JP5506355B2 - Imaging device - Google Patents

Description

The present invention relates to an imaging apparatus having a function of wirelessly transmitting image data.

JP 2005-167634 A

  Image data taken by an imaging device such as a digital camera can be easily transferred to a remote place via a public line or a computer network. Recently, a wireless communication environment such as a wireless LAN and a mobile phone has been improved, and a digital camera having a wireless communication function for directly connecting to a network and transferring an image has been realized. For example, a photographed image can be transmitted to a remote place by inserting a wireless LAN card into a memory card slot of a digital camera and connecting to a network via this wireless LAN card. An adapter type wireless LAN unit connected to a digital camera with a cable has also been commercialized.

  Wireless data communication in a digital camera is characterized in that there are many one-way communications in which captured image data is transferred to an external PC or an image server, etc., compared to wireless communication using a mobile communication terminal or personal computer (PC). . In addition, there is a demand to immediately transfer captured image data to an external device due to the limited storage capacity of the captured image.

  Patent Document 1 discloses a digital camera that transmits a captured image to an external device using a wireless communication device. In the technique described in Patent Document 1, power consumption is reduced by controlling the power supply of the wireless communication unit according to the transmission state of image data.

  In the case of a camera, the posture of the camera changes at the time of shooting or after shooting, and the surrounding environment also changes, so that wireless communication cannot always be performed in an optimal state. In some cases, the communication speed is reduced, and it takes a very long time to transmit an image, and power consumption required for communication increases.

The present invention aims to be able to efficiently wirelessly transmitting shooting images.

An imaging apparatus according to the present invention includes a plurality of antennas, and wireless communication means for transmitting image data generated by performing a shooting preparation operation and a shooting operation using one of the plurality of antennas. In order to select one of the plurality of antennas based on the received signal level of the plurality of antennas after the start of the shooting preparation operation is instructed until the start of the shooting operation is instructed It performs processing, after said starting the shooting operation is instructed, the processing for transmission is to be performed using the antenna selected from among the plurality of antennas of the image data by the wireless communication means And a control means for performing the above.

According to the present invention, it is possible to efficiently wirelessly transmitting shooting images.

It is a schematic block diagram of Example 1 of the present invention. 2 is a rear view of Example 1. FIG. 2 is a configuration example of network connection according to the first embodiment. It is an example of the positional relationship between the attitude | position of a digital camera and a wireless LAN access point. It is another example of the positional relationship between the attitude of the digital camera and the wireless LAN access point. 3 is a flowchart illustrating an image transfer operation according to the first exemplary embodiment. It is a timing chart at the time of single shooting. It is a timing chart at the time of continuous shooting. 6 is a schematic configuration block diagram of Embodiment 2. FIG. 6 is a rear view of Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of a digital single-lens reflex camera which is an embodiment of an imaging apparatus or imaging system according to the present invention. FIG. 2 shows a rear view of one embodiment of the present invention.

  The interchangeable lens 10 can be detached from the camera body 20. The interchangeable lens 10 includes a photographing lens 12 and a lens control CPU 14 that controls zooming and focusing of the photographing lens 12.

  When the release switch 34 of the camera body 20 is half-pressed, the single-lens reflex camera of this embodiment is ready for shooting. That is, the overall control / image processing CPU 26 communicates with the lens control CPU 14 to drive the photographing lens 12 and starts an autofocus operation. Thereafter, when the release switch 34 is fully pressed, the overall control / image processing CPU 26 causes the image sensor 22 to perform an exposure operation by the sensor drive circuit 42. Thereby, the imaging device 22 converts the optical image from the photographing lens 12 of the interchangeable lens 10 into an image signal having a preset resolution.

  The A / D converter 24 converts the output image signal of the image sensor 22 into a digital signal. The overall control / image processing CPU 26 performs known camera signal processing such as color balance adjustment and gamma correction on the digital image signal from the A / D converter 24. The captured image is supplied to the image display device 28 for quick review display, and is stored in an image data recording medium such as the SD card 38 or the CF card 40.

  The user can set in advance using the operation device 32 whether or not to transfer the captured image to an external image server, PC, or the like by wireless communication. This setting information is stored in the memory 44.

  The posture detection device 46 detects the orientation of the camera body 120 about three axes. Thereby, the CPU 26 can determine whether the camera body 20 is in the horizontal position or the vertical position.

  When the wireless module 50 is not performing a wireless communication operation, the wireless module 50 is controlled to a stopped state or a non-powered state in order to reduce power consumption. Three antennas 52, 54, and 56 are connected to the wireless module 50.

  When the captured image is set to be wirelessly transferred, the overall control / image processing CPU 26 controls the wireless module 50 to the operating state in response to the half-pressing operation of the release switch 34 to link the image transfer destination. Establish.

  The real time clock 48 measures the current time. The battery 58 supplies electric power necessary for the operation of each part of the main body 20.

  The antenna 52 is disposed on the top of the optical viewfinder. The antenna 54 is disposed on the right side of the main body. The antenna 56 is disposed on the left side of the main body. The built-in type is more advantageous in terms of design and operability than the external antenna, considering various ways of holding the camera and connecting peripheral devices such as lenses and strobes.

  On the rear surface of the camera body 20, an operation button 32 a and an operation dial 32 b of the operation device 32 are arranged, and three display devices of the image display device 28, the information display device 30, and the LED display device 36 are also arranged. A release switch 34 is disposed on the upper surface of the camera. The image display device 28 displays a captured image and a reproduced image. The information display device 30 displays the current wireless communication link speed and antenna reception signal level. When the image is actually transferred, the LED display device 36 blinks.

  FIG. 3 is a schematic diagram showing the relationship between the camera of this embodiment and an external network. In this embodiment, a wireless LAN is assumed as a wireless communication standard. However, a wireless communication standard such as a public wireless line such as a mobile phone, WiMAX or WirelessUSB can also be used.

  In FIG. 3, an FTP server is assumed as an image transfer destination. First, wireless communication with the wireless LAN access point 60 or 62 is established using SSID information, wireless authentication information, and wireless encryption information set in the digital camera body 20 in advance. In FIG. 3, two wireless LAN access points 60 and 62 are illustrated, but wireless communication may be established with either of them. In general, wireless communication is established with a wireless LAN access point having a better radio wave condition. When the digital camera body 20 moves and the radio wave condition with another wireless LAN access point is improved, the wireless communication is established again using the roaming function.

  When the wireless communication is established, the camera body 20 displays the received signal level at that time on the information display device 30. In FIG. 2, as an example of this display, the information display device 30 displays it in the form of an antenna mark. The example shown in FIG. 2 is a display when the received signal level is the highest, and the number of bars on the right side of the antenna mark decreases to 2, 1, and 0 as the received signal level decreases. become. Further, in FIG. 2, the link speed of the wireless communication is also displayed at the same time.

  When the IP address is automatically acquired, the DHCP server 64 is accessed to acquire the IP address, and in some cases, the camera body 20 (or the user) is authenticated by the authentication server 66.

  When the IP address of the FTP server is not known, the IP address of the FTP server 70 is acquired from the DNS server 68 and the FTP server 70 is accessed. The user account and password information are transmitted to the FTP server 70 to log in to the FTP server 70. Thereby, the preparation for transmitting image data is completed.

  The photographing operation is performed by fully pressing the release switch 34, and the photographed image data is stored in the recording medium 38 or 40, and at the same time, the camera body 20 transmits the photographed image data to the FTP server 70.

  At this time, the radio wave conditions of the antennas 52, 54, and 56 differ depending on the positional relationship between the posture of the camera body 20 and the wireless LAN access point. Depending on the antenna, sufficient throughput performance may not be exhibited. 4 and 5 show examples of the positional relationship between the camera posture and the wireless LAN access point.

  FIG. 4 shows the horizontal position shooting. When the wireless LAN access point is on the right side, good throughput can be obtained by communication using the antenna 52. Even when the antenna 54 is used, good throughput can be expected as the positional relationship with the access point. However, since the radio wave is blocked by the photographer holding the vicinity of the antenna 54 at the time of shooting, the radio wave condition is generally deteriorated. The antenna 56 has a radio wave condition worse than that of the antennas 52 and 54 because the camera body 20 is located between the access point and the radio wave obstruction.

  FIG. 5 shows the positional relationship during vertical position shooting. In this case, the antenna 54 has the best radio wave condition. Since the antenna 56 is covered with a photographer's hand, the radio wave is weakened. The antenna 52 causes the camera body 20 to interfere with radio waves.

  In a general single-lens reflex digital camera, a strobe is attached to the top or side of the camera, and a lens can be exchanged. A lens with a long overall length can be attached. In some cases, the camera is attached to a tripod. In addition to the photographer's hand and the camera body, such peripheral devices are factors that deteriorate the radio wave condition. The same problem occurs when the shooting mode changes in a digital camera of a single-lens reflex type, a digital camera of a compact type, or a mobile phone with a built-in digital camera.

  As described above, the position of the camera is moved by photographing, and the posture of the camera and the place where the photographer holds the camera are also changed. Also, the position where the wireless LAN access point is installed varies, and there may be a case where there is a radio wave obstacle between the wireless LAN access point and the camera. The photographer himself may become a radio obstacle. Accordingly, considering that image data is transferred wirelessly at the same time as or immediately after shooting, it is necessary to select an optimal antenna for data transfer according to radio wave conditions.

  Diversity functions are installed in information communication devices such as PCs and PDAs, in-vehicle radios, and in-vehicle televisions in order to solve similar problems. Diversity-equipped wireless communication devices use the best antenna by comparing the received signal levels of all antennas, that is, the absolute level of the received signals or the noise ratio (SNR) of the antenna received signals, at regular intervals. However, in this method, communication cannot be performed while the received signal level of the antenna is checked and the antenna is switched, and throughput is reduced. Since packets cannot be received during the check, the link is likely to break.

  In this embodiment, the radio reception signal levels of the antennas 52, 54, and 56 are determined in response to half-pressing of the release switch 34, that is, at the time of shooting preparation operation, and the one having a high reception signal level is used. That is, during image transmission, image data can always be transmitted at high speed without checking the reception levels of the antennas 52, 54, and 56 and switching the antennas. Further, since the time required for transferring one image is short, the power consumption required for transmission is small.

  Further, when a posture change of the camera body is detected by the posture detection device 46, the reception signal levels of all the antennas 52, 54, 56 are determined again, and the antennas are switched to use the antennas with higher reception signal levels. . As a result, it is possible to always select the optimum antennas 52, 54 and 56 while minimizing the number of times of checking the reception levels of the antennas 52, 54 and 56 and switching the antennas 52, 54 and 56. Communication is always possible at high speed, and power consumption for transmission can be suppressed.

  FIG. 6 shows a flowchart of the antenna selection sequence of the present embodiment. When the release switch 34 is half pressed (S1), the reception signal levels of all the antennas 52, 54, 56 are determined (S2), and an antenna with a high reception signal level is selected (S3). As a method of determining the antenna to be used, the absolute level of the received signal may be compared, or the antenna reception signal-to-noise ratio (SNR) may be determined and the best one may be selected.

  Using the antenna thus selected, the user logs in to the image transmission destination server 70 (S4), and the image transmission preparation is completed. Before the release switch 34 is fully pressed (S8), if a change in the posture of the camera body 20 is detected (S5), the reception signal levels of all the antennas 52, 54, 56 are determined again (S6), and the reception signal level is determined. A high antenna is selected (S7).

  When the release switch 34 is fully pressed (S8), as described above, the photographing operation is performed to save the photographed image data (S9), and the photographed image data is transmitted to the server 70 (S10). When a certain time has elapsed after the captured image data is transmitted to the server 70 (S11), the wireless communication is disconnected (S12).

  The operation when continuously shooting a plurality of images will be described. In a single-lens reflex type digital camera, there are a single shooting mode in which the release switch 34 needs to be fully pressed every time shooting is performed, and a continuous shooting mode in which a plurality of images are continuously shot while the release switch 34 is held down. is there.

  FIG. 7 is a diagram illustrating the operation timing in the single shooting mode. As described with reference to FIG. 6, the antenna is selected during the shooting preparation operation by half-pressing the release switch 34, and shooting is executed in response to the full-press. In the single shooting mode, the interval between the shooting time of one image and the shooting time of the next image is a disjoint time. At the same time as shooting is performed and the shot image is stored in the recording medium, transfer of the shot image to the server starts. The wireless communication link is maintained if a certain period of time has not elapsed after the image transfer. During this time, in order to always maintain the optimum radio link state, the reception signal levels of all the antennas 52, 54 and 56 are determined, and the antenna selection operation based on the determination is performed.

  In single shooting mode, once a single image is shot, the composition and subject are often changed in the next shooting, and the radio wave status in wireless communication is likely to change with each shooting. Therefore, as shown in FIG. 7, the antenna selection operation is performed every time one image is taken. Although the photographing operation ends in an instant, the communication operation for one image usually takes about 1 to several seconds. Therefore, every time one image is transmitted, an antenna selection operation is performed to prepare for the transfer of the next image.

  From the end of transferring one image to the start of the next image transfer, the connection state is usually maintained, so that the throughput performance of wireless transfer is not particularly required. By performing the antenna selection operation during this period, the timing of the entire operation is optimized. As a result, image data can always be transferred at high speed with low power consumption.

  In the continuous shooting mode, the composition or subject is relatively constant during one continuous shooting operation. There is a high possibility that the radio wave condition in wireless communication will not change so much. Since the amount of image data in one continuous shooting operation is large, the overall throughput is improved by reducing the number of antenna selection operations with priority on the transfer operation. Therefore, as shown in FIG. 8, in one continuous shooting operation, the reception signal level determination and the antenna selection operation are not performed between successive shooting operations. However, if the antenna selection operation is not performed at all, it becomes impossible to cope with a change in the situation. Therefore, the antenna selection operation is performed during image transfer. When a change in the posture of the camera is detected, an antenna selection operation is executed. In this way, even in the continuous shooting mode, image data can always be transferred at high speed with low power consumption.

  FIG. 9 shows a schematic block diagram of a digital single-lens reflex camera that is Embodiment 2 of the present invention. FIG. 10 is a rear view of the second embodiment. In this embodiment, the wireless module is configured to be detachable from the camera body 120. Constituent elements having the same functions as those of the embodiment shown in FIG.

  The wireless module 150, the antennas 152 and 154, the information display device 130 and the LED display device 136 are accommodated in the wireless adapter 160, and the operation button 132 is further provided in the wireless adapter 160. The wireless adapter 160 is connected to the overall control / image processing CPU 126 of the camera body 120 via the connector 170. The information display device 130 corresponds to the information display device 30, and the LED display device 136 corresponds to the LEF display device 36. That is, the information display device 130 displays the link speed of the wireless communication and the antenna reception signal level. The LED display device 136 blinks during transfer of image data. The operation device 132 of the wireless adapter 160 is used for operations when the camera body 120 is held in a vertical position.

  The overall control / image processing CPU 126 controls the wireless module 150, the LED display device 136, and the information display device 130 of the wireless adapter 160. The operations of the wireless module 150, the LED display device 136, and the information display device 130 of the wireless adapter 160 are the same as the operations of the corresponding devices in the first embodiment.

  By making the wireless adapter 160 separate from the camera body 120, the number of antennas 152 and 154 and the degree of freedom in position are reduced. However, as in the first embodiment, it is easy to deal with various shooting situations as compared with the case of a single antenna.

  In the present embodiment, similarly to the first embodiment, the reception signal levels of the two antennas 154 and 156 are determined at the optimum timing linked to the photographing operation and the transmission operation, and which antenna 154 is determined according to the determined reception signal level. Switch whether to use 156. By taking out the wireless module from the camera body and making it a separate body, the cost, size, weight, etc. of the camera body can be reduced. As in the first embodiment, high-speed image data transfer with low power consumption can be realized while minimizing the number of antenna reception level checks and antenna switching.

Claims (10)

Multiple antennas,
Wireless communication means for transmitting image data generated by performing the shooting preparation operation and the shooting operation using one of the plurality of antennas;
Between from the start instruction of the photographic preparation operation until the start of the photographing operation is instructed, for selecting one of the plurality of antennas based on the received signal level of the plurality of antennas after the treatments start of the photographing operation is instructed, the processing in order to transmit the image data by the wireless communication unit is performed using the antenna selected from among the plurality of antennas An imaging apparatus comprising: a control unit that performs the operation. Have a detection means that detect a change in posture of the imaging device,
The process for selecting one of the plurality of antennas based on the reception signal levels of the plurality of antennas from the start of the shooting preparation operation to the start of the shooting operation Even when the control unit performs the control , the control unit detects one of the plurality of antennas based on the reception signal level of the plurality of antennas when a change in the attitude of the imaging device is detected. The imaging apparatus according to claim 1, wherein a process for selection is performed . Even when the image data is transmitted by the wireless communication unit, the control unit selects one of the plurality of antennas based on a reception signal level of the plurality of antennas. The imaging apparatus according to claim 1, wherein processing is performed. 4. An operation means for instructing the start of the photographing preparation operation in the first operation state and instructing the start of the photographing operation in the second operation state. The imaging device according to any one of the above. The first operation state corresponds to a half-pressed state,
The imaging apparatus according to claim 4, wherein the second operation state corresponds to a fully pressed state. One of the plurality of antennas is disposed on the left side of the imaging device,
6. The imaging apparatus according to claim 1, wherein one of the plurality of antennas is disposed on a right side of the imaging apparatus. One of the plurality of antennas is disposed on the top of the imaging device,
6. The imaging apparatus according to claim 1, wherein one of the plurality of antennas is disposed on a right side or a left side of the imaging apparatus. One of the plurality of antennas is disposed on the top of the imaging device,
One of the plurality of antennas is disposed on the right side of the imaging device,
The imaging apparatus according to claim 1, wherein one of the plurality of antennas is disposed on a left side of the imaging apparatus. The imaging apparatus according to claim 1, further comprising a recording unit that records the image data on a recording medium. The imaging apparatus according to Izu Re of claims 1 to 9, characterized in that have a display means for displaying the information for notifying the reception signal level of the selected antenna.

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