JP2007159021A - Camera device and wiper control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera device and a wiper control method, wherein influences on a captured image by a wiper can be reduced at a relatively low cost without complicating a structure of the camera device. <P>SOLUTION: A wiper 60 is mounted to the camera device, and comprises a camera unit 57 having a image capturing part for capturing an image, and a control circuit 11. The control circuit 11 distinguishes whether or not contaminants adhered to a front face glass 59 are present, based on an image signal S57 obtained by the camera unit 57, and operates the wiper 60 when the contaminants are distinguished. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera device to which a wiper is attached and a wiper control method thereof.

  In a camera device installed outdoors such as a surveillance camera, water droplets, dirt, and the like adhere to the lens and the protective glass that protects the lens. Therefore, there is a surveillance camera device equipped with a wiper to remove attached water droplets and dirt.

  In a camera device to which such a wiper is attached, the wiper itself (for example, the wiper blade) prevents the subject from being photographed while the wiper is being driven. Therefore, in order to obtain a clear monitoring image, the wiper Special consideration is required for driving the mechanism.

  For example, Patent Document 1 describes a method of controlling a wiper system for wiping the surface of a windshield such as an automobile. In this method, in order to detect the state of the surface of the windshield glass, a special optical sensor is installed on the windshield glass, the light transmittance of the glass surface is detected, and the rain pattern is detected. Specifically, raindrops and cloudiness are detected by recognizing the edge of the change that occurs in the detection signal due to the raindrop falling.

JP-A-6-199208

  However, in the above method, it is indispensable to install a special sensor to detect raindrops on the glass surface. Therefore, by adopting such a technique in the camera device, the structure becomes complicated. There was a situation that the increase in cost was inevitable.

  The present invention has been made in view of the above circumstances, and is capable of reducing the influence of a wiper on a captured image at a relatively low cost without complicating the structure of the camera device. An object is to provide a control method.

  The camera device of the present invention includes an imaging unit that captures an image, a wiper that cleans a surface imaged by the imaging unit, and a surface that is cleaned by the wiper based on image data obtained by the imaging unit. A foreign matter identifying unit that identifies the presence or absence of an attached foreign matter, and a wiper control unit that operates the wiper when a foreign matter is identified by the foreign matter identifying unit.

  With this configuration, since the foreign matter identifying unit identifies the presence or absence of foreign matter based on the image data obtained by the imaging unit provided in the camera itself, there is no need to install a special sensor. There is no increase. Further, since the wiper mechanism is driven only when the adhesion of foreign matter is detected, it is possible to prevent image quality deterioration.

  In addition, the camera device of the present invention includes an imaging region control unit that controls an imaging region of the imaging unit, and the foreign object identification unit is configured to capture the imaging when the imaging region control unit changes the imaging region. The amount of movement is detected for each predetermined image area in the image data based on the difference between the plurality of image data captured by the unit, and the presence or absence of foreign matter is determined based on the difference in the amount of movement for each detected image area Is to identify.

  When the imaging region of the imaging unit is changed by adjusting the camera posture or the like, the position of the subject image in the image frame moves with the movement. On the other hand, the foreign matter attached to the glass or the like disposed in front of the imaging unit moves together with the imaging unit, so that the position of the image of the foreign matter in the image frame does not change even when the shooting direction is being changed. Therefore, with the above-described configuration, it is possible to identify the image of the subject and the foreign matter on the glass surface by distinguishing the difference in the amount of movement of the images in the frames of the plurality of images taken at different times.

  In the camera device according to the aspect of the invention, the foreign matter identifying unit may calculate a movement amount outside a predetermined movement amount range including a movement amount determined according to a control amount of an imaging region change by the imaging region control unit in the image region. A foreign matter detection amount is obtained based on at least one of the number of pixels and the number of pixels whose movement amount is substantially zero, and the presence or absence of foreign matter is identified by comparing the foreign matter detection amount with a predetermined threshold value. is there.

  With this configuration, the foreign object detection amount is obtained based on the pixel that moves differently from the change in the imaging region, so that the adhesion of the foreign object can be detected from the captured image.

  In addition, the camera device of the present invention includes a threshold update unit that updates a threshold with which the foreign object identification unit compares with the foreign object detection amount based on the foreign object detection amount after the operation of the wiper.

  With this configuration, the threshold used for foreign matter identification is updated every time the wiper is driven, so that moisture and foreign matter can be removed to a sufficient level according to the situation.

  In the camera device of the present invention, the foreign matter identifying unit detects a spatial frequency in the image based on image data obtained by imaging of the imaging unit, and recognizes the decrease in the spatial frequency as adhesion of foreign matter. Is.

  With this configuration, since it is detected that a component having a high spatial frequency included in the image is reduced due to adhesion of foreign matter to the glass or the like on the photographing surface, it is possible to recognize the attachment of foreign matter.

  In the camera device of the present invention, the imaging unit includes an automatic focus adjustment mechanism, and the foreign object identification unit is detected from an image captured immediately after being brought into focus by the operation of the automatic focus adjustment mechanism. The maximum value of the spatial frequency is held as the initial frequency value, and the difference between the spatial frequency detected from the image at each time point and the initial frequency value is used as a parameter for determining the adhesion of foreign matter.

  With this configuration, the spatial frequency of the image that is taken immediately after the in-focus state, which is considered to be the maximum value of the spatial frequency, is obtained as the initial value by holding the automatic focus adjustment mechanism. By comparing the spatial frequency in the obtained image with the initial frequency value, the presence or absence of foreign matter can be identified.

  The wiper control method of the present invention includes the steps of capturing an image with an imaging unit, identifying the presence or absence of foreign matter attached to the surface to be cleaned by the wiper based on the image data obtained by the imaging unit, And operating the wiper based on a foreign object identification result.

  With this method, since the foreign matter identifying unit identifies the presence or absence of foreign matter based on the image data obtained by the imaging unit provided in the camera itself, it is not necessary to install a special sensor, thereby reducing the cost of the camera device. There is no increase. Further, since the wiper mechanism is driven only when the adhesion of foreign matter is detected, it is possible to prevent image quality deterioration.

  The present invention provides a wiper control program that causes a computer to execute the steps recited in claim 7.

  With this program, the foreign matter identifying unit identifies the presence or absence of foreign matter based on the image data obtained by the imaging unit provided in the camera itself, so there is no need to install a special sensor. There is no increase. Further, since the wiper mechanism is driven only when the adhesion of foreign matter is detected, it is possible to prevent image quality deterioration.

  According to the present invention, it is possible to provide a camera device and a wiper control method capable of reducing the influence of a wiper on a captured image at a relatively low cost without complicating the structure of the camera device. In addition, since no special sensor is installed, the failure probability is not increased.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of a main part related to the camera apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the camera device according to the present embodiment includes a control circuit 11, a rotary base fixing unit 50, a rotary base movable unit 51, a gear 52, a pan drive motor 53, a gear 54, and a magnet 55. The magnetic sensor 56, the camera unit 57, the tilt drive motor 58, the front glass 59, the wiper 60, the wiper drive motor 61, the connecting rod 62, the magnet 63, the magnetic sensor 64, the support frame 65, and the like. 66.

  The camera unit 57 functions as an example of an imaging unit, and has an imaging element such as a two-dimensional CCD image sensor therein, and can photograph an arbitrary subject located in front. In front of the camera unit 57 in the shooting direction, a transparent front glass 59 is installed to protect the internal image sensor and optical system from dirt and moisture.

  In addition, if foreign matter such as dirt or water droplets adheres to the front glass 59, the photographing of the camera unit 57 is hindered. Therefore, a wiper 60 is provided to wipe off dirt and water droplets on the front glass 59. The wiper 60 is connected to a wiper drive motor 61 via a connecting rod 62. The connecting rod 62 converts the rotational motion of the wiper drive motor 61 into a linear motion and transmits the driving force to the wiper 60. Therefore, by driving the wiper drive motor 61, dirt and water droplets on the front glass 59 can be wiped off with the wiper 60.

  The camera unit 57 is supported by support frames 65 and 66 on both sides. The support frames 65 and 66 support the camera unit 57 so that the camera unit 57 can swing around a predetermined support shaft. Therefore, the direction of the camera unit 57 can be changed in the arrow A1 direction (tilt direction). Further, the drive shaft of the tilt drive motor 58 installed on the support frame 65 is connected to the camera unit 57. By driving the tilt drive motor 58, the direction of the camera unit 57 is changed to the arrow A1 direction. Can do.

  The support frames 65 and 66 are fixed on the turntable movable part 51 formed in a disk shape. Further, the turntable movable part 51 is disposed above the turntable fixing part 50 and is supported by the turntable fixing part 50 in a state of being rotatable in the arrow A2 direction (pan direction). A pan drive motor 53 is installed on the side of the turntable fixing unit 50. A gear 54 is mounted on the drive shaft of the pan drive motor 53, and this gear 54 is connected to a gear 52 mounted on the rotary base movable unit 51.

  Therefore, when the pan drive motor 53 is driven, the rotary base movable unit 51 is driven via the gear 54 and the gear 52, and rotates in the direction of the arrow A2. When the turntable movable unit 51 rotates, the direction of the camera unit 57 also rotates in the direction of the arrow A2.

  In order to detect the position of the turntable movable unit 51 in the rotation direction, a magnet 55 is mounted at a predetermined position on the peripheral surface of the turntable movable unit 51. A magnetic sensor 56 is mounted on the peripheral surface of the turntable fixing unit 50 at a position that can face the magnet 55. In order to detect the position of the camera unit 57 in the tilt direction, a magnet 63 is mounted on the side surface of the camera unit 57. A magnetic sensor 64 is mounted on the support frame 65 at a position that can face the magnet 63.

  When the camera device is actually used, an operation terminal 22 including an image display unit 21 is used. The image display unit 21 is used for displaying a real-time video or the like taken by the camera unit 57. Further, by inputting a predetermined command from the operation terminal 22, for example, an operation instruction regarding the shooting direction of the camera unit 57 can be given.

  Next, the wiper control method of this embodiment will be described. In the camera device of this embodiment, the control circuit 11 detects the adhesion of foreign matter to the front glass 59 based on the video actually taken by the camera unit 57 itself, and operates the wiper 60 when this foreign matter is identified. It is something to be made.

  FIG. 2 is a block diagram showing a schematic configuration of the control circuit of the camera apparatus according to the first embodiment of the present invention.

  As shown in FIG. 2, the control circuit 11 functions as an example of a foreign substance identification unit, and includes a wiper drive circuit 33, an operation count generation circuit 320, a command decoder 230, a pan drive circuit 380, and an image timing generation circuit 70. A target image extraction circuit 71, a luminance change detection circuit 72, an image memory 73, an image memory 74, a motion vector extraction circuit 75, a timing signal output circuit 76, a maximum vector holding circuit 77, and a detection region determination circuit. 78, a target pixel number calculation circuit 79, a stop pixel number calculation circuit 80, a prediction vector calculation circuit 81, an abnormal pixel number calculation circuit 82, a first ratio calculation circuit 83, a second ratio calculation circuit 84, Third ratio calculation circuit 85, first threshold holding circuit 86, second threshold holding circuit 87, third threshold holding circuit 88, wiper operation information circuit 89, threshold update And a road 90. The control circuit 11 is mainly composed of a processor that operates according to a wiper control program, for example.

  The command decoder 230 is a circuit that interprets the content of an instruction input from the operation terminal 22 and gives an operation instruction to each unit of the control circuit 11. The operation frequency generation circuit 320 is a circuit that receives the instruction from the command decoder 230 and generates the wiper operation frequency. The wiper drive circuit 33 is a circuit for operating the wiper as many times as the number of wiper operations generated by the operation number generation circuit 320. The pan driving circuit 380 functions as an example of an imaging region control unit, and is a circuit that drives the pan driving motor 53 based on the rotation direction information and the rotation amount information input from the command decoder 230.

  The image timing generation circuit 70 is a circuit that generates the update timing of the image memory based on the frame update timing of the image signal S57 output from the camera unit 57. The target image extraction circuit 71 is a circuit that extracts image information of a predetermined image area from images taken by the camera unit 57. The luminance change detection circuit 72 is a circuit that calculates a luminance change between adjacent pixels for each pixel in the image region extracted by the target image extraction circuit 71.

  The image memory 73 is a memory for storing each piece of pixel information processed by the luminance change detection circuit 72 or the target image extraction circuit 71. The image memory 74 is a memory for reading and storing image information delayed in time by a predetermined frame from the image memory 73 in accordance with the timing of the signal output from the image timing generation circuit 70.

  The motion vector extraction circuit 75 compares the contents of the image memory 73 holding the image information having different shooting times with the contents of the image memory 74 to thereby obtain the motion vector (movement direction and movement amount) for each target pixel. Or a moving speed).

  The timing signal output circuit 76 is a circuit that outputs a timing signal each time the target image range is rotated by an angle corresponding to one screen. The maximum vector holding circuit 77 is a circuit that holds the maximum vector amount as an extraction vector for each target pixel and clears the holding value at the timing of the timing signal output circuit 76.

  The detection area determination circuit 78 is a circuit that excludes the vector data of a pixel row from the target of foreign object detection when the pixel row corresponding to the rotation direction among the target pixels does not include a vector in a predetermined range.

  The target pixel number calculation circuit 79 is a circuit that calculates the total number of pixels that are the target of foreign object detection output as a result from the detection region determination circuit 78. The stop pixel number calculation circuit 80 is a circuit that calculates the number of pixels having no amount of motion among the pixels that are subject to foreign object detection by the detection region determination circuit 78.

  The prediction vector calculation circuit 81 is a circuit that calculates a target value of the motion vector based on the movement amount information input from the command decoder 230 and the shooting angle of the camera, and calculates a prediction vector range in consideration of the detection error. The abnormal pixel number calculation circuit 82 is a circuit that calculates the number of pixels (abnormal pixels) in which a vector outside the range of the prediction vector is detected among the pixels that are subject to foreign object detection by the detection region determination circuit 78.

  The first ratio calculation circuit 83 is a circuit that calculates a value obtained by dividing the number of stop pixels by the number of target pixels. The second ratio calculation circuit 84 is a circuit that calculates a value obtained by dividing the number of abnormal pixels by the number of target pixels. The third ratio calculation circuit 85 is a circuit that calculates a value obtained by dividing the number of stop pixels by the number of target pixels minus the number of abnormal pixels.

  The first threshold value holding circuit 86 is a circuit for holding a first threshold value used for determining the wiper operation based on the output of the first ratio calculation circuit 83. The second threshold value holding circuit 87 is a circuit for holding a second threshold value used to determine the wiper operation based on the output of the second ratio calculation circuit 84. The third threshold value holding circuit 88 is a circuit for holding a third threshold value used for determining the wiper operation based on the output of the third ratio calculation circuit 85.

  The wiper operation information circuit 89 includes a value output from any one of the first ratio calculation circuit 83, the second ratio calculation circuit 84, and the third ratio calculation circuit 85, a first threshold holding circuit 86, and a second threshold holding circuit 87. The difference from the threshold output by any one of the third threshold holding circuits 88 is calculated, and the result is output as wiper operation information. The wiper operation information circuit 89 selects any one of the first ratio calculation circuit 83, the second ratio calculation circuit 84, the third ratio calculation circuit 85, the first threshold holding circuit 86, the second threshold holding circuit 87, and the third threshold holding circuit 88. Whether to select is determined according to determination means switching information input from the command decoder 230.

  The threshold update circuit 90 compares the values output by the first ratio calculation circuit 83, the second ratio calculation circuit 84, and the third ratio calculation circuit 85 at the timing output by the timing signal output circuit 76 immediately after the wiper operation. This is a circuit that assigns a value larger by a predetermined value as a threshold value of the first threshold value holding circuit 86, the second threshold value holding circuit 87, and the third threshold value holding circuit 88.

  Next, the operation of the control circuit 11 shown in FIG. 2 will be described below. By giving predetermined instruction information from the operation terminal 22 to the command decoder 230, the operation of each part of the circuit is controlled. For example, when manual operation instruction information is generated, the command decoder 230 outputs direction information S23a and rotation amount information S23b necessary for manual operation control. The pan driving circuit 380 drives the pan driving motor 53 according to these pieces of information. The driving force of the pan drive motor 53 is transmitted to the rotary base movable unit 51 via the gear 54 and the gear 52, and the rotary base movable unit 51 rotates. Along with this, the camera unit 57 disposed on the turntable movable unit 51 also rotates in the arrow A2 direction, and the photographing direction changes. At this time, when a real-time image photographed by the camera unit 57 is viewed on the image display unit 21, the displayed image moves in the left-right direction.

  When the wiper operation instruction is output, the operation number generation circuit 320 controls to drive the wiper 60 according to the information output from the wiper operation information circuit 89.

  Next, an operation for detecting the presence of foreign matter or water droplets attached to the surface of the front glass 59 will be described.

  The target image extraction circuit 71 limits the range of the image used for extracting the motion vector on the image to, for example, the range of a predetermined area. That is, the range is limited in order to reduce the amount of data to be processed when extracting motion vectors.

  The luminance change detection circuit 72 performs image processing so that the luminance change portion of the subject is emphasized as preprocessing in order to facilitate the extraction of motion vectors.

  The motion vector extraction circuit 75 detects a motion vector for each pixel by comparing two images having different shooting times.

  FIG. 3 is a diagram illustrating an example of a captured image when the imaging region is changing. When the direction of the camera unit 57 is rotated by driving the pan drive motor 53, for example, the subject in the captured image moves in the direction opposite to the turning direction of the camera unit 57 as shown in FIG. . Accordingly, when two images taken at different points in time while the camera unit 57 is turning are compared, movement on the image is detected for each pixel. Therefore, the motion vector extraction circuit 75 recognizes the movement amount and movement direction detected for each pixel as a motion vector. However, since foreign matters, water droplets, and the like attached to the surface of the front glass 59 rotate together with the camera unit 57, movement of pixels corresponding to the foreign matters, water droplets, and the like on the image is not detected.

  The maximum vector holding circuit 77 performs a peak hold operation on instantaneous values of motion vectors sequentially output by the motion vector extraction circuit 75 while the camera unit 57 rotates by a predetermined amount. That is, the maximum value among the instantaneous values of the motion vector input during the predetermined detection period is held and output as a result.

  The detection area determination circuit 78 considers the area as a non-luminance change area and excludes the area from the foreign object detection area when the motion vector amount cannot be detected for all the pixel columns in the rotation direction of the camera unit 57. To do.

  The following three types of parameters P1 to P3 can be used as parameters representing the actual foreign matter detection amount.

P1 = N0 / Nt
P2 = Nx / Nt
P3 = N0 / (Nt−Nx)

  Here, N0 indicates the number of pixels in which no motion is detected, that is, the number of stop pixels. Nt indicates the total number of pixels in the detection area. Further, Nx indicates the number of pixels having a vector amount outside the predetermined vector amount range including the vector amount of the prediction vector, that is, the number of abnormal pixels. Here, the prediction vector is a photographing time difference between two images to be compared. The motion vector calculated | required from the rotation amount of the camera unit 57 in the meantime is shown.

  In the control circuit 11 shown in FIG. 2, the parameter P1 is calculated by the first ratio calculation circuit 83, the parameter P2 is calculated by the second ratio calculation circuit 84, and the parameter P3 is calculated by the third ratio calculation circuit 85.

  Actually, as to which of the three types of parameters P1 to P3 is to be used, an optimum parameter may be selected according to rain, snow, dust, or the like that may actually adhere to the front glass 59. . In the control circuit 11 shown in FIG. 2, the wiper operation information circuit 89 selectively uses one of the three types of parameters P1 to P3 according to the determination switching signal S23c output from the command decoder 230 in accordance with an instruction from the operation terminal 22. To do.

  For example, when the parameter P1 is selected by the determination switching signal S23c, the wiper operation information circuit 89 outputs the foreign matter detection amount (P1) output by the first ratio calculation circuit 83 and the first threshold holding circuit 86. A value corresponding to the threshold value is output to the operation count generation circuit 320. Specifically, a value representing (foreign object detection amount−threshold) is output. Similarly, when the parameter P2 is selected, the wiper operation information circuit 89 responds to the foreign object detection amount (P2) output from the second ratio calculation circuit 84 and the threshold output from the second threshold holding circuit 87. When the parameter P3 is selected, the wiper operation information circuit 89 outputs the detected foreign matter (P3) output by the third ratio calculation circuit 85 and the third threshold value holding. A value corresponding to the threshold output from the circuit 88 is output to the operation number generation circuit 320.

  The operation number generation circuit 320 determines the number of wiper operations and the operation frequency according to the value output from the wiper operation information circuit 89. As a specific example, if the value output from the wiper operation information circuit 89 is a positive number, the wiper operation is turned on. If the value is zero or a negative number, the wiper operation is turned off. In addition, the number of operations and the frequency are increased in proportion to the positive number.

  The wiper drive circuit 33 functions as an example of a wiper control unit, and drives the wiper drive motor 61 and moves the wiper 60 in accordance with a signal output from the operation number generation circuit 320. Since the wiper 60 wipes the surface of the front glass 59, foreign matter that hinders subject shooting is removed, and a good image is obtained.

  Based on the foreign object detection amount immediately after the wiper operation is completed, the threshold update circuit 90 sets a value larger than the predetermined value as a new threshold (eg, a value obtained by adding a constant value or a value multiplied by 1.1). The thresholds held by the first threshold holding circuit 86, the second threshold holding circuit 87, and the third threshold holding circuit 88 are reset. This makes it possible to use a threshold value optimized according to the shooting environment, and to perform an efficient wiper operation.

  According to the camera device according to the first embodiment of the present invention, the presence or absence of a foreign object is identified based on the motion vector of the image data obtained by the imaging unit provided in the camera itself. Since there is no need to install a sensor, the cost of the camera device is not increased, and the failure probability is not increased. Further, since the wiper mechanism is driven only when the adhesion of foreign matter is detected, it is possible to prevent image quality deterioration.

(Second Embodiment)
FIG. 4 is a block diagram showing a schematic configuration of a control circuit of the camera apparatus according to the second embodiment of the present invention. The control circuit 12 shown in FIG. 4 is applied instead of the control circuit 11 in the camera apparatus shown in FIG. 4 that are the same as those in FIGS. 1 and 2 described in the first embodiment are denoted by the same reference numerals.

  Note that the camera unit 57 applied to the present embodiment has a function of a single automatic focus adjustment mechanism (hereinafter referred to as single AF).

  As shown in FIG. 4, the control circuit 12 of the camera device of the present embodiment includes a wiper drive circuit 33, an operation count generation circuit 321, a command decoder 231, a pan drive circuit 380, a target image extraction circuit 71, A high-frequency component extraction circuit 101, an initial value determination circuit 102, a focus degree change calculation circuit 103, a threshold value holding circuit 104, and a wiper operation information circuit 105 are provided.

  The command decoder 231 interprets the content of the instruction input from the operation terminal 22 and gives an operation instruction to each part of the circuit. The operation frequency generation circuit 321 is a circuit that receives the instruction from the command decoder 230 and generates the wiper operation frequency. The wiper drive circuit 33 is a circuit that drives the wiper 60 by the number of times that the operation number generation circuit 32 outputs. The pan driving circuit 380 is a circuit that drives the pan driving motor 53 based on the rotation direction information S23a and the rotation amount information S23b input from the command decoder 230.

  The target image extraction circuit 71 is a circuit that performs a process of extracting only image information of a predetermined specific image area from a video obtained by photographing with the camera unit 57. The high frequency component extraction circuit 101 is a circuit that obtains the high frequency component level of the target image area and outputs the result as a focus degree value.

  The initial value determination circuit 102 assigns the value of the high-frequency component extraction circuit 101 as the initial focus degree value at the timing when the autofocus operation of the camera unit 57 ends after the single AF instruction S23d from the command decoder 231 is input. Circuit. The focus degree change calculation circuit 103 is a circuit for outputting the difference between the value of the high frequency component extraction circuit 101 and the value of the initial value determination circuit 102 as a focus degree deterioration value.

  The threshold value holding circuit 104 is a circuit for holding a threshold value of a focus degree deterioration value for determining the wiper operation. The wiper operation information circuit 105 is a circuit for outputting the difference between the value of the focus degree change calculation circuit 103 and the value of the threshold value holding circuit 104 to the operation number generation circuit 321.

  Next, the operation of the control circuit 12 shown in FIG. 4 will be described below.

  The command decoder 231 controls the operation of each unit according to the instruction information output from the operation terminal 22. When the command decoder 231 outputs direction information and rotation amount information as manual operation instruction information, the pan driving circuit 380 drives the pan driving motor 53. Since the driving force of the pan drive motor 53 is transmitted to the rotary base movable unit 51 via the gear 54 and the gear 52, the rotary base movable unit 51 rotates and the camera unit 57 installed on the rotary base movable unit 51 rotates. The direction changes in the direction of arrow A2. At this time, when a real-time image taken by the camera unit 57 is viewed on the image display unit 21, the position of the subject on the displayed image moves in the left-right direction as the camera unit 57 rotates. When a wiper operation instruction is output from the command decoder 231, the operation count generation circuit 321 drives the wiper 60 according to the output information of the wiper operation information circuit 105.

  Next, an operation for detecting the presence of foreign matter or water droplets attached to the surface of the front glass 59 will be described. FIG. 5 is a diagram illustrating an example of a captured image when a foreign object is adhered, and FIG. 6 is a side view illustrating the front glass when the foreign object is adhered.

  The target image extraction circuit 71 receives the image signal S57 output from the camera unit 57, and extracts a specific image region as a motion vector extraction target from this image. Accordingly, the image data from which motion vectors are to be extracted is limited to only a partial area in the image of each frame.

  The high frequency component extraction circuit 101 processes the image data of the image area extracted by the target image extraction circuit 71 and detects the spatial frequency therein. Then, the level of the high frequency component of the spatial frequency is output as the focus degree value.

  When the single AF command S23d is output from the command decoder 231 in this state, the autofocus function in the camera unit 57 is activated, and the AF operation ends after a focused image is obtained.

  At the end timing of the AF operation, the value output from the high frequency component extraction circuit 101 is input to the initial value determination circuit 102 and assigned as an initial value.

  In an in-focus image, the image of each part of the subject is clearly shown in detail, so that the spatial frequency detected from this image includes a high-frequency component. The value assigned as an initial value to the initial value determination circuit 102 represents the level of the high frequency component in the focused state.

  On the other hand, when rain or snow adheres to the surface of the front glass 59 as a foreign object as time passes, for example, as shown by the hatched portion in FIG. 6, an image photographed by the camera unit 57 is shown in FIG. As described above, the image is blurred due to the influence of light refraction and the like, so the level of the high frequency component of the spatial frequency included in this image is lowered. That is, the focus degree value output from the high frequency component extraction circuit 101 decreases.

  The focus degree change calculation circuit 103 calculates a change in the focus degree value based on the focus degree value output from the high frequency component extraction circuit 101 and the initial value output from the initial value determination circuit 102. As a specific example, the focus degree change calculation circuit 103 outputs (initial value−focus degree value) as a change amount. Therefore, if foreign matter or the like adheres to the surface of the front glass 59, the amount of change output from the focus degree change calculation circuit 103 increases.

  The wiper operation information circuit 105 uses the difference between the amount of change in focus output from the focus degree change calculation circuit 103 and the threshold held in the threshold holding circuit 104 as wiper operation information to the operation count generation circuit 321. Output.

  Since the frequency band of the spatial frequency extracted from the image as the high frequency component by the high frequency component extraction circuit 101 affects the foreign object detection characteristics, it is desirable to assign an optimal frequency band according to the type of foreign object to be detected. That is, since foreign matters such as rain, snow, and dust have greatly different sizes and characteristics, differences in the spatial frequency characteristics in the image accompanying the attachment of the foreign matter also appear according to the type of foreign matter. Therefore, if the frequency band can be selectively switched according to the type of foreign matter to be detected, the adhesion of foreign matter can be detected more effectively.

  The operation frequency generation circuit 321 determines the wiper operation frequency and the operation frequency according to the value output from the wiper operation information circuit 105. For example, if the value is a positive number, the wiper operation is turned on. If the value is zero or a negative number, the wiper operation is turned off. Further, the number of operations and the frequency may be increased in proportion to the size of the positive number.

  The wiper drive circuit 33 drives the wiper 60 by driving the wiper drive motor 61 according to the output of the operation number generation circuit 321. When the wiper 60 wipes the surface of the front glass 59, the foreign matter that hinders subject shooting is removed, and a good image is obtained.

  According to the camera device according to the second embodiment of the present invention, the presence or absence of a foreign object is identified based on the spatial frequency of image data obtained by an imaging unit provided in the camera itself. Since it is not necessary to install a sensor, the cost of the camera device is not increased, and the failure probability is not increased. Further, since the wiper mechanism is driven only when the adhesion of foreign matter is detected, it is possible to prevent image quality deterioration.

  In the first and second embodiments, the pan driving circuit that drives the camera unit in the pan direction has been described as an example of the circuit that controls the imaging region. A drive circuit or a zoom control circuit for controlling the zoom of the camera unit may be used.

  Moreover, in the said 1st and 2nd embodiment, although the example of the wiper which wipes off a glass surface directly was shown as a foreign material removal method, another foreign material removal methods, such as the method of spraying gas and the method of evaporating a water | moisture content, were shown. It may be used.

  The camera device and the wiper control method of the present invention have an effect capable of reducing the influence on the captured image by the wiper relatively inexpensively without complicating the structure of the camera device. Useful.

1 is a block diagram showing a configuration example of main parts related to a camera device according to a first embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a control circuit of a camera device according to a first embodiment of the present invention. The figure which shows the example of the captured image when the imaging area is changing The block diagram which shows schematic structure of the control circuit of the camera apparatus which concerns on the 2nd Embodiment of this invention. The figure which shows the example of the captured image when the foreign material has adhered Side view showing the front glass when a foreign object is attached

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Image display part 22 Operation terminal 230,231 Command decoder 320,321 Operation frequency generation circuit 33 Wiper drive circuit 380 Pan drive circuit 50 Turntable fixed part 51 Turntable movable part 52 Gear 53 Pan drive motor 54 Gear 55 Magnet 56 Magnetic sensor 57 camera unit 58 tilt drive motor 59 front glass 60 wiper 61 wiper drive motor 62 connecting rod 63 magnet 64 magnetic sensor 65, 66 support frame 70 image timing generation circuit 71 target image extraction circuit 72 luminance change detection circuit 73, 74 image memory 75 Motion vector extraction circuit 76 Timing signal output circuit 77 Maximum vector holding circuit 78 Detection region determination circuit 79 Target pixel number calculation circuit 80 Stopped pixel number calculation circuit 81 Predictive vector calculation circuit 82 Abnormal pixel number calculation circuit 83 1 ratio calculation circuit 84 second ratio calculation circuit 85 third ratio calculation circuit 86 first threshold holding circuit 87 second threshold holding circuit 88 third threshold holding circuit 89 wiper operation information circuit 90 threshold update circuit 101 high frequency component extraction circuit 102 initial stage Value determining circuit 103 In-focus degree change calculating circuit 104 Threshold holding circuit 105 Wiper operation information circuit

Claims (8)

An imaging unit that captures an image;
A wiper for cleaning a surface imaged by the imaging unit;
A foreign matter identification unit for identifying the presence or absence of foreign matter attached to the surface to be cleaned by the wiper based on the image data obtained by the imaging unit;
And a wiper control unit that operates the wiper when a foreign object is identified by the foreign object identification unit. The camera device according to claim 1,
An imaging region control unit for controlling an imaging region of the imaging unit;
The foreign matter identifying unit is configured to detect, for each predetermined image region in the image data, based on a difference between a plurality of image data captured by the imaging unit when the imaging region control unit is changing the imaging region. A camera device that detects a moving amount and identifies the presence or absence of a foreign substance based on the detected moving amount difference for each image area. The camera device according to claim 2,
In the image area, the foreign matter identifying unit has a substantial number of pixels having a movement amount outside a predetermined movement amount range including a movement amount determined according to a control amount of an imaging region change by the imaging region control unit and a movement amount. A camera device that obtains a foreign matter detection amount based on at least one of zero pixels and compares the foreign matter detection amount with a predetermined threshold value to identify the presence or absence of foreign matter. The camera device according to claim 3,
The camera apparatus provided with the threshold value update part which updates the threshold value with which the said foreign material identification part compares with the said foreign material detection amount based on the said foreign material detection amount after the operation | movement of the said wiper. The camera device according to claim 1,
The said foreign material identification part is a camera apparatus which detects the spatial frequency in an image based on the image data obtained by the imaging of the said imaging part, and recognizes the fall of the said spatial frequency as adhesion of a foreign material. The camera device according to claim 5,
The imaging unit has an automatic focus adjustment mechanism,
The foreign object identification unit retains the maximum value of the spatial frequency detected from an image captured immediately after being brought into focus by the operation of the automatic focus adjustment mechanism as an initial frequency value, and is detected from the image at each time point. A camera device that uses a difference between a spatial frequency and a frequency initial value as a parameter for determining foreign matter adhesion. Capturing an image with the imaging unit;
Identifying the presence or absence of foreign matter adhering to the surface cleaned by the wiper based on the image data obtained by the imaging unit;
A wiper control method comprising: operating the wiper based on the identification result of the foreign matter.   A wiper control program for causing a computer to execute each step according to claim 7.

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