JP6041752B2 - Camera focus adjustment device - Google Patents

Description

  The present invention relates to a camera focus adjustment apparatus for adjusting the focus of the camera in advance before assembling a camera with an image pickup device of CCD or CMOS and a focus adjustment mechanism of a manual type into an image processing apparatus or the like. .

  2. Description of the Related Art In recent years, for example, an image processing apparatus that captures an object to be photographed at a predetermined position and processes the photographed image is known. Or, a camera that is a CMOS is generally assembled. Since the camera mounting position is determined with respect to the shooting position of the subject, the focus adjustment mechanism manually prepares an inexpensive camera and manually focuses on the position corresponding to the shooting distance in advance. The manufacturing cost of the apparatus can be reduced by assembling what has been stored.

  By the way, in a camera with a manual focus adjustment mechanism, it is not known whether the focal position is shifted to the back side or the near side with respect to the object to be photographed. It is necessary to actually shoot the reference object and focus on the focus adjustment mechanism while looking at the captured image. In particular, when mass-producing the image processing apparatus as described above, the camera is focused on each image processing apparatus to be manufactured. It was necessary and complicated to work.

  In order to avoid this, for example, it is conceivable that each camera is focused in advance by using a camera focus adjustment device such as that disclosed in Patent Document 1.

In Patent Document 1, a differential value f _n (x _n ) ′ between adjacent pixels from a luminance value f _n (x _n ) of each pixel x _n (n = 1, 2,...) Arranged in a line of a captured image. Then, a frequency distribution (histogram) for each predetermined class in the absolute value of each differential value f _n (x _n ) ′ is calculated. A value obtained by multiplying the calculated frequency of each class by the value of each class is defined as a focus evaluation value P, and the calculated focus evaluation value P is a focus evaluation when the focus of the camera is in the focus range. The focus adjustment mechanism of the camera is adjusted so as to approach the value P ′.

JP 2008-83267 A (paragraphs 0013 to 0042, FIGS. 1 to 9)

  However, in Patent Document 1, when calculating the frequency distribution, the data obtained from each pixel of the captured image is not used as it is, but the differential calculation is sequentially performed between adjacent pixels, and then the frequency distribution is calculated. It is carried out. Therefore, the number of calculation processes of the apparatus increases, and a large load is applied to the calculation process acquisition part, the calculation speed is slowed down, and as a result, the focusing work may take a lot of time.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a camera focus adjustment device in which the arithmetic processing of the device is fast and the time required for the focusing operation of each camera is short. is there.

  In order to achieve the above object, the differential operation is not performed between adjacent pixels of the captured image.

  Specifically, the following solution was taken for a camera focus adjustment device for adjusting the focus of a camera whose imaging element is a CCD or CMOS and whose lens focus adjustment mechanism is a manual type.

That is, according to the first aspect of the present invention, a fixture for detachably fixing the camera, a to-be-photographed object having a black and white chart surface disposed opposite to the camera fixed to the fixture, and detachable from the camera. And a control means for outputting an operation signal to the camera and photographing the object to be photographed, the control means selecting any one of R value, B value and G value as color intensity, When the color intensity of each pixel in the photographed image taken by the camera is X ₁ <X ₂ (X ₁ and X ₂ are predetermined integers), those in the range of 0 to X ₁ belong to the black side region. And a sorting unit that classifies each pixel in the range of X _{2 to} 255 as belonging to the white side region, and the white color of each pixel sorted into the white side region by the sorting unit from the frequency distribution of the color intensity of each pixel in the captured image Sorted into side average color intensity Y and black side area The ratio calculation unit for calculating the ratio H = Z / Y of the white side average color intensity Y and the black side average color intensity Z and the ratio H A lens for storing the focal point of the camera based on the position of the focal point of the camera stored in the storage unit corresponding to the ratio H, and a storage unit storing the corresponding focal point of the camera And a lens movement amount calculation unit for calculating the movement amount D.

  According to a second invention, in the first invention, the black and white chart surface is provided at each of a maximum position and a minimum position of a focusing range of the camera, and the ratio calculation unit is configured to generate a ratio H for each black and white chart surface. And the lens movement amount calculation unit is configured to calculate the lens movement direction of the focus adjusting mechanism by comparing the ratios H calculated by the ratio calculation unit.

  According to a third invention, in the second invention, there is provided drive means for detachably attaching to the focus adjustment mechanism, driving the focus adjustment mechanism to move the lens, and the control means is connected to the drive means. And an operation signal is output to the driving means based on the lens movement amount D calculated by the lens movement amount calculation unit and the lens movement direction, and the focus of the camera is moved to the in-focus range. .

  In the first invention, instead of processing a differential distribution of adjacent pixels as in Patent Document 1 as a frequency distribution, the data of each pixel of the captured image is processed as it is as a frequency distribution. Compared with an apparatus such as that disclosed in Patent Document 1, the time required for focusing can be shortened.

  In the second invention, since the moving direction of the lens for focusing the camera is known, it is avoided that the focusing mechanism is operated a plurality of times with the wrong lens moving direction when the camera is focused. And the time required for the focusing operation can be further shortened.

  In the third invention, since the camera can be automatically focused, the focusing operation is simplified and the burden on the operator can be reduced.

It is a schematic block diagram of the camera focus adjustment apparatus which concerns on embodiment of this invention. (A) is an image obtained by photographing an object in the focusing range of the camera, and (b) is a pixel color in a photographed image of a black and white chart surface arranged at a position corresponding to the minimum depth of (a). (C) shows a graph of intensity distribution of pixels in a captured image of a black and white chart surface arranged at a position corresponding to the maximum depth of (a). (A) is a black and white chart arranged at a position corresponding to the minimum depth of (a), (b) is an image obtained by photographing a subject whose only black and white chart surface of the minimum depth is within the focusing range of the camera. A graph of the color intensity distribution of pixels in the captured image of the surface, (c) shows a graph of the color intensity distribution of pixels in the captured image of the black and white chart surface arranged at the position corresponding to the maximum depth of (a). (A) is an image obtained by photographing a subject whose only black-and-white chart surface of the maximum depth is within the focusing range of the camera, and (b) is a black-and-white chart arranged at a position corresponding to the minimum depth of (a). A graph of the color intensity distribution of pixels in the captured image of the surface, (c) shows a graph of the color intensity distribution of pixels in the captured image of the black and white chart surface arranged at the position corresponding to the maximum depth of (a).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  FIG. 1 shows a camera focus adjusting apparatus 1 according to an embodiment of the present invention. The camera focus adjusting apparatus 1 is configured to mount the camera 10 in which the image pickup device 10b is a CMOS and the focus adjusting mechanism 10a for adjusting the focus by moving the position of the lens 10c is a manual type to an image processing apparatus (not shown). This is for adjusting the focus of the camera 10 in advance.

  The camera focus adjustment device 1 includes a fixture 2 that detachably fixes the camera 10, a subject 3 that is disposed facing the camera 10 that is fixed to the fixture 2, and a focus adjustment mechanism 10a. A drive device (drive means) 4 that is detachably attached and drives the focus adjustment mechanism 10 a, a control unit (control means) 5 connected to the camera 10 and the drive device 4, and a connection to the control unit 5 The monitor 6 is provided.

  The subject 3 includes a grid-like black and white chart surface 3 a, 3 b (see FIGS. 2 to 4), and the black and white chart surface 3 a is the minimum position of the focusing range of the camera 10 fixed to the fixture 2. On the other hand, the black-and-white chart surface 3b is arranged at the maximum position in the focusing range of the camera 10 fixed to the fixture 2. Note that the black and white chart surface shown in the upper half of FIGS. 2A to 4A is used for focusing work of a camera having a different focusing range, and is used in this embodiment. do not do.

  The control unit 5 outputs an operation signal to the camera 10 to photograph the object to be imaged 3, and a sorting unit 5a and a ratio calculation unit 5b that perform calculation processing for each of the black and white chart surfaces 3a and 3b. It has.

  The sorting unit 5a selects the R value among the R value, the B value, and the G value as the color intensity on the black and white chart surfaces 3a and 3b, and the color of each pixel in a predetermined region of the photographed image taken by the camera 10 When the intensity is in the range of 0 to 65 and belongs to the black side region, the range of 110 to 255 is classified as belonging to the white side region.

In the present embodiment, the color intensity of each pixel in the range of 0 to 65 belongs to the black side region, and the range of 110 to 255 belongs to the white side region. can be set arbitrarily, X ₁ <when X ₂ where (X _1, X ₂ are predetermined integer) was, as belonging to a range of 0 to X ₁ on the black side region, the X ₂ to 255 Those in the range can be classified as belonging to the white side region.

As shown in FIGS. 2 (b) to 4 (b), the ratio calculation unit 5b is arranged on the black-and-white chart surface 3a from the frequency distribution of the color intensity of each pixel in a predetermined region of the photographed image. Thus, the white side average color intensity Y _{1 of} the pixels sorted into the white side area and the black side average color intensity Z _{1 of} the pixels sorted into the black side area are respectively calculated.

In addition, the ratio calculation unit 5b, as with the black-and-white chart surface 3a, on the black-and-white chart surface 3b, as shown in FIGS. 2 (c) to 4 (c), for each pixel in a predetermined region of the photographed image. From the frequency distribution of the color intensity, the white side average color intensity Y _{2 of} the pixels sorted into the white side area by the sorting unit 5a and the black side average color intensity Z _{2 of} the pixels sorted into the black side area are respectively calculated. It has become.

Then, the ratio calculation unit 5b calculates the ratio H ₁ = Z ₁ / Y ₁ from the white side average color intensity Y ₁ and the black side average color intensity Z _{1 of} the black and white chart surface 3a to obtain the white side of the black and white chart surface 3b. The ratio H ₂ = Z ₂ / Y ₂ is calculated from the average color intensity Y ₂ and the black side average color intensity Z ₂ .

Further, the control unit 5 includes a storage unit 5c that stores the position of the focal point of the camera 10 corresponding to each ratio H _1, H _2, is stored in the storage unit 5c corresponding to the ratio H _1, H ₂ And a lens movement amount calculation unit 5d for calculating a lens movement amount D for the focal point of the camera 10 to be in a focusing range based on the focal position of the camera 10.

The lens movement amount calculation unit 5d is configured to calculate the movement direction of the lens 10c of the focus adjustment mechanism 10a by comparing the ratios H ₁ and H ₂ calculated by the ratio calculation unit 5b.

  Then, the control unit 5 outputs an operation signal to the driving device 4 based on the lens movement amount D calculated by the lens movement amount calculation unit 5d and the movement direction of the lens 10c, and focuses the camera 10 on the focus. It moves to the focal range.

  Further, the monitor 6 displays an image taken by the camera 10, a frequency distribution table shown in FIGS. 2 to 4, and a calculation result in the ratio calculation unit 5b or the lens movement amount calculation unit 5d. It has become.

  Next, the focusing operation of the camera 10 using the camera focus adjustment device 1 will be described.

  First, the operator fixes the camera 10 for adjusting the focus to the fixture 2 and connects the driving device 4 and the control unit 5 to the camera 10.

  Next, the operator presses a focus adjustment start button (not shown). Then, the control unit 5 outputs an operation signal so as to photograph the black and white chart surfaces 3a and 3b to the camera 10, and based on the signal, the camera 10 photographs the black and white chart surfaces 3a and 3b.

  Thereafter, the sorting unit 5a selects the R value among the R value, the B value, and the G value as the color intensity in a predetermined region set in advance for each of the black and white chart surfaces 3a and 3b of the photographed image. When the color intensity of each pixel in the predetermined area is in the range of 0 to 65, the pixel in the range of 110 to 255 belongs to the white area.

Thereafter, as shown in FIGS. 2 (b) to 4 (b), the ratio calculation unit 5b performs the above classification from the frequency distribution of the color intensity of each pixel in a predetermined region of the photographed image on the black and white chart surface 3a. The white side average color intensity Y _{1 of} the pixels sorted into the white side area and the black side average color intensity Z _{1 of} the pixels sorted into the black side area are respectively calculated by the unit 5a.

Further, the ratio calculation unit 5b is configured to calculate the classification unit from the frequency distribution of the color intensity of each pixel in a predetermined region of the photographed image on the black and white chart surface 3b as shown in FIGS. 2 (c) to 4 (c). respectively calculating a black-side average color intensity Z ₂ white side mean color intensity Y ₂ and the black-side region sorted pixel sorting pixels into the white side region 5a.

Then, the ratio calculation unit 5b calculates the ratio H ₁ = Z ₁ / Y ₁ from the white side average color intensity Y ₁ and the black side average color intensity Z _{1 of} the black and white chart surface 3a to obtain the white side of the black and white chart surface 3b. The ratio H ₂ = Z ₂ / Y ₂ is calculated from the average color intensity Y ₂ and the black side average color intensity Z ₂ .

For example, FIG. 2 (a) is an image taken with the camera 10 in focus on both the black and white chart surfaces 3a and 3b, and the ratio H from the frequency distribution of FIGS. 2 (b) and 2 (c). _{When 1} and H ₂ are calculated, H ₁ = 0.26 and H ₂ = 0.27 are obtained. 3A is an image taken with the camera 10 in focus only on the black and white chart surface 3a. From the frequency distributions of FIGS. 3B and 3C, the ratios H ₁ , H _{When 2} is calculated, H ₁ = 0.26 and H ₂ = 0.49. Further, FIG. 4A is an image taken with the camera 10 in focus only on the black and white chart surface 3b. From the frequency distributions of FIGS. 4B and 4C, the ratios H ₁ , H _{When 2} is calculated, H ₁ = 0.47 and H ₂ = 0.27. Thus, it can be seen that the lower the ratio H, the more focused the camera 10 is.

Thereafter, the lens movement amount calculation unit 5d determines that the focus of the camera 10 matches the in-focus range based on the focus position of the camera 10 stored in the storage unit 5c corresponding to the ratios H ₁ and H _2. The lens movement amount D for becoming is calculated.

For example, in the photographed image of FIG. 3A, H ₂ = 0.49, and the storage unit 5c stores the focal position X of the camera 10 corresponding to H ₂ = 0.49. lens movement amount calculating section 5d calculates the distance between the position X ₀ to the position X where the focus of the camera 10 is aligned as a lens movement amount D.

The lens movement amount calculation unit 5d compares the ratios H ₁ and H ₂ and calculates the movement direction of the lens 10c of the focus adjustment mechanism 10a.

For example, in the captured image of FIG. 3A, since H ₁ <H ₂ , it can be seen that the lens 10 c needs to be moved away from the object 3 to focus the camera 10.

  Then, the control unit 5 outputs an operation signal to the driving device 4 based on the lens movement amount D calculated by the lens movement amount calculation unit 5d and the moving direction of the lens 10c to focus the camera 10 on the focus. Move to range.

  As described above, according to the embodiment of the present invention, the data obtained by sequentially differentiating pixels adjacent to each other as in Patent Document 1 is not processed as a frequency distribution, but the data of each pixel of the captured image is not calculated as it is. In addition, since the processing is performed with a frequency distribution, the time required for the focusing operation can be shortened as compared with the apparatus disclosed in Patent Document 1.

Further, since the black and white chart surface 3a, the moving direction of the lens 10c for adjusting the ratio H _1, H ₂ which is calculated for each 3b focus of the camera 10 can be seen, when the focusing of the camera 10, the moving direction of the lens 10c It is possible to avoid mistakenly performing the operation of the focus adjustment mechanism 10a a plurality of times, and the time required for the focusing operation can be further shortened.

  Furthermore, since the camera 10 can be automatically focused by the driving device 4, the focusing operation is simplified and the burden on the operator can be reduced.

  In the embodiment of the present invention, the focus of the camera 10 in which the image sensor 10b is a CMOS is adjusted by the camera focus adjustment apparatus 1, but the focus of the camera 10 in which the image sensor 10b is a CCD is also adjusted by the camera focus adjustment. It can be adjusted with the device 1.

  In the embodiment of the present invention, the control unit 5 selects the R value as the color intensity from the R value, the B value, and the G value, and performs the subsequent calculation. However, the R value, the B value, and the G value are performed. Of these, the B value or the G value may be selected as the color intensity, and the subsequent calculation may be performed.

  Further, in the embodiment of the present invention, the focus adjustment mechanism 10a is driven by the driving device 4 to move the focus of the camera 10 to the in-focus range. However, the lens movement amount D and the lens 10c displayed on the monitor 6 are moved. Based on the moving direction, the operator may manually adjust the focus adjustment mechanism 10a.

  In the embodiment of the present invention, the focus of the camera 10 incorporated in an image processing apparatus (not shown) is adjusted by the camera focus adjustment apparatus 1. However, if the imaging element is a camera having a CCD or CMOS, it is incorporated in another apparatus. Even if it exists, the focus of the camera can be adjusted in advance by the camera focus adjustment apparatus 1.

  Further, the control unit 5 outputs an operation signal to the camera 10 before performing the image processing described above to capture one image of the object 3 to be captured, and any one of the R value, the B value, and the G value. While selecting one as the color intensity, the average color intensity is calculated from the frequency distribution of the color intensity of all the pixels of the photographed image, and the calculation result is compared with the color intensity 70 (average value of the color intensity) to calculate the average color The shutter speed of the camera 10 may be adjusted so that the intensity approaches 70. If it does so, the picked-up image by the camera 10 will become clear, and the above-mentioned image processing can be performed reliably.

  The present invention includes a CCD or CMOS image sensor, and a camera focus adjustment for adjusting the focus of the camera in advance before the focus adjustment mechanism is assembled to a manual camera. Suitable for equipment.

DESCRIPTION OF SYMBOLS 1 Camera focus adjustment apparatus 2 Fixing tool 3 Object 3a, 3b Black-and-white chart surface 4 Drive apparatus (drive means)
5 Control unit (control means)
5a Sorting unit 5b Ratio calculation unit 5c Storage unit 5d Lens movement amount calculation unit 10 Camera 10a Imaging element 10b Focus adjustment mechanism 10c Lens H ₁ , H ₂ ratio Y ₁ , Y ₂ White side average color intensity Z ₁ , Z ₂ Black side Average color intensity D Lens movement

Claims (3)

The imaging device is a CCD or CMOS, and the lens focus adjustment mechanism is a camera focus adjustment device for adjusting the focus of a manual camera,
A fixture for detachably fixing the camera;
A to-be-photographed object having a black and white chart surface disposed opposite to the camera fixed to the fixture;
Control means for detachably connecting to the camera, outputting an operation signal to the camera, and photographing the object to be photographed,
The control means selects any one of the R value, the B value, and the G value as the color intensity, and the color intensity of each pixel in the captured image captured by the camera is X ₁ <X ₂ (X ₁ , X _{when 2} was given integer), as belonging to a range of 0 to X ₁ on the black side region, and a sorting unit to sort each in the range of X ₂ to 255 as belonging to the white side region,
From the frequency distribution of the color intensity of each pixel in the photographed image, the white side average color intensity Y of each pixel sorted into the white side area by the sorting unit and the black side average color intensity Z of each pixel sorted into the black side area And a ratio calculator that calculates a ratio H = Z / Y of the white side average color intensity Y and the black side average color intensity Z;
A storage unit that stores the focal position of the camera corresponding to the ratio H;
A lens movement amount calculation unit that calculates a lens movement amount D for allowing the focus of the camera to be in a focusing range based on the focus position of the camera stored in the storage unit corresponding to the ratio H. A camera focus adjustment device characterized by the above. The camera focus adjusting apparatus according to claim 1,
The black and white chart surface is provided at each of the maximum position and the minimum position of the focusing range of the camera,
The ratio calculation unit calculates a ratio H for each black and white chart surface,
The camera focus adjustment apparatus, wherein the lens movement amount calculation unit is configured to calculate the lens movement direction of the focus adjustment mechanism by comparing the ratios H calculated by the ratio calculation unit. The camera focus adjustment device according to claim 2,
Removably attached to the focus adjustment mechanism, and provided with drive means for moving the lens by driving the focus adjustment mechanism,
The control means is connected to the drive means and outputs an operation signal to the drive means based on the lens movement amount D calculated by the lens movement amount calculation unit and the lens movement direction to focus the camera. A camera focus adjustment device characterized by moving to a focal range.