JP2018004663A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of discriminating the kind of an all-round fish-eye lens, calculating the range of an imaging element effective for photometry and light source estimation by using the information of a radius corresponding to the discriminated kind, and performing optimum photometry and light source estimation by using the signal of an effective range.SOLUTION: The imaging apparatus to which an interchangeable lens is attached includes the imaging element which receives light transmitted through the interchangeable lens and performs conversion into an image signal, read-out means which reads lens information related to the interchangeable lens from the interchangeable lens, calculation means which calculates the photographing state reference range of the imaging element by using the lens information, image signal read-out means which reads the image signal from the photographing state reference range which is the calculation result of the calculation means, and photographing state determination means which determines a photographing state on the basis of the image signal read by the image signal read-out means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus that performs accurate photometry and light source estimation even when an all-around fisheye lens is attached.

  In an imaging device capable of exchanging lenses, interchangeable lenses having various focal lengths can be attached to the imaging device. For this reason, it is desired that the imaging device accurately estimates the light and estimates the light source no matter what interchangeable lens is attached.

  In general, an imaging apparatus performs photometry or light source estimation based on information obtained by converting light transmitted through an interchangeable lens into an image signal by an image sensor.

  However, when shooting with an all-around fisheye lens attached to the imaging device, the image circle of light that has passed through the all-around fisheye lens does not reach the subject light in the vicinity of the long side direction of the image sensor and the short side direction of the image sensor. There may not be. When shooting with such an all-around fisheye lens attached, the periphery in the long side direction of the image sensor and the short side direction of the image sensor where the subject light does not reach is not useful for photometry and light source estimation of the peripheral region. Specifically, there is a problem that the final image is overexposed as a result of determining that the entire image is dark by using the image signal of the area where the subject light of the image sensor does not reach for photometry. Therefore, as described in Patent Document 1, there is provided a discriminating means for discriminating whether or not an all-round fisheye lens is mounted as an interchangeable lens using a photometric device capable of photometrically measuring the central area and the peripheral area of the image. When the discriminating means determines that the all-round fisheye lens is mounted, correction is performed to replace the luminance information of the peripheral area with the luminance information of the central area, or correction for obtaining the photometric value only with the luminance information of the central area. A photometric device that performs this has been proposed.

  Further, Patent Document 2 has information to be read from the image sensor for each interchangeable lens attached to the image pickup device, so that when a fisheye lens is attached and photographed, the image is based on information on a read area stored in the image pickup device. There has been proposed an imaging apparatus that does not affect photometry or light source estimation by not reading an image signal from outside the range of the image circle from the sensor.

JP 63-154921 A JP 2009-77129 A

  However, the photometric device described in Patent Document 1 has a problem that when the pattern of the area is fixed and the vignetting range of all-around fisheye is different, optimal photometry / light source estimation cannot be performed.

  Next, the imaging device described in Patent Document 2 stores a plurality of vignetting-free information in the imaging device, and appropriately selects the vignetting-free information stored in accordance with an external command. The read range is changed. Therefore, when an interchangeable lens having information in a range different from the information in a plurality of vignetting areas stored in the imaging apparatus is mounted, there is a problem that optimal photometry / light source estimation cannot be performed because the readout range is not suitable. In addition, when dealing with an interchangeable lens having information in a new range, it is necessary to add to the imaging device, so that there is a problem that firmware of the imaging device needs to be updated each time.

  Further, in order to deal with sensors of various sizes, there is a problem that if the imaging apparatus has a plurality of read information indicating whether or not to read data for each pixel, the data amount of the read information increases.

  The present invention has been made in view of such a situation, and determines the type of an all-around fisheye lens, and calculates the range of an image sensor effective for photometry and light source estimation using information on the radius corresponding to the determined type. The purpose is to perform optimal photometry and light source estimation.

  1st invention which is a means for solving the above-mentioned subject is an image pick-up device, and in an image pick-up device which mounts an exchange lens, an image pick-up element which receives light which permeate | transmitted said exchange lens, and converts it into an image signal, Reading means for reading out lens information relating to the interchangeable lens from the interchangeable lens, calculation means for calculating a photographing state reference range of the image sensor using the lens information, and the photographing state reference range which is a calculation result of the calculating means An image pickup apparatus comprising: an image signal reading unit that reads the image signal from the image signal; and a shooting state determination unit that determines a shooting state based on the image signal read by the image signal reading unit.

  According to a second aspect of the present invention, which is a means for solving the above-described problem, in an imaging apparatus to which an interchangeable lens is attached, an imaging element that receives light transmitted through the interchangeable lens and converts it into an image signal, and the interchangeable lens A reading means for reading out lens information relating to the interchangeable lens, a determining means for determining whether or not the interchangeable lens mounted on the imaging device is an all-round fisheye lens based on the lens information relating to the interchangeable lens, and the imaging device. When the discriminating unit discriminates the mounted interchangeable lens as an all-round fisheye lens, a calculating unit that calculates a shooting state reference range of the image sensor using the lens information, and the photographing that is a calculation result of the calculating unit Image signal reading means for reading the image signal from the state reference range, and photographing based on the image signal read by the image signal reading means Imaging apparatus characterized by comprising: a determining imaging state judgment means condition, the.

  According to a third aspect of the present invention, which is a means for solving the above-described problem, in an imaging apparatus to which an interchangeable lens is mounted, an imaging element that receives light transmitted through the interchangeable lens and converts it into an image signal, and the interchangeable lens A lens information storage unit that stores lens information regarding, a lens information selection unit that selects lens information corresponding to the interchangeable lens mounted on the imaging device from lens information stored in the lens information storage unit, and A calculation unit that calculates a shooting state reference range of the image sensor using lens information selected by a lens information selection unit, and an image signal reading unit that reads the image signal from the shooting state reference range that is a calculation result of the calculation unit. And photographing state determining means for determining a photographing state based on the read image signal of the image signal reading means. Imaging device.

  A fourth invention, which is a means for solving the above-mentioned problem, is the imaging apparatus according to any one of the first invention to the third invention, wherein the calculation means includes: An image pickup apparatus that performs calculation using information on the size of the image pickup element and a value of a ratio of an image height based on the size of the reference image pickup element.

  According to the present invention, the type of the all-around fisheye lens is determined, the range of the image sensor effective for photometry and light source estimation is calculated using the radius information corresponding to the determined type, and the signal of the effective range is used. Thus, it is possible to provide an imaging apparatus capable of performing optimal photometry and light source estimation.

The block diagram which shows the structure of the imaging device of this invention Flowchart of the first embodiment of the present invention Relationship between angle of view and measurement area Flow chart of embodiment 2 of the present invention

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

  FIG. 1 is a diagram showing a main configuration of an imaging apparatus 100 according to the present invention.

  As illustrated in FIG. 1, the imaging apparatus 100 includes an interchangeable lens 200 and a camera body 300.

  The interchangeable lens 200 is a zoom lens or a single focus lens having a substantially cylindrical shape, and includes an imaging optical system 210 therein.

  The interchangeable lens 200 includes a lens side mount (not shown) at the rear end.

  The camera body 300 includes a camera-side mount (not shown) on the front surface. The interchangeable lens 200 and the camera body 300 are detachably fixed by coupling both mounts.

  The inside of the camera body 300 on the optical axis of the imaging optical system 210 includes an image sensor 310 composed of a CCD, a CMOS, or the like that photoelectrically converts a subject light velocity.

  Focus on the appearance of the camera body 300. The camera body 300 includes a display device (LCD, organic EL, etc.) and various operation units (not shown) on the back. The photographer can operate the various operation units to display the photographed image on the display device for confirmation, or to change settings such as exposure correction and white balance.

  Further, the camera body 300 includes a recording medium slot (not shown) on the side surface. Image data obtained by the image sensor 310 in the camera body 300 is recorded on a recording medium loaded in this slot.

  The camera body 300 includes a release button (not shown), a mode setting dial, and the like on the upper surface of the exterior.

  The release button includes a first switch that is turned on when the photographer is half-pressed and a second switch that is turned on when the photographer is fully pressed. The photographing apparatus 100 performs photographing preparation operations such as focus detection, automatic focusing on a main subject, and photometry of a field luminance value with the first switch turned on. When the second switch is subsequently turned on, the image data of the subject is acquired via the image sensor 310 under the shooting conditions set by the shooting preparation operation.

  The shooting mode is changed with a mode setting dial (not shown). The mode setting dial is a rotatable dial switch. A plurality of exposure mode icons that can be recognized by the photographer are printed on the upper surface of the dial. The photographer can arbitrarily set the shooting mode of the imaging apparatus 100 by rotating the mode setting dial so that the icon of the intended shooting mode is positioned at the index position.

  The type of shooting mode is, for example, an auto mode (AUTO) in which all parameters such as shutter speed, aperture value, ISO sensitivity, white balance, etc. are automatically determined on the camera side, and shutter speed and aperture value parameters on the camera side. There is a program mode (P) that is automatically determined by the user, and a manual mode (M) in which the photographer manually sets the shutter speed and aperture value according to preference. As for other types of shooting modes, the photographer sets an arbitrary aperture value and the camera side automatically determines the optimum shutter speed accordingly, and the photographer sets an arbitrary shutter speed. There is a shutter speed priority mode (S) or the like in which the camera side automatically determines the optimum aperture value accordingly. In addition to these still image shooting modes, there may be a moving image shooting mode for shooting moving images.

  Attention is focused on the inside of the imaging apparatus 100. In addition to the image sensor 310 described above, the camera body 300 includes a shutter drive unit 340 that drives a focal plane shutter (not shown) to adjust the exposure time of the image sensor 310, that is, the shutter speed. . The image sensor 310 and the shutter drive unit 340 are connected to a camera CPU 350 further provided in the camera body 300, and are controlled by the camera CPU 350 so as to operate appropriately.

  Inside the interchangeable lens 200, in addition to the imaging optical system 210 described above, a lens driving unit 220 for driving a focus adjustment lens 211 in the imaging optical system 210 to perform a focusing operation, and imaging optics A diaphragm drive unit 230 for adjusting the aperture of the system 210, a lens memory 241 for storing lens data unique to the interchangeable lens 200, a zoom encoder 260 for detecting a zoom position when the focusing operation is performed, and the like. ing.

  The lens data stored in the lens memory 241 includes, for example, information on the focal length and open F value of the interchangeable lens 200, whether or not the interchangeable lens 200 is a zoom lens with a variable focal length, and the like. The lens memory 241 further stores a shooting distance data table including a focus position signal output from the focus encoder 250 and a shooting distance corresponding to the position signal as lens data. Similarly, the lens data stored in the lens memory 241 also stores a zoom position signal output from the zoom encoder 260 and a focal length data table related to the focal length position corresponding to the position signal. Thus, the shooting distance and focal length at that time can be known from the position signals obtained by the encoders.

  These lens drive unit 220, aperture drive unit 230, focus encoder 250, and zoom encoder 260 are connected to a lens CPU 240 further provided in the interchangeable lens 200. The lens CPU 240 appropriately controls the connected lens driving unit 220, aperture driving unit 230, focus encoder 250, and zoom encoder 260.

  The lens memory 241 constitutes a part of the lens CPU 240. The lens CPU 240 accesses the lens memory 241 as necessary, and acquires and rewrites necessary information. The lens CPU 240 is electrically connected to the camera body 300 via the communication contact 110, transmits lens data in the lens memory 241 to the camera body 300, and receives various commands from the camera body 300 side.

  Next, an embodiment when the interchangeable lens 200 is attached to the imaging apparatus 100 of the present application will be described based on the flowchart of FIG.

  In step # 1, when the interchangeable lens 200 is attached to the camera body 300 and the camera body 300 is turned on, the camera body 300 and the interchangeable lens 200 communicate lens data.

  The communication content of the lens data is information regarding the lens model of the attached interchangeable lens 200, and the content of the lens data is information regarding whether or not the zoom lens has a variable lens ID and focal length, and whether or not it is a fisheye lens. Information on the radius, the radius information in the case of a fisheye lens, the focal length and aperture value of the interchangeable lens 200, and the like, which are transmitted from the lens memory 241 to the camera CPU 350 through the lens CPU 240.

  In step # 2, the camera body 300 determines whether or not the interchangeable lens 200 mounted is an all-round fisheye lens based on the lens data sent from the interchangeable lens 200. When it is determined that the interchangeable lens 200 attached to the camera body 300 is an all-round fisheye lens, the process proceeds to step # 3. If it is not determined to be an all-round fisheye lens, the process proceeds to step # 6.

  Whether or not the interchangeable lens 200 attached to the camera body 300 is an all-round fisheye is determined by setting a flag indicating whether or not the interchangeable lens 200 is an all-round fisheye in the lens data stored in the lens CPU 241 of the interchangeable lens 200. It may be discriminated by inclusion, or radius information may be given to the lens data only in the all-around fisheye lens.

  The radius information will be described. The radius information indicates an effective range that is a range of an image signal to be referred to when performing photometry or light source estimation, and is indicated by a ratio of an image height from the center of the image sensor in a 35 mm version image sensor serving as a standard size. It is. Specifically, the center of the image is 0, and the maximum point in the diagonal direction is 1. An effective range where no vignetting occurs in the imaging apparatus is calculated from the image height. The radius information is the value of the image height in the 35 mm size image sensor, which is the reference size. Therefore, when the size of the image sensor 310 is not the 35 mm size, the radius information is adjusted by multiplying by a coefficient.

  The purpose of calculating the effective range will be described. Effective range is the range where vignetting does not occur, and only the image signal of the effective range from the image sensor is used for photometry and light source estimation, so that photometry that is not affected even if vignetting occurs for all-round fisheye with various radii And the result of light source estimation can be obtained.

  In step # 3, the camera CPU 350 acquires radius information from the lens data acquired from the interchangeable lens 200 attached to the camera body 300 in step # 1. Proceed to step # 4.

  In step # 4, the camera CPU 350 calculates an effective range using the radius information acquired in step # 3. The calculation of the effective range will be described later. Proceed to step # 5.

  In step # 5, the range calculated in step # 4 is set as a target for photometry and light source estimation. An image signal is extracted from the set effective range, and the process proceeds to step # 7.

  In step # 6, since the interchangeable lens 200 attached to the camera body 300 in step # 2 is not determined to be an all-round fisheye lens, the camera CPU 350 sets all the areas of the image sensor 310 as targets for photometry and light source estimation. Set. An image signal is extracted from the set effective range, and the process proceeds to step # 7.

  In step # 7, the camera CPU 350 determines the shooting state based on the image signal acquired from the effective range of the image sensor 310 set in step # 5 and step # 6, respectively. In this embodiment, photometry and light source determination are performed.

  A method of calculating the effective range will be described. Radius information is used from the lens data acquired in step # 3. Since the radius information indicates the ratio of the image height in the 35 mm version image sensor as described above, the camera CPU 350 of the camera body 300 calculates the effective range of the photometric / light source estimation area when the radius information is acquired. To do.

  The camera CPU 350 has information on whether or not the size of the image sensor 310 of the camera body 300 is a 35 mm version. If the size of the image sensor 310 is not a 35 mm version, the camera CPU 350 has side ratio information with respect to the 35 mm version. There is a need.

  In the embodiment of the present specification, the camera body 300 has been described using a so-called mirrorless type imaging device that performs distance measurement, photometry, and the like based on the image signal of the image sensor 310. However, it goes without saying that the camera body 300 may be a single-lens reflex type imaging device. In that case, distance measurement and photometry are performed by the distance measurement sensor and the photometry sensor, respectively.

  Next, an effective range calculation method will be described. Using the radius information acquired in step # 3, the camera CPU 350 sets the effective image height of the effective range as r and the image size as X (pixel) × Y (pixel) for the 35 mm size image sensor size. The effective range is the radius ((X ^ 2 + Y ^ 2) ^ (1/2)) / 2 * r from the center (X / 2, Y / 2) of the image. Further, if the size of the image sensor 310 of the camera body 300 is a 35 mm version, there is no problem as it is, but if the number of pixels is the same but the size of the image sensor 310 is different, the size of the image sensor 310 is APS−. If C, r × 0.6 is required. If the size of the image sensor 310 is APS-H, r × 0.8 is required. The coefficient will be described later.

  Let's actually calculate the effective range. When the effective image height r of the effective range is 0.4 and the image size is 400 (pixels) × 300 (pixels), the centers of the effective radii are 200 (pixels) and 150 (pixels), and the effective radii are 100 ( If the size of the image sensor 310 is a 35 mm version, there is no problem as it is. However, as described above, when the number of pixels is the same but the size of the image sensor 310 is different, the size of the image sensor 310 is Since APS-C is multiplied by r × 0.6, the effective radius is 60 (pixel), and when APS-H is multiplied by r × 0.8, the effective radius is 80 (pixel). Note that the center of the effective radius is not related to the size of the image sensor 310.

  Further, the coefficient to be multiplied by the above-described effective range calculation formula varies depending on the actual size of the image sensor 310. The method of obtaining the coefficient is the ratio of the long side or the short side of the image sensor 310 to the 35 mm version image sensor. As an example, since an APS-H size image sensor is 28.8 × 19.2 (mm) and a 35 mm version image sensor is 36 × 24 (mm), 28.8 / 36 using the long side. From 0.8, the coefficient is 0.8. Similarly, the short side is 19.2 / 24 = 0.8, which is the same as the long side.

  In the present application, the effective range of the photometric / light source estimation region in the image sensor 310 of the camera body 300 is set in step # 5. Hereinafter, description will be made with reference to the image circle of the all-around fisheye lens shown in FIG.

  If all the areas in FIG. 3 are the areas of the image sensor 310 of the camera body 300, the image circle of the light that has passed through the all-around fisheye lens attached to the camera body 300 is an area inside the center circle.

  Therefore, when the all-round fisheye lens is attached to the camera body 300, the central portion becomes an imaging region as shown in FIG. 3, and the peripheral region appears black because of vignetting. Even if this black portion of information is used for photometry or light source estimation, it does not reflect the subject light, so it is not useful. Specifically, there is a problem that overexposure occurs as in the case of shooting in a dark place and using a signal in a dark portion. Therefore, in the present invention, the accuracy of photometry and light source estimation is maintained by setting an effective range.

  Next, Embodiment 2 in the case where the interchangeable lens 200 is attached to the camera body 300 storing lens data will be described based on the flowchart of FIG.

  In Example 1, the interchangeable lens 200 stores lens data, and the image pickup apparatus reads lens data from the interchangeable lens after being attached to the image pickup apparatus. On the other hand, in the second embodiment, the imaging device stores a plurality of lens data, and appropriate lens data is selected according to the imaging device attached to the imaging device.

  In step # 21, when the interchangeable lens 200 is attached to the camera body 300 and the power of the camera body 300 is turned on, the camera body 300 and the interchangeable lens 200 perform data communication. Proceed to step # 22.

  In step # 22, the camera body 300 determines whether or not the interchangeable lens mounted based on the lens ID sent from the interchangeable lens 200 is an all-around fisheye lens. When it is determined that the interchangeable lens 200 attached to the camera body 200 is an all-round fisheye lens, the process proceeds to step # 23. If it is not determined to be an all-round fisheye lens, the process proceeds to step # 26.

  Whether the interchangeable lens 200 attached to the camera body 300 is an all-round fisheye lens is determined by storing the ID of the all-around fisheye lens in the camera CPU 350 of the camera body 300 and replacing the lens attached to the camera body 300. It is determined whether or not the interchangeable lens 200 is an all-around fisheye lens depending on whether or not the lens ID of the lens 200 is included.

  In step # 23, radius information suitable for the interchangeable lens 200 attached to the camera body 300 is set from the lens ID of the all-around fisheye lens stored in the camera CPU 350.

  As the data communication content, radius information suitable for the interchangeable lens 200 is set from information on a plurality of radii stored in the camera body 300 in advance from the interchangeable lens 200.

  In step # 24, the camera CPU 350 calculates an effective range using the radius information set in step # 23. Since the calculation method of the effective range is the same as that of the first embodiment, the description thereof is omitted. Proceed to step # 25.

  In step # 25, the effective range calculated in step # 24 is set as a target for photometry and light source estimation. An image signal is extracted from the set effective range, and the process proceeds to step # 26.

  In step # 26, since the interchangeable lens 200 attached to the camera body 300 in step # 22 has not been determined to be an all-round fisheye lens, the camera CPU 350 sets all areas of the image sensor 310 as targets for photometry and light source estimation. Set. An image signal is extracted from the set effective range, and the process proceeds to step # 27.

  In step # 27, the camera CPU 350 determines the shooting state based on the image signal acquired from the effective range of the image sensor 310 set in step # 25 and step # 26, respectively. In this embodiment, photometry and light source estimation are performed.

  The invention of this application makes it possible to perform optimal photometry and light source estimation by obtaining a non-vignetting range in the image sensor based on the radius information and setting the obtained range as the readout range of the image signal.

DESCRIPTION OF SYMBOLS 100 Imaging device 200 Interchangeable lens 210 Imaging optical system 220 Lens drive unit 230 Aperture drive unit 240 Lens CPU
241 Lens memory 250 Focus encoder 260 Zoom encoder 300 Camera body 310 Image sensor 340 Shutter drive unit 350 Camera CPU

Claims (4)

In an imaging device equipped with an interchangeable lens,
An image sensor that receives light transmitted through the interchangeable lens and converts it into an image signal;
Reading means for reading lens information related to the interchangeable lens from the interchangeable lens;
Calculating means for calculating a photographing state reference range of the image sensor using the lens information;
Image signal readout means for reading out the image signal from the imaging state reference range which is a calculation result of the calculation means;
Shooting state determining means for determining a shooting state based on the image signal read by the image signal reading means;
An imaging apparatus comprising: In an imaging device equipped with an interchangeable lens,
An image sensor that receives light transmitted through the interchangeable lens and converts it into an image signal;
Reading means for reading lens information related to the interchangeable lens from the interchangeable lens;
Discriminating means for discriminating whether or not the interchangeable lens mounted on the imaging device is an all-around fisheye lens based on lens information relating to the interchangeable lens;
When the discriminating means discriminates the interchangeable lens mounted on the imaging device as an all-around fisheye lens,
Calculating means for calculating a photographing state reference range of the image sensor using the lens information;
Image signal readout means for reading out the image signal from the imaging state reference range which is a calculation result of the calculation means;
Shooting state determining means for determining a shooting state based on the image signal read by the image signal reading means;
An imaging apparatus comprising: In an imaging device equipped with an interchangeable lens,
An image sensor that receives light transmitted through the interchangeable lens and converts it into an image signal;
A lens information storage unit that stores lens information related to the interchangeable lens;
A lens information selection unit that selects lens information corresponding to the interchangeable lens attached to the imaging device from lens information stored in the lens information storage unit;
Calculating means for calculating a shooting state reference range of the image sensor using the lens information selected by the lens information selection unit;
Image signal readout means for reading out the image signal from the imaging state reference range which is a calculation result of the calculation means;
A shooting state determination unit that determines a shooting state based on a read image signal of the image signal reading unit;
An imaging apparatus comprising: The calculating means includes the lens information.
4. The image pickup apparatus according to claim 1, wherein calculation is performed using information on a size of the image pickup element and a value of a ratio of an image height based on a size of the reference image pickup element.

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