JP2006005456A - Camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera system capable of satisfying diversified photographing requirements by selecting an imaging unit provided with a function or the performance adapted to conditions and photographing purposes of an object and using the selected imaging unit. <P>SOLUTION: The camera system includes: a camera body 2; a color photographing imaging unit 3A provided with a color separation filter and an optical low pass filter; a color photographing imaging unit 3B not provided with a color separation filter and an optical low pass filter; black/white photographing imaging units 3C, 3E not provided with a color separation filter but provided with an optical low pass filter; and a black/white photographing imaging unit 3D not provided with a color separation filter and an optical low pass filter, and the camera system is used for a digital camera by selectively mounting any of the imaging units 3A to 3E to the camera body 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a camera system in which an imaging unit including an imaging element is detachable from a camera body.

  Digital cameras that record still images as digital data are widely used. Most digital cameras currently on the market have a structure in which an image sensor, an image processing circuit, and a photographing lens unit are fixed to a camera body.

  Because the digital camera has the above structure, for example, it may be black-and-white, so you want to shoot a high-resolution image, or you may need a high-sensitivity shoot because it may be low-resolution. When a digital camera with specifications was needed, a new digital camera had to be purchased again. In addition, since camera manufacturers have to answer average demands, only digital cameras with a general specification range could be put on the market.

  Patent Document 1 below discloses a digital camera in which a camera body (a lens unit in Patent Document 1) and an imaging unit (a camera body unit in Patent Document 1) are detachable. However, Patent Document 1 does not consider the above problem at all.

JP-A-10-271376

  An object of the present invention is to provide a camera system that can satisfy various shooting requirements by selecting and using an imaging unit having a function or performance suitable for a subject condition and a shooting purpose. There is.

Such an object is achieved by the present inventions (1) to (8) below.
(1) Camera body,
An image sensor that captures a subject image, an image sensor drive circuit that drives the image sensor, and an image processing circuit that processes an output signal of the image sensor, and a plurality of image capture units having different functions or performances ,
A camera system characterized by being used as a digital camera in a state in which any one of the plurality of imaging units is selectively mounted on the camera body.

Accordingly, various photographing requirements can be satisfied by selecting and using an imaging unit having a function or performance suitable for the condition of the subject and the purpose of photographing.
In addition, since the camera body can be used in common, it is possible to reduce the user's economic burden as compared with the case of having a plurality of digital cameras in the kitchen, and it is also convenient to carry.

  (2) The plurality of imaging units include an imaging unit for color photography equipped with an imaging device having a color separation filter and an imaging unit for monochrome photography equipped with an imaging device not equipped with a color separation filter. The camera system according to (1) above.

  As a result, for example, when shooting at night or shooting a news photo, black and white photography is acceptable, but when high sensitivity is required, an imaging unit for monochrome photography can be used for color photography. High-sensitivity and high-resolution imaging can be performed as compared with the case of using this imaging unit.

  (3) The plurality of imaging units includes the imaging unit including an optical low-pass filter installed on the light receiving surface side of the imaging element and the imaging unit not including the optical low-pass filter. The camera system according to (2).

  As a result, when shooting a subject under conditions where moiré is unlikely to occur, by using an imaging unit that does not include an optical low-pass filter, it is possible to exhibit the original resolution of the imaging device as it is, and an optical low-pass filter is provided. High-resolution imaging can be performed as compared with the case where the imaging unit is used.

(4) The plurality of image pickup units each include an image pickup unit equipped with an image pickup device including a color separation filter, and an optical low-pass filter installed on the light receiving surface side of the image pickup device;
An imaging unit for color photography that is equipped with an image sensor with a color separation filter and does not have an optical low-pass filter;
An image pickup unit for monochrome photography equipped with an image pickup device not equipped with a color separation filter and provided with an optical low-pass filter installed on the light receiving surface side of the image pickup device;
The camera system according to (1), including an imaging unit for monochrome photography that includes an imaging element that does not include a color separation filter and does not include an optical low-pass filter.

  This makes it possible to select the imaging unit according to whether it is color photography or black-and-white photography, and whether the subject is less likely to cause moiré. Can be taken.

  (5) The camera system according to any one of (1) to (4), wherein the plurality of imaging units includes an imaging device having an imaging device having a different number of pixels from that of another imaging unit.

  Thereby, it is possible to select and use an imaging unit having a suitable number of pixels in accordance with the required sensitivity and resolution conditions.

(6) Each of the imaging units includes a housing that houses the imaging device, the imaging device driving circuit, and the image processing circuit;
A door that is slidably installed in a closed position that covers the light receiving surface side of the image sensor and an open position that does not cover the housing,
6. The camera system according to any one of (1) to (5), wherein the door is opened by using an insertion operation force when the imaging unit is inserted into the camera body.

As a result, when the image pickup unit is removed from the camera body, the light receiving surface of the image pickup unit can be protected by being covered with a door, so that dust or dirt adheres to the light receiving surface of the image pickup unit or is scratched. Can be reliably prevented.
In addition, as the image pickup unit is attached to and detached from the camera body, the door covering the light receiving surface of the image sensor can be automatically opened and closed, and the operation force for inserting the image pickup unit into the camera body can be utilized. Since the door is configured to open, a door drive mechanism is not required. Therefore, the mechanism including the camera body side is extremely simple and can be manufactured at low cost, and the door can be reliably opened and closed without any risk of failure.

  (7) Each of the imaging units further includes a connector for electrical connection with the camera body, and the connector is provided at a distal end portion of the imaging unit in the insertion direction of the camera body. The camera system according to 6).

  Accordingly, the connection of the connector can be completed simultaneously with the loading of the imaging unit into the camera body, and the connector can be connected extremely easily and reliably.

  (8) The camera system according to any one of (1) to (7), wherein each of the imaging units further includes a display device capable of displaying an image captured by the imaging element.

  Thereby, circuits related to imaging and image processing can be concentrated on the imaging unit, and the independence between the imaging unit and the camera body can be further enhanced.

According to the present invention, it is possible to satisfy various shooting requirements by selecting and using an imaging unit having a function or performance suitable for a subject condition and a shooting purpose.
In addition, since the camera body can be used in common, it is possible to reduce the user's economic burden as compared with the case of having a plurality of digital cameras in the kitchen, and it is also convenient to carry.

  Hereinafter, the camera system of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a rear perspective view of the camera system according to the present invention, as viewed obliquely from behind, with one imaging unit mounted on the camera body.

  The camera system 1 of the present embodiment includes a camera body 2 and five imaging units 3A to 3E, and any one of the imaging units 3A to 3E is selectively attached to the camera body 2. It is used as a digital camera.

  Hereinafter, the camera body 2 and the imaging units 3A to 3E will be described in order, but the imaging units 3A to 3E have the same configuration except that their functions or performance are different in the points described later. Only the unit 3A will be described.

  The camera body 2 is provided with a lens barrel 21 containing a photographing lens on the front side. Further, the camera body 2 is provided with an operation system such as a shutter button 22 and a zoom button 23 and an optical viewfinder 24.

  A holding unit 25 that holds the imaging unit 3 </ b> A is provided on the back side of the camera body 2. The imaging unit 3A can be mounted on the camera body 2 by inserting the imaging unit 3A from the slot 251 which is the entrance of the holding unit 25. As indicated by arrows in FIG. 1, the direction in which the imaging unit 3A is inserted into the camera body 2 (hereinafter simply referred to as “insertion direction”) is a direction orthogonal to the optical axis Ax of the photographing lens. The image pickup unit 3A attached to the camera body 2 can be detached from the camera body 2 by pulling it out in the direction opposite to the insertion direction.

  The imaging unit 3A is equipped with an imaging unit 4 having a CCD imaging device 41 that captures a subject image formed through a photographing lens. The imaging unit 4 is arranged so that the light receiving surface faces the front side. When the imaging unit 3A is mounted on the camera body 2, the center of the imaging unit 4 coincides with the position of the optical axis Ax of the photographing lens. To do. The image sensor is not limited to the CCD image sensor 41, and other types of image sensors such as a CMOS image sensor may be used.

  In addition, the image pickup unit 3A reproduces and displays an image photographed and recorded by the CCD image pickup device 41 and displays a live view that is a real-time moving image picked up by the CCD image pickup device 41 (liquid crystal display). Device) 5 is installed. Note that the display device of the imaging unit 3A is not limited to the LCD monitor 5, and other types of display devices such as an organic EL display device may be used. The display screen 51 of the LCD monitor 5 is directed to the side opposite to the light receiving surface of the imaging unit 4, that is, the back side.

  The holding portion 25 is formed with a notch 252 for exposing the back surface of the imaging unit 3A. In a state where the imaging unit 3 </ b> A is mounted on the camera body 2, the display screen 51 of the LCD monitor 5 can be viewed through the notch 252. Note that an opening may be formed like a window while leaving a portion of the slot 251 instead of the notch 252.

  On the back side of the imaging unit 3A, there are provided a monitor display switch 31 for switching on / off the LCD monitor 5 and an image advance button 32 operated when selecting a display image to be reproduced and displayed. It is exposed from the notch 252.

  FIG. 2 is a block diagram of the camera system 1 shown in FIG. Hereinafter, the internal structure of the camera body 2 and the imaging unit 3A will be described with reference to FIG.

  The camera body 2 includes a mechanical shutter (not shown), a shutter drive mechanism 26 that drives the mechanical shutter, a lens drive mechanism 27 that performs zoom driving and AF driving of the photographing lens, and an operation system such as the shutter button 22 and the zoom button 23. And a body CPU 28 for controlling the operation of the shutter drive mechanism 26, the lens drive mechanism 27, and the like based on the input signal.

  A battery 100 can be loaded in the camera body 2, and power is supplied from the battery 100 to each part of the camera body 2 and the imaging unit 3 </ b> A via the power supply circuit 29.

In the image pickup unit 3A, an image pickup device substrate 60 on which the CCD image pickup device 41 is mounted and a main substrate 70 are installed.
The image sensor substrate 60 is provided with an image sensor drive circuit 61 and an analog amplifier 62 that amplifies the output signal of the CCD image sensor 41.

  On the main substrate 70, an A / D conversion circuit 71 that performs analog-digital conversion on the output signal of the CCD image pickup device 41, and predetermined color process processing, γ correction, and the like are performed on the digitized output signal of the CCD image pickup device 41. An image processing circuit 72 that performs image processing, a system controller 73 that controls each circuit of the main substrate 70 and the image pickup device substrate 60, and an SDRAM (Synchronous Dynamic Random Access Memory) 74 that temporarily stores image data when generating data A flash memory 75, which is a non-volatile memory for storing captured image data for recording, and an LCD interface (display device drive circuit) 76 for driving the LCD monitor 5 are provided.

  Among these circuits, an A / D conversion circuit 71, an image processing circuit 72, a system controller 73, and an LCD interface 76 control a processing operation of image processing and image recording in a DSP (Digital Signal Processor). ) 77 is configured.

  In addition, the imaging unit 3 </ b> A has a connector 33 that performs electrical connection with the camera body 2. In a state where the imaging unit 3A is mounted on the camera body 2, the imaging element substrate 60 and the main substrate 70 and the body CPU 28 of the camera body 2 are connected via the connector 33 via the connector bus 331.

  The system controller 73 and the body CPU 28 are configured to communicate with each other via a connector bus 331 so that control can be coordinated. Control signals such as the shutter button 22 and the zoom button 23 are transmitted via the connector bus 331. Is transmitted from the body CPU 28 to the system controller 73.

  In addition, power is supplied from the camera body 2 to the imaging unit 3A via the connector bus 331.

  Next, a process for displaying a real-time image captured by the CCD image sensor 41, that is, a live view on the LCD monitor 5, will be described.

  The subject image formed on the light receiving surface of the CCD image pickup device 41 via the photographing lens in the lens barrel 21 is photoelectrically converted into charge data, and this charge data (signal) is used for creating live view image data. Then, the pixels are thinned out by predetermined pixels from the CCD image pickup device 41 and sequentially read out, subjected to correlated double sampling (CDS) and automatic gain control (AGC), and then input to the DSP 77.

  In the DSP 77, after the input signal is converted from analog to digital, signal processing such as predetermined color process processing and γ correction is performed, and live view image data (luminance signal data Y, two color difference signal data Cr, Cb) is generated, and a live view image is displayed on the LCD monitor 5 based on this data. The live view image data is image data having a smaller number of pixels (the number of thinned data) than the number of effective pixels of the CCD image sensor 41 corresponding to the number of display pixels of the LCD monitor 5.

  The live view image data generation process is periodically updated as the CCD image sensor 41 is read, and is displayed on the LCD monitor 5 as a real-time moving image.

Next, processing during photographing / recording will be described.
When the shutter button 22 is half-pressed and the photometry switch 221 is turned on, the body CPU 28 sends a signal to the effect that the photometry and exposure calculation should be started to the system controller 73. Photometry and exposure calculation are performed based on the output signal of the image sensor 41. Further, the system controller 73 performs AF control, operates the lens driving mechanism 27 via the body CPU 28, and performs AF driving.

  From this state, when the shutter button 22 is further fully pressed and the release switch 222 is turned on, the body CPU 28 performs exposure control by operating the mechanical shutter by the shutter drive mechanism 26 based on the exposure time calculated by the system controller 73. At the same time, for example, a signal related to the start of exposure, such as a mechanical shutter opening signal and exposure (charge accumulation) time, is transmitted to the imaging unit 3A.

  In response to this signal, the DSP 77 performs unnecessary charge sweeping control and exposure control (charge accumulation time control) of the CCD image pickup device 41, and through the same process as described above, charge data is obtained from the CCD image pickup device 41 without thinning out pixels. Is temporarily stored in the SDRAM 74. Then, the DSP 77 performs predetermined signal processing on the charge data read from the SDRAM 74, thereby generating recording still original image data with a large number of pixel data.

  The DSP 77 performs a pixel data thinning process from the generated recording still original image data to generate a screen nail of a display still image that matches the number of display pixels of the LCD monitor 5 and displays it on the LCD monitor 5 for a certain period of time. To do.

  Further, the DSP 77 performs image data compression processing such as JPEG on the generated recording still original image data, and records the obtained compressed image data in the flash memory 75.

  When viewing the captured image stored in the flash memory 75 using a personal computer (hereinafter abbreviated as “personal computer”), the imaging unit 3A is removed from the camera body 2 and connected to the personal computer via the connector 33. Thus, the captured image data can be taken into the personal computer. At this time, the power of the imaging unit 3A is supplied from the personal computer.

  3 and 4 are perspective views of the imaging unit 3A as viewed obliquely from the front. FIG. 3 shows a state in which the door 35 is opened, and FIG. 4 shows a state in which the door 35 is closed. FIG. 5 is an enlarged view of a part of FIG.

  As shown in FIG. 3, the imaging unit 3A has a flat housing 34, and the imaging unit 4, the imaging device substrate 60, and the main substrate including the CCD imaging device 41 described above are included in the housing 34. 70 is stored. An opening is formed in the housing 34 at a position on the light receiving surface side of the imaging unit 4. The light receiving surface of the imaging unit 4 is exposed to the front surface of the housing 34 through the opening.

  The connector 33 described above is disposed at the distal end of the housing 34 in the direction of insertion into the camera body 2. An electrical contact (not shown) that is joined to the terminal 332 of the connector 33 is installed in the back of the holding part 25 of the camera body 2. When the imaging unit 3A is inserted into the holding part 25 of the camera body 2, this electrical contact is provided. The contact and the terminal 332 of the connector 33 come into contact with each other and are electrically connected.

  In the present embodiment, the connector 33 is a connector conforming to the USB (Universal Serial Bus) standard. By adopting a standard interface connector such as USB as the connector 33, the imaging unit 3A can be easily connected to a personal computer.

  The connector 33 is not limited to the USB connector as shown in the figure, and may be, for example, a connector conforming to a PC card standard. In this case, the outer shape of the imaging unit 3A is a shape that conforms to the PC card standard, that is, the thickness of the imaging unit 3A is Type 1 (3.3 mm), Type 2 (5.0 mm), Type 3 (10.5 mm) of the PC card standard. ) Or Type 4 (16.0 mm). In such a case, when taking captured image data into a personal computer, this can be easily performed by loading the imaging unit 3A into a PC card slot equipped in the personal computer.

  The imaging unit 3 </ b> A further includes a door (sliding door) 35 slidably installed with respect to the housing 34. The door 35 is movable between a closed position (the position shown in FIG. 4) covering the light receiving surface of the imaging unit 4 and an open position (the position shown in FIG. 3) that is not covered. The moving direction of the door 35 is parallel to the direction in which the imaging unit 3A is inserted into the camera body 2.

  The door 35 is urged in the closing direction by a coil spring 36 as urging means. The left end portion in FIG. 3 of the coil spring 36 is fixed to a fixing pin 351 protruding from the inner surface side of the door 35, and the right end portion in FIG. 3 of the coil spring 36 is fixed to the housing 34. Yes. The coil spring 36 is housed in a groove 341 formed in the housing 34.

  As shown in FIG. 4, when the imaging unit 3 </ b> A is not attached to the camera body 2, the door 35 is closed by the urging force of the coil spring 36 and the light receiving surface of the imaging unit 4 is covered. Thereby, it is possible to prevent dust or dirt from adhering to the light receiving surface of the imaging unit 4 or to be damaged by hitting other objects, and to protect the light receiving surface of the imaging unit 4.

  Further, when it is necessary to clean the light receiving surface of the imaging unit 4 using a blower or the like, the door 35 can be easily opened against the urging force of the coil spring 36.

  The door 35 is configured to automatically open using the force of the insertion operation when the imaging unit 3A is inserted into the holding unit 25 of the camera body 2.

  As shown in FIG. 1, a locking pin (locking portion) 253 that locks to the door 35 protrudes from the holding portion 25 of the camera body 2. As shown in FIG. 4, a groove 342 into which the locking pin 253 can be inserted is formed at the tip of the housing 34.

  When the imaging unit 3A is inserted into the holding portion 25 of the camera body 2, the locking pin 253 moves relatively in the groove 342 at the beginning of the insertion, and comes into contact with the tip of the door 35 ( (See FIG. 5). When the imaging unit 3A is further inserted from the state shown in FIG. 5, the locking pin 253 is locked to the door 35, thereby preventing the door 35 from moving forward in the insertion direction. That is, the door 35 moves relative to the housing 34 in the direction opposite to the insertion direction, and slides to the open position shown in FIG.

  When the door 35 opens, the coil spring 36 extends and energy is stored in the coil spring 36. When the imaging unit 3A is detached from the camera body 2, the coil spring 36 is contracted by this energy, and the door 35 is automatically closed.

  In this manner, the door 35 can be automatically opened and closed as the imaging unit 3A is attached to and detached from the camera body 2. Further, since the door 35 is configured to be opened by using the operation force for inserting the imaging unit 3A into the camera body 2, a drive mechanism for the door 35 is unnecessary. Therefore, the mechanism including the camera body 2 side is extremely simple and can be manufactured at low cost, and the door 35 can be reliably opened and closed without fear of failure.

  In the present embodiment, as shown in FIG. 4, when the door 35 is closed, the door 35 is positioned closer to the tip than the center in the insertion direction of the imaging unit 3 </ b> A into the camera body 2. As a result, when the imaging unit 3A is inserted into the holding unit 25, the door 35 can be opened from the beginning of insertion, so that the door 35 can be opened larger and more reliably.

6 is a sectional front view of the imaging unit 3A, and FIG. 7 is a sectional view taken along line XX in FIG.
As shown in FIG. 6, in the housing 34 of the imaging unit 3 </ b> A, the imaging element substrate 60 is installed on the front end side in the insertion direction to the camera body 2 when viewed from the front, and the main substrate 70 is installed on the rear end side. Has been. The imaging unit 4 is fixed substantially at the center of the imaging element substrate 60, and the LCD monitor 5 is fixed almost at the center of the main substrate 70.

  As shown in FIG. 7, the image pickup unit 4 holds a CCD image pickup device 41, an optical low-pass filter 43 and an infrared cut filter 44 that are placed on the light receiving surface side of the CCD image pickup device 41, and an outer peripheral portion thereof. And a housing 45.

  The optical low-pass filter 43 reduces the spatial frequency component close to the sampling spatial frequency determined by the pixel interval of the CCD image sensor 41 from the spatial frequency of the subject light. By providing this optical low-pass filter 43, it is possible to prevent the occurrence of moire (false color).

  As will be described later, the optical low-pass filter 43 is not installed in the imaging units 3B and 3D.

  The infrared cut filter 44 removes infrared wavelength components. By installing the infrared cut filter 44, it is possible to prevent the CCD image sensor 41 from receiving infrared light that is invisible to human eyes.

  The housing 45 is fixed to the housing 34, and the imaging element substrate 60 is fixed to the housing 45.

  The imaging unit 4 and the LCD monitor 5 do not overlap each other when viewed from the direction perpendicular to the light receiving surface of the imaging unit 4 (see FIG. 6), and part of each other is viewed from the direction parallel to the light receiving surface of the imaging unit 4. It arrange | positions so that it may overlap (refer FIG. 7). As described above, the imaging unit 4 having a large thickness dimension and the LCD monitor 5 are arranged not in the thickness direction but shifted in the plane direction, so that the thickness dimension of the housing 34 can be reduced, and imaging is performed. The LCD monitor 5 can be mounted while reducing the thickness of the unit 3A.

  Further, as shown in FIG. 6, the imaging unit 4 and the LCD monitor 5 are arranged in this order from the front end side to the rear end side in the insertion direction into the camera body 2, that is, from the right side to the left side in FIG. Has been. As a result, as described above, the position when the door 35 is closed can be arranged closer to the tip than the center in the insertion direction. Therefore, when the imaging unit 3A is inserted into the holding unit 25, the stage of the beginning of insertion is performed. Can start opening the door 35, and the door 35 can be opened larger and more reliably.

  Further, the image pickup device substrate 60 and the main substrate 70 are arranged with their positions in the thickness direction shifted (see FIG. 7), and when viewed from the direction perpendicular to the light receiving surface of the image pickup unit 4, the image pickup device substrate 60 and The main board 70 is disposed so that parts thereof overlap each other (see FIG. 6). As a result, the size of the housing 34 can be reduced by the size of the overlapping portion, and the image pickup unit 3A can be downsized.

  FIG. 8 is a perspective view showing the entire camera system 1 of the present invention. As shown in the figure, the camera system 1 includes five imaging units 3A to 3E having different functions or performances, and selectively selects one of the imaging units 3A to 3E as a camera body. 2 can be used as a digital camera. Hereinafter, specifications of the imaging units 3A to 3E will be described.

[Imaging unit 3A]
The image pickup unit 3A has a general specification, is equipped with a CCD image pickup element 41 having a color separation filter, and has the optical low-pass filter 43.

  According to the image pickup unit 3A, since the CCD image pickup element 41 is provided with the color separation filter, color shooting can be performed. Further, since the optical low-pass filter 43 is provided, it is possible to make it difficult to produce moire. For this reason, the imaging unit 3A is suitable for normal imaging.

  The color separation filter is usually formed on the image sensor chip 411. The color separation filter may be a primary color filter or a complementary color filter, and may have any arrangement such as a Bayer arrangement or a color difference sequential arrangement.

[Imaging unit 3B]
The image pickup unit 3B is equipped with a CCD image pickup device 41 having a color separation filter and not having an optical low-pass filter 43. Further, the number of pixels of the CCD image pickup device 41 is the same as that of the image pickup unit 3A (in this embodiment, about 6 million pixels).

  According to the image pickup unit 3B, since the color separation filter is provided in the CCD image pickup device 41, color shooting can be performed. In addition, since the optical low-pass filter 43 is not provided, the moiré is likely to occur compared to the imaging unit 3A, but the resolution is improved by about 4 times compared to the imaging unit 3A. This is because the spatial cutoff frequency of the optical low-pass filter 43 is normally designed to be about ½ of the imaging element spatial Nyquist frequency (1 / (2 × pixel pitch)), and thus the optical low-pass filter 43 is not provided. This is because the resolution inherent in the CCD image pickup device 41 is exhibited as it is without being impaired.

  For this reason, when shooting a subject under conditions where moiré is unlikely to occur, using the imaging unit 3B can improve the resolution by about 4 times compared to the general-purpose imaging unit 3A. High resolution shooting is possible.

[Imaging unit 3C]
The imaging unit 3 </ b> C includes a CCD imaging device 41 that does not include a color separation filter and an optical low-pass filter 43. Further, the number of pixels of the CCD image pickup device 41 is the same as that of the image pickup unit 3A.

  Although this imaging unit 3C is for monochrome photography since the CCD imaging device 41 is not provided with a color separation filter, both sensitivity and resolution can be improved by about three times compared to the imaging unit 3A. Hereinafter, this reason will be described with reference to FIG. 9 by taking as an example the case where the color separation filter is a Bayer-array primary color filter.

  As shown in FIG. 9, when a color image is captured using a CCD image sensor 41 having a Bayer array primary color filter, the luminance of four adjacent pixels (one red, two green, and one blue) is shown. The luminance signal for one dot of the photographed image is obtained by averaging the signals, and the luminance signal of the adjacent dot averages the luminance signals of four pixels shifted by one pixel in the vertical or horizontal direction. Have gained. In this case, although the number of dots of the captured image is the same as the number of pixels of the CCD image sensor 41, the luminance signal of each dot of the captured image is a mixture of the luminance signals from the four pixels. The original resolution of the image sensor 41 is not exhibited, and the resolution is lowered.

  On the other hand, when a monochrome image is captured by the CCD image sensor 41 that does not include a color separation filter, the luminance signal of each pixel of the CCD image sensor 41 directly becomes the luminance signal of each dot of the captured image, and the luminance of each pixel. Since the signals are independent without being mixed, the resolution inherent in the CCD image sensor 41 is exhibited as it is.

  In the case of the CCD image sensor 41 having a color separation filter, each pixel photoelectrically converts only light of a specific color that has passed through the filter. In the CCD image sensor 41 not having a color separation filter, each pixel has Because all the light is photoelectrically converted, the sensitivity is high.

  For the reasons described above, the imaging unit 3C using the CCD imaging device 41 that does not include the color separation filter can improve both sensitivity and resolution by about three times compared to the imaging unit 3A. Can be taken. Therefore, for example, when shooting at night or shooting a news photo, black-and-white photography is required but high sensitivity is required, the imaging unit 3C is suitable.

  On the other hand, since the image pickup unit 3C includes the optical low-pass filter 43, it is possible to make it difficult to generate moire as with the image pickup unit 3A.

[Imaging unit 3D]
The imaging unit 3D includes a CCD imaging device 41 that does not include a color separation filter and does not include an optical low-pass filter 43. Further, the number of pixels of the CCD image pickup device 41 is the same as that of the image pickup unit 3A.

  Similar to the imaging unit 3C, the imaging unit 3D is for monochrome photography because the CCD imaging device 41 is not provided with a color separation filter, but the sensitivity can be improved by about three times compared to the imaging unit 3A. .

  Further, since the optical low-pass filter 43 is not provided, moiré is likely to occur compared to the imaging unit 3C, but the resolution is improved by about 4 times compared to the imaging unit 3C, and is about 12 times higher than that of the imaging unit 3A. Resolution can be obtained.

  For this reason, when shooting an object under conditions where black and white photography is possible and moiré is unlikely to occur, a higher resolution than that of the imaging unit 3C can be obtained by using the imaging unit 3D.

[Imaging unit 3E]
The imaging unit 3E is equipped with a CCD imaging device 41 that does not include a color separation filter and an optical low-pass filter 43. Further, the number of pixels of the CCD image pickup device 41 is smaller than that of the image pickup units 3A to 3D (in this embodiment, about 2 million pixels).

  This imaging unit 3E is for monochrome photography since the CCD imaging device 41 is not provided with a color separation filter. Further, although the number of pixels of the CCD image pickup device 41 is small (about ３) as compared with the image pickup units 3A to 3D, the original resolution of the CCD image pickup device 41 is exhibited due to the absence of the color separation filter. And a resolution equivalent to or better than 3B.

  Further, in the image pickup unit 3E, the area per pixel is increased by reducing the number of pixels of the CCD image pickup device 41, so that higher sensitivity than the image pickup units 3C and 3D can be obtained.

  For this reason, black-and-white photography may be used, but when particularly high sensitivity is required, by using the imaging unit 3E, the imaging unit 3C is maintained while maintaining a resolution equal to or higher than that of the imaging units 3A and 3B. And it can shoot with higher sensitivity than 3D.

  On the other hand, since the image pickup unit 3E includes the optical low-pass filter 43, it is possible to make it difficult to generate moire as with the image pickup unit 3A.

  As described above, in the camera system 1, an image pickup unit 3 </ b> A to 3 </ b> E having an optimal function / performance is selected and mounted on the camera body 2 according to the condition of the subject and the shooting purpose. Can satisfy various photographing requirements.

  In addition, since the camera body 2 can be used in common, the user's economic burden is greatly reduced as compared with the case of having a plurality of digital cameras in the kitchen. Also, carrying it is easier than carrying multiple digital cameras.

  In addition, when a user is faced with a new photographing request, the user can achieve the desired object with a small economic burden by purchasing an imaging unit that satisfies the photographing request.

  The camera system of the present invention has been described above with reference to the illustrated embodiment. However, the present invention is not limited to this, and each component constituting the camera system has an arbitrary configuration that can exhibit the same function. Can be substituted. Moreover, arbitrary components may be added.

  Further, in the camera system of the above-described embodiment, the number of imaging units is five. However, the camera system of the present invention only needs to include at least two imaging units having different functions or performances. . Further, the difference in function or performance of the plurality of imaging units is not limited to the combination of the presence / absence of a color separation filter, the presence / absence of an optical low-pass filter and the difference in the number of pixels as in the above-described embodiment, and the presence / absence of a color separation filter. Only the presence or absence of an optical low-pass filter, or only the difference in the number of pixels.

  In addition, the camera system of the present invention may be sold as a set of a predetermined number of imaging units and camera bodies, or a user can select an imaging unit having specifications desired by the user and purchase it in combination with the camera body. You may do it. In addition, a single imaging unit may be additionally purchased as necessary for a camera body that has already been purchased.

  Further, the external shape and structure of the imaging unit, the arrangement of internal devices, and the like are not limited to the illustrated configuration.

  In the illustrated embodiment, the nonvolatile memory for storing the image data of the photographed image is built in the imaging unit. However, the present invention is not limited to this, and a memory card including the nonvolatile memory is used. You may comprise so that a recording medium may be loaded in the slot provided in the imaging unit or the camera body.

  In addition, the camera body in the illustrated embodiment is provided with a zoom lens, but is not limited thereto, and may be provided with a single focus photographing lens. Further, the camera body is not limited to the one in which the photographing lens is integrated, but may be an interchangeable lens type having a lens mount.

It is the back perspective view which looked at the camera system of the present invention from the slanting back. It is a block diagram of the camera system shown in FIG. It is the perspective view which looked at the imaging unit in the camera system shown in FIG. 1 from diagonally forward. It is the perspective view which looked at the imaging unit in the camera system shown in FIG. 1 from diagonally forward. It is the figure which expanded a part of FIG. It is a cross-sectional front view of the imaging unit in the camera system shown in FIG. It is the XX sectional view taken on the line in FIG. It is a perspective view which shows embodiment of the camera system of this invention. It is a schematic diagram for demonstrating the method to produce | generate the luminance signal of each dot of the picked-up image at the time of using an image sensor with a color separation filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera system 2 Camera body 21 Lens barrel 22 Shutter button 221 Metering switch 222 Release switch 23 Zoom button 24 Optical viewfinder 25 Holding part 251 Slot 252 Notch 253 Locking pin 26 Shutter drive mechanism 27 Lens drive mechanism 28 Body CPU
29 Power supply circuit 3A, 3B, 3C, 3D, 3E Imaging unit 31 Monitor display switch 32 Image feed button 33 Connector 331 Connector bus 332 Terminal 34 Housing 341, 342 Groove 35 Door 351 Fixing pin 36 Coil spring 4 Imaging unit 41 CCD imaging Element 411 Image sensor chip 412 Package 413 Protection glass plate 43 Optical low-pass filter 44 Infrared cut filter 45 Housing 5 LCD monitor 51 Display screen 60 Image sensor substrate 61 Image sensor drive circuit 62 Analog amplifier 70 Main substrate 71 AD converter circuit 72 Image processing circuit 73 System controller 74 SDRAM
75 Flash memory 76 LCD interface 77 DSP
100 Battery Ax Optical axis

Claims (8)

Camera body,
An image sensor that captures a subject image, an image sensor drive circuit that drives the image sensor, and an image processing circuit that processes an output signal of the image sensor, and a plurality of image capture units having different functions or performances ,
A camera system characterized by being used as a digital camera in a state in which any one of the plurality of imaging units is selectively mounted on the camera body.   The plurality of imaging units include an imaging unit for color photography equipped with an imaging device equipped with a color separation filter and an imaging unit for monochrome photography equipped with an imaging device not equipped with a color separation filter. The camera system according to 1.   3. The imaging unit according to claim 1, wherein the plurality of imaging units include an imaging unit including an optical low-pass filter installed on a light receiving surface side of the imaging element and an imaging unit not including the optical low-pass filter. Camera system. The plurality of image pickup units are equipped with an image pickup device including a color separation filter, and an image pickup unit for color photographing including an optical low-pass filter installed on the light receiving surface side of the image pickup device;
An imaging unit for color photography that is equipped with an image sensor with a color separation filter and does not have an optical low-pass filter;
An image pickup unit for monochrome photography equipped with an image pickup device not equipped with a color separation filter and provided with an optical low-pass filter installed on the light receiving surface side of the image pickup device;
The camera system according to claim 1, further comprising: an imaging unit for monochrome photography that includes an imaging device that does not include a color separation filter and does not include an optical low-pass filter.   5. The camera system according to claim 1, wherein the plurality of image pickup units include an image pickup device having an image pickup device having a different number of pixels from the image pickup device of another image pickup unit. Each of the imaging units includes a housing that houses the imaging device, the imaging device drive circuit, and the image processing circuit;
A door that is slidably installed in a closed position that covers the light receiving surface side of the image sensor and an open position that does not cover the housing,
The camera system according to any one of claims 1 to 5, wherein the door is configured to open using a force of an insertion operation when the imaging unit is inserted into the camera body.   Each said imaging unit is further equipped with the connector which performs an electrical connection with the said camera body, This connector is provided in the front-end | tip part of the insertion direction to the said camera body of the said imaging unit. Camera system.   The camera system according to claim 1, wherein each of the imaging units further includes a display device capable of displaying an image captured by the imaging element.

Images