which shows the normalization state of three area | regions of the relationship table by the example of 1 embodiment of this invention. It is a flowchart which shows the selection process of three area | regions of the relationship table by the example of 1 embodiment of this invention. It is explanatory drawing which shows the example of the calculation state of f value by one embodiment of this invention. It is a flowchart which shows the process at the time of mask setting and mask effective by the example of 1 embodiment of this invention. It is explanatory drawing which shows the example (setting example of the center of a mask range) of the mask range by one embodiment of this invention. It is explanatory drawing which shows the example (setting example of the four corners of a mask range) of the mask range by one embodiment of this invention. It is explanatory drawing which shows the example of addition of the mask signal by one embodiment of this invention. It is explanatory drawing which shows the example of calculation of the angle of 1 pixel by one embodiment of this invention. It is explanatory drawing which shows the example of calculation of the moving amount | distance of the mask according to the pan angle and tilt angle at the time of mask effective by one example of this invention.

Hereinafter, an embodiment of the present invention (hereinafter referred to as “this example”) will be described with reference to the accompanying drawings.
[1. System configuration example]
FIG. 1 shows a configuration example of the entire surveillance camera which is the imaging apparatus of this example.
The surveillance camera of this example is configured as a PTZ surveillance camera with a camera body mounted on a turntable (not shown) capable of panning and tilting rotation and a lens unit 101 having a zoom lens 102 mounted thereon. .

The lens unit 101 includes a zoom lens 102, a focus lens 103, and an iris 104. The focal length can be adjusted by the position of the zoom lens 102, and the focus can be adjusted by the position of the focus lens 103. The iris 104 can adjust the amount of external light captured by the lens unit 101.
The external light that has passed through the lens unit 101 is applied to the image sensor 105. The image sensor 105 acquires a video signal by photoelectric conversion of the irradiated light. As the image sensor 105, any type of image such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor may be applied.
The video signal obtained by the image sensor 105 is supplied to an analog front end circuit (AFE circuit) 106. The AFE circuit 106 performs correlated double sampling (CDS) processing, automatic gain adjustment (AGC) processing, digital conversion processing, and the like. The video signal digitally converted by the AFE circuit 106 is supplied to the image processing unit 110.

  The image processing unit 110 includes an edge level calculation unit 111, and calculates a change level (edge level) of a luminance signal included in a video signal necessary for autofocus control. The edge level is a video signal input to the image processing unit 110, and increases as the difference in luminance level between pixels increases. Information on the edge level calculated by the edge level calculation unit 111 is supplied to an autofocus control unit 203 described later, and is used for autofocus control based on the edge level. The video signal output from the edge level calculation unit 111 is supplied to the signal processing unit 112 and subjected to various signal processing such as noise reduction processing, sensitivity enhancement processing, and color reproducibility improvement processing. The video signal output from the signal processing unit 112 is supplied to the adder 114, and a mask signal output from the mask signal adding unit 113 when the mask is valid is added. The mask signal added here is a signal for hiding a preset privacy protection area.

  The video signal subjected to the addition processing by the adder 114 is supplied to the analog / digital conversion unit 107 as an output of the image processing unit 110 and converted into an analog video signal. The converted analog video signal is supplied from the video signal output unit 108 to a display device (not shown) such as a monitor, and a captured image is displayed. Note that outputting an analog video signal is one example, and the digital video signal may be supplied from the video signal output unit 108 to the display device. Further, the recording device may record the video signal output from the video signal output unit 108.

Next, the camera control unit 200 that controls the imaging operation of the imaging apparatus will be described.
The camera control unit 200 includes a pan / tilt / zoom information acquisition unit 204. The pan / tilt / zoom information acquisition unit 204 acquires operation information based on a user operation by the camera operation unit 131. Based on the acquired operation information, the pan / tilt / zoom information acquisition unit 204 supplies pan rotation angle information and tilt rotation angle information to a turntable (not shown), and the turntable is instructed to the camera body. Set to rotation angle. Further, the pan / tilt / zoom information acquisition unit 204 instructs the zoom lens motor control unit 201 to drive the zoom lens motor 121 based on the acquired operation information. The zoom lens motor control unit 201 drives the zoom lens motor 121 to move the position of the zoom lens 102. By moving the position of the zoom lens 102, the zoom lens position designated by the user operation is controlled.
Further, the pan / tilt / zoom information acquisition unit 204 supplies pan rotation angle information, tilt rotation angle information, and zoom lens position information to the mask control unit 230. Based on these pieces of information, the mask control unit 230 calculates the position where the mask signal adding unit 113 adds a mask. Details of the mask controller 230 will be described later.

  The autofocus control unit 203 of the camera control unit 200 instructs the focus lens motor control unit 202 to drive the focus lens motor 122. As described above, edge level information is supplied to the autofocus control unit 203, and the autofocus control unit 203 drives the focus lens motor 122 so that the edge level is maximized. Images can be taken in a focused state.

In addition, the camera control unit 200 includes an f value calculation unit 210. The f value calculation unit 210 is a processing unit that calculates the f value (focal length) of the lens unit 101, and includes a zoom lens position information acquisition unit 211, a focus lens position information acquisition unit 212, and an f value calculation unit 213. Prepare.
The zoom lens position information acquisition unit 211 acquires zoom lens position information from the zoom lens motor control unit 201. The focus lens position information acquisition unit 212 acquires focus lens position information from the autofocus control unit 203. Note that the lens position information is acquired from the zoom lens motor control unit 201 or the autofocus control unit 203 is an example, and may be directly acquired from a sensor (potentiometer or the like) mounted on each of the lenses 102 and 103. .

The zoom lens position information acquired by the zoom lens position information acquisition unit 211 and the focus lens position information acquired by the focus lens position information acquisition unit 212 are supplied to the f value calculation unit 213. The f value calculation unit 213 refers to the information of the relationship table between the lens position and the f value stored in the relationship table storage unit 221 of the memory 220, and determines the current f of the lens unit 101 from the supplied lens position information. Calculate the value. In this example, the relationship table storage unit 221 stores two tables, a relationship table A and a relationship table B. Specific examples of these two tables will be described later.
Information on the f value of the lens unit 101 calculated by the f value calculation unit 213 is supplied to the mask setting information acquisition unit 241 and the mask display position calculation unit 245 of the mask control unit 230.

The mask control unit 230 includes a mask state determination unit 231, a mask setting time processing unit 232, a mask valid time processing unit 233, and a mask display position information generation unit 234. The mask state determination unit 231 selectively activates the mask setting time processing unit 232 and the mask effective time processing unit 233 based on an instruction from the camera operation unit 131.
The mask setting time processing unit 232 includes a mask setting information acquisition unit 241, a mask display position calculation unit 242, and a mask display processing unit 243. The mask setting information acquisition unit 241 acquires mask setting information based on a user operation at the camera operation unit 131. Also, the mask setting information acquisition unit 241 acquires pan rotation angle information, tilt rotation angle information, and zoom lens position information at the time of mask setting from the pan / tilt / zoom information acquisition unit 204.
Then, from each information acquired by the mask setting information acquisition unit 241, the mask display position calculation unit 242 calculates a mask display position, and the calculated mask display position information is stored in the camera display position information storage unit 223 of the memory 220. The At this time, the f-value at the time of calculating the mask display position information and information at the time of mask setting such as the screen size and the angle of view information are stored in the camera display position information storage unit 223. The camera information storage unit 222 of the memory 220 stores the current screen size, field angle information, and the like.

  Then, the mask display position information calculated by the mask display position calculation unit 242 is supplied to the mask display processing unit 243, and the mask display processing unit 243 performs a process for displaying the mask at the corresponding position. The mask display processing unit 243 causes the mask display position information generation unit 234 to generate mask display position information. The mask display position information generated by the mask display position information generation unit 234 is supplied to the mask signal addition unit 113 of the image processing unit 110, and a mask signal specified by the mask display position information is generated.

  The mask valid time processing unit 233 includes a mask display position calculation unit 245 and a mask display processing unit 246. The mask display position calculation unit 245 acquires the current pan rotation angle information, tilt rotation angle information, and zoom lens position information from the pan / tilt / zoom information acquisition unit 204. Further, the mask display position calculation unit 245 acquires information on the f value of the lens unit 101. The mask display position calculation unit 245 calculates the mask display position based on these pieces of information, and the mask display processing unit 246 performs a process for displaying the mask at the corresponding position. The mask display processing unit 246 causes the mask display position information generation unit 234 to generate mask display position information. The mask display position information generated by the mask display position information generation unit 234 is supplied to the mask signal addition unit 113 of the image processing unit 110, and a mask signal specified by the mask display position information is generated. Note that the processing in the mask valid time processing unit 233 is executed in real time, and the mask display position information at that time is obtained in real time.

  Note that each processing unit in the camera control unit 200 shown in FIG. 1 may be configured by software, with some or all of the processing units being configured in addition to hardware. That is, a program that realizes a function executed by each processing unit may be stored in the memory 220, and the camera control unit 200 may be obtained by executing the program.

[2. Example of stored data in memory]
Next, data stored in the storage units 221, 222, and 223 of the memory 220 will be described.
The relationship table storage unit 221 stores two types of lens relationship tables. Details of the lens relationship table will be described later.

The camera information storage unit 222 stores the screen size information of the number of pixels MONI_H in the horizontal direction and the number of lines MONI_V in the vertical direction of the video signal output from the video signal output unit 108, and the horizontal and vertical angles of view of the camera screen. Is stored.
The camera display position information storage unit 223 stores information at the time of mask setting. Information at the time of mask setting includes pan angle, tilt angle, zoom lens position (focal length: f value, normalization information), mask position, and mask size.

FIG. 2 shows an example of a lens relationship table stored in the relationship table storage unit 221 of the memory 220.
The lens relationship table of this example shows the relationship between the position of the zoom lens 102 and the f value. Data on the relationship between the position of the zoom lens 102 and the f value is provided by, for example, a manufacturer that manufactures the lens unit 101. In the lens unit 101, when the position of the focus lens 103 changes, the relationship between the position of the zoom lens 102 and the f value changes, and the change state is shown in the relationship table. In the case of this example, as a relation table, table A indicating the correspondence between the focal length and the zoom lens position when the focus lens 103 is at infinity, and the focal length and zoom lens when the focus lens 103 is the closest distance. A table B indicating the correspondence between positions is provided.

  That is, as shown in FIG. 2, the relationship table storage unit 221 changes the f value from the wide end (W end) to the tele end (T end) of the zoom lens 102 according to the position of the focus lens 103. Two types are stored. The characteristics shown in Table A in FIG. 2 are when the focus lens 103 is at infinity. The characteristic shown by Table B in FIG. 2 is when the focus lens 103 is at the closest distance.

This relationship table between the lens position and the f value is divided into a plurality of areas, and is stored in the memory 220 as a normalized value for each area.
FIG. 3 shows an example of region setting status and normalization.
In this example, the zoom lens position from the W end to the T end is set to 256 steps of values from 0 to 255, the range from 0 to 84 is set as region 1, the range from 85 to 169 is set as region 2, and the value Is a region 3 from 170 to 255. Area 1 is normalized by 256, area 2 is normalized by 512, and area 3 is normalized by 1024. Data normalized by 256 is represented by 8 bits, data normalized by 512 is represented by 9 bits, and data normalized by 1024 is represented by 10 bits.
By normalizing in this way, the f value in the region 1 is relatively small, and the f value increases as the region 2 and the region 3 are advanced. Therefore, the region 1 is normalized with a resolution suitable for each region.

When normalizing, for example, the following equation (1) can be used.
Y = INT ((f_data_a * X) / f_data_max) (1)
In the equation (1), Y means the normalized f value, f_data_a means the actual f value, f_data_max means the maximum value of the f value, and INT means that the fractional part is rounded down and treated as an integer value.
By normalizing in this way, all the f values become integer values, and the calculation load on the f value calculation unit 210 can be reduced.

FIG. 4 shows a specific example of the table of the areas 1, 2 and 3.
In area 1, for each value from 0 to 84 indicating the zoom lens position, a minimum value (here 7) to a maximum value (here 255) is assigned as the f value.
In region 2, for each value from 0 to 84 indicating the zoom lens position (a value obtained by subtracting 85 from the values from zoom lens position 85 to 169), the f value is changed from the minimum value (128 here) to the maximum value (here). Then, up to 511) is allocated.
In the area 3, for each value from 0 to 84 indicating the zoom lens position (a value obtained by subtracting 170 from the value from the zoom lens position 170 to 255), the f value is set from the minimum value (here 256) to the maximum value (here Up to 1023) are allocated.
In this way, by assigning and gradually increasing values such as 256, 512, and 1024, normalization errors in obtaining the current f value can be minimized. In addition, since the area where the f value is small is expressed by data with a small number of bits, it contributes to the reduction of the data amount of the entire table.

  Specifically, when the data range of the zoom lens position is 0 to 255, when the normalized value is 1024 (0 to 1023) regardless of the zoom lens position, one data is 10 bits. At this time, the data amount of the f value is 256 × 10 bits = 2560 bits (320 bytes), and two types of table A and table B are held, so the total amount is 640 bytes.

  On the other hand, in the example of FIG. 3 in which the normalization value is changed for each region, the normalization value for region 1 is 256, so one unit of data is 8 bits, and the normalization value for region 2 is 512. Since the data is 9 bits and the normalized value of area 3 is 1024, one unit of data is 10 bits. Therefore, the total of the three areas is 85 × 8 bits + 85 × 9 bits + 86 × 10 bits = 2305 bits (about 289 bytes). Since this is stored in two types, table A and table B, the total is 578 bytes, and a data amount of 62 bytes can be saved as compared to the case where all areas are normalized with the same normalized value.

  As shown in FIG. 2 and FIG. 3, as two relational tables, preparing two tables, one at infinity and the one at the closest distance, is one example, and the other two focus lens positions. The table may be prepared. There are two tables as an example, and three or more tables may be prepared. In addition, as shown in FIG. 3, the setting of three areas and normalization is an example, and two or more areas may be set and normalized. The point where normalization values are 256, 512, and 1024 is also an example, and normalization may be performed with other values.

[3. Example of f-value calculation processing]
Next, details of the process in which the f value calculation unit 210 calculates the f value will be described.
The zoom lens position information acquisition unit 211 in the f value calculation unit 210 acquires the current zoom lens position, and the focus lens position information acquisition unit 212 acquires the current focus lens position. Then, the f value calculation unit 213 calculates the current f value f_data_now by referring to the data in the two relationship tables A and B, the current focus lens position focus_position_now, the current zoom lens position zoom_position_now. When calculating the f value, the focus lens operating range focus_range is also referred to.
The range of the zoom lens position focus_position_now is 0 to 1023 (the closest side is 0 and the infinity side is 1023). The focus lens operating range focus_range is 1024, and the current zoom lens position zoom_position_now is 0 to 255 (0: W end, 255: T end). The range of these values is an example.

The process in which the f value calculation unit 210 calculates the f value will be described in order.
First, the f value calculation unit 210 obtains the f value f_data_a at the infinity and the f_data_b at the closest distance in the zoom lens position zoom_position_now from the current zoom lens position zoom_position_now and the two relationship tables A and B.
FIG. 5 is a flowchart illustrating a processing example when the f value calculation unit 210 reads the f value from the relationship table storage unit 221.
First, the f-value calculation unit 210 determines whether the current zoom lens position zoom_position_now is “area 1 to 84 range”, “area 2: 85 to 169 range”, or “3 area: 170 to 170”. It is determined which of the range “255” (step S11).
Here, when the current zoom lens position zoom_position_now is “range 1 to 84”, the f value and the normalized value normalize_now at the time of the array number [zoom_position_now] of the region 1 are read (step S12).
When the current zoom lens position zoom_position_now is “region 2: range of 85 to 169”, the f value and the normalized value normalize_now at the time of the array number [zoom_position_now-85] of the region 2 are read (step S13).
If the current zoom lens position zoom_position_now is “region 3: range of 170 to 255”, the f value and the normalized value normalize_now at the time of the array number [zoom_position_now−170] of the region 3 are read (step S14).

  The readout process shown in FIG. 5 is performed for each of the relationship tables A and B, thereby obtaining the f value f_data_a at infinity and the f value f_data_b at the closest distance at the current zoom lens position zoom_position_now.

Next, the current f value considering the focus position is obtained from the focus lens operating range focus_range, the current focus lens position focus_position_now, the f value f_data_a at infinity, and f_data_b at the closest distance. The following expression (2) is an expression for calculating the current f value f_data_now from these values.
f_data_now = | f_data_a−f_data_b | × focus_position_now / focus_range + f_data_b (2)

As described above, the current f value f_data_now can be obtained, and the current f value f_data_now obtained by the f value calculation unit 210 and the normalized value normalize_now are supplied to the mask control unit 230 in real time.
FIG. 6 shows the relationship between these values on the characteristic curve of the relationship table.

[4. Example of mask control processing]
Next, processing in the mask control unit 230 in the camera control unit 200 will be described with reference to the flowchart in FIG.
First, the mask state determination unit 231 determines one of a control-off state in which no mask is added to the screen, a state in which a mask range is set, and a mask addition valid state in which a mask is added to the screen (step S21). ).

Here, in the case of a control-off state in which no mask is added to the screen, the process ends without performing any processing regarding mask addition.
When the mask range is set, the mask setting time processing unit 232 performs mask setting time processing (step S22). When the mask is set, the privacy protection area to be masked is displayed on the video output from the video signal output unit 108. At this time, an arbitrary position (range) on the video is set as a mask area (privacy protection area) by an operation by the user. Then, the process of displaying the privacy protection area is executed by the mask signal adding unit 113 (step S23).

  When the mask is valid, the mask valid time processing unit 233 performs a mask valid time process (step S24). Here, a mask signal for hiding the mask area set in step S22 is added to the video signal by the mask signal adding unit 113 (step S25). At this time, a mask signal is added so as to hide the subject existing in the privacy protection area set in step S22 regardless of any change in pan angle, tilt angle, or zoom lens position of the imaging apparatus.

[5. Example of processing when setting a mask]
Next, a processing example at the time of mask setting performed by the mask control unit 230 will be described with reference to FIGS.
Communication between the camera operation unit 138 and the camera control unit 200 causes the mask setting information acquisition unit 241 to acquire information necessary for the user to set a mask on the camera screen (on the video signal).

  FIG. 8 shows information A, B, C, and D acquired at this time. Here, the mask position information A and B are moniMASK_Hposi and moniMASK_Vposi, and the mask size information C and D are moniMASK_Hsize and moniMASK_Vsize. In FIG. 8, the horizontal direction of the camera screen is the X axis and the vertical direction is the Y axis, the right side is positive, the left side is negative, the lower side is positive, the upper side is negative, and the user masks at an arbitrary position on the camera screen. Can be specified. Mask position information A and B indicate the distance between the X axis and the Y axis from the center of the screen to the center of the mask, and mask size information C and D indicate the X axis and Y axis from the center to the end of the mask range. Indicates the size. In the example of FIG. 8, the mask range is a rectangle.

  Here, as an example, moniMASK_Hposi and moniMASK_Vposi can be set in the range of −127 to 127, and moniMASK_Hsize and moniMASK_Vsize are data that can be set in the range of 0 to 128. This setting range is an example, and other arbitrary mask setting specifications may be used. Further, although the mask shape set in this example is a quadrangle, the mask shape may be other than a quadrangle, for example, a trapezoid or a circle.

  Also, the pan / tilt / zoom information acquisition unit 204 acquires pan rotation angle information, tilt rotation angle information, and zoom lens position information at the time of mask setting as PANs degrees and TILTs degrees, respectively. Also, the current f value f_data_now and the normalized value normalize_now are acquired from the f value calculation unit 210.

Then, using the information A, B, C, D (FIG. 8) received from the camera operation unit 131 by the mask display position calculation unit 242, vertex coordinates p1, p2, p3 for pasting the mask on the camera screen. , P4 is calculated.
FIG. 9 shows four vertex coordinates p1, p2, p3, and p4. Here, the four vertex coordinates p1, p2, p3, and p4 are shown as follows.
p1_moniMASK (x1_moniMASK, y1_moniMASK),
p2_moniMASK (x2_moniMASK, y2_moniMASK),
p3_moniMASK (x3_moniMASK, y3_moniMASK),
p4_moni (x4_moni MASK, y4_moni MASK)

  The calculation of the vertex coordinates in the mask display position calculation unit 242 is performed by referring to the camera screen size information MONI_H and MONI_V from the camera information storage unit 222 of the memory 220 as follows (3), (4), (5 ) And (6). The coordinate system of the camera screen at this time is assumed to be handled as shown in FIG. However, the direction of the coordinate axes shown in FIG. 9 is an example and may be an arbitrary direction.

x1_moniMASK = x3_moniMASK = (MONI_H / 2) +
(MONI_H / 256) × (−moniMASK_Hsize + moniMASK_Hposi) (3)
x2_monMASK = x4_monMASK = (MONI_H / 2) +
(MONI_H / 256) × (moniMASK_Hsize + moniMASK_Hposi) (4)
y1_moniMASK = y2_moniMASK = (MONI_V / 2) −
(MONI_V / 256) × (moniMASK_Vsize + moniMASK_Vposi) (5)
y3_moniMASK = y4_moniMASK = (MONI_V / 2) −
(MONI_V / 256) × (−moniMASK_Vsize + moniMASK_Vposi) (6)

  The memory 220 stores the mask display position information obtained by these equations, the PANs degree and the TILTs degree acquired from the pan / tilt / zoom information acquisition unit 204, the f value f_data_now and the normalized value normalize_now at the time of mask setting. Let These pieces of information are stored in the camera display position information storage unit 223 as f_data_set and normalize_set.

Then, the mask display processing unit 243 performs setting for displaying the mask on the mask signal adding unit 113 of the image processing unit 110 using the coordinate information obtained by the mask display position calculation unit 242. With this setting, the mask display position information generation unit 244 generates mask display position information and sends it to the mask signal addition unit 113.
FIG. 10 shows an example of the generation timing of the mask signal in the horizontal direction and the generation timing in the vertical direction instructed from the mask display position information generation unit 244 to the mask signal addition unit 113.
The start point mask_h_start and the end point mask_h_end are specified as the generation timing of the mask signal in the horizontal direction, and the start point mask_v_start and the end point mask_v_end are specified as the generation timing of the mask signal in the vertical direction.
As the horizontal start point mask_h_start, x1_moniMASK (= x3_moniMASK) shown in FIG. 9 is used. As the horizontal end point mask_h_end, x2_moniMASK (= x4_moniMASK) shown in FIG. 9 is used.
As the vertical start point mask_v_start, y1_moniMASK (= y2_moniMASK) shown in FIG. 9 is used. As the vertical end point mask_v_end, y3_moniMASK (= y4_monMASK) shown in FIG. 9 is used.

These horizontal and vertical signals of the mask signal generation timing are, for example, as shown in FIG. 10, a signal that is at a high level “H” during the mask generation period and is at a low level “L” during other periods than the mask generation period. .
Based on these pieces of information, a mask display scheduled portion is set in the camera screen as shown in FIG. Note that the camera screen in this specification indicates a screen displayed on the display by the video signal output from the video signal output unit 108.

[6. Example of processing when mask is enabled]
Next, a processing example when the mask is valid will be described.
FIG. 11 shows a process for obtaining an angle per pixel when the mask is valid.
First, the mask display position calculation unit 245 performs processing for acquiring information of vertex coordinates p1, p2, p3, and p4 (FIG. 9) for pasting the mask stored in the camera display position information storage unit 223. Then, calculation is performed to correct the acquired vertex coordinates p1, p2, p3, and p4 according to the pan, tilt, and zoom states at that time.
For this calculation, the horizontal angle of view H_GAKAKU and the vertical angle of view V_GAKAKU (FIG. 11) of the image stored in the camera display position information storage unit 223 are referred to.

Then, by dividing the vertical field angle H_GAKAKU and the horizontal field angle V_GAKAKU by the camera screen size information MONI_H and MONI_V by the following formulas (7) and (8), angles H_1PIXEL_KAKU and V_1PIXEL_KAKU per pixel are obtained.
H_1PIXEL_KAKU = H_GAKAKU / MONI_H (7)
V_1PIXEL_KAKU = V_GAKAKU / MONI_V (8)

FIG. 12 shows an example of setting the pan angle, tilt angle, and zoom position when adding a mask when the mask is valid.
As shown in FIG. 12, the number of pixels moved in the horizontal and vertical directions from the mask setting with reference to the pan angle, tilt angle, zoom position information PANs degree, TILTs degree, f_data_set, and normalize_set at the time of mask setting. Calculate Here, the movement amounts in the horizontal direction and the vertical direction calculated here are referred to as pixel movement amounts.
By this calculation, the coordinates p1, p2, p3, and p4 of the mask displayed on the camera screen are obtained. p1, p2, p3, and p4 are shown as follows.
p1_moniMASK ′ (x1_moniMASK ′, y1_moniMASK ′),
p2_moniMASK ′ (x2_moniMASK ′, y2_moniMASK ′),
p3_moniMASK ′ (x3_moniMASK ′, y3_moniMASK ′),
p4_moni '(x4_moniMASK', y4_moniMASK ')

When the pan angle when the mask is valid is PANa degrees and the tilt angle is TILTa degrees, the pixel movement amounts H_IDORYO and V_IDORYO in the horizontal direction and the vertical direction can be calculated by the equations (9) and (10).
H_IDORYO = (PANa-PANs) / H_1PIXEL_KAKU (9)
V_IDORYO = (TILTa-TILTs) / V_1PIXEL_KAKU (10)

The mask coordinates p1_moniMASK ′, p3_moniMASK ′, and p1_moniMASK ′ displayed on the camera screen when the mask is valid from the following equations (11), (12), (13), and (14) using the equations (9) and (10). , P4_moniMASK ′.
x1_moniMASK ′ = x3_moniMASK ′ = x1_moniMASK−H_IDORYO (11)
x2_moniMASK ′ = x4_moniMASK ′ = x2_moniMASK−H_IDORYO (12)
y1_moniMASK ′ = y2_moniMASK ′ = y1_moniMASK−V_IDORYO (13)
y3_moniMASK ′ = y4_moniMASK ′ = y3_moniMASK−V_IDORYO (14)

  Next, in order to enlarge or reduce the mask when the zoom magnification (position) at the time of mask setting becomes the zoom magnification at the time when the mask is valid, a calculation for interpolating the mask coordinates is performed in accordance with the change of the zoom position. That is, an operation for interpolating the mask coordinates p1_moniMASK ′, p2_moniMASK ′, p3_moniMASK ′, and p4_moniMASK ′ is performed. By this calculation, the mask coordinates p1_moni MASK ″ (x1_moni MASK ″, y1_moni MASK ″), p2_moni MASK ″ (x2_moni MASK ″, y2_moni MASK ″), p3_moni MASK ″ (x3_moniSm ″ i × Mi ″ m iSkin_i_M i_Sm_i_M i_Sm '', Y4_moniMASK '').

Then, using the f value and the normalized value at the time of mask setting stored in the camera display position information storage unit 223, the current f value acquired in real time from the f value calculation unit 210, and the normalized value, the mask is used. The zoom magnification ZOOMs changed from the setting time is calculated by the following equation (15).
Here, the f value at the time of mask setting is f_data_set and the normalized value normalize_set at the time of mask setting, the current f value is f_data_now, and the current normalized value is normalize_now.
ZOOMs = (f_data_now × normalize_set) / (f_data_set × normalize_now) (15)

Therefore, the calculation of the mask coordinates is performed by the following equations (16), (17), (18), and (19).
x1_moniMASK ″ = x3_moniMASK ″ = (x1_moniMASK′−MONI_H / 2) * ZOOMs + MONI_H / 2 (16)
x1_moniMASK ″ = x3_moniMASK ″ = (x1_moniMASK′−MONI_H / 2) * ZOOMs + MONI_H / 2 (17)
y1_moniMASK ″ = y2_moniMASK ″ = (y1_moniMASK′−MONI_V / 2) * ZOOMs + MONI_V / 2 (18)
y3_moniMASK ″ = y4_moniMASK ″ = (y3_moniMASK′−MONI_V / 2) * ZOOMs + MONI_V / 2 (19)

Information necessary for generating a mask signal is sent from the mask display processing unit 243 to the mask display position information generating unit 234 using the mask coordinates calculated in this way, and the mask signal adding unit 113 adds a mask. Set up.
The mask signal adding unit 113 sets a horizontal start point mask_h_start, a horizontal end point mask_h_end, a vertical start point mask_v_start, and a horizontal end point mask_v_end, as in the mask setting. In this way, a mask adjusted to an appropriate position and size is added to the camera screen based on the video signal output from the video signal output unit 108, so that the area to be hidden cannot be seen.

  Here, as illustrated in FIG. 12, the mask display position information generation unit 234 gives the coordinate x1_moniMASK ″ as the horizontal start point mask_h_start to the mask signal addition unit 113 of the image processing unit 110. Further, the coordinate x2_moniMASK ″ is given as the horizontal end point mask_h_end. Also, the coordinate y1_moniMASK ″ is given as the vertical start point mask_v_start. Further, the coordinate y3_moniMASK ″ is given as the vertical end point mask_v_end.

  As described above, according to the imaging apparatus of this example, the mask display size and position can be changed according to changes in pan angle and tilt angle, and changes in focus lens position and zoom lens position. An object can be masked accurately and reliably. In particular, since the f value is calculated in consideration of the change in the focus lens position, an accurate zoom magnification that takes into account the change in the focus lens position can be calculated, and the correct mask position regardless of the focus lens position. And range can be set. In general, the higher the zoom magnification, the larger the difference in f value at the focus lens position on the telephoto end, and the fluctuation of the f value cannot be ignored depending on the focus lens position. Therefore, according to the surveillance camera of this example, even when a high-magnification lens is mounted, the zoom magnification can be obtained with high accuracy, and the object can be continuously masked accurately.

[7. Modified example]
It should be noted that the specific processing contents at the time of mask setting and mask validity described in the above-described embodiment are merely examples, and the present invention is not limited to this. For example, the zoom magnification at the time of changing from the f value at the time of mask setting to the current f value is calculated by a mathematical expression, and the information obtained by the calculation is used to control the display range of the mask with another algorithm. You may make it perform. Moreover, although the example which set only one mask in the camera screen was shown, you may set a some mask in one camera screen.

  Further, the calculated f value information may be used in addition to mask control. For example, the calculated f value may be displayed as a numerical value or the like on the camera screen based on the video signal output from the video signal output unit 108, so that accurate zoom magnification information may be transmitted to the user.

In the above-described embodiment, the imaging apparatus is applied to a so-called PTZ monitoring camera having all functions of pan rotation, tilt rotation, and zoom. On the other hand, for example, when a zoom lens is attached to a fixed imaging apparatus, an accurate zoom magnification may be obtained and the mask position may be set accurately.
Alternatively, the rotating table that rotates the imaging apparatus main body may be applied to one that performs only one of pan rotation and tilt rotation.

Further, the invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to easily understand the present invention, and are not necessarily limited to those having all the configurations described.
Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.
Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

DESCRIPTION OF SYMBOLS 101 ... Lens unit, 102 ... Zoom lens, 103 ... Focus lens, 104 ... Iris, 105 ... Imaging element, 106 ... Analog front end circuit (AFE circuit), 107 ... Digital / analog conversion part, 108 ... Video signal output part, DESCRIPTION OF SYMBOLS 110 ... Image processing part, 111 ... Edge level calculation part, 112 ... Signal processing part, 113 ... Mask signal addition part, 114 ... Adder, 121 ... Motor for zoom lens control, 122 ... Motor for focus lens control, 131 ... Camera Operation unit 200 ... Camera control unit 201 ... Zoom lens motor control unit 202 ... Focus lens motor control unit 203 ... Auto focus control unit 204 ... Pan / tilt / zoom information acquisition unit 210 ... f value calculation unit 211 ... Zoom lens position information acquisition unit, 212 ... Focus lens Position information acquisition unit, 213... F value calculation unit, 220... Memory, 221... Relationship table storage unit, 222... Camera information storage unit, 223 ... camera display position information storage unit, 230. , 232... Mask setting processing unit, 233. Mask effective processing unit, 234. Mask display position information generation unit, 241. Mask setting information acquisition unit, 242 and 245. Mask display position calculation unit, 243 and 246. Display processing section

Claims (8)

An imaging device equipped with a zoom lens and a focus lens as imaging lenses,
A mask control unit for acquiring setting information of a mask display position set in advance at a specific focal length;
A mask signal adding unit that adds a mask signal for covering a specific range calculated based on the setting information of the imaging position including the zoom lens and the setting information of the mask display position to the video signal;
The mask control unit has two tables with different focus positions indicating the correspondence between the focal length of the zoom lens and the position of the zoom lens, and the current focus lens position is calculated using the two tables. And calculating a zoom magnification based on the calculated current focal distance, and a range in which the mask signal adding unit adds a mask signal based on the calculated zoom magnification, An imaging device that performs processing to match the range indicated by the mask display position setting information. The imaging apparatus according to claim 1, wherein the two tables are a table that indicates a correspondence between a focal length at infinity and a zoom lens position, and a table that indicates a correspondence between a focal length at a closest distance and a zoom lens position. The imaging device according to claim 2, wherein each of the two tables is a table that is divided into at least two regions and stores a normalized value for each region. It has a turntable that can rotate pan and tilt,
The imaging device according to any one of claims 1 to 3, wherein the mask display position is information preset at a specific focal length in a specific rotation direction. An imaging method applied to an imaging device equipped with a zoom lens and a focus lens as an imaging lens,
Mask display position setting information acquisition processing for acquiring mask display position setting information set in advance at a specific focal length;
The current focal length is calculated from the current focus lens position by calculation using two tables with different focus positions, showing the correspondence between the focal length of the zoom lens and the position of the zoom lens, and the calculated focus A mask control process that calculates a zoom magnification based on the distance and matches a range in which a mask signal is added based on the calculated zoom magnification with a range indicated by the setting information of the mask display position. The imaging method according to claim 5, wherein the two tables are a table indicating a correspondence between a focal length and a zoom lens position at infinity, and a table indicating a correspondence between a focal length and a zoom lens position at the closest distance. The imaging method according to claim 6, wherein each of the two tables is a table that is divided into at least two regions and stores a normalized value for each region. The imaging device is mounted on a turntable capable of rotating a pan and a tilt,
The imaging method according to claim 5, wherein the mask display position is information preset at a specific focal length in a specific rotation direction.