JP2010147612A - Camera and camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that snapshot nature and a frame speed are influenced, if the transmission/reception of information for the optical characteristics of a photographing lens used for image processing is performed with respect to all the object images. <P>SOLUTION: An image processing means discriminates objects and does not perform transmission/reception of the information for the optical characteristics of the photographic lens, from the photographing lens to a camera in the case of an object image that does not need correction processing by the contrast or straightness of the object image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera that performs image processing on an image obtained by an image sensor.

  A digital camera photoelectrically converts an optical image formed by a photographic lens (lens device) provided with a photographic optical system by an image sensor such as a CCD (Charge Coupled Device), and performs image processing on an output image signal as a memory. It is stored in a recording medium such as a card.

  Among such digital cameras, there is also an interchangeable lens type digital camera (camera system).

  In an interchangeable lens camera system, lenses with various focal lengths can be freely combined depending on the photographing situation, and a photographing lens for a interchangeable lens camera using a film can often be used.

  Accordingly, the photographed image may not be the image intended by the photographer due to the inherent optical characteristics of the photographing lens, such as distortion (distortion aberration), shading (peripheral dimming), and lateral chromatic aberration.

  If these aberrations are present, an image of the subject cannot be accurately captured.

  As a solution to the above problem, Patent Document 1 includes a circuit that stores information related to optical characteristics of the photographing lens such as distortion information and shading information in the photographing lens.

  When the photographic lens is attached to the camera, information on all the optical characteristics stored in the storage circuit is sent to the camera.

  Thereafter, there has been proposed a camera system that corrects an image signal obtained from an image sensor using information on these optical characteristics in the camera and stores a high-quality image in a memory.

Patent Document 2 stores information on the optical characteristics of the photographic lens in the photographic lens, and transmits information on the optical characteristics from the photographic lens to the camera after the completion of the imaging preparation sequence such as autofocus operation and photometry operation. A camera system has been proposed.
JP-A-2-123879 JP 2004-112529 A

  In the camera system proposed in each of the above publications, information regarding the optical characteristics of the photographing lens represented by distortion, shading, lateral chromatic aberration, and the like is stored in advance in a storage circuit provided in the photographing lens for each photographing lens.

  A configuration in which the camera accesses the storage circuit of the photographing lens to read information, or transmits all information stored in the storage circuit on the photographing lens side to the camera side when the photographing lens is mounted on the camera. Has been adopted.

  By the way, in the above conventional example, information on the optical characteristics of the photographing lens is always transmitted from the photographing lens to the camera regardless of the shape, contrast, brightness, etc. of the subject, and the image signal obtained from the image sensor is corrected.

  However, the influence of aberrations such as distortion and lateral chromatic aberration does not necessarily appear for all subjects, and there are subjects that are easily noticeable and subjects that are not easily noticeable.

  For example, distortion tends to be noticeable on subjects with many straight lines to the periphery of the screen, such as architectural photography, but less noticeable on people and sports photos.

  Further, chromatic aberration of magnification tends to appear at the edge portion of a subject with high contrast.

  Patent Document 1 is configured to send information about all the optical characteristics stored in the photographing lens to the camera when the photographing lens is attached to the camera, and the time required for this communication can start photographing. First, there was a problem with the quickness.

  In addition, in the interchangeable lens digital camera system, it is necessary to perform an autofocus operation and a photometric operation as an imaging preparation operation at a timing intended by the photographer, and on the other hand, a fast shooting property is required.

  For this reason, if transmission / reception of information relating to the optical characteristics of the photographic lens used for image processing from the photographic lens to the camera is performed during the imaging preparation operation, the imaging preparation operation may be delayed, which may hinder the rapid photographing.

  For this reason, Patent Document 2 proposes a camera system that transmits information about optical characteristics from the photographing lens to the camera after the completion of the imaging preparation sequence such as autofocus operation and photometry operation, that is, during shutter release.

  However, if there is a large amount of data sent from the photographic lens to the camera and the shutter time is short, the communication speed of the next frame will be delayed because the data communication will not be completed during the release, and the frame speed will slow down. was there.

  The present invention eliminates the above-described problems and prevents communication of information relating to optical characteristics of a photographing lens used for image processing in a subject image in which aberrations such as distortion and lateral chromatic aberration are not conspicuous by determining the subject. To do.

  Accordingly, it is an object of the present invention to provide a camera and a camera system that can reduce the communication amount and eliminate the influence on the rapid shooting performance and the frame speed.

  To achieve the above object, the present invention is detachable from a lens apparatus comprising a photographing optical system and storage means for storing optical characteristic information relating to the optical characteristics of the photographing optical system. The camera is capable of communication, and the camera includes an image sensor that photoelectrically converts a subject image formed by the photographing optical system, and an image processing unit that performs correction processing on an image signal output from the image sensor. The image processing means acquires a contrast value of the subject image from the image signal, and when the contrast value is higher than a predetermined value, causes the lens device to transmit the optical characteristic information to the camera, and When the contrast value is lower than a predetermined value, the optical characteristic information is not transmitted from the lens device to the camera.

  According to a second aspect of the present invention, there is provided a detachable lens apparatus comprising a photographic optical system and storage means for storing optical characteristic information relating to the optical characteristics of the photographic optical system. The camera is capable of communication, and the camera includes an image sensor that photoelectrically converts a subject image formed by the photographing optical system, and an image processing unit that performs correction processing on an image signal output from the image sensor. The image processing unit obtains the linearity value of the subject image from the image signal, and when the linearity value is higher than a predetermined value, causes the lens device to transmit the optical characteristic information to the camera. The optical characteristic information is not transmitted from the lens apparatus to the camera when the linearity value is lower than a predetermined value.

  The present invention relates to a system for improving the image quality of an image obtained by an image sensor by image processing.

  When photographing a subject in which an object image is discriminated and distortion, chromatic aberration of magnification and the like are not conspicuous and image processing is not necessary, communication of optical characteristic information of a photographing lens used for image processing is not performed between the camera and the lens.

  As a result, it is possible to provide a camera that can reduce the amount of communication between the camera and the lens and reduce the effect on the speed and the frame speed.

Example 1
FIG. 1 shows the configuration of an interchangeable lens digital camera system that is an embodiment of the present invention.

  The camera system includes a photographic lens 10 and a digital camera 40.

  The taking lens 10 is a zoom lens that can be attached to and detached from the camera 40.

  In the photographic lens of this embodiment, the photographic optical system for forming a subject image is composed of a fixed first lens 11, second lens 12, third lens 13, and fixed fourth lens 14. It is composed of groups.

  The second lens 12 is a lens for zooming, and the third lens 13 is a lens for focusing.

  An aperture unit 15 is disposed in the photographing optical system.

  A light beam from a subject (not shown) is guided to the movable mirror 41 in the camera 40 via the first lens 11, the second lens 12, the aperture unit 15, the third lens 13, and the fourth lens 14.

  In addition, a zoom encoder 17, a focus encoder 18, and an aperture encoder 20 for detecting the positions of the second lens 12 and the third lens 13 and the aperture state of the aperture unit 15 are provided in the photographing lens 10. The lens control circuit 21 is connected.

  Connected to the lens control circuit 21 are a zoom drive circuit 24 that drives the zoom motor 25, a focus drive circuit 26 that drives the focus motor 27, and an aperture drive circuit 28 that drives the aperture motor 29. Each drive circuit operates in accordance with a control signal from the lens control circuit 21.

  The lens control circuit 21 is connected with a lens switch input circuit 30 and a nonvolatile memory (EEPROM) 31.

  Further, the lens control circuit 21 is provided with a communication controller 21 a that performs communication with the camera 40 via the communication line 32 and the communication contact 33.

  The lens control circuit 21 controls the zoom motor 25 via the zoom drive circuit 24 to drive the lens 12. The initial position and stop position of the lens 12 are detected by counting pulse signals output from the zoom encoder 17 according to the movement of the lens 12.

  Then, the zoom motor 25 is feedback-controlled using the detected position information.

  The lens control circuit 21 controls the focus motor 27 via the focus drive circuit 26 to drive the lens 13.

  The initial position and stop position of the lens 13 are detected by counting the pulse signals output from the focus encoder 18 according to the movement of the lens 13. Then, the focus motor 27 is feedback-controlled using the detected position information.

  Further, the lens control circuit 21 controls the operation of the aperture unit 15 via the aperture drive circuit 28.

  The initial state and the aperture position of the aperture unit 15 are detected by counting the pulse signals output from the aperture encoder 20 according to the operating state of the aperture unit 15.

  Then, the aperture motor 29 is feedback-controlled using the detected operation state information.

  In this way, the lens control circuit 21 performs overall control of the zoom drive circuit 24, the focus drive circuit 26, and the aperture drive circuit 28 based on the outputs of the zoom encoder 17, the focus encoder 18, and the aperture encoder 20.

  Then, various operations necessary for overall control are performed.

  The lens control circuit 21 communicates with the camera 40 at any time via the communication controller 21 a, the communication line 32, and the communication contact 33, and reflects it in the control of each circuit in the photographing lens 10. And it transmits to the information camera 40 showing the information (optical characteristic information) regarding the optical characteristic of the taking lens 10 mentioned later, and the state of the taking lens 10.

  In the non-volatile memory 31 as the storage means, optical characteristic information of the photographing optical system unique to the photographing lens 10, specifically, information on distortion and information on chromatic aberration of magnification according to the positions and aperture values of the lenses 12 and 13 are stored. Is remembered.

  “Distortion” refers to the aberration in which an image of an object projected through a taking lens does not resemble the object, for example, a straight line is distorted. “Shading” refers to the periphery of the screen compared to the center of the screen. This means that the amount of light is reduced and darkened.

  “Magnification chromatic aberration” means that when the light from the subject is decomposed into a plurality of color lights and imaged on the imaging surface, the refractive index varies depending on the wavelength. Appears as a difference in image magnification and means color shift.

  The optical characteristic information of the photographing optical system specific to the photographing lens 10 may be any information as long as it is used for correction processing in the image processing process of the image captured by the camera 40.

  The nonvolatile memory 31 also stores optical characteristic information necessary for focusing control, which is different from or partially overlapped with the optical characteristic information of the photographing optical system used for the image processing described above.

  The information indicating the state of the photographing lens 10 is information such as the state of various lens switches, the lens position and the aperture state obtained through the encoders.

  The lens switch input circuit 30 transmits the state of a switch (not shown) provided in the photographing lens 10 to the lens control circuit 21.

  In this embodiment, a zoom selection switch for setting the zoom state to tele, middle and wide is provided as a switch provided in the photographing lens 10 as the lens device.

  When the zoom selection switch is operated by the photographer, the lens control circuit 21 detects the operation via the lens switch input circuit 30, and zooms via the zoom drive circuit 24 so that the selected zoom state is obtained. The motor 25 is controlled to move the second lens 12.

  Next, the configuration on the camera 40 side will be described.

  The subject light that has passed through the photographing lens 10 is incident on the movable mirror 41 having a half mirror at the substantially central portion.

  A sub-mirror 42 that reflects the light beam that has passed through the movable mirror 41 is provided on the central back side of the movable mirror 41.

  The light beam reflected downward by the sub mirror 42 is separated into two light beams by the separator optical system 43, and two images are formed on the pair of CCD line sensors 44.

  The separator optical system 43 and the CCD line sensor 44 constitute a focus detection unit for detecting the focus adjustment state (focus detection) of the photographing optical system.

  A signal photoelectrically converted and output by the CCD line sensor 44 is input to a focus detection circuit 69. The focus detection circuit 69 detects the phase difference between the two images formed on the pair of CCD line sensors 44, and the detection result. Is input to the camera control circuit 55.

  A camera control circuit 55 serving as an image processing unit calculates a focus shift amount (defocus amount) of the photographing optical system based on the input signal representing the phase difference.

  That is, focus detection by the phase difference detection method is performed.

  Then, the camera control circuit 55 transmits information representing the calculated defocus amount to the lens control circuit 21 via the communication controller 55a, the communication line 65, and the communication contact 66 provided in the camera control circuit 55.

  The lens control circuit 21 obtains the driving amount of the lens 13 (that is, the focus motor 27) necessary for obtaining the focus based on the received defocus amount information, and drives the focus motor 27 by the driving amount. .

  Thereby, automatic focusing control is performed.

  Further, the camera of the present embodiment can perform hill-climbing focus detection (TV-AF) in addition to the phase difference detection focus detection.

  When hill-climbing focus detection is performed, the movable mirror 41 is moved up and the shutter 50 is opened to form a subject image on the image sensor 52.

  Then, charge accumulation in the image sensor 52 is started.

  The image processing circuit 62 and the camera control circuit 55 detect the contrast of the subject image formed on the image sensor 52 and acquire the value.

  The third lens 13 for focusing is finely driven so that this contrast is maximized.

  This micro drive command is issued by communication to the photographic lens as in the phase difference detection method.

  The automatic focusing control ends at the lens position where the contrast is maximized.

  Note that, as a configuration in which the movable mirror 41 is a full-surface half mirror, a method of forming an object image on the image sensor 52 without moving the movable mirror 41 may be used.

  In that case, hill-climbing focus detection is possible without moving the movable mirror 41 upward.

  On the other hand, a focusing plate 46, a pentaprism 47, and an eyepiece optical system 48 that constitute a finder optical system are disposed on the reflected light path of the subject light flux by the movable mirror 41.

  Further, behind the movable mirror 41, a shutter 50, an optical low-pass filter 51, and an image sensor 52 are arranged.

  The image sensor 52 is composed of a CCD, a CMOS sensor, or the like, and photoelectrically converts a subject image formed on the light receiving surface and outputs an image signal.

  The image sensor 52 is driven and controlled by an image processing circuit 62 that has received an imaging command from the camera control circuit 55.

  When the movable mirror 41 is moved upward and the shutter 50 is opened, a subject image is formed on the image sensor 52 and charge accumulation in the image sensor 52 is started.

  When the charge accumulation is completed, the shutter 50 is closed.

  Connected to the camera control circuit 55 are a mirror drive circuit 56, a line sensor drive circuit 57, a focus detection circuit 69, a shutter drive circuit 58, a photometric sensor drive circuit 59, an image processing circuit 62, and a strobe circuit 63, all of which. Control the operation of the circuit.

  In addition, a shutter detection circuit 61 and a switch input circuit 64 are connected to the camera control circuit 55.

  The mirror driving circuit 56 drives the movable mirror 41 so as to advance and retract with respect to the photographing optical path.

  When the movable mirror 41 is in the photographing optical path, the subject light flux is guided to the finder optical system, and when the movable mirror 41 is retracted from the photographing optical path, the subject light flux is guided to the image sensor 52.

  The line sensor drive circuit 57 drives the line sensor 44.

  The shutter drive circuit 58 drives the shutter 50 for controlling the amount of light received by the image sensor 52.

  Further, a photometric sensor 60 for measuring the luminance of the subject is provided in the vicinity of the upper part of the pen prism 47 and the eyepiece optical system 48.

  The photometric sensor 60 is driven by a photometric sensor drive circuit 59.

  The output from the photometric sensor 60 is input to the camera control circuit 55, and the camera control circuit 55 calculates the luminance of the subject light based on the input signal.

  The shutter detection circuit 61 detects the open / closed state of the shutter 50.

  The image processing circuit 62 converts the image signal (analog signal) output from the image sensor 52 into a digital signal, and then performs correction processing using the optical characteristic information of the photographing lens 10 described above.

  An image corresponding to the corrected image signal is recorded on a recording medium (not shown) (semiconductor memory, magnetic disk, optical disk, etc.) that is detachably attached to the camera 40.

  Details of the image processing circuit 62 will be described later.

  The strobe circuit 63 drives a light emitting unit (not shown) for illuminating the subject.

  The switch input circuit 64 detects the states of various operation switches provided in the camera 40 and inputs detection signals to the camera control circuit 55.

  There is a release switch as an operation switch on the camera 40 side.

  The release switch outputs a SW1ON signal for starting an imaging preparation operation sequence, which will be described later, by a one-step depression operation, and outputs a SW2ON signal for starting an imaging sequence, which will be described later, by another one-step depression operation.

  In addition, there is a mode switch as an operation switch on the camera 40 side, and the camera control circuit 55 operates in an imaging mode (aperture priority mode, shutter speed priority mode, program mode, etc.) by operating this mode switch (according to the number of operations). Set.

  The camera 40 is provided with a power source 68.

  The power supply 68 supplies power to each circuit in the camera 40 and also supplies power to the photographing lens 10 via the communication contact 66.

  FIG. 2 shows the configuration of the image processing circuit 62 described above.

  The image processing circuit 62 includes a control unit 71, an A / D conversion unit 72, an image processing unit 73, a buffer memory unit 74, an external recording unit 75, and a correction value memory unit 76. The

  In addition, the image processing unit 73, the buffer memory unit 74, the external recording unit 75, and the correction value memory unit 76 are connected by a common data bus 77 so that data can be exchanged.

  Further, the operations of the A / D conversion unit 72, the image processing unit 73, the buffer memory unit 74, the external recording unit 75, and the correction value memory unit 76 are controlled by the control unit 71 that receives a control signal from the camera control circuit 55. The

  The control unit 71 also performs drive control of the image sensor 52.

  In FIG. 2, the analog image signal output from the image sensor 52 is converted into a digital signal by the A / D conversion unit 72 and input to the image processing unit 73.

  The control unit 71 temporarily stores in the correction value memory unit 76 each piece of information (hereinafter referred to as correction data) regarding the optical characteristics of the shooting lens 10 transmitted from the shooting lens 10 side.

  The image processing unit 73 performs various correction processes such as distortion correction and magnification color correction on the digital image signal input from the A / D conversion unit 72 using the correction data stored in the correction value memory unit 76. At the same time, processing such as image compression is performed.

  Then, the image signal processed by the image processing unit 73 is stored in the buffer memory unit 74 and further transferred to the external recording unit 75, and the recording medium detachably mounted on the camera 40 described above. To be recorded.

  Further, in this embodiment, the image processing unit 73 performs subject discrimination.

  Specifically, the contrast value of the subject image is acquired and determined.

  If the subject image has a high contrast as shown in FIG. 5A, the chromatic aberration of magnification is easily noticeable, and correction data relating to the chromatic aberration of magnification is received from the photographing lens 10.

  In the case of a subject image with a low contrast as shown in FIG. 5B, the chromatic aberration of magnification is not conspicuous, so that correction data relating to the chromatic aberration of magnification is not received from the photographing lens 10 to reduce the amount of communication.

  Next, the operation of the camera 40 (mainly the camera control circuit 55) in this embodiment will be described with reference to the flowchart of FIG.

  When a power switch (not shown) is turned on, the camera control circuit 55 starts operating.

[Step (denoted as S in the figure) 101]
The camera control circuit 55 determines whether or not the SW1ON signal is input from the switch input circuit 64.

  If it has been input, the process proceeds to the next step 102 to perform subject discrimination.

  If not, the process returns to step 101.

[Step 102]
If SW1 is ON, the subject discrimination routine is executed.

  The details of the subject determination routine will be described later. In this routine, the contrast and shape of the subject image are determined, and it is determined whether or not the current subject image needs image correction.

  Here, in order to perform subject discrimination, it is necessary to form a subject image on the image sensor 52, so the shutter 50 is opened.

  At the same time, it is necessary to move the movable mirror 41 upward. However, in the case of performing phase difference type focus detection, it is necessary to form a subject image on the CCD line sensor 44, so it is preferable to use a half mirror configuration. .

[Step 103]
In step 103, the camera preparation circuit starts, and the camera control circuit 55 activates the photometric sensor driving circuit 59, and uses the output from the photometric sensor 60 and the F number of the photographing lens 10 to use the shutter speed used in the imaging sequence described later. And determine the aperture value.

[Step 104]
Next, the camera control circuit 55 activates the line sensor drive circuit 57 and the focus detection circuit 69 and calculates the defocus amount based on the output obtained from the focus detection circuit 69.

[Step 105]
The camera control circuit 55 transmits information indicating the defocus amount calculated in step 103 to the lens control circuit 21 as a focus drive command.

  In this embodiment, the case where the camera control circuit 55 transmits defocus amount information to the lens control circuit 21 is described.

  However, the camera control circuit 55 may determine the driving amount of the lens 13 based on the defocus amount information and the optical information of the photographing lens 10, and transmit the determined driving amount information to the lens control circuit 21. .

  In this case, by the initial communication when the photographing lens 10 is mounted on the camera 40, the camera control circuit 55 takes in the optical characteristic information of the photographing lens 10 necessary for calculating the driving amount of the lens 13, and the memory (FIG. (Not shown) should be memorized.

[Step 106]
When the camera control circuit 55 receives from the lens control circuit 21 that the driving of the lens 13 has been completed, the camera control circuit 55 again calculates the defocus amount based on the output from the focus detection circuit 69.

  Then, it is determined whether or not the calculated defocus amount is within a predetermined allowable range (that is, whether or not the subject is in focus).

  If not in focus, the process returns to step 101 again. If in focus, the process proceeds to the next step 107.

  With this focus determination, the imaging preparation sequence ends.

[Step 107]
After the imaging preparation sequence ends, the camera control circuit 55 determines whether or not the SW2 ON signal is input from the switch input circuit 64.

  If it has not been input, the process returns to step 101. If it has been input (if the start of the imaging sequence is instructed), the process proceeds to step 108.

[Step 108]
If it is determined in the subject determination routine in step 102 that correction data for performing various image correction processes is necessary, the process proceeds to step 109. If it is determined that correction data is not necessary, the process proceeds to step 110.

[Step 109]
The camera control circuit 55 transmits to the lens control circuit 21 a communication command that requests transmission of correction data relating to the optical characteristics of the photographing lens 10 used for image processing in the image processing circuit 62.

  Here, the correction data requested to be transmitted by the communication command may be a part of the various correction data described above, or may be data corresponding to the aperture value determined in step 103 and the positions of the lenses 12 and 13. Good.

  As a result, the transmission / reception amount of correction data can be minimized.

  In this case, the communication command may be different depending on the type of correction data to be requested, or information indicating the aperture value determined in step 103 may be included.

  The camera control circuit 55 receives the correction data transmitted from the lens control circuit 21 that has received the communication command, and stores the correction data in the correction value memory unit 76 (see FIG. 2) in the image processing circuit 62.

[Step 110]
The camera control circuit 55 transmits an aperture drive command for driving the aperture unit 15 to the aperture value determined in step 103 to the lens control circuit 21.

[Step 111]
Next, the camera control circuit 55 causes the movable mirror 41 to move up through the mirror drive circuit 56.

[Step 112]
Next, the camera control circuit 55 operates the shutter 50 at the shutter speed determined in step 103 through the shutter drive circuit 58.

  Simultaneously with the shutter opening operation, charge accumulation by photoelectric conversion in the image sensor 52 is started through the control unit 71 of the image processing circuit 62.

  If the shutter has already been opened in order to determine the subject in step 102, the shutter operation is performed with the electronic shutter.

[Step 113]
When the operation of the shutter 50 is completed (charge accumulation in the image sensor 52 is completed), the camera control circuit 55 transmits a command to drive the aperture unit 15 to the lens control circuit 21 in the open state.

[Step 114]
Next, the camera control circuit 55 causes the movable mirror 41 to perform a down operation through the mirror drive circuit 56 and then returns to step 101.

  In the present embodiment, a case has been described in which the photographic lens 10 is requested to receive correction data necessary for image processing in response to the start of an imaging sequence (input of SW2 ON).

  However, for example, if a plurality of types of correction data are requested in step 109, a command requesting transmission of all types of correction data may be transmitted in step 109, and the correction data may be received collectively. Good.

  Alternatively, the correction data may be requested or received in a divided manner at any timing from the step 110 to the end of the operation of the step 114.

  Next, the operation of the taking lens 10 (mainly the lens control circuit 21) will be described with reference to the flowchart of FIG.

  When the power supply from the camera 40 is started, the lens control circuit 21 is activated. The lens control circuit 21 operates the switch on the photographing lens 10 side, the lens according to the analysis result of the command transmitted from the camera control circuit 55, and the like. Drive control processing and information transmission processing.

[Step 201]
The lens control circuit 21 determines whether a signal (zoom selection signal) from the zoom selection switch for changing the focal length is input from the lens switch input circuit 30.

  If it has been input, the process proceeds to step 202. If it has not been input, the process proceeds to step 203.

[Step 202]
The lens control circuit 21 compares the zoom state (tele, middle, or wide) corresponding to the zoom selection signal from the zoom selection switch with the current zoom state.

  If they are different, the lens 12 (zoom motor 25) is driven through the zoom drive circuit 24 so as to be in a zoom state corresponding to the zoom selection signal.

  Thereafter, the process returns to step 201.

[Step 203]
The lens control circuit 21 determines whether or not the command transmitted from the camera control circuit 55 is a correction data transmission request command related to the optical characteristics of the photographing lens 10 used for image processing.

  If it is a correction data transmission request command, the process proceeds to step 204; otherwise, the process proceeds to step 205.

[Step 204]
When the lens control circuit 21 determines that it is a correction data transmission request command, the lens control circuit 21 further analyzes what type of correction data the transmission request command requires, and stores the correction data stored in the nonvolatile memory 31. The requested correction data is transmitted to the camera control circuit 55.

  Thereafter, the process returns to step 201.

[Step 205]
The lens control circuit 21 determines whether or not the command transmitted from the camera control circuit 55 is a focus drive command.

  If it is a focus drive command, the process proceeds to step 206;

[Step 206]
The lens control circuit 21 determines the defocus amount information and information related to the optical characteristics of the photographing lens 10 necessary for determining the driving amount of the lens 13 (as described above, different from the correction data used for image processing). Or the amount of driving of the lens 13 is calculated based on the information partially overlapped).

  Then, the focus motor 27 is driven for the calculated drive amount.

  Thereafter, the process returns to step 201.

[Step 207]
The lens control circuit 21 determines whether or not the command transmitted from the camera control circuit 55 is an aperture drive command.

  If it is an aperture drive command, the process proceeds to step 208; otherwise, the process proceeds to step 209.

[Step 208]
The lens control circuit 21 drives the aperture unit 15 according to the aperture drive command so that the aperture value included in the command is obtained. Thereafter, the process returns to step 201.

[Step 209]
Here, processing corresponding to commands other than the above commands and processing for lens control are performed, and the process returns to step 201.

  Next, the operation of the subject discrimination routine of this embodiment will be described using the flowchart of FIG.

[Step 301]
The contrast of the subject image is determined, and if the subject image has a contrast higher than a predetermined value, the lateral chromatic aberration is conspicuous and the lateral chromatic aberration correction is necessary, and the routine proceeds to step 302.

  On the other hand, if the subject image has a contrast lower than a predetermined value, the chromatic aberration of magnification is not noticeable and correction of the chromatic aberration of magnification is unnecessary, and the process proceeds to step 303.

[Step 302]
It is remembered that lateral chromatic aberration correction is necessary. To store it, turn on a special flag.

[Step 303]
It is remembered that the lateral chromatic aberration correction is unnecessary.

  To store, turn off the dedicated flag.

  As described above, according to the present embodiment, communication of optical characteristic information of a photographing lens used for image processing is not performed in a subject image in which aberration such as lateral chromatic aberration is not noticeable by subject discrimination.

  As a result, it is possible to provide a camera and a camera system that can reduce the amount of communication between the camera and the lens, and can eliminate the influence on the speed and the frame speed.

(Example 2)
In the present embodiment, the straightness of the subject image is acquired and discriminated by subject discrimination performed by the image processing unit 73.

  As shown in FIG. 6A, distortion is conspicuous if the subject image has a high degree of linearity, and correction data related to distortion is received from the photographic lens 10.

  In the case of a subject image with a low linearity as shown in FIG. 6B, since distortion is not conspicuous, correction data related to distortion is not received from the photographing lens 10 to reduce the communication amount. The operation of the subject discrimination routine of this embodiment will be described using the flowchart of FIG.

[Step 401]
The straightness of the subject image is determined, and if the subject image has a straightness higher than a predetermined value, the distortion is conspicuous and distortion correction is necessary, and the process proceeds to step 305.

  On the other hand, if the subject image has a linearity lower than the predetermined value, the distortion is not noticeable and the distortion correction is unnecessary, and the process proceeds to step 406.

[Step 402]
Remember that distortion correction is required.

  To store, turn on a dedicated flag.

[Step 403]
Remember that no distortion correction is required.

  To store, turn off the dedicated flag.

  As described above, according to the present embodiment, communication of optical characteristic information of a photographing lens used for image processing is not performed in a subject image in which aberration such as distortion is not conspicuous by subject discrimination.

  As a result, it is possible to provide a camera and a camera system that can reduce the amount of communication between the camera and the lens, and can eliminate the influence on the speed and the frame speed.

  In the embodiment, the contrast and linearity of the subject image are discriminated as methods for discriminating the subject image. Of course, these may be discriminated at the same time, or the combination of these may be judged comprehensively. good.

The block diagram which shows the structure of the digital camera system in a present Example. Block diagram showing the configuration of the image processing circuit A flowchart showing the operation of the camera control circuit 55 Flow chart showing operation of lens control circuit The figure explaining the subject discrimination method The figure explaining the subject discrimination method 7 is a flowchart illustrating the operation of the subject determination method according to the first embodiment. Flowchart showing the operation of the subject discrimination method of the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shooting lens 21 Lens control circuit 31 Non-volatile memory 40 Camera 52 Image pick-up element 62 Image processing circuit

Claims (4)

A camera capable of being attached to and detached from a lens apparatus including a photographing optical system and storage means storing optical characteristic information relating to optical characteristics of the photographing optical system, and capable of communicating with the lens apparatus,
The camera includes an image sensor that photoelectrically converts a subject image formed by the photographing optical system, and an image processing unit that corrects an image signal output from the image sensor,
The image processing means acquires a contrast value of the subject image from the image signal;
When the contrast value is higher than a predetermined value, the optical characteristic information is transmitted from the lens apparatus to the camera,
The camera, wherein the optical characteristic information is not transmitted from the lens device to the camera when the contrast value is lower than a predetermined value. A camera capable of being attached to and detached from a lens apparatus including a photographing optical system and storage means storing optical characteristic information relating to optical characteristics of the photographing optical system, and capable of communicating with the lens apparatus,
The camera includes an image sensor that photoelectrically converts a subject image formed by the photographing optical system, and an image processing unit that corrects an image signal output from the image sensor,
The image processing means obtains a linearity value of the subject image from the image signal;
When the linearity value is higher than a predetermined value, the optical characteristic information is transmitted from the lens device to the camera,
The optical characteristic information is not transmitted from the lens apparatus to the camera when the linearity value is lower than a predetermined value.   The camera according to claim 1, wherein the optical characteristic information includes at least one of information on distortion and information on lateral chromatic aberration.   A camera system comprising the camera according to any one of claims 1 to 3 and the lens device.

Images