JP2008005059A - Imaging apparatus, control method thereof, program, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire a more accurate foreign matter information profile in the case of photographing a uniform object such as a white wall to obtain a foreign matter information profile. <P>SOLUTION: An imaging apparatus includes: a body section 101 to which a lens is interchangeably mounted; an imaging element 40 for applying photoelectric conversion to an object image; an acquisition section 1 for acquiring information unique to the lens from the lens by means of the communication section; a foreign matter information generating section 40 for generating foreign matter information including at least information of positions and sizes of the foreign matter on the basis of a foreign matter detection image including an image of the foreign matter imaged by the imaging element and adhering to the surface of the imaging element or the surface of the optical element arranged in front of the imaging element; and a restriction section 1 for inhibiting imaging of the foreign matter detection image when it is determined that the lens mounted on the body section is an improper lens to image the foreign matter detection image. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for acquiring information such as the position and size of a foreign substance attached in an optical system in an imaging apparatus such as a digital camera.

  Conventionally, in a digital camera, when foreign objects such as dust adhere to the optical system (especially the surface of an optical element such as a low-pass filter disposed in front of the image sensor), the shadows of the foreign objects are shadowed on the captured image. There is a problem that the image quality is deteriorated.

In order to solve this problem, the following method has been proposed. First, a uniform subject such as a white wall is photographed, and an image in which only foreign matter in the optical system is reflected is photographed. Then, information on the foreign matter in the optical system is obtained from the image, and the correction processing of the actually captured image is performed to improve the image quality (see Patent Document 1).
JP 2004-222231 A

  However, when photographing a uniform subject such as a white wall by the above-described conventional method and acquiring foreign matter information, high quality foreign matter information may not be obtained depending on the lens attached to the camera.

  Specifically, when a white wall or the like is photographed to obtain a uniform image, the quality depends on the characteristics of the lens attached to the camera. For example, even if a white wall is intended to be copied, an image including a portion that is determined to be a foreign object is obtained, or even if a foreign object is attached in the optical system of the camera, the foreign object is not clearly visible.

  In order to obtain high quality foreign object information, it is desirable to attach a lens to the camera so that the shadow of the foreign object is clearly reflected at an accurate position on the image sensor.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to obtain more accurate foreign object information when photographing a uniform subject such as a white wall to obtain foreign object information. That is.

  In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes a main body unit in which a lens is replaceably mounted, an imaging element that photoelectrically converts a subject image, and communication that communicates with the lens. Means for acquiring information specific to the lens from the lens by means of the communication means, and an optical device disposed on the surface of the image sensor or in front of the image sensor, which is imaged by the image sensor. Obtained by the foreign matter information generating means for generating foreign matter information which is information including at least the position and size information of the foreign matter based on the foreign matter detection image containing the foreign matter image attached to the surface of the element, and acquired by the obtaining means When it is determined that the lens attached to the main body is an inappropriate lens for capturing the foreign object detection image based on the information unique to the lens, Characterized by comprising a regulating means for inhibiting imaging of the foreign substance detection image.

  An image pickup apparatus control method according to the present invention is a method for controlling an image pickup apparatus including a main body unit in which a lens is replaceably mounted and an image pickup element that photoelectrically converts a subject image, and communicates with the lens. Performing an acquisition step of acquiring information specific to the lens from the lens, and attached to the surface of the image sensor, or the surface of the optical element disposed in front of the image sensor, captured by the image sensor Based on a foreign object detection image including a foreign object image, a foreign object information generation step for generating foreign object information, which is information including at least the position and size information of the foreign object, and the lens-specific information acquired in the acquisition step Based on the information, when it is determined that the lens attached to the main body is an inappropriate lens for capturing the foreign object detection image, the foreign object detection image Characterized in that it comprises a and a regulating step of prohibiting the image.

  A program according to the present invention causes a computer to execute the above control method.

  A storage medium according to the present invention stores the above program.

  According to the present invention, more accurate foreign object information can be obtained when foreign object information is obtained by photographing a uniform subject such as a white wall.

  Hereinafter, an embodiment in which the present invention is applied to an interchangeable lens digital single-lens reflex camera will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a camera system which is an embodiment of an imaging apparatus of the present invention, and shows a shooting preparation state of a digital single lens reflex camera system including a camera body and an interchangeable lens.

  In FIG. 1, reference numeral 101 denotes a camera body. An interchangeable lens 180 that can be attached to and detached from the camera body 101 is fixed by a camera mount 102 and a lens mount 182. When the camera side contact 103 and the lens side contact 184 come into contact with each other, the in-camera control unit and the in-lens control unit are electrically connected to supply power from the camera body 101 to the interchangeable lens 180 and control the lens. To communicate. The in-camera control unit is the microcomputer 1 shown in FIG. 2, and the in-lens control unit is the in-lens microcomputer 16 shown in FIGS. The camera-side contact 103 includes a plurality of contacts such as contacts 12, 13, 14, and 15 shown in FIGS. Further, the lens side contact 184 includes a plurality of contacts such as contacts 22, 23, 24, and 25 shown in FIGS.

  The light beam that has passed through the photographing optical system 181 of the interchangeable lens 180 is incident on the main mirror 105 of the camera. The main mirror 105 is a half mirror, and the light beam reflected here is guided to the finder screen 109, and a subject image is formed on the finder screen 109. The photographer can observe the subject image on the viewfinder screen 109 via the penta roof prism 111 and the eyepiece 112.

  On the other hand, the light beam transmitted through the main mirror 105 is reflected downward by the sub mirror 107 and guided to the focus detection unit 8. The focus detection unit 8 detects a focus shift amount of the photographic optical system 181, a so-called defocus amount, and calculates a lens driving amount of the focus lens in the photographic optical system 181 so that the photographic optical system 181 is in a focused state. . When this lens driving amount is sent to the interchangeable lens 180 via the contacts 103 and 184, the in-lens control unit controls a motor (not shown) to drive the focus lens in the photographing optical system 181 to adjust the focus. .

  The main mirror 105 is bonded and fixed to the main mirror holding frame 106, and is rotatably supported with respect to the mirror box 199 by a hinge shaft 106a. Further, the sub mirror 107 is bonded and fixed to the sub mirror holding frame 108, and the sub mirror holding frame 108 is pivotally supported with respect to the main mirror holding frame 106 by a hinge shaft 108a.

  A focal plane shutter 113 is disposed behind the sub-mirror 107, and the shutter front curtain 113a is normally closed, that is, a state in which an image sensor to be described later is shielded. An optical filter 114 in which an optical low-pass filter and an infrared cut filter are integrated is disposed behind the shutter 113, and a light beam that has passed through the optical filter 114 is incident on an image sensor 115 disposed further rearward during photographing.

  The image sensor 115 includes a cover glass 115a, a sensor package 115b, a sensor chip 115c, and a sensor substrate 115d. Here, the image pickup device or the image pickup means refers to a sensor chip 115c alone in a narrow sense, an image pickup device unit including the above-described 115a to 115d in a broad sense, and a structure in which the image pickup device unit and the optical filter 114 are combined. To do.

  Reference numeral 160 denotes a display such as an LCD, which displays information related to the shooting mode of the camera, a preview image before shooting, a confirmation image after shooting, and the like.

  FIG. 2 is a diagram illustrating a configuration of an electric control block in a state where the zoom lens 202 as the interchangeable lens 180 is attached to the camera body 101 of the interchangeable lens digital single lens reflex camera according to the embodiment.

  In FIG. 2, a microcomputer (microcomputer) 1 serving as an in-camera control unit controls the operation of the entire camera. The microcomputer 1 has a built-in memory (RAM, ROM, EEPROM, etc.), which may be externally attached, and stores various setting values, lens information, and the like of the camera. Further, the microcomputer 1 is connected to SW2, which is a switch for operating the focal plane shutter 113. When the switch SW2 is turned on in a state where a predetermined condition is satisfied, shutter control is performed and exposure of the image sensor 115 is started. .

  Here, the switch SW2 is a switch that is turned on when a release button (not shown) provided in the camera body 101 is fully pressed, and the imaging operation of the camera is performed when the switch SW2 is turned on. Be started. The switch SW1, which will be described later, is a switch that is turned on when the release button is pressed halfway (while the release button is being operated), and when this switch SW1 is turned on, a preparatory operation for imaging is started. The

  The strobe control circuit 2 includes a strobe light emission control circuit (not shown) and a zoom strobe control circuit that controls the irradiation angle in accordance with the focal length of the lens 202. The strobe light emission control circuit controls the light emission and dimming of the strobe. A circuit that accumulates charges for light emission, a xenon tube that is a light emission unit, a trigger circuit, a circuit that stops light emission, an imaging surface reflected light photometry circuit, It consists of an integration circuit. Then, the flash of the strobe is started when the X contact point which is turned on when the focal plane shutter 113 is driven in the first curtain is turned on. The zoom strobe control circuit is a circuit that changes the irradiation angle by moving a reflector or the like according to the focal length because the necessary and appropriate strobe irradiation angle varies depending on the focal length of the lens 202 mounted. Both the strobe light emission control circuit and the zoom strobe control circuit are known circuits.

  The liquid crystal display circuit 3 is a circuit for displaying each camera shooting information such as shutter speed and aperture control value, and performs serial communication via the DBUS (connection bus) while receiving a display signal from the microcomputer 1. Displays liquid crystal depending on the content.

  The switch detection circuit 7 is always supplied with power together with the liquid crystal display circuit 3. The above-described switches SW1 and SW2, other switches for determining an exposure mode (not shown), switches for determining an automatic focus adjustment (AF) mode of the camera, and the like can always be read. When the switch is switched, the switch detection circuit 7 performs serial communication via DBUS and communicates each switch information to the microcomputer 1.

  The focus detection unit 8 calculates and detects in which position the subject is focused by the lens 202 from the image signal of the subject obtained through the lens 202 by a phase difference detection method. The battery 9 is a power source for each part of the camera and each part of the lens. Note that the entire camera system is reset when a battery is mounted for battery replacement or the like.

  The imaging unit 40 includes the imaging device 115 illustrated in FIG. 1, an A / D converter that converts an analog signal output from the imaging device 115 into a digital signal, an image processing circuit that performs various image processing, and the like. Yes.

  The DC / DC converter 10 stabilizes the output voltage of the battery 9 that changes depending on the load state, and supplies the output voltage to each part of the camera and the lens 202. The DC / DC converter 10 is controlled by the microcomputer 1 and stops when the microcomputer 1 operates with a low-speed clock, or when the stabilized power supply is not required and the battery 9 can be operated as it is. In the stopped state, the voltage of the battery 9 is output as it is from the DC / DC converter 10 to reduce power consumption.

  The lens detection circuit 11 detects the lens attachment / detachment state and inputs it to the microcomputer 1, and controls power supply to the lens mounted according to an instruction from the microcomputer 1. The power supply terminal 12 is a terminal for supplying power from the camera body 101 to the lens 202. When the lens 202 is attached, power is supplied from the lens detection circuit 11. The lens mounting detection terminal 13 of the camera body 101 is connected to the terminal 23 on the lens 202 side when the lens is mounted. Reference numeral 14 denotes a ground terminal on the camera body 101 side. Each communication terminal 15a, 15b, 15c on the camera body 101 side performs serial communication with the lens 202.

  On the other hand, on the lens 202 side, the microcomputer 16 in the lens communicates with the microcomputer 1 on the camera body side to drive focus, aperture, and zoom according to instructions from the camera body 101 and to communicate information specific to the lens to the camera. . Information unique to the lens includes information such as focal length, aperture, minimum aperture, and focus position.

  The focus drive circuit 17 drives a focus lens (not shown) according to an instruction from the microcomputer 16 in the lens, and a focus position detection unit 18 detects the position and amount of movement of the focus lens driven by the focus drive circuit 17.

  The diaphragm drive circuit 19 drives the diaphragm in accordance with instructions from the microcomputer 16 in the lens, and the diaphragm position detection unit 20 detects the position and movement amount of the diaphragm driven by the diaphragm drive circuit 19.

  The zoom position detector 21 detects the position and movement amount of a zoom lens (not shown).

  The power terminal 22 on the lens 202 side is supplied with power from the power supply terminal 12 of the camera. When the lens mounting detection terminal 23 on the lens 202 side is normally connected to the lens mounting detection terminal 13 on the camera body 101 side, the camera body 101 detects the lens mounting. The ground terminal 24 on the lens 202 side is connected to the ground terminal 14 on the camera body 101 side and is also connected to the lens mounting detection terminal 23.

  The communication terminals 25a, 25b, and 26c on the lens 202 side and the communication terminals 15a, 15b, and 15c on the camera body 101 side are connected to perform serial communication between the microcomputer 16 in the lens and the microcomputer 1 in the camera.

  FIG. 3 is a diagram illustrating a configuration of an electric control block in a state where a single focus lens 204 as the interchangeable lens 180 is attached to the camera body 101 of the interchangeable lens type digital single lens reflex camera according to the embodiment. In FIG. 3, the same parts as those in FIG.

  In FIG. 3, the microcomputer 26 in the single focus lens 204 communicates with the microcomputer 1 in the camera, drives the focus, aperture, and zoom according to instructions from the microcomputer 1 in the camera, and communicates lens-specific information to the camera. To do.

  The focus drive circuit 27 drives the focus lens in accordance with an instruction from the microcomputer 26 in the lens, and the focus position detection unit 28 detects the position and movement amount of the focus lens driven by the focus drive circuit 27. The diaphragm drive circuit 29 drives the diaphragm in accordance with an instruction from the microcomputer 26 in the lens, and the diaphragm position detection unit 30 detects the position and movement amount of the diaphragm driven by the diaphragm drive circuit 29.

  The power supply terminal 22 on the lens 204 side receives power from the power supply terminal 12 on the camera body 101 side, and the lens mounting detection terminal 23 on the lens 204 side is normally connected to the lens mounting detection terminal 13 on the camera body 101 side. Then, the camera detects lens mounting. The communication terminals 25a, 25b, and 25c on the lens 204 side are connected to the communication terminals 15a, 15b, and 15c on the camera body 101 side, and serial communication is performed between the microcomputer 26 in the lens and the microcomputer 1 in the camera.

  FIG. 4 is a flowchart showing the operation at the time of detecting the lens mounting according to this embodiment.

  With reference to FIG. 4, an operation in which the microcomputer 1 detects lens attachment via the lens detection circuit 11 when the interchangeable lens 180 is attached to the camera body 101 will be described.

  First, a predetermined initialization operation is performed to operate various circuits in the camera, and the operation of the camera is started by operating the DC / DC converter 10 (step S101). Then, the power supply control circuit of the lens detection circuit 11 is controlled to start supplying power to the lens (step S102).

  The microcomputer 1 in the camera communicates with the microcomputer 16 or 26 in the lens through the communication terminals 15a to 15c on the camera side and the communication terminals 25a to 25c on the lens side, reads out lens information, and determines whether the mounted lens is a zoom lens. Judge whether it is a focus lens. If the attached lens is a zoom lens, only the information that the attached lens is a zoom lens is stored in the EEPROM, and the process proceeds to step S106 (step S103). When the mounted lens is a single focus lens, information unique to the lens in the lens is read (step S104). Then, the read data and information that the mounted lens is a single focus lens are stored in the EEPROM (step S105).

  After the operation of the microcomputer 16 or 26 in the lens is stopped by communication, the power supply control circuit of the lens detection circuit 11 is controlled to stop the power supply to the lens, and the lens power is turned off (step S106).

  Various operations for ending the operation of the camera are performed, the operation of the DC / DC converter 10 is stopped, and the camera operation is stopped and ended (step S107).

  In this way, the type of the interchangeable lens mounted on the camera body 101 is determined. In the case of a single focus lens, the lens-specific information is read and stored in the memory in the camera body. Only the operation is discriminated and the mounting operation is terminated.

  FIG. 5 is a flowchart showing a foreign matter information profile generation operation in the digital camera of this embodiment. The foreign substance information profile is a position (coordinates) and size of a foreign object created by photographing a uniform subject such as a white wall, which is created based on an image in which only the foreign substance in the optical system is reflected. A file that manages information such as.

  First, the interchangeable lens 180 is attached to the camera body 101. Then, as shown in FIG. 7, a menu using a GUI (graphical user interface) is displayed on the display 160 of the camera body 101. The user selects an application DL (profile creation for foreign substance removal correction by an application) that is a process for generating a foreign substance information profile from the GUI menu (step S1).

  When the user selects the application DL, the microcomputer 1 reads unique information of the attached interchangeable lens 180 (step S2).

  FIG. 6 is a subroutine showing an operation of reading lens specific information executed in step S2 of FIG.

  First, in step S121, it is determined whether the mounted lens is a zoom lens or a single focus lens based on the data in the EEPROM that has been determined and stored at the time of lens mounting detection.

  When the mounted lens is a zoom lens, the power supply circuit in the lens detection circuit 11 is controlled to supply power to the lens, and the microcomputer 16 in the lens is activated (step S122). Then, information on the current focal length in the lens and information on an aperture value that can be set are read out and stored in a RAM or the like in the camera body 101 (step S123).

  Next, power supply to the lens is turned off by the lens detection circuit 11 (step S124), this subroutine is terminated, and the process returns to step S3 in FIG.

  If the lens discrimination result in step S121 is a single focus lens, lens information is read from the previously stored EEPROM and stored in the RAM or the like in the camera body 101 (step S125). Then, this subroutine is terminated, and the process returns to step S3 in FIG.

  Next, in step S3 of FIG. 5, if the aperture value of the mounted lens can be set to F22 from the lens specific information read in step S2, the process proceeds to step S4, and if it cannot be set, the process proceeds to step S11.

  In step S4, it is determined from the lens unique information read in step S2 whether or not the focal length value of the mounted lens exceeds 28 mm. For example, assuming that the focal length value of the lens is 105 mm, since it exceeds 28 mm, the process proceeds to step S7. On the other hand, if the focal length value of the lens is 24 mm, for example, it is smaller than 28 mm, so the process proceeds to step S5.

  As described above, in the present embodiment, when creating a foreign substance information profile, the aperture is stopped down to F22, and a subject such as a white wall is imaged. The reason is that with a general lens, when the aperture is opened, the subject image formed on the image sensor is blurred, so that it is necessary to narrow the aperture in order to clearly capture the foreign matter adhering to the optical system. .

  In this embodiment, when creating a foreign substance information profile, an ultra-wide angle lens with a short focal length is not used. One reason for this is that if an ultra-wide-angle lens is used, a wider range of the subject, such as a white wall, is captured than necessary, so that stains on the wall may be reflected in the image. This is because it may be erroneously detected as a foreign matter adhering to the optical system of the lens. In addition, since the angle of incidence of the light beam on the image sensor increases as the lens becomes wider, the position of the shadow of the foreign object on the image sensor depends on the distance from the surface of the low-pass filter or the like to which the foreign object is attached to the image sensor. This is because the deviation of the angle increases and it becomes difficult to detect the exact position of the foreign matter.

  Next, in step S5, parameters read from the lens are checked. If the mounted lens is a zoom lens and the focal length can be set to 28 mm or more, the process proceeds to step S6. If it is not a zoom lens, or if the focal length cannot be set to 28 mm or more, the process proceeds to step S11. When a zoom lens and a lens whose focal length can be set to 28 mm or more is attached, a warning by the GUI shown in FIG. 8 is displayed in step S6, and the zoom lens is set to the tele side (telephoto side) to the user. Prompt and return to step S4.

  In step S7, shooting preparation and date display are performed. In step S8, the user is inquired whether or not to continue the process. If the user continues the process, the process proceeds to step S9. If the process is interrupted, the process ends.

  In step S9, in order to create a foreign substance information profile, a white wall or the like is photographed in response to a release instruction from the user, and the surface of an optical element such as a low-pass filter disposed on the imaging surface of the imaging element or in front of the imaging element. Take a picture of foreign matter such as adhering dust. Then, information on the coordinates and size of foreign matter such as dust adhering to the imaging surface of the imaging element or the surface of the optical element is generated by the image processing unit arranged in the imaging unit 40 and stored as a profile. .

  That is, the user can generate a foreign matter information profile by setting the digital camera to the foreign matter information profile creation mode and photographing a single gradation subject (white wall or the like) that is free from scratches and dirt. At this time, the user needs to shoot a single-tone object without scratches or dirt, but if the photographic object is not suitable for foreign object information profile generation, the user re-shoots (step S10). Specifically, when a substantially uniform image has not been captured or there is a region with insufficient brightness in part, it is determined that the image is not suitable for foreign object information profile generation.

  The generated foreign object information profile is stored in a memory in the camera body 101.

  If it is determined in step S3 that the attached lens is not suitable for foreign object information profile generation, a GUI warning as shown in FIG. 9 is displayed, and the process ends (step S11).

  The generated foreign substance information profile is saved in the header portion of the JPEG file when a photograph is actually taken with a digital camera and saved as a JPEG file. Hereinafter, the information written in the header part will be described in detail.

  Image data taken by a digital camera is recorded in a format that complies with the image file format standard for JEITA digital still cameras (hereinafter referred to as the Exif standard). The Exif standard defines two types of file formats, an uncompressed data file and a compressed data file. The uncompressed data format is compatible with TIFF Rev. 6.0, and the compressed data format is a format conforming to the JPEG format.

  FIG. 10 shows the structure of the JPEG format. In the JPEG format, an application marker segment (APP1) is described immediately after an SOI (Start of Image) marker indicating the beginning of a file. Following this, a quantization table (DQT), a Huffman table (DHT), a frame header (SOF), a scan header (SOS), entropy encoded data, and an entropy encoded data end code (EOI) are described in order. Yes.

  FIG. 11 is a diagram illustrating the internal structure of APP1.

  A thumbnail image can be recorded in the structure of APP1, and the thumbnail image is recorded independently of the main image data. Two Image File Directories (IFD) can be described in a single file. The IFD described at the beginning of this file is called “0th JPEG IFD”. In the 0th IFD, information on the main image, that is, the primary image is described. The IFD following the 0th IFD is called “1st IFD”, and describes information related to a thumbnail image.

  Following the APP1 marker 1227, the APP1 length 1228 describes the field length of APP1. The Exif Identifier 1229 includes a fixed value indicating Exif. A “0th IFD pointer” 1231 is written after the header 1230, and this pointer indicates the head address of the 0th IFD. Following the “0th IFD pointer” 1231, the IFD (“0th IFD for Primary Data” 1233) related to the main image is described below with the entry count code 1232 at the head. The “0th IFD for Primary Data” 1233 includes an image width, an image height, an Exif IFD pointer, and the like.

  Following “0th IFD for Primary Data” 1233, “1st IFD pointer” 1234 is described, and specific data of “0th IFD” (“Value of 0th IFD” 1235) is described below. When “1st IFD” does not exist in the file, a terminal code (terminal) is described instead of “1st IFD pointer” 1234.

  After “Value of 0th IFD” 1235, “Exif Private Tag” 1237 is described below with the entry count code 1236 at the head. The “Exif Private Tag” 1237 includes Exif version information, manufacturer notes, and the like.

  In the manufacturer note area, a foreign substance information profile stored in a memory in the digital camera used is stored.

  A terminal 1238 is described at the end of the “Exif Private Tag” 1237, and the terminal 1238 is followed by an Exif data value 1239 and manufacturer note data 1240. Below that, the IFD (“1st IFD for thumbnail Data” 1242) related to the thumbnail image is described, starting with the entry count code 1241. “1st IFD for thumbnail Data” 1242 includes the width of the image and the height of the image. Following the terminal 1243, the 1st IFD Value (“Value of 1st IFD”) 1244 and thumbnail image data 1245 are described, followed by the main image data.

  Specifically, the foreign substance information profile in this maker note area has a structure as shown in FIG. As shown in FIG. 12, the foreign substance correction data stores lens information and information on the position and size of the foreign substance when the detection image is captured. More specifically, the actual aperture value (F value) at the time of detection image shooting and the lens pupil position at that time are stored as lens information at the time of detection image shooting. Subsequently, the number of detected foreign substance areas (integer value) is stored in the storage area, and subsequently, the specific parameters of the specific foreign substance areas are repeatedly stored by the number of foreign substance areas. The parameter of the foreign substance area is a set of three numerical values including the radius of the foreign substance (for example, 2 bytes), the x coordinate (for example, 2 bytes) of the center in the effective image area, and the y coordinate (for example, 2 bytes) of the center.

Next, how to obtain the position (coordinates) and size of the foreign substance region from the captured image will be described.
First, the captured image region is divided into a plurality of blocks, the maximum luminance Lmax and the average luminance Lave in the block are calculated, and the threshold value T1 in the block is calculated using the following equation.

T1 = Lave × 0.6 + Lmax × 0.4
Next, a pixel that does not exceed the threshold value T1 is defined as a foreign substance pixel, and an isolated area constituted by the foreign substance pixel is defined as one foreign substance area di (i = 0, 1,..., N).

  FIG. 13 is a diagram showing an outline of foreign object region size calculation. As shown in FIG. 13, for each foreign substance area, the maximum value Xmax and the minimum value Xmin of the horizontal coordinates of the pixels constituting the foreign substance area, the maximum value Ymax and the minimum value Ymin of the vertical coordinates are obtained, and the foreign substance area di The radius ri representing the size of is calculated by the following equation.

ri = √ [{(Xmax−Xmin) / 2} ² − {(Ymax−Ymin) / 2} ² ]
Further, the central coordinates (Xdi, Ydi) at this time are approximately Xdi = (Xmax + Xmin) / 2.
Ydi = (Ymax + Ymin) / 2
Sought in The position (coordinates) and radius determined in this way are recorded as a foreign substance information profile.

  As described above, the foreign substance information profile generated by the method of the above embodiment adheres to the surface of an optical element such as a low-pass filter disposed on the imaging surface of the imaging element of the camera or in front of the imaging element. It contains information on the position and size of the foreign object. For this reason, it is possible to identify the position and size of the shadow of the foreign object from an image obtained by normal photographing and correct the image to remove the influence of the foreign object. As a method of correcting the image, a method of interpolating an image of a portion where a shadow of a foreign object is reflected with image information of surrounding pixels can be considered. As another method, a plurality of images with slightly different framing are taken, and an image at a position where a foreign object in one image is reflected is interpolated with an image at a position where the foreign object is not reflected in another image. And so on. Image processing for correcting these images may be performed in the camera body, or may be performed in the external image processing apparatus by transferring the image data to the external image processing apparatus. This external image processing apparatus may be configured as an apparatus that specializes in image processing, or may be configured as an apparatus that performs an image processing function by operating application software on a personal computer.

  As described above, if a foreign object information profile including information on the position and size of a foreign object is obtained by the method of the present embodiment, the information is corrected using the information, and a captured image without the influence of the foreign object can be obtained. It becomes possible.

  In this embodiment, the focal length is set to 28 mm or more and the aperture value is set to F22 as the lens parameters for obtaining a stable quality foreign matter information profile. However, these parameter values vary depending on conditions, and values other than the above set values are used. May be adopted.

  In this embodiment, the focal length and the aperture value are listed as the limited items of the lens that can obtain the foreign substance information profile with stable quality. However, as a limited item, a lens (short back focus) having a smaller distance between the exit pupil and the imaging surface is not used, and a special lens such as a TS lens is not used.

  Further, in the present embodiment, the foreign substance information profile has been described on the assumption that the position of dust is specified from an image obtained by photographing a single gradation subject, and data in which the coordinates and size are recorded is stored in the header of the image file. . However, the foreign substance information profile may be image data obtained by photographing a uniform surface, or information other than dust coordinate data that can be derived from the image data.

(Other embodiments)
The object of each embodiment is also achieved by the following method. That is, a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded is supplied to the system or apparatus. Then, the computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but the present invention includes the following cases. That is, based on the instruction of the program code, an operating system (OS) or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  Furthermore, the following cases are also included in the present invention. That is, the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, a CPU or the like provided in the function expansion card or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  When the present invention is applied to the above storage medium, the storage medium stores program codes corresponding to the procedure described above.

It is sectional drawing which shows the structure of the digital single-lens reflex camera system which is one Embodiment of the imaging device of this invention. It is a figure which shows the structure of the electric control block in the state which attached the zoom lens as an interchangeable lens to the camera main body of the interchangeable lens digital single-lens reflex camera concerning one Embodiment. It is a figure which shows the structure of the electric control block in the state which mounted | wore the camera main body of the interchangeable lens digital single-lens reflex camera concerning one Embodiment with the single focus lens as an interchangeable lens. It is a flowchart which shows the operation | movement at the time of lens mounting | wearing detection in the digital camera of one Embodiment. It is a flowchart which shows the production | generation operation | movement of the foreign material information profile in the digital camera of one Embodiment. It is a subroutine which shows the operation | movement which reads the specific information of the lens performed by step S2 of FIG. It is a figure which shows GUI displayed on a display, when a lens is mounted | worn with a camera main body. It is a figure which shows GUI displayed on a display when a zoom lens is attached to a camera body. It is a figure which shows GUI displayed on a display, when an inappropriate lens is mounted | worn in order to produce a foreign substance information profile in a camera body. It is a figure which shows the structure of a JPEG format. It is a figure explaining the internal structure of APP1. It is a figure which shows the example of a foreign material information profile format. It is a figure which shows the outline | summary of dust area size calculation.

Claims (7)

A main body for mounting the lens interchangeably;
An image sensor that photoelectrically converts a subject image;
Communication means for communicating with the lens;
Acquisition means for acquiring information specific to the lens from the lens by the communication means;
Based on a foreign object detection image including an image of a foreign object attached to the surface of the image sensor or the surface of an optical element disposed in front of the image sensor as captured by the image sensor, at least the foreign object Foreign matter information generating means for generating foreign matter information, which is information including position and size information;
When it is determined that the lens mounted on the main body is an inappropriate lens for capturing the foreign object detection image based on the information specific to the lens acquired by the acquisition unit. A regulation means for prohibiting the detection image from being captured;
An imaging apparatus comprising:   The lens-specific information acquired by the acquisition unit includes at least focal length information of the lens, minimum aperture value information of the lens, and information on whether a single-focus lens or a zoom lens is used. The imaging apparatus according to 1.   The imaging according to claim 2, further comprising warning output means for outputting a warning to a user when a lens inappropriate for taking the foreign object detection image is attached to the main body. apparatus.   The imaging apparatus according to claim 3, wherein the warning output unit outputs a warning that prompts the user to set the zoom position to the telephoto side when a zoom lens is attached to the main body. A method for controlling an image pickup apparatus including a main body unit in which a lens is replaceably mounted and an image pickup device that photoelectrically converts a subject image,
An acquisition step of communicating with the lens and acquiring information specific to the lens from the lens;
Based on a foreign object detection image including an image of a foreign object attached to the surface of the image sensor or the surface of an optical element disposed in front of the image sensor as captured by the image sensor, at least the foreign object A foreign matter information generation step for generating foreign matter information, which is information including position and size information;
When it is determined that the lens attached to the main body is an inappropriate lens for capturing the foreign object detection image based on the information specific to the lens acquired in the acquisition step. A regulatory process that prohibits the detection of images for detection;
An image pickup apparatus control method comprising:   A program for causing a computer to execute the control method according to claim 5.   A computer-readable storage medium storing the program according to claim 6.

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