JP2006203679A - Imaging apparatus, imaging apparatus body and imaging unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce display lag of a through image in an arrangement where an imaging unit integrating an optical system and an imaging element can be attached removably to the imaging apparatus body. <P>SOLUTION: When a mode for displaying a through image is selected, a body CPU 92 inquires an imaging unit 14 for the number of pixels of an area CCD sensor 42, operates the phase difference between an imaging timing signal for driving the area CCD sensor 42 and a reproduction timing signal for regulating the reading timing of image data from the frame memory 106 such that read out of image data from the frame memory 106 is started upon elapsing a time required for writing or reading data of one line after writing of image data received from the imaging unit 14 into the frame memory 106 is started based on the number of pixels of the area CCD sensor 42, and then sets the phase difference in a reproduction TG 108. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image pickup apparatus, an image pickup apparatus main body, and an image pickup unit, and in particular, an image pickup apparatus in which an image pickup unit including an optical system and an image pickup element is detachable from the image pickup apparatus main body, and an image pickup apparatus main body constituting the image pickup apparatus. And an imaging unit.

  Recently, single-lens reflex type DSCs capable of exchanging lenses have also become widespread in digital still cameras (DSCs). Cameras with interchangeable lenses can be interchanged according to the subject to be photographed, etc., so there is an advantage that images that match the intended purpose of photographing can be easily taken.However, when lenses are exchanged, dust enters the camera body. There is a drawback that the dust that easily enters often adversely affects the image quality of the captured image. For this reason, the applicant of the present application has already provided a technique for preventing dust from entering the optical path of the imaging light by providing the imaging element on the interchangeable lens unit side and integrating the imaging element together with the optical system as a single unit. is suggesting.

  By the way, in general, an imaging device such as a digital still camera (DSC) or a digital video camera (DVC) is provided with a display device that is configured by an LCD or the like and can display an image, and an image captured by an imaging element such as a CCD. Is displayed on the display device as a through image, so that the photographer can check the photographed image at the time of photographing. In general, since the display device is driven asynchronously with the image sensor, display of a through image on the display device is performed by temporarily storing image data obtained by imaging with the image sensor in a frame memory and then driving the display device. This is realized by reading from the frame memory at the synchronized timing and outputting it to the display device.

  In relation to the above, Patent Document 2 discloses that one of two memories having a capacity for one image is externally transmitted when image data transferred asynchronously from outside is continuously reproduced on a display device at 60 fields per second. Is disclosed for switching the function allocation of two memories when there is no more data to be read from the memory allocated for data reading while the other is allocated for data reading for image reproduction and the other is allocated for data reading for image reproduction. ing.

Further, in Patent Document 3, three frame buffers A to C are provided in a digital still camera to control input / output of data to / from the three frame buffers, and while supplied data is written to the frame buffer A, The remaining frame buffers B and C are used for data reading. When the data writing to the frame buffer A is completed, the data writing to the frame buffer B is started and the data writing to the frame buffer A is completed before the frame buffer A Since the data written in the frame buffer C is displayed as an image during the period until the reading of data from is started, the fetching rate of the supplied data and the reading rate of the fetched data are different. Even when preventing double access to individual frame buffers Surgery is disclosed.
JP 2000-175089 A JP-A-6-124073 Japanese Patent Laid-Open No. 11-296155

  However, since the techniques described in Patent Documents 2 and 3 switch the writing / reading of data to / from the memory in units of one frame, the through image display timing is delayed by one frame or more with respect to the imaging timing by the imaging device. Will do. For this reason, the display delay of the above-mentioned through image is a factor that hinders the appropriate shooting operation when performing a shooting operation to take a picture while checking the displayed through image visually while pressing the shutter. There are problems such as. In particular, as in the technique described in Patent Document 1, in a configuration in which an imaging unit in which an optical system and an imaging element are integrated is detachable from the imaging apparatus body, display delay of a through image is reduced. In fact, no effective technology has been established.

  The present invention has been made in consideration of the above facts, and in a configuration in which an image pickup unit in which an optical system and an image pickup device are integrated is detachable from the image pickup apparatus main body, a through image display delay is reduced. It is an object to obtain an imaging device, an imaging device main body, and an imaging unit that can be used.

  In order to achieve the above object, an image pickup apparatus according to a first aspect of the present invention includes at least an optical system that forms an image of an object and an image pickup device that forms an image of the object formed by the optical system as a unit. An image pickup unit that is detachable from the image pickup apparatus main body, a drive signal generating means for generating a drive timing signal for driving the image pickup device, and a timing synchronized with the drive timing signal Storage means for storing an image signal obtained by imaging the subject by the image pickup element driven by a reproduction signal generation means for generating a reproduction timing signal for reproducing an image; and An image signal obtained by imaging the subject is written in the storage means, and the image signal written in the storage means is the reproduction signal generation. A writing / reading control unit that controls to read out from the storage unit at a timing synchronized with the reproduction timing signal generated by the unit, and an image signal of an arbitrary frame obtained by the imaging device capturing an image of a subject. Reading the image signal of the arbitrary frame from the storage means within a predetermined time shorter than the time required for writing or reading the image signal for one frame to the storage means after the writing to the storage means is started. Synchronization control means for synchronizing the drive timing signal and the reproduction timing signal with a phase difference corresponding to the number of pixels of one frame image in the image signal output from the image sensor so that It is characterized by having prepared.

  According to the first aspect of the present invention, at least an optical system that forms an image of an object and an image pickup device that picks up an image of the object formed by the optical system are integrated as a unit to form an image pickup unit. Is detachable from the main body of the image pickup apparatus. According to the first aspect of the present invention, drive signal generation means for generating a drive timing signal for driving the image pickup device is provided, and the image pickup element of the image pickup unit is driven by the drive timing signal generated by the drive signal generation means. The image signal obtained by driving the image pickup device at a timing synchronized with the image pickup device and picking up an image of the subject is stored in the storage means. Further, in the first aspect of the present invention, reproduction signal generation means for generating a reproduction timing signal for reproducing an image is provided, and the writing / reading control means is obtained by the image pickup device picking up an object. The image signal written in the storage means is controlled so that the image signal written in the storage means is read from the storage means at a timing synchronized with the reproduction timing signal generated by the reproduction signal generation means.

  According to the first aspect of the present invention, the image signal obtained by the imaging device driven at a timing synchronized with the drive timing signal capturing an image of the subject is once written in the storage means and then synchronized with the reproduction timing signal. It is read from the storage means at the timing and used for image reproduction (through image display). Therefore, if the drive timing signal and the reproduction timing signal are synchronized, a time difference from when the image signal is once written in the storage means until it is read out for image reproduction (this time difference corresponds to a through image display delay). ) Is determined in accordance with the phase difference between the drive timing signal and the reproduction timing signal, so that the display delay of the through image synchronizes the drive timing signal and the reproduction timing signal, and the drive timing signal and the reproduction timing signal. Can be reduced by appropriately setting the phase difference.

  However, the drive timing signal is a signal that defines the drive timing of the image sensor, and the timing at which the image signal obtained by the image sensor taking an image of the subject is written in the storage means is that of the image sensor that is defined by the drive timing signal. There is a slight deviation from the drive timing. When the image pickup unit is detachable from the image pickup apparatus body as in the first aspect of the invention, a plurality of types of image pickup units having different optical system and image pickup element configurations are prepared, Any of the plurality of types of imaging units may be attached to the imaging apparatus main body, and depending on the number of pixels of the imaging element provided in the imaging unit attached to the imaging apparatus main body, Since the time required to output the image signal from the image sensor changes, the shift time between the timing at which the image signal is written in the storage means and the drive timing of the image sensor also changes accordingly.

  On the other hand, the synchronization control means according to the first aspect of the present invention provides 1 to the storage means after the start of the writing of the image signal of an arbitrary frame obtained by the image pickup device picking up the subject to the storage means. At least in the image signal output from the image sensor so that reading of the image signal of the arbitrary frame from the storage means is started within a predetermined time shorter than the time required for writing or reading the image signal for the frame. The drive timing signal and the reproduction timing signal are synchronized with a phase difference corresponding to the number of pixels of one frame image. As a result, the image pickup unit integrated with the optical system and the image pickup device is detachable from the image pickup device main body, and accordingly, the image pickup device provided in the image pickup unit attached to the image pickup device main body. Even if the number of pixels (the number of pixels of one frame image in the image signal output from the image sensor) is indefinite, the display delay of the through image is constant and shorter than the conventional delay time (one frame for the storage means). The predetermined time is shorter than the time required for writing or reading the image signal.

  Therefore, according to the first aspect of the invention, in a configuration in which an imaging unit in which an optical system and an imaging element are integrated is detachable from the imaging apparatus body, it is possible to reduce a delay in displaying a through image, By making the display delay of the through image constant, when the shooting operation is performed while visually confirming the through image, it is also possible to prevent the display delay of the through image from hindering an appropriate shooting operation. Can do.

  In the first aspect of the present invention, it is preferable that the predetermined time is substantially the same as the time required for writing or reading one line of the image signal to / from the storage means, as described in the second aspect, for example. . Thereby, the display delay of the through image can be minimized, and the subject imaged by the image sensor can be displayed as a through image in substantially real time.

  In the first aspect of the present invention, the number of pixels of one frame image in the image signal output from the image sensor may be recognized by, for example, analyzing the image signal (for example, counting the number of pixels). Although possible, for example, as described in claim 3, a storage unit that stores the number of pixels of an image of one frame is provided in the imaging unit, and a synchronization control unit is provided in the imaging apparatus main body. The number of pixels stored in the unit may be acquired from the imaging unit so as to recognize the number of pixels of one frame image. In this case, even when the image pickup unit attached to the image pickup apparatus body is replaced, the number of pixels of one frame image in the image signal output from the image pickup element provided in the image pickup unit after replacement is quickly determined. Can be recognized.

  Further, in the first aspect of the present invention, when the first conversion means for converting the image signal written in the storage means so that the resolution of the image represented by the image signal matches the resolution in image reproduction is provided, For example, as described in claim 4, the synchronization control means preferably determines the phase difference between the drive timing signal and the reproduction timing signal in consideration of the time required for the conversion of the image signal by the first conversion means. When the first conversion unit is provided, the time difference between the timing at which the image signal is written in the storage unit and the drive timing of the image sensor is required for the conversion of the image signal (resolution conversion process) by the first conversion unit. In this case, the phase difference between the drive timing signal and the reproduction timing signal is determined in consideration of the time required for the conversion of the image signal by the first conversion means. Therefore, the display delay of the through image can be reduced regardless of the time required for the conversion of the image signal by the first conversion means.

  Further, in the first aspect of the invention, an image area designated from the image represented by the image signal is extracted from the image signal written in the storage means, and the resolution of the extracted image area matches the resolution in image reproduction. In the case where the second conversion means for converting is provided, the synchronization control means converts the phase difference between the drive timing signal and the reproduction timing signal into an image by the second conversion means, for example, as described in claim 5. It is preferable to determine the time required for signal conversion. In the case where the second conversion unit is provided, the time difference between the timing at which the image signal is written in the storage unit and the drive timing of the image sensor is required for the conversion of the image signal (electronic zoom processing) by the second conversion unit. In this case, the phase difference between the drive timing signal and the reproduction timing signal is determined in consideration of the time required for the conversion of the image signal by the second conversion means. Therefore, display delay of the through image can be reduced regardless of the time required for the conversion of the image signal by the second conversion means.

  In the first aspect of the present invention, for example, as described in the sixth aspect, the image pickup unit is in a state of being attached to the image pickup apparatus main body and in contact with a first contact provided on the image pickup apparatus main body. Contact is provided, and transmission / reception of signals between the imaging unit and the imaging apparatus main body in a state where the imaging unit is mounted on the imaging apparatus main body is performed by serial communication via the first contact and the second contact. It is preferable to configure so that the Thereby, compared with the case where transmission / reception of the signal between an imaging unit and an imaging device main body is performed by parallel communication, the number of the 1st contact and the 2nd contact can be decreased, and the imaging device concerning the present invention can be reduced. The configuration can be simplified.

  The imaging apparatus main body according to the invention of claim 7 includes at least an optical system for imaging a subject, an imaging device for imaging the subject imaged by the optical system, and a drive timing signal for driving the imaging device. An image pickup apparatus body in which an image pickup unit in which a drive signal generating means to be generated is integrated as a unit is detachable, and the image pickup element driven at a timing synchronized with the drive timing signal picks up an image of a subject. Storage means for storing the image signal obtained in step (b), reproduction signal generation means for generating a reproduction timing signal for reproducing an image, and an image signal obtained by the imaging element picking up an image of the subject. The reproduction timing signal generated by the reproduction signal generation unit is written to the storage unit and the image signal written to the storage unit is generated. And writing / reading control means for controlling the reading so as to be read from the storage means, and writing of an image signal of an arbitrary frame obtained by imaging the subject by the imaging device to the storage means is started. The reading of the image signal of the arbitrary frame from the storage means is started within a predetermined time shorter than the time required for writing or reading the image signal for one frame to the storage means. By inputting a phase control signal for controlling the phase of the drive timing signal to the drive signal generation means of the imaging unit, a phase difference corresponding to at least the number of pixels of one frame image in the image signal output from the image sensor And synchronization control means for synchronizing the drive timing signal and the reproduction timing signal. Therefore, similarly to the first aspect of the invention, in a configuration in which an image pickup unit in which an optical system and an image pickup device are integrated is detachable from the image pickup apparatus main body, display delay of a through image is reduced. be able to.

  An imaging unit according to an eighth aspect of the invention is an imaging unit that is detachable from the imaging apparatus main body according to the seventh aspect, and is formed by an optical system that forms an image of a subject and the optical system. An image sensor that images the subject, and a drive signal generation unit that generates a drive timing signal for driving the image sensor at a timing synchronized with the phase control signal input from the synchronization control unit according to claim 7; Is integrated as a unit, so that the image pickup unit in which the optical system and the image pickup device are integrated is attached to and detached from the image pickup apparatus main body, as in the first and seventh aspects of the invention. In a free configuration, it is possible to reduce the display delay of the through image.

  As described above, according to the present invention, the image signal obtained by the imaging device driven at a timing synchronized with the drive timing signal capturing an image of the subject is written in the storage unit, and the image signal written in the storage unit Is read from the storage means at a timing synchronized with the reproduction timing signal, and writing of the image signal for one frame to the storage means is started after the start of writing of the image signal of an arbitrary frame to the storage means. At least according to the number of pixels of one frame image in the image signal output from the image sensor so that reading of the image signal of an arbitrary frame from the storage means is started within a predetermined time shorter than the time required for reading. Because the drive timing signal and the playback timing signal are synchronized with the phase difference In the configuration where the imaging unit image element is formed by integral is detachable from the imaging device body, can be reduced display delay through image, has an excellent effect that.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a digital still camera 10 (hereinafter referred to as DSC 10) according to the present embodiment. As shown in FIG. 1, the DSC 10 includes a DSC main body 12 and an imaging unit 14. The DSC main body 12 is substantially box-shaped, and a mount portion 16 for mounting the imaging unit 14 is provided at the center portion when viewed from the front.

  As shown in FIG. 2, the mount portion 16 has a recess 16 </ b> A formed at the center, and a corresponding portion of the imaging unit 14 has a protrusion 14 </ b> A shaped to fit into the recess 16 </ b> A. Although not shown, the mount 16 has a convex portion 14A while maintaining a state in which the imaging unit 14 is in a fixed orientation around the optical axis of a lens group 40 described later with respect to the DSC main body 12. Is pressed against the mount portion 16 of the DSC main body 12 so as to fit into the recess 16A, the imaging unit 14 is pressed against the mount portion 16 by the biasing force of a biasing means (not shown) (the imaging unit 14 is in contact with the DSC main body 12). A locking mechanism is provided for locking in the state of being attached to the head. Further, an unlock button 18 is provided in the vicinity of the mount portion 16 (see also FIG. 1). When the lock release button 18 is pressed, the lock mechanism is unlocked, and the imaging unit 14 is mounted on the mount portion 16. The DSC main body 12 can be separated. As described above, in the DSC 10 according to this embodiment, the imaging unit 14 is detachable from the DSC main body 12.

  In addition, a plurality of contacts 20 are provided at locations corresponding to the periphery of the recess 16 </ b> A in the mount portion 16, and contacts 20 corresponding to the imaging unit 14 are also attached to the DSC main body 12 in a state of being attached to the DSC main body 12. A plurality of contacts 22 are provided to contact each other. Accordingly, when the imaging unit 14 is mounted on the DSC main body 12, the contact 22 contacts the contact 20, whereby the imaging unit 14 (internal circuit) is electrically connected to the DSC main body 12 (internal circuit). It becomes a state. Thus, the DSC 10 corresponds to the imaging device according to the present invention, the DSC main body 12 corresponds to the imaging device main body according to the present invention, and the imaging unit 14 corresponds to the imaging unit according to the present invention. The contact 20 corresponds to the first contact of claim 6, and the contact 22 corresponds to the second contact of claim 6.

  As shown in FIG. 1, above the mount portion of the DSC main body 12, an optical finder 24 for a user to visually confirm a photographing range and the like, and a strobe for emitting auxiliary light in the case of photographing at low illuminance, etc. 26 is attached. On the top surface of the DSC main body 12, a release button 28 is provided on the left side when viewed from the front, and a dial 30 for selecting a shooting mode or the like on the right side. Further, although not shown, a color LCD 124 (see FIG. 3), various operation buttons (for example, a button for instructing a change in zoom magnification), an operation switch (for example, a power switch 114 ( 3) and the like, and a side surface (or bottom surface) of the DSC main body 12 is provided with a memory card slot 120 (see FIG. 3) for inserting a memory card 122 (see FIG. 3). .

  On the other hand, as illustrated in FIG. 2, a lens group 40 that includes a plurality of lenses 40 </ b> A to 40 </ b> F and forms an image of a subject is disposed inside the imaging unit 14. Specifically, the lens group 40 is a zoom lens (focal length variable lens) having an autofocus (AF) mechanism. Although not shown, the imaging unit 14 includes a motor that drives the AF mechanism of the lens group 40, A motor for driving the zoom mechanism of the lens group 40 and a motor for driving a diaphragm (not shown) disposed in the middle of the lens group 40 are provided. The lens group 40 may be a fixed focal length lens having only an AF mechanism. The lens group 40 corresponds to the optical system according to the present invention.

  An area CCD sensor 42 is disposed at a position corresponding to the focal position of the lens group 40 inside the imaging unit 14, and light incident on the lens group 40 after reflecting the subject is received by the area CCD sensor 42. The image is formed on the surface. On the light receiving surface of the area CCD sensor 42, a large number of photoelectric conversion cells in which R, G, or B filters are arranged on the light incident side are arranged in a matrix. The area CCD sensor 42 is arranged on the light receiving surface. The subject is imaged by converting and accumulating the incident and imaged light into charges corresponding to the amount of light received by each photoelectric conversion cell. An imaging timing signal is input to the area CCD sensor 42, and the area CCD sensor 42 is driven at a timing synchronized with the input imaging timing signal (charge accumulation / accumulation charge output is performed). R, G, B image signals representing the amount of light received in each photoelectric conversion cell are output. The area CCD sensor 42 corresponds to the image sensor according to the present invention.

  Note that a plurality of types of imaging units 14 are prepared in the DSC 10 according to the present embodiment. The plurality of types of imaging units 14 have the same basic configuration (configuration in which the lens group 40 and the area CCD sensor 42 are provided), but the configuration of the lens group 40 itself (for example, the focal length, the presence or absence of a zoom mechanism, zoom The range of magnification and the like are different from each other, and the effective area and the number of pixels of the light receiving surface of the area CCD sensor 42 are optimized according to the configuration of the lens group 40. In a conventional single-lens reflex type DSC, the image pickup device is mounted on the main body side, and only the optical system can be exchanged. In order not to occur, the effective area of the light receiving surface of the image sensor is designed to have a margin, which contributes to an increase in the size of the apparatus. On the other hand, the DSC 10 can be downsized by optimizing the effective area of the light receiving surface of the area CCD sensor 42 in each imaging unit 14 as described above.

  The area CCD sensor 42 is mounted on a substrate 44. As shown in FIG. 3, each substrate 44 is provided with motors (motors for driving a diaphragm, AF mechanisms) provided on the imaging unit 14. An aperture / focus / zoom control unit 46 for controlling the driving of the motor and the zoom mechanism), an imaging timing generator (TG) 48, an analog signal processing unit 50, an A / D converter 52, an integrating circuit 54, a unit Various circuits such as a CPU 56, a system memory 58 including a ROM and a RAM, a nonvolatile memory 60, a three-wire serial driver 62, a high-speed serial driver 64, a power supply controller 66, and a DC / DC converter 68 are mounted. Of these circuits, each circuit except the analog signal processing unit, the A / D converter 52 and the DC / DC converter 68 is a bus. They are connected to each other through a 0. When the power of the DSC 10 is turned on while the imaging unit 14 is mounted on the DSC main body 12, power is supplied from the DSC main body 12 to the DC / DC converter 68, and the DC / DC converter 68 is controlled by the power control unit 66. Below, the electric power supplied from the DSC main body 12 is converted into a predetermined voltage and supplied to each circuit in the imaging unit 14.

  An analog signal processing unit 50, an A / D converter 52, and a high-speed serial driver 64 are sequentially connected to the signal output terminal of the area CCD sensor. The imaging timing signal is generated by the imaging timing generator 48 (the imaging timing signal corresponds to the driving timing signal according to the present invention, and the imaging timing generator 48 corresponds to the driving signal generating means according to the present invention. The imaging timing signal is also input to the analog signal processing unit 50 and the A / D converter 52, respectively. Accordingly, the analog signal processing unit 50 and the A / D converter 52 also operate at a timing synchronized with the imaging timing signal, and the analog signal processing unit 50 amplifies the image signal output from the area CCD sensor 42 and amplifies it. The A / D converter 52 converts the image signal output from the analog signal processing unit 50 into digital image data. The image data output from the A / D converter 52 is transmitted to the DSC main body 12 by the high-speed serial driver 64 by high-speed serial communication. The image data is also input to the integrating circuit 54. An integration calculation for determining the exposure and focus position is performed by the integration circuit 54, and the calculation result is transmitted to the unit CPU 56 via the bus 70.

  As described above, since the imaging unit 14 according to the present embodiment is configured by integrating the lens group 40, the area CCD sensor 42, and various circuits as a single unit, it extends from the lens 40A to the area CCD sensor 42. Dust or the like does not enter the optical path, and it is possible to prevent image quality degradation or the like from occurring due to the dust or the like that has entered the optical path. In the present embodiment, since the number of pixels of the area CCD sensor 42 differs depending on the type of the imaging unit 14 as described above, the number of pixels of the area CCD sensor 42 (horizontal direction and vertical direction) is stored in the nonvolatile memory 60. The number of pixels) is stored in advance.

  The DSC main body 12 includes a strobe controller 74, a timer circuit 76, a calendar circuit 78, a three-wire serial driver 80, a high-speed serial driver 82, an input / output controller 84, a DC / DC converter 86, a power controller 88, and a battery 90. , Main body CPU 92, system memory 94 composed of ROM and RAM, nonvolatile memory 96, USB driver 98, input / output control unit 100, digital signal processing unit 102, card I / F unit 104, frame memory 106, reproduction timing generator ( (TG) 108 and various circuits of the image reproduction control unit 110 are provided. Among these, circuits other than the DC / DC converter 86, the battery 90, and the image reproduction control unit 110 are connected to each other via a bus 112.

  The DC / DC converter 86 and the power control unit 88 are connected to the battery 90, and power is supplied from the battery 90. The power control unit 88 is connected to a power switch 114 provided on the DSC main body 12. The DC / DC converter 86 converts the power supplied from the battery 90 into a predetermined voltage under the control of the power supply control unit 88 and supplies it to each circuit in the DSC main body 12. The strobe control unit 74 is connected to the strobe 26 and causes the strobe 26 to emit light when it is detected that the illumination is low or when the user instructs to emit light. The 3-wire serial driver 80 and the high-speed serial driver 82 are electrically connected to the 3-wire serial driver 62 and the high-speed serial driver 64 on the imaging unit 14 side in a state where the imaging unit 14 is mounted on the DSC main body 12. In cooperation with the drivers 62 and 64 on the imaging unit 14 side, information is transmitted and received by high-speed serial communication or relatively low-speed three-wire serial communication. As described above, since transmission / reception of information between the DSC main body 12 and the imaging unit 14 is performed by serial communication, by reducing the number of contacts 20 and 22 as compared with the case of transmitting / receiving information by parallel communication. The configuration can be simplified, and the area of each contact can be increased by reducing the number of contacts, so that the reliability of electrical connection between the DSC main body 12 and the imaging unit 14 can be improved.

  The input / output control unit 84 is electrically connected to the power supply control unit 66 on the imaging unit 14 side in a state where the imaging unit 14 is mounted on the DSC main body 12, and is connected to the bus 112 from the power supply control unit 88 on the DSC main body 12 side. The on / off of the power switch 114 transmitted via is transmitted to the power control unit 66 on the imaging unit 14 side. The USB driver 98 is connected to a USB connector 116 provided on the side surface of the DSC main body 12, and performs USB communication with an external device connected to the DSC 10 via the USB connector 116 via a USB cable. Further, the input / output control unit 100 is connected to a dial 30 (a switch provided corresponding to) provided on the DSC main body 12, various operation buttons (a switch provided corresponding to), an operation switch, an LED, and the like. (In FIG. 3, these dials 30, operation buttons, operation switches, LEDs, and the like are shown as operation unit 118), and various switches by operating the dial 30, operation buttons, and operation switches. Is transferred to the main body CPU 92 via the bus 112, and lighting and extinguishing of LEDs and the like are controlled in accordance with an instruction from the main body CPU 92.

  The digital signal processing unit 102 is connected to a high-speed serial driver 82, and from the imaging unit 14 side by high-speed serial communication between the high-speed serial driver 64 on the imaging unit 14 side and the high-speed serial driver 82 on the DSC main body 12 side. The image data transmitted to the DSC main body 12 side is input to the digital signal processing unit 102. The digital signal processing unit 102 performs various processes such as color correction, γ correction, and Y / C conversion on the input image data, and also performs resolution conversion processing, electronic zoom processing, and the like as necessary, and a frame memory. 106. As described above, the frame memory 106 corresponds to the storage unit according to the present invention, and the digital signal processing unit 102 includes the write / read control unit according to the present invention, the first conversion unit according to claim 4, and the claim 5. Respectively corresponding to the second conversion means. The card I / F unit 104 is connected to the memory card slot 120, and writes data to the memory card 122 loaded in the memory card slot 120 and reads data from the memory card 122.

  The image reproduction control unit 110 is connected to the frame memory 106, the reproduction timing generator 108, the LCD 124, and a connector 126 for connecting an external display to the DSC 10. A reproduction timing generator 108 specifies a reproduction timing signal for reading out image data from the frame memory 106 in order to display an image represented by the image data stored in the frame memory 106 on the LCD 124 or an external display. And output to the image reproduction control unit 110. The image reproduction control unit 110 reads image data from the frame memory 106 at a timing synchronized with the input reproduction timing signal, and outputs the read image data to the LCD 124 or the external display, thereby displaying the image on the LCD 124 or the external display. Let The reproduction timing signal corresponds to the reproduction timing signal according to the present invention, the reproduction timing generator 108 corresponds to the reproduction signal generation means according to the present invention, and the image reproduction control unit 110 also performs the write / read control according to the present invention. Corresponds to the means.

  In the DSC 10 according to the present embodiment, the reproduction timing generator 108 on the DSC body 12 side is electrically connected to the imaging timing generator 48 on the imaging unit 14 side in a state where the imaging unit 14 is mounted on the DSC body 12. Is done. Although details will be described later, when an image captured by the area CCD sensor 42 of the imaging unit 14 is displayed on the LCD or the like as a through image, the reproduction timing generator 108 is used to reproduce the imaging timing signal with a predetermined phase difference. Generation of the synchronization control signal VDRST for synchronizing with the timing signal is instructed from the main body CPU 92. When this instruction is input, the reproduction timing generator 108 generates, as the synchronization control signal VDRST, a signal whose phase is advanced by the phase difference instructed from the main body CPU 92 with respect to the reproduction timing signal, and the generated synchronization control signal VDRST is output to the imaging timing generator 48 on the imaging unit 14 side. When the synchronization control signal VDRST is input, the imaging timing generator 48 generates and outputs an imaging timing signal synchronized with the input synchronization control signal VDRST.

  Next, as an operation of the present embodiment, the DSC 10 is powered on, and as the operation mode, the area CCD sensor 42 of the imaging unit 14 performs imaging, and the image captured by the area CCD sensor 42 is displayed as a through image on the LCD 124. This is realized by executing a predetermined program stored in the system memory 94 by the main body CPU 92 when a mode (referred to as a “through image display photographing mode”) to be displayed on (or an external display) is selected. The through image display shooting mode process will be described with reference to the flowchart of FIG.

  In this through image display photographing mode process, first, in step 150, it is determined whether or not the imaging unit 14 is attached to the DSC main body 12. This determination may be performed based on, for example, whether predetermined information is transmitted to the imaging unit 14 and a response is received from the imaging unit 14, or whether the imaging unit 14 is mounted / not mounted mechanically. It is also possible to carry out based on the output of the sensor to be detected. If the determination is negative, the process proceeds to step 152 where the image data of a predetermined error screen is read from the system memory 94 and written to the frame memory 106, and the image reproduction control unit 110 is instructed to display the error screen. End the process. As a result, the image reproduction control unit 110 sequentially reads out the image data of the error screen from the frame memory 106 at a timing synchronized with the reproduction timing signal generated and input by the reproduction timing generator 108, and sequentially reads out the read image data to the LCD 124. By outputting, an error screen is displayed on the LCD 124.

  On the other hand, when the imaging unit 14 is attached to the DSC main body 12, the determination in step 150 is affirmed and the process proceeds to step 154, and inquiry information for inquiring the number of pixels of the area CCD sensor 42 is sent via the bus 112. Transfer to the line serial driver 80. Thus, the inquiry information is sent from the 3-wire serial driver 80 on the DSC main body 12 side to the 3-wire serial driver 62 on the imaging unit 14 side by serial communication, and then sent from the 3-wire serial driver 62 to the unit CPU 56 via the bus 70. Transferred. When the above inquiry information is received, the unit CPU 56 reads the number of pixels (the number of pixels in the horizontal direction and the vertical direction) of the area CCD sensor 42 stored in the nonvolatile memory 60 and outputs 3 pixels via the bus 70 as pixel number notification information. Transfer to the line serial driver 62. As a result, the pixel number notification information is sent from the 3-wire serial driver 62 on the imaging unit 14 side to the 3-wire serial driver 80 on the DSC main body 12 side by serial communication, and then the main body via the bus 112 from the 3-wire serial driver 80. The data is transferred to the CPU 92.

  In the next step 156, it is determined whether or not a response has been received from the imaging unit 14 side. Step 156 is repeated until the determination is affirmed, and when the pixel number notification information is received from the imaging unit 14 side as described above. If the determination in step 156 is affirmed, the process proceeds to step 158, and the number of pixels of the area CCD sensor 42 notified by the pixel number notification information is stored in the system memory 94. In the next step 160, first, based on whether or not an external display is connected to the connector 126, it is determined whether the device that displays the through image is the LCD 124 or the external display, and based on the determination result, the through image is displayed. Recognize the number of pixels. Next, the number of display pixels of the recognized through image is compared with the number of pixels of the CCD sensor 42 stored in the system memory 94, and whether or not resolution conversion processing is required for the image data based on whether or not they match. To determine.

  If the determination in step 160 is negative, the process proceeds to step 162. When the area CCD sensor 42 of the imaging unit 14 is driven at a timing synchronized with the imaging timing signal, and imaging of the subject by the area CCD sensor 42 is started, the imaging unit 14 synchronizes with the imaging timing signal. The image data is sequentially input at the frame rate. In step 162, “after the image data of the specific frame received from the imaging unit 14 starts to be written to the frame memory 106 through the processing in the digital signal processing unit 102. Imaging for satisfying the condition that “the reading of the image data of the specific frame from the frame memory 106 is started after the time required for writing or reading the image data for one line to the frame memory 106 has elapsed” Timing signal and playback timing Calculating a phase difference between the grayed signal.

  When the determination in step 160 is negative, the digital signal processing unit 102 does not need to perform resolution conversion processing on the image data received from the imaging unit 14. However, the imaging timing signal is a signal that defines the driving timing of the area CCD sensor 42, and the timing at which the image data received from the imaging unit 14 is written into the frame memory 106 (see “memory writing” shown in FIG. 5). The imaging timing signal is slightly deviated from the drive timing of the area CCD sensor 42 defined by the imaging timing signal (see “imaging timing signal” shown in FIG. 5). The time required for signal readout (first time lag shown in FIG. 5) and the time required for processing in the digital signal processing unit 102 (second time lag shown in FIG. 5) are included. When the digital signal processing unit 102 does not perform resolution conversion processing, the time required for processing in the digital signal processing unit 102 (second time lag) is substantially constant, but the time required for reading the image signal from the area CCD sensor 42. The (first time lag) depends on the number of pixels of the area CCD sensor 42 (the number of photoelectric conversion cells). As the number of pixels of the area CCD sensor 42 increases, the time required for reading the image signal increases. The deviation time is also increased.

  Therefore, in step 162, a first time lag is calculated based on the number of pixels of the area CCD sensor 42 notified from the imaging unit 14, and a second time lag is added to the first time lag (a fixed time in step 162). As a result, the shift time between the drive timing of the area CCD sensor 42 defined by the imaging timing signal and the timing at which the image data is written to the frame memory 106 is obtained. Then, by adding the time required for writing or reading one line of image data to / from the frame memory 106 to the shift time, the phase difference between the imaging timing signal and the reproduction timing signal for satisfying the above-described conditions is obtained. Calculate. Then, the calculation result of the phase difference is set to the reproduction timing generator 108 via the bus 112, and an instruction is generated to generate and output the synchronization control signal VDRST whose phase is advanced from the reproduction timing signal by the set phase difference. In the next step 168, the image reproduction control unit 110 is instructed to display a through image.

  Accordingly, the reproduction timing generator 108 generates and outputs a synchronization control signal VDRST (see FIG. 5) whose phase is advanced from the reproduction timing signal by the set phase difference. The synchronization control signal VDRST is output from the imaging unit. 14 to the imaging timing generator 48. In addition, the imaging timing generator 48 generates and outputs an imaging timing signal (see FIG. 5) synchronized with the input synchronization control signal VDRST. As a result, the imaging timing signal generated and output by the imaging timing generator 48 is controlled to synchronize with the reproduction timing signal with the phase difference calculated in step 162.

  In addition, the area CCD sensor 42 of the imaging unit 14 is driven at a timing synchronized with the imaging timing signal to start imaging of the subject, and from the timing specified by the imaging timing signal in each cycle of the imaging timing signal. After the image signal read time corresponding to the number of pixels of the area CCD sensor 42 has elapsed, one frame of image signal is sequentially output from the area CCD sensor 42. This image signal is converted into image data through processing by the analog signal processing unit 50 and the A / D converter 52, and through serial communication by the high-speed serial drivers 64 and 82, as shown as "valid data capture" in FIG. The DSC main body 12 sequentially receives the first time lag after the timing specified by the imaging timing signal. In addition, the image data received by the DSC main body 12 undergoes various processes in the digital signal processing unit 102, and then sequentially passes to the frame memory 106 after a second time lag has elapsed, as shown as "memory write" in FIG. Written.

  Further, since the image reproduction control unit 110 reads the image data from the frame memory 106 at a timing synchronized with the reproduction timing signal generated by the reproduction timing generator 108, as shown in FIG. When one line of image data is written to 106, this one line of image data is immediately read from the frame memory 106, output to the LCD 124 or an external display, and displayed as a through image. Thereby, the display delay of the through image is minimized, and the subject imaged by the area CCD sensor 42 is displayed as a through image in almost real time. In addition, since the phase difference between the imaging timing signal and the reproduction timing signal is determined according to the number of pixels of the area CCD sensor 42, the imaging unit 14 mounted on the DSC main body 12 has different area CCD sensors. Even if the image pickup unit 14 is replaced with another type of image pickup unit 14, the phase difference between the image pickup timing signal and the reproduction timing signal is changed according to the number of pixels of the new area CCD sensor 42, so that a through image is obtained. The display delay is kept to a minimum. Thus, the above-described steps 154 to 158 and 162 correspond to the synchronization control means according to the present invention together with the reproduction timing generator 108 that actually generates and outputs the synchronization control signal VDRST.

  On the other hand, when the resolution conversion processing for the image data is necessary, the determination in step 160 is affirmed and the process proceeds to step 164, where the number of pixels per frame of the image data received from the imaging unit 14 (= the CCD sensor 42). Resolution conversion conditions for matching the number of pixels) with the number of display pixels of the through image are obtained, and the resolution conversion conditions are set in the digital signal processing unit 102 so that the resolution conversion process is performed under the set resolution conversion conditions. Instructs the digital signal processing unit 102. Then, in the next step 166, after the writing of the image data of the specific frame received from the imaging unit 14 to the frame memory 106 is started through the processing in the digital signal processing unit 102, one line for the frame memory 106 is set. Imaging timing signal and reproduction timing for satisfying the condition that reading of the image data of the specific frame from the frame memory 106 is started after the time required to write or read the image data of Calculate the phase difference of the signal.

  As described above, the time (first time lag) required for reading the image signal from the area CCD sensor 42 varies depending on the number of pixels (the number of photoelectric conversion cells) of the area CCD sensor 42, but the digital signal processing unit When the resolution conversion process is performed in 102, the time required for the resolution conversion process changes according to the resolution conversion condition. Therefore, the time required for the processing in the digital signal processing unit 102 (second time lag) also depends on the resolution conversion condition. Change (see also second time lag shown in FIG. 6). Therefore, in step 166, the first time lag is calculated based on the number of pixels of the area CCD sensor 42, and the second time lag is calculated based on the resolution conversion condition set in the digital signal processing unit 102. By adding the first time lag and the second time lag, a shift time between the drive timing of the area CCD sensor 42 defined by the imaging timing signal and the timing at which the image data is written to the frame memory 106 is obtained. Then, by adding the time required for writing or reading one line of image data to / from the frame memory 106 to the shift time, the phase difference between the imaging timing signal and the reproduction timing signal for satisfying the above-described conditions is obtained. Calculate. Then, the calculation result of the phase difference is set to the reproduction timing generator 108 via the bus 112, and an instruction is generated to generate and output the synchronization control signal VDRST whose phase is advanced from the reproduction timing signal by the set phase difference. In the next step 168, the image reproduction control unit 110 is instructed to display a through image.

  As a result, the reproduction timing generator 108 generates and outputs a synchronization control signal VDRST (see FIG. 6) whose phase is advanced from the reproduction timing signal by the set phase difference, and the imaging timing generator 48 performs synchronization control. An imaging timing signal (see FIG. 5) synchronized with the signal VDRST is generated and output. Thus, the imaging timing signal generated and output by the imaging timing generator 48 is controlled so as to be synchronized with the reproduction timing signal by the phase difference calculated in step 166. The area CCD sensor 42 is driven at a timing synchronized with the imaging timing signal to start imaging of the subject. In each cycle of the imaging timing signal, the area CCD sensor 42 starts from the timing specified by the imaging timing signal. After the image signal readout time corresponding to the number of pixels has elapsed, one frame of image signal is sequentially output from the area CCD sensor 42. This image signal is converted into image data through processing by the analog signal processing unit 50 and the A / D converter 52, and through serial communication by the high-speed serial drivers 64 and 82, as shown as "valid data acquisition" in FIG. The DSC main body 12 sequentially receives the first time lag after the timing specified by the imaging timing signal. In addition, the image data received by the DSC main body 12 undergoes various processes including the resolution conversion process in the digital signal processing unit 102, and the second data corresponding to the resolution conversion condition as shown in FIG. After the elapse of the time lag, the frame memory 106 is sequentially written. In the example of FIG. 6, the case where the resolution conversion process for converting the resolution to double in the vertical direction is performed as an example, but it goes without saying that the resolution conversion condition is not limited to this.

  Further, since the image reproduction control unit 110 reads out the image data from the frame memory 106 at a timing synchronized with the reproduction timing signal generated by the reproduction timing generator 108, as shown in FIG. When one line of image data is written to 106, this one line of image data is immediately read from the frame memory 106, output to the LCD 124 or an external display, and displayed as a through image. Thereby, even when the resolution conversion process is performed in the digital signal processing unit 102, the display delay of the through image is minimized, and the subject imaged by the area CCD sensor 42 is displayed as a through image in almost real time. . Step 166 described above corresponds to the synchronization control means described in claim 4.

  In the next step 170, it is determined whether or not shooting of the subject has been instructed by operating the release button 28. If the determination is negative, the process proceeds to step 174, where the electronic zoom is instructed (the instructed zoom magnification is within the range where the electronic zoom is necessary, or the electronic zoom magnification is already performed. Whether or not change is instructed). If this determination is also denied, the process returns to step 170, and steps 170 and 174 are repeated until the operation mode is changed or the power is turned off. When the release button 28 is operated to instruct photographing and recording of the subject, the determination in step 170 is affirmed and the process proceeds to step 172, and image data corresponding to the timing when the release button 28 is operated is stored in the card I / F. The photographing process to be recorded on the memory card 122 is performed via the unit 104, and the process returns to Step 170.

  If electronic zoom is instructed, the determination in step 174 is affirmed, and the process proceeds to step 176, where processing conditions for electronic zoom processing for enlarging the image by the instructed zoom magnification are calculated and calculated. By setting the processing conditions in the digital signal processing unit 102, the digital signal processing unit 102 is instructed to perform electronic zoom processing under the set processing conditions. When the digital signal processing unit 102 performs the electronic zoom processing, the time required for the electronic zoom processing varies depending on the processing conditions of the electronic zoom processing, as in the case where the digital signal processing unit 102 performs the resolution conversion processing described above. Therefore, the time required for processing in the digital signal processing unit 102 (second time lag) also changes according to the processing conditions of the electronic zoom processing.

  For this reason, in the next step 178, the second time lag is calculated based on the processing conditions of the electronic zoom process, and the calculated second time lag and the second phase difference in the current phase difference between the imaging timing signal and the reproduction timing signal are calculated. The difference from the time lag of the frame memory 106 is calculated, “after the image data of the specific frame received from the imaging unit 14 starts to be written into the frame memory 106 through the processing in the digital signal processing unit 102, After the time required for writing or reading the image data has elapsed, the imaging timing is set by the calculated deviation so as to continue to satisfy the condition that reading of the image data of the specific frame from the frame memory 106 is started. Correct and correct the current phase difference between the signal and the playback timing signal Resetting the phase difference in the reproduction timing generator 108. Accordingly, even when the digital signal processing unit 102 newly starts the electronic zoom process or when the processing conditions of the electronic zoom process that has been executed are changed, the display delay of the through image is minimized, and the area CCD sensor The state in which the subject imaged by 42 is displayed as a through image in almost real time is maintained. The above processing corresponds to the synchronization control means described in claim 5.

  In the above, when the digital signal processing unit 102 performs the resolution conversion process, the phase difference between the imaging timing signal and the reproduction timing signal is set in consideration of the resolution conversion condition in the resolution conversion process, and the digital signal processing is performed. In the case where the unit 102 performs electronic zoom processing, the example in which the phase difference between the imaging timing signal and the reproduction timing signal is set in consideration of the processing conditions of the electronic zoom processing has been described. In addition to the electronic zoom processing, a specific effect that affects the display delay time of the through image (the shift time between the drive timing of the area CCD sensor 42 defined by the imaging timing signal and the timing at which the image data is written to the frame memory 106). When a process is selectively executed, imaging is performed in consideration of the execution of the specific process and the processing time. Timing signal may be set phase difference of the reproduction timing signal.

  In the above description, the DSC has been described as an example of the imaging apparatus according to the present invention. However, the present invention is not limited to this, and the present invention can also be applied to other imaging apparatuses such as a digital video camera.

It is a perspective view which shows the external appearance of DSC which concerns on this embodiment. It is sectional drawing of an imaging unit, and a side view of a DSC main body. It is a block diagram which shows schematic structure of DSC. It is a flowchart which shows the content of the through image display imaging | photography mode process performed with the main body CPU of DSC. 6 is a timing chart showing timings of data fetching, memory writing, memory reading, and image display when resolution conversion processing is not performed. 6 is a timing chart showing timings of data fetching, memory writing, memory reading, and image display when resolution conversion processing is performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital still camera 12 DSC main body 14 Imaging unit 20 Contact 22 Contact 40 Lens group 42 Area CCD sensor 48 Imaging timing generator 58 System memory 60 Non-volatile memory 64 High-speed serial driver 82 High-speed serial driver 102 Digital signal processor 106 Frame memory 108 Reproduction timing generator 110 Image reproduction control unit 124 LCD

Claims (8)

An imaging device in which an imaging unit in which at least an optical system that forms an image of an object and an image sensor that images an object imaged by the optical system is integrated as a unit is detachable from the imaging device body. There,
Drive signal generating means for generating a drive timing signal for driving the image sensor;
Storage means for storing an image signal obtained by imaging the subject by the imaging element driven at a timing synchronized with the driving timing signal;
Reproduction signal generation means for generating a reproduction timing signal for reproducing an image;
An image signal obtained by the imaging device capturing an image of a subject is written in the storage unit, and the image signal written in the storage unit is synchronized with the reproduction timing signal generated by the reproduction signal generation unit. Write / read control means for controlling to read from the storage means at timing;
More than the time required for writing or reading out one frame of image signals to or from the storage means from the start of writing to the storage means of an image signal of an arbitrary frame obtained by imaging the subject by the imaging device A phase difference corresponding to at least the number of pixels of an image of one frame in the image signal output from the image sensor so that reading of the image signal of the arbitrary frame from the storage means is started within a short predetermined time. Synchronization control means for synchronizing the drive timing signal and the reproduction timing signal with
An imaging apparatus comprising:   The imaging apparatus according to claim 1, wherein the predetermined time is a time substantially equal to a time required to write or read an image signal for one line with respect to the storage unit. The imaging unit is provided with a storage unit that stores the number of pixels of the image of the one frame,
The synchronization control unit is provided in the imaging apparatus main body, and recognizes the number of pixels of the image of one frame by acquiring the number of pixels stored in the storage unit from the imaging unit. The imaging apparatus according to claim 1. First conversion means for converting the image signal written in the storage means so that the resolution of the image represented by the image signal matches the resolution in image reproduction;
The imaging according to claim 1, wherein the synchronization control means determines a phase difference between the drive timing signal and the reproduction timing signal in consideration of a time required for conversion of an image signal by the first conversion means. apparatus. Second conversion means for converting an image signal written in the storage means so that a specified image area is extracted from an image represented by the image signal and the resolution of the extracted image area matches the resolution in image reproduction. Further comprising
The imaging according to claim 1, wherein the synchronization control means determines a phase difference between the drive timing signal and the reproduction timing signal in consideration of a time required for conversion of an image signal by the second conversion means. apparatus.   The imaging unit is provided with a second contact that contacts the first contact provided on the imaging device body when the imaging unit is mounted on the imaging device body, and the imaging unit is mounted on the imaging device body. 2. The signal transmission / reception between the imaging unit and the imaging apparatus main body in the performed state is performed by serial communication via the first contact and the second contact. Imaging device. At least an optical system that forms an image of an object, an image sensor that images the object imaged by the optical system, and a drive signal generation unit that generates a drive timing signal for driving the image sensor are integrated as a unit. An imaging apparatus body in which an imaging unit consisting of
Storage means for storing an image signal obtained by imaging the subject by the imaging element driven at a timing synchronized with the driving timing signal;
Reproduction signal generation means for generating a reproduction timing signal for reproducing an image;
An image signal obtained by the imaging device capturing an image of a subject is written in the storage unit, and the image signal written in the storage unit is synchronized with the reproduction timing signal generated by the reproduction signal generation unit. Write / read control means for controlling to read from the storage means at timing;
More than the time required for writing or reading out one frame of image signals to or from the storage means from the start of writing to the storage means of an image signal of an arbitrary frame obtained by imaging the subject by the imaging device A phase control signal for controlling the phase of the drive timing signal is sent to the drive signal generation unit of the imaging unit so that reading of the image signal of the arbitrary frame from the storage unit is started within a short predetermined time. Synchronization control means for synchronizing the drive timing signal and the reproduction timing signal with a phase difference corresponding to the number of pixels of an image of one frame in the image signal output from the image sensor by inputting,
An image pickup apparatus main body characterized by comprising: An imaging unit that is detachable from the imaging apparatus main body according to claim 7,
An optical system for imaging a subject;
An image sensor that images a subject imaged by the optical system;
Drive signal generation means for generating a drive timing signal for driving the image sensor at a timing synchronized with the phase control signal input from the synchronization control means according to claim 7;
Is an integrated imaging unit.

Images