JP5233640B2 - Electronic camera - Google Patents

Description

  The present invention relates to an electronic camera capable of displaying a moving image during shooting standby.

  2. Description of the Related Art Conventionally, an electronic camera that reduces power consumption required for live view moving image display during shooting standby has been disclosed (for example, see Patent Document 1).

In the electronic camera disclosed in Patent Document 1, when a live view moving image is displayed on a liquid crystal display monitor during shooting standby, the A / D converter generates image data having a smaller number of bits than image data at the time of still image shooting. . Thereby, the power consumption required for the live view moving image display during shooting standby is reduced by reducing the power consumption of the memory.
JP 2007-174160 A

  In recent years, with the increase in the number of pixels of image sensors used in electronic cameras, it is necessary to achieve both the use of still image shooting that requires high-definition and high-speed readout and the display of moving images that may have low resolution such as live view. There is. For example, in a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, A / D converters corresponding to the number of channels are required for high-speed multi-channel reading. Therefore, there is a problem that the power consumption of the A / D converter (including an analog circuit described later) increases during the live view. In this case, there is a problem that the power consumption of the A / D converter is larger than the power consumption of the memory during live view.

  However, since the electronic camera disclosed in Patent Document 1 does not assume high-speed multi-channel readout, the problem that the power consumption of the A / D converter increases during live view during shooting standby is considered. Absent.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an electronic camera that suppresses power consumption during live view during shooting standby.

An electronic camera according to a first invention includes an imaging device, a plurality of A / D conversion units for multi-channel reading , a display unit, and a power supply control unit. The image sensor photoelectrically converts the subject image. The A / D conversion unit digitizes the output signal of the image sensor and generates image data. The display unit displays the moving image in real time based on the image data during shooting standby. The power supply control unit stops power supply to the A / D conversion unit specified in advance during shooting standby and continues power supply to other A / D conversion units. Output signals from different pixels of the image sensor are input to each A / D converter. The power supply control unit stops power supply to the A / D conversion unit that is unnecessary for displaying a moving image during shooting standby .

  According to a second invention, in the first invention, there are further provided a plurality of analog circuits connected between the imaging device and the plurality of A / D converters, respectively, for adjusting the waveform of the output signal. The power supply control unit further stops power supply to the analog circuit connected to the A / D conversion unit that stops power supply during imaging standby.

  In a third aspect based on the first aspect, the power supply control unit resumes the power supply to the A / D conversion unit in a state where the power supply is stopped when the standby mode is switched to the still image capturing mode.

  According to a fourth aspect, in the second aspect, when switching from standby to standby during still image shooting, the power supply control unit is connected to the A / D conversion unit in which power supply is stopped and the A / D conversion unit. Restart the power supply to the analog circuit.

  According to a fifth invention, in the first invention, a power supply availability designation unit that designates an A / D conversion unit for stopping power supply during shooting standby and an A / D conversion unit for operation to continue power supply Is further provided.

An electronic camera according to a sixth aspect includes an imaging device, a plurality of A / D conversion units for multi-channel reading, a plurality of analog circuits, a display unit, a power feeding control unit, and a control unit. The image sensor photoelectrically converts the subject image. The A / D conversion unit digitizes the output signal of the image sensor and generates image data. The analog circuits are respectively connected between the image sensor and the plurality of A / D converters, and adjust the waveform of the output signal. The display unit displays the moving image in real time based on the image data during shooting standby. The power supply control unit stops power supply to an A / D conversion unit designated in advance during shooting standby and an analog circuit connected to the designated A / D conversion unit, and another A / D conversion unit and When the power supply to the analog circuit connected to the other A / D conversion unit is continued and switched from the standby state to the still image shooting mode, the A / D conversion unit in which the power supply is stopped and its A / D conversion The power supply to the analog circuit connected to the unit is resumed. The control unit operates all of the plurality of A / D conversion units and the plurality of analog circuits at the time of still image shooting, and makes the A / D conversion speed per unit time faster than that at the time of shooting standby.
In a sixth aspect based on the sixth aspect, the power supply propriety designating unit is further provided. The power supply enable / disable specifying unit specifies a stop A / D conversion unit that stops power supply during shooting standby and an operation A / D conversion unit that continues power supply. Designate an analog circuit and an analog circuit for operation in which power feeding is continued.
In an eighth aspect based on the fifth or seventh aspect, the imaging element has a color filter of three primary colors on the light receiving surface. The power supply availability designation unit designates a stop A / D conversion unit so that the operation A / D conversion unit thins and reads out the output signals of the three primary color pixels output from the image sensor. .

  According to the electronic camera of the present invention, it is possible to suppress power consumption during live view during shooting standby.

(Description of the first embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the electronic camera 1 of the present embodiment. As shown in FIG. 1, the electronic camera 1 includes a photographing lens 11, an image sensor 12, a timing generator (TG) 13, a first analog circuit 14a, a second analog circuit 14b, a first A / D converter 15a, a first 2A / D conversion unit 15b, signal processing unit 16, RAM (Random Access Memory) 17, flash memory 18, liquid crystal display monitor 19, power supply unit 20, operation unit 21, and CPU (Central processing Unit) 22, a recording interface (recording I / F) 23, a recording medium 24, and a bus 25. Among these, the signal processing unit 16, the RAM 17, the flash memory 18, the liquid crystal display monitor 19, the CPU 22 and the recording interface (recording I / F) 23 are connected to each other via a bus 25. The operation unit 21 is connected to the CPU 22.

  The photographing lens 11 is composed of a plurality of lens groups including a zoom lens and a focus lens. For the sake of simplicity, FIG. 1 shows the photographing lens 11 as a single lens.

  The image sensor 12 generates an image signal by photoelectrically converting incident light from the photographing lens 11. In the present embodiment, an XY address CMOS (Complementary Metal-Oxide Semiconductor) is used for the image sensor 12. Note that three types of color filters of red (R), green (G), and blue (B) are arranged in a known Bayer array on the imaging surface of the imaging device 12 in order to detect the color of the subject image. . Thereby, three types of pixels of the R pixel, the G pixel, and the B pixel are arranged on the imaging surface of the imaging element 12. That is, the image sensor 12 outputs three types of image signals, that is, an R signal, a G signal, and a B signal. Note that the Bayer array is an example, and the present invention is not limited to this array.

  The timing generator (TG) 13 supplies a drive signal to each of the image sensor 12, the A / D converter 15a, and the A / D converter 15b in accordance with an instruction from the CPU 22, thereby synchronizing the drive timing of both. Control.

  The first analog circuit 14 a and the second analog circuit 14 b are circuits that shape the waveform of the image signal output from the image sensor 12.

  The first A / D conversion unit 15a and the second A / D conversion unit 15b digitize the output signal of the image sensor 12 and generate image data.

  FIG. 2 is a block diagram showing the configuration of the first A / D converter 15a. The same applies to the second A / D converter 15b. As shown in FIG. 2, the first A / D conversion unit 15a includes a CDS (Correlated Double Sampling) circuit 151a, an AGC (Automatic Gain Control) circuit 152a, and an A / D converter 153a.

  The CDS (correlated double sampling) circuit 151a is a circuit for reducing noise generated when signal charges output from the image sensor 12 are converted into signal voltages.

  The AGC (automatic gain control) circuit 152a is a circuit that adjusts the gain of the image signal after being processed by the CDS circuit 151a.

  The A / D converter 153a is a circuit that converts the image signal (analog) from the AGC (automatic gain control) circuit 152a into a digital image signal.

  The signal processing unit 16 temporarily stores the image data of the digital signal output from the first A / D conversion unit 15 a and the second A / D conversion unit 15 b in the RAM 17. Further, the signal processing unit 16 performs image processing such as white balance correction on the image data stored in the RAM 17. The flash memory 18 stores a program for controlling each part of the electronic camera 1.

  The liquid crystal display monitor 19 performs live view (LV) display during shooting standby. In response to an instruction from a power supply control unit 22a described later, the power supply unit 20 supplies power to each block. For convenience of explanation, the first analog circuit 14a, the second analog circuit 14b, the first A / D conversion unit 15a, and the second A / D conversion unit 15b are drawn with wirings connecting the power supply unit 20. . It is assumed that the other blocks are actually connected to the power supply unit 20 by wiring. However, the photographing lens 11 and the recording medium 24 are excluded.

  The operation unit 21 receives an operation of a release button or a power button of the electronic camera 1 and issues a processing instruction to the CPU 22.

  The CPU 22 is a processor that performs overall control of the electronic camera 1. The CPU 22 calculates a parameter for each process and controls each part of the electronic camera 1 by executing a sequence program stored in advance in the flash memory 18. The CPU 22 functions as a power supply control unit 22a and a power supply availability specifying unit 22b.

  The power supply control unit 22a stops power supply to the second analog circuit 14b and the second A / D conversion unit 15b during live view (LV) display during shooting standby. On the other hand, the power supply control unit 22a continues to supply power to the first analog circuit 14a and the first A / D conversion unit 15a during live view (LV) display during shooting standby.

  In addition, when switching from standby to shooting during still image shooting, the power supply control unit 22a resumes power supply to the second analog circuit 14b and the second A / D conversion unit 15b.

  The power supply availability specifying unit 22b specifies a second A / D conversion unit 15b for stopping power supply during shooting standby and an A / D conversion unit 15a for operation where power supply is continued during standby for shooting.

  In addition, the power supply availability specifying unit 22b is an A / D conversion unit for stopping, in order to cause the first A / D conversion unit 15a to thin out and read out the output signals of the three primary color pixels output from the imaging device 12. Specify 15b. By doing so, known thinning-out reading can be performed.

  A connector for connecting the recording medium 24 is formed in the recording interface (recording I / F) 23. The recording interface (recording I / F) 23 accesses the recording medium 24 connected to the connector according to an instruction from the CPU 22 and performs image recording processing.

  Next, an example of the operation of the electronic camera 1 in the first embodiment will be described. For simplicity, the case of high-speed 2-channel reading will be described.

  FIG. 3 is a flowchart showing the operation of the electronic camera 1. This flowchart starts when the power of the electronic camera 1 is turned on. Thereby, the electronic camera 1 shifts to a photographing standby state.

  Step S101: As described above, the power supply availability specifying unit 22b is used for stopping so that the first A / D conversion unit 15a thins out and reads out the output signals of the three primary colors output from the image sensor 12. The A / D converter 15b is designated (details will be described later). Further, the power supply availability specifying unit 22b specifies the second analog circuit 14b connected to the second A / D conversion unit 15b as a stop analog circuit that stops power supply during imaging standby. Thus, power is not supplied to the second analog circuit 14b and the second A / D converter 15b during startup after the power is turned on.

  Step S102: The CPU 22 causes the liquid crystal display monitor 19 to perform live view display (through image display) as a standby state for shooting. When displaying live view, since it is not necessary to have a high-definition image, the CPU 22 operates the first analog circuit 14a and the first A / D converter 15a, and the output image signal is temporarily stored in the RAM 17. Remembered. The signal processing unit 16 performs image processing such as interpolation processing in consideration of the absence of an image signal output from the second A / D conversion unit 15b during shooting standby. This interpolation process can be realized by a known thinning-out interpolation process. A through image is displayed on the liquid crystal display monitor 19.

  FIG. 4 is a diagram illustrating an example of 2-channel reading in the Bayer array according to the present embodiment. As described above, three types of color filters of red (R), green (G), and blue (B) are arranged in a Bayer array on the imaging surface of the imaging device 12. In FIG. 4, a two-line Bayer array is shown. In this case, the first A / D conversion unit 15a can read out image signals corresponding to three kinds of colors of red (R), green (G), and blue (B). As a result, as shown in FIG. 4, it is possible to avoid the problem that the first A / D conversion unit 15a can read only two colors in two-channel reading depending on the combination.

  Step S103: The CPU 22 determines whether or not a half-press operation has been performed. When the half-press operation is not performed from the operation unit 21 (step S103: No), the processing routine returns to step S102. In other words, a through image is displayed on the liquid crystal display monitor 19 as a shooting standby state until a half-press operation is performed.

  On the other hand, when a half-press operation is performed from the operation unit 21 (step S103: Yes), the processing routine proceeds to step S104.

  Step S104: The power supply control unit 22b of the CPU 22 starts power supply to the second analog circuit 14b and the second A / D conversion unit 15b.

  Step S105: The CPU 22 accepts a full press operation from the operation unit 21.

  Step S106: The CPU 22 executes still image shooting. Here, when reading a still image, since it is necessary to perform high-definition and high-speed reading, the first analog circuit 14b, the second analog circuit 14b, the first A / D converter 15a, and the second A / D converter 15b will be operated. Thereby, the A / D conversion speed per unit time is increased. The image signals output from the first A / D conversion unit 15 a and the second A / D conversion unit 15 b are temporarily stored in the RAM 17. The signal processing unit 16 performs image processing such as interpolation processing considering the image signals output from the first A / D conversion unit 15a and the second A / D conversion unit 15b. The signal processing unit 16 further performs image processing such as white balance correction. The CPU 22 records the image data subjected to the image processing on the recording medium 24 via the recording interface (recording I / F) 23.

  Step S107: When the CPU 22 receives power-off of the electronic camera 1 from the operation unit 21 (Step S107: Yes), this processing routine ends. When the CPU 22 does not accept the power-off of the electronic camera 1 from the operation unit 21 (step S107: No), the processing routine proceeds to step S108.

  Step S108: The power supply control unit 22b of the CPU 22 stops the power supply to the second analog circuit 14b and the second A / D conversion unit 15b again. Then, the processing routine returns to step S102.

  In the present embodiment, high-speed 2-channel reading has been described. However, this is an example, and the present invention is not limited to high-speed 2-channel reading, and can be applied to high-speed multi-channel reading. For example, in the case of high-speed 12 channel reading, 6 channels are read during shooting standby. In this way, the power consumption of the A / D converter (including the analog circuit) during live view is halved. Furthermore, in this embodiment, it is not necessary to decrease the frame rate during shooting standby, and it is not necessary to decrease the number of bits per pixel.

  In addition, although CMOS was employ | adopted as the image pick-up element 12, you may apply to CCD (Charge Coupled Device) of multi-channel reading. For example, the present invention may be applied to a 4-channel readout CCD.

  As described above, according to the electronic camera 1 of the present embodiment, it is possible to suppress power consumption during live view during shooting standby. Further, at the time of still image shooting, a high-definition still image can be obtained while performing high-speed reading. Further, in the present embodiment, since the power consumption of the A / D conversion unit is suppressed, the effect of suppressing the total power consumption of the electronic camera 1 is higher than in the conventional case where the power consumption of the memory is suppressed. . Further, since the power consumption of the analog circuit is also suppressed, the power consumption suppressing effect can be further enhanced.

  In the present embodiment, the power supply availability specifying unit 22b is configured to specify the A / D conversion unit for stopping and the A / D conversion unit for operation. Good.

1 is a block diagram illustrating a configuration of an electronic camera 1 according to an embodiment. The block diagram which shows the structure of the 1st A / D conversion part 15a. A flowchart showing the operation of the electronic camera 1 The figure explaining an example of 2 channel reading in a Bayer arrangement

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 12 ... Image pick-up element, 14a ... 1st analog circuit, 14b ... 2nd analog circuit, 15a ... 1st A / D conversion part, 15b ... 2nd A / D conversion unit, 22a ... feed control unit, 20 ... power supply unit

Claims (8)

An image sensor that photoelectrically converts a subject image;
A plurality of A / D converters for multi-channel reading , which generate image data by digitizing an output signal of the image sensor;
A display unit for displaying a moving image in real time based on the image data during shooting standby;
A power supply control unit for stopping power supply to the A / D conversion unit designated in advance during the shooting standby and continuing power supply to other A / D conversion units;
Equipped with a,
Each of the A / D converters receives the output signal from a different pixel of the image sensor,
The electronic camera according to claim 1, wherein the power supply control unit stops power supply to the A / D conversion unit unnecessary for displaying the moving image during the photographing standby . The electronic camera according to claim 1,
A plurality of analog circuits that are respectively connected between the image sensor and the plurality of A / D converters, and adjust the waveform of the output signal;
The electronic camera according to claim 1, wherein the power supply control unit further stops power supply to an analog circuit connected to an A / D conversion unit that stops the power supply during the imaging standby. The electronic camera according to claim 1,
The electronic camera is characterized in that, when the shooting is switched from the shooting standby to the still image shooting, the power supply control unit resumes the power supply to the A / D conversion unit in a state where the power supply is stopped. The electronic camera according to claim 2,
When switching from the shooting standby to the still image shooting, the power supply control unit resumes power supply to the A / D conversion unit in which power supply is stopped and the analog circuit connected to the A / D conversion unit. An electronic camera characterized by that. The electronic camera according to claim 1,
The electronic apparatus further includes a power supply availability specifying unit that specifies an A / D conversion unit for stopping the power supply during the imaging standby and an A / D conversion unit for operation for which the power supply is continued. camera. An image sensor that photoelectrically converts a subject image;
A plurality of A / D converters for multi-channel reading, which generate image data by digitizing an output signal of the image sensor;
A plurality of analog circuits connected between the image sensor and the plurality of A / D converters, respectively, for adjusting the waveform of the output signal;
A display unit for displaying a moving image in real time based on the image data during shooting standby ;
The power supply to the analog circuit connected to the A / D conversion unit designated in advance and the designated A / D conversion unit at the time of shooting standby is stopped, and another A / D conversion unit and the other A A / D conversion unit and its A / D conversion unit in a state where the power supply is stopped when the power supply to the analog circuit connected to the / D conversion unit is continued and switched from the standby mode to the still image shooting mode A power supply control unit that resumes power supply to the analog circuit connected to
A control unit that operates all of the plurality of A / D conversion units and the plurality of analog circuits at the time of shooting the still image, and makes the A / D conversion speed per unit time faster than that at the time of shooting standby;
An electronic camera comprising: The electronic camera according to claim 6.
A stop analog circuit for designating a stop A / D converter for stopping the power supply during the imaging standby and an operation A / D converter for continuing the power supply and for stopping the power supply And an analog circuit for operation for which power supply is continued. The electronic camera according to claim 5 or 7,
The image sensor has color filters of three primary colors on the light receiving surface,
The power supply availability specifying unit is configured to stop the A / D for stopping in order to cause the A / D converter for operation to thin out and read out the output signals of the three primary color pixels output from the image sensor. An electronic camera characterized by designating a conversion unit.

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