JP4047346B2 - IMAGING DEVICE AND IMAGING DEVICE CONTROL METHOD - Google Patents

Description

The present invention relates to an imaging apparatus that performs digital signal processing and a method for controlling the imaging apparatus .

  FIG. 6 is a block diagram showing the configuration of a conventional digital camera. In the figure, 51 is an optical block such as a lens or shutter, 52 is a CCD which is a solid-state image sensor, and a general movie type sensor is used.

  53 is a CPU that controls each block and the entire system, 54 is an A / D converter that converts the imaging output of the CCD 52 into a digital signal, and 55 digitally processes a video signal input from the A / D converter 54 through the ADC bus 59. A digital signal processing unit 56 is a recording unit that digitally records image data input from the CCD 52 through the ADD bus 60 onto a recording medium.

  A D / A converter 57 converts the digital signal from the digital signal processing unit 55 into an analog signal, and a video output unit 58 outputs the output of the D / A converter 57 to an external TV monitor or the like.

In the camera having the above-described configuration, the video signal output from the CCD 52 through the optical block 51 is converted into a digital signal by the A / D converter 54, the gamma processing and other signal correction are performed by the digital signal processing unit 55, and the recording unit The digital data is recorded in 56. Further, after the data in the recording unit 56 is converted into an analog signal by the D / A converter 57 through the digital signal processing unit 55, the data is converted into a TV signal by the video output unit 58, and an image is projected on an external TV monitor or the like. (For example, see Patent Documents 1 to 10).
Japanese Patent Laid-Open No. 04-271654 Japanese Patent Laid-Open No. 06-098335 JP 05-111170 A Japanese Patent Laid-Open No. 06-261336 JP-A-63-222585 Japanese Patent Laid-Open No. 06-153067 JP 07-288826 A Japanese Patent Laid-Open No. 06-233446 Japanese Patent Laid-Open No. 03-247083 Japanese Patent Laid-Open No. 05-207345

  However, the conventional camera as described above has a problem that it may not be able to cope with various photographing operations.

  For example, since the low battery detection at the time of shooting is not performed using a plurality of means, it cannot flexibly cope with various shooting operations.

  Also, since AF, AE, and AWB (automatic white balance) all use the same image area on the entire screen, optimum exposure with AF cannot be obtained. Furthermore, AE and AWB have a problem in accuracy, and the measurement takes time because each measurement is performed individually by AF, AE, and AWB.

The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide an imaging apparatus capable of flexibly dealing with various imaging operations and an imaging apparatus control method.

An imaging apparatus and an imaging apparatus control method according to the present invention are configured as follows.

(1) Imaging means for converting a photographed subject image into an electrical image signal, an A / D converter for converting an analog image signal from the imaging means into a digital signal, and a predetermined signal for the digital signal Signal processing means for performing processing, an information acquisition operation for obtaining predetermined information for photographing by processing of the signal processing means, and performing main photographing after obtaining the predetermined information and performing digital photography by the signal processing means An imaging apparatus for performing a main photographing operation for generating an image signal, wherein during the information acquisition operation, a detection operation for detecting a low battery state in which a power supply voltage drops below a predetermined voltage is performed, and the low battery state cut off the power when it is detected is, the checks of the battery level enough to completion of the present photographing operation immediately before the photographing operation, before in the main photographing Without recognizing that the power supply voltage is the low battery state even drop below the predetermined voltage, and to have a control means for controlling so as to complete the main photographing operation.

(2) converting the photographed subject image into an electrical image signal; converting the image signal into a digital signal; performing predetermined signal processing on the digital signal; and During execution of the step of obtaining predetermined information for photographing, the step of generating a digital image signal by performing main photographing after obtaining the predetermined information, and the step of obtaining the predetermined information, the power supply voltage is predetermined. Detection operation to detect a low battery state that has dropped below the voltage of the battery, and when it is detected that the low battery state is detected, the power is shut off, and the main photographing operation can be completed immediately before the main photographing operation. Checking the remaining amount of the battery, and even if the power supply voltage drops below the predetermined voltage during the main photographing, the low battery state Without identification, and to have a control step of controlling so as to complete the step of generating a digital image signal by performing the main photographing.

According to the present invention, it is possible to provide an imaging apparatus and an imaging apparatus control method that can flexibly cope with various imaging operations.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing the system configuration of a camera according to the present invention. Here, the system configuration of a digital camera is shown.

  In the figure, 1 is an optical block having a lens, a shutter, etc. 2 is a CCD (solid-state imaging device), TG (timing generator), CDS (Correlation Double Sampling), etc. that converts a captured subject image into an electrical image signal. The CCD used here is provided with a light receiving portion close to a square pixel in consideration of image processing by a computer.

  Reference numeral 3 denotes an MPU (microprocessor unit) which is a control means for controlling each block and the entire system. A bus is connected from the MPU 3, image data is transferred from a memory on the bus, and an image is processed by an arithmetic circuit inside the MPU 3. Data calculation processing can be performed.

  4 is an A / D converter (converter) that converts the imaging output of the CCD into a digital signal, 5 is a digital signal processing unit that performs predetermined signal processing on the video signal from the A / D converter, and 6 is an output from the CCD. This is a memory (storage means) consisting of a readable / writable DRAM that temporarily stores image data. In addition to image data, various data necessary for this system such as work areas can be written and read. It is possible. The digital signal processing unit 5 transfers image data onto the memory 6 in the camera photographing mode, and then transmits and receives data between the digital signal processing unit 5 and the memory 6 through the ADD bus 12 while white balance (WB). ), AE correction, gamma processing, image compression, and other various image processing.

  Reference numeral 7 denotes a built-in recording unit that records a digital signal on a built-in recording medium, and uses a non-volatile memory such as a flash memory. Reference numeral 8 denotes a PC card interface for reading and writing a PC card conforming to the PCMCIA, and a recording medium such as a hard disk (HDD) or a flash memory card of the PC card Type III can be connected thereto. Reference numeral 9 denotes an external bus interface (I / F) for transmitting / receiving data to / from an external expansion unit, which is mainly used for connection with a personal computer.

  Reference numeral 10 denotes a strobe unit for strobe shooting of the camera. In the strobe unit 10, the start / stop of light emission, charging of the main capacitor, and the like are controlled by a control signal from the MPU 3. Further, the full charge is detected by reading the voltage level (charging voltage) of the main capacitor of the strobe unit 10 using an A / D converter inside the MPU 3.

  Reference numeral 11 denotes an ADC bus (10-bit bus line) for transferring data from the A / D converter 4 to the digital signal processing unit 5, and the above-mentioned ADD bus 12 includes the MPU 3, the digital signal processing unit 5, the memory 6 and the built-in recording. This is a bus (16-bit bus line) for data transmission / reception among the unit 7, the PC card interface 8 and the external interface 9.

  Reference numeral 13 denotes a release interface of the camera, various other operation changeover switches, and an operation unit related to a user interface that performs display by using an LCD, an LED, and the like. Here, a single-chip microcomputer is provided to exchange information with the MPU 3 through serial communication. Interface-related operations are performed.

  Reference numeral 14 denotes a battery (built-in power supply), and examples of the battery type include alkaline manganese AA batteries, NiCd batteries, and AC adapters. The detection of the battery level is configured to read the voltage level of the battery 14 using an A / D converter inside the MPU 3, and a low battery or the like is detected. Reference numeral 15 denotes the power supply circuit.

  FIG. 2 is a diagram showing an internal circuit configuration of the digital signal processing circuit 5. In the figure, 11 is the ADC bus (10-bit bus line) shown in FIG. 1, and 12 is the ADD bus (16-bit bus line).

  In FIG. 2, reference numeral 20 denotes an interface unit between the ADC bus 11 and the ADD bus 12 and an internal signal processing circuit. For example, 10-bit width data of the ADC bus is converted into 16-bit width data of the ADD bus (10/16 A data conversion circuit that performs conversion or reverse conversion (16/10 conversion), and the flow of data can be changed by control from the MPU 3.

  A signal processor 21 generates and processes raw data from the input CCD into a luminance / color difference video signal. In addition to the output of the video signal, the photometric value, the colorimetric value, and the video obtained in the process are processed. Various information data such as high frequency components can be obtained as required.

  Reference numeral 22 denotes a compression circuit composed of an IC for JPEG compression of a video signal from the signal processor unit 21, and reference numeral 23 denotes a JPEG bus for exchanging data between the data interface unit 20 and the compression circuit 22.

  Next, the photographing operation of the camera having the above configuration will be described.

  When the user shoots a subject, when the release switch on the operation unit 13 is first pressed, the microcomputer of the operation unit 13 detects that the release switch is pressed and controls the power supply circuit 15 to control the digital signal shown in FIG. The processing unit 5, memory 6, built-in recording unit 7, PC card interface 8, external bus interface 9, and strobe unit 10 are powered on. When the MPU 3 is turned on, program data is loaded from the internal program ROM, and initialization processing is performed.

  In the initialization process described above, each of the above-described units is set in an operation preparation state or the minimum necessary operation is performed. For example, it communicates with the microcomputer of the operation unit 13 to check the state operated by the user or perform a default liquid crystal display. In addition, for example, if a PC card is inserted, the remaining amount of the PC card is obtained or a necessary directory is created. When an abnormality is detected in the PC card, the abnormality is displayed on the LCD as an error.

  If it is detected as a result of communication with the microcomputer of the operation unit 13 that the release switch has been pressed, processing of the photographing sequence is executed. FIG. 3 shows a main flow diagram of this photographing sequence. Note that the release switch is a switch for starting the photographing operation of the camera, and has a double switch structure of SW1 and SW2 having different strokes.

  In the flow of FIG. 3, when SW1 is pressed first, a load test in step 100 is performed, and then a safety low battery (Safety LB) check is performed. At the same time, the Safety LB check with a fixed period in step 101 is performed in another task. If LB is detected by the Safety LB check in either step 100 or step 101, the shooting sequence is immediately terminated and LB display is displayed on the liquid crystal panel. At this time, the system power is not turned off. Thereafter, most camera operations are not accepted. The operations accepted at this time include battery replacement, PC card replacement, barrier (role of camera operation main switch), and the like.

  If it is not Safety LB in the Safety LB check in step 101, the Safety LB check is continued at a constant cycle until SW1 is released or SW2 is pressed. This fixed period is approximately 200 milliseconds. If SW1 is released or SW2 is pressed (step 102), another task is terminated (step 103). This separate task indicates another program that is running almost simultaneously with the main flow of the shooting sequence by OS task switching.

  In the Safety LB check after the load test in step 100, the Safety LB check is performed by temporarily increasing the load of the power supply circuit 15 in FIG. As a temporary load at this time, the power load of the optical block 1 and the imaging block 2 in FIG. 1 is anticipated.

  If Safety LB is detected in the Safety LB check in step 100, the imaging sequence is terminated without turning on the optical block 1 or the imaging block 2, and LB is displayed. If it is not Safety LB in step 100, power is turned on to the optical and imaging blocks 1 and 2 in step 110, and preparation for shooting operation is set. The processing in step 110 will be described in detail later with reference to FIG.

  When the processing of step 110 is completed, the optical block 1 to the digital signal processing unit 5 in FIG. 1 are in a movie operating state, and AF (Auto Focus), AE (Auto Exposure), and AWB (Auto White Balance) of later-described AF Preparation for control is completed. Then, by the AF control in step 120, TTL AF using only the CCD sensor is performed.

  In this AF system, an area near the center of all the pixels of the CCD is designated as a distance measurement area to the signal processor 21 in FIG. 2, and the integrated value of the image data in that area is used as AE data, and its high frequency component Are obtained as AF data. First, simple AE is performed prior to AF, and AF is adjusted in a proper exposure state.

  What should be emphasized here is that in the simple AE described above, appropriate exposure for AF is adjusted for a pixel area equivalent to the pixel area to be measured. That is, even if there is a deviated brightness subject at the top or bottom of all the pixel areas, the exposure is neglected and the AF is accurately performed. Thereby, appropriate distance measurement of the target pixel region can be performed.

  When the AF control in step 120 is completed, a green LED is turned on as the completion mark. Subsequently, AE and AWB control in step 130 is executed. The AE system and the AWB system are operating almost simultaneously in the separate tasks described above.

  In the AE system, first, in order to measure the image data of a wide area different from the pixel area used in the above-mentioned distance measurement, the area is redesignated in the signal processor 21 of FIG. That is, the photometric window is switched. The area at this time is set wide so as to cover almost the entire screen.

  In the AE system, the exposure value is adjusted so as to obtain an appropriate EV value while correcting the AV value without changing the TV value based on the photometric data. That is, in AE at step 130, the shutter speed is kept constant, and control is performed so as to be within an appropriate exposure range while changing the aperture.

  On the other hand, in the AWB system, color measurement is performed at a plurality of locations in a relatively small area of about 1/16 of the entire screen. For example, color measurement is performed for a total of eight locations, four corners on the top, bottom, left, and right and four near the center. Then, the colorimetric data of each block is limited in range, and data outside a certain range is not referred to.

  As a result, for example, a portion of a subject whose color is dark or a portion where the color is not correct due to over-luminance can be excluded. Then, the statistics of the data within the range are taken and the subject's white balance is adjusted more accurately. Further, the AWB system repeats the reading of the colorimetric data of the 8-block area five times to calculate white balance correction data.

  Next, as shown in the condition determination in step 140, when the user continues to press only the release switch SW1, AE and AWB continue to operate. Accordingly, it is possible to follow when the framing of the camera is changed while pressing SW1 or when the proof of the subject is changed. If it is determined in step 140 that SW1 has been released or some other cancellation has occurred, the process proceeds to the end of step 141 to stop the photographing operation.

  If SW2 is pressed, the main imaging exposure at step 150 is executed. The photographing main exposure in step 150 will be described in detail later with reference to FIG. 5. In brief, the CCD is switched to the exposure mode, the shutter is released, and image data for one screen is transferred along with the CCD transfer. Is transferred to the memory 6 at once.

  Subsequently, in step 160, LB detection is prohibited and signal processing is performed. Here, raw image data on the memory is read every several lines, and the digital signal processing unit 5 performs digital image processing on JPEG-compressed image data. .

  The LB detection here is different from the Safety LB check described above, and a power supply voltage lower than that of the Safety LB check is detected. When the LB is detected, the system is immediately turned off. This is a task (program) that is always operating since the system is turned on regardless of the imaging sequence.

  Therefore, the purpose of prohibiting the detection of the LB at this time is to prevent the LB from being interrupted in an incomplete file state during signal processing (for example, while a JPEG file is being written to a PC card or the like) for the LB. When the signal processing is completed, LB detection is started again. In addition, during the above signal processing, BUSY characters are displayed on the liquid crystal panel.

  Subsequently, the remaining amount calculation and the next number display in step 170 are executed, and the Safety LB check in step 161 is executed as a separate task. Since the steps 161 to 163 perform the same processing as the steps 101 to 103 described above, description thereof will be omitted.

  In the remaining amount calculation in step 170, the remaining capacity after the file is written to the built-in recording unit 7 or the medium of the PC card is obtained. At that time, the liquid crystal panel switches from the BUSY mark during signal processing to the next file number.

  Next, it is detected in step 180 whether or not SW1 has been released. If it has been released, post-processing of this processing routine is performed, the optical power and the imaging blocks 1 and 2 are turned off, and the remaining percentage is displayed on the liquid crystal panel (step 191). In step 192, the photographing process is terminated. At this time, do not turn off the power of this system immediately, but wait for a certain period before turning it off. This is so that the next time the switch is pressed again, it can react quickly and start operation.

  If SW1 is not released in the condition determination in step 180, the process proceeds to condition determination in step 190. In step 190, it is detected that SW2 is released and pressed again (pressed again). This is to return the process to step 180 when SW2 is kept pressed in the previous state or when only SW2 is released.

  That is, steps 180 and 190 are looped to wait until SW1 is eventually released or SW2 is pressed again. If SW2 is pressed again, the main photographing exposure at step 150 is executed again. If SW2 continues to be pressed again, steps 150 to 190 are repeated.

  Next, the internal flow of powering on the imaging / optical block in step 110 described above and preparation for photographing operation will be described in detail with reference to FIG. In the flow of FIG. 4, in step 201, initial setting of the data interface unit 20 of FIG. 2 is performed. Specifically, prior to turning on the optical block 1 and the imaging block 2, the state of each drive pulse signal is set to a low level, or the drive pulse signal inside the data interface unit 20 is set to a predetermined state. Or the flow of image data is set in advance.

  In step 202, the optical and imaging blocks 1 and 2 are turned on. In step 203, an imaging pulse is set, and a setting for reading the CCD in the field and a pixel size for driving in the pseudo TV signal synchronization are set. In this system, a high-quality image is signal-processed using a sensor with 570,000 pixels, but it is necessary to drive a movie to perform TTL AF, AE, and AWB at the shooting preparation stage of SW1.

  For this reason, when SW1 is on, the minimum pixel data is read without reading all the pixel data. Therefore, for this purpose, the pixel size for driving in the pseudo TV signal synchronization is set, and the CCD is driven.

  When the pulse setting in step 203 is completed, in step 204, the aperture and electronic shutter are initially set. Here, an intermediate aperture state is set as the initial aperture, and the electronic shutter is also set at the intermediate operation position of the mechanical shutter during the main exposure. For example, the aperture is set to 4 with an Av value, and the electronic shutter is set to 7 with a Tv value.

  Next, in step 205, the main clock is switched, and the basic clock of the entire system is switched from the clock oscillating in the circuit inside the data interface unit 20 to the clock oscillating in the imaging block. This is to protect the imaging circuit that is sensitive to noise from noise such as clock distortion and to obtain high image quality, and thus the entire system is synchronized with the drive pulse centered on the imaging circuit.

  Next, in step 206, the movie operation is set, and not only the driving of the imaging block 2, but also the settings of the A / D converter 4, the data interface unit 20, and the signal processor 21 are set so as to correspond to the movie operation. Specifically, the CCD output signal of the movie from the imaging block 2 is converted into a digital signal by the A / D converter 4, and the digital signal is directly input to the signal processor 21.

  The signal processor 21 processes the input digital signal in real time and calculates necessary data by AF, AE, AWB or the like. The calculated data is sent to the MPU 3 through the data interface unit 20 and the ADD bus 12 by serial communication. In other words, the MPU 3 reads when necessary. Accordingly, in step 206, preparation for setting is made.

  Next, in step 207, an environment setting in the MPU 3 is performed so that the AF, AE, and AWB systems operate in the MPU 3. For example, a certain area of the DRAM of the memory 6 is secured in the work area, each AF / AE / AWB system sets the image processing area to the signal processor 21, and the image processing data from the signal processor 21 is stored in the memory 6. Set up the environment to keep it.

  Finally, in step 208, DMA preparation for main exposure is performed, and image data saving area of DRAM for securing the image data of all the pixels of the CCD onto the DRAM of the memory 6 at the time of main exposure is secured. This image data saving area has a list structure for each line, and when post-signal processing is performed, it has a data structure that can be read and erased in units of lines.

  Next, the internal flow of the photographing main exposure at step 150 in FIG. 3 will be described in detail with reference to FIG.

  When SW2 is pressed in step 140 in FIG. 3, the photographing main exposure routine in step 150 is executed. First, in the flow in FIG. 5, a Safety LB check is performed after the load test in step 211. The load test at this time is different from the load test in step 100 in FIG. 3 and is a load that anticipates the operation load of the medium (PC processor, JPEG compression circuit, etc.) used in the medium driving of the PC card and signal processing. A test is conducted.

  Immediately thereafter, a Safety LB check is performed. If the load is a Safety LB, the subsequent processing is not executed, the processing is immediately terminated, and LB is displayed on the liquid crystal panel. If not LB, the remaining amount is checked in step 212, and the remaining amount of the recording medium (built-in recording unit or PC card) is checked.

  Here, the file size created by signal processing is calculated and predicted according to the current shooting state, and it is checked whether one or more images can be shot. When the number is one or less, 0 Shot is displayed on the liquid crystal panel, the photographing process is terminated, and the red LED blinks at 8 Hz as an error mark while the release switch is being pressed. If it is not 0 Shot, an abnormality of the switches is detected at Step 213, and the error content is displayed on the liquid crystal panel along with blinking of the red LED at 8 Hz at the time of abnormality.

  In the present system, the above-described abnormality of the switches enables color image recording and high-resolution black-and-white recording, and detects when the changeover switch has an abnormality and is in an intermediate state. If there is no switch abnormality in step 213, a cancel check is performed in step 214. This cancel check is to check whether or not a user operation that interrupts the photographing operation is performed.

  Specifically, user operations that interrupt the shooting operation include barrier closing, dial change, PC card opening lid opening, and color image recording and high-resolution monochrome recording mode changeover switches. There are cases. If such a cancel operation is performed, the photographing process is immediately terminated.

  If the cancellation has not been performed, the self-timer SW is checked in step 215. When the self-timer state is detected by the self-timer SW check in step 215, the self-timer operation is executed in the next step 216. In this self-timer operation, the infrared LED for AF correction on the front of the camera blinks for a certain period, informs the user on the subject side that it is in the self-timer state, and this LED blinks 2 Hz 2 seconds before the main exposure. Is switched to blinking at 8 Hz to notify the user that shooting is about to occur.

  After the operation of the self-timer at step 216 or when the self-timer SW check at step 215 is not in the self-timer state, an operation start OK signal for SW2 is executed at step 217. This sets a flag for starting the operation of SW2 so that it cannot be canceled until the signal processing is completed thereafter. Then, by executing a cancel check in step 218, a recheck is performed as to whether or not a cancel has occurred before step 217. Thereby, it is possible to eliminate missed cancellations.

  Next, in step 219, a resetting operation at the time of repeated shooting is executed. This is for making preparations for shooting when shooting is repeated after the processing of step 190 of FIG. 3 described above. Specifically, the setting is performed to reuse the operation of step 216 to step 218 shown in FIG. 4 and the previous AF / AE / AWB data.

  Therefore, nothing is executed in the shooting by the SW2 operation after the first SW1 operation. Next, in step 220, the full strobe charge before photographing is performed by the strobe charge after the SW2 operation. At the same time, the LED mark for charging and the LED mark for low brightness warning are turned off.

  Then, in Step 221, a Safety LB check is performed to check whether the battery is exhausted due to the charging of the strobe and the battery is not LB. Thereafter, in step 222, AE immediately before the main exposure is performed. This is because the AE at SW1: ON is simple exposure control by aperture control, but exposure measurement is performed again from that state, and the shutter speed is finely controlled so that the final exposure is properly achieved. Prepare to do. Thereby, the final shutter speed is determined.

  At this time, if it is determined that the subject is dark and has low luminance, or if the flash is in the forced flash mode, the EF system operates in step 223 to detect the presence or absence of flash photography. In step 224, strobe pre-emission is performed, and exposure level photometry is performed during this pre-emission. Then, the strobe light emission time during the main exposure is calculated from the data result.

  Subsequently, in step 225, the strobe light emission time is set when setting the shutter speed for the main exposure, and in step 226, the strobe light emission, the mechanical shutter control, and the CCD exposure control are performed. However, if the subject is bright or the strobe is set to off when the strobe shooting is detected in step 223, the operation in step 224 is not executed, and the strobe is not emitted during the main exposure in step 225.

  When the next CCD data is read, DMA of image data for all pixels is performed from the A / D converter 4 through the data interface unit 20 to the DRAM of the memory 6. Finally, when the DMA is completed at step 227, a signal flag is set and the signal processing at step 160 in FIG. 3 is executed.

  As described above, in this embodiment, the imaging block 2 that can read an arbitrary image area from the CCD, its drive pulse generation circuit, the A / D converter 4 that converts the read image data into a digital signal, and the digital A digital signal processing unit 5 having a signal processor 21 capable of calculating necessary AF / AE / AWB from an image signal, a memory 6 capable of temporarily saving data, and an MPU 3 capable of freely controlling each of these circuits, The AF, AE, and AWB processing when the release switch SW1 is operated can be improved.

  In addition to the above configuration, by providing a low-battery detection means for checking the power load test circuit of each part and a plurality of power supply voltage levels, it is possible to perform shooting interruption processing at various low batteries in the shooting operation, A flexible response to various shooting operations is possible.

  As described above, according to the present invention, there is an effect that it is possible to flexibly cope with various photographing operations.

  In other words, when the battery is extremely weak, the system power is turned off instantly so that no unnecessary load is applied to the battery. When the battery is slightly weak, only the shooting operation is interrupted without turning off the system power. By providing a plurality of battery check means as described above, the operation of the system can be safely terminated depending on the state of the battery.

  In addition, by performing a load test before turning on power to the optical and imaging block immediately after SW1: ON, the battery can be checked without turning on the optical or imaging block when the battery is weak. The imaging operation can be terminated without applying unnecessary load.

  Furthermore, by performing a load test immediately before the signal processing after SW2: ON and performing a battery check, at the same time, the low battery is not detected during the signal processing, and charging of the strobe is prohibited during the signal processing. The power consumption during signal processing is reduced so that the battery does not suddenly weaken during signal processing and does not become a low battery. As a result, a complete image file can be created without shutting down the system during signal processing and without interrupting signal processing in an incomplete state.

  Further, when SW1: ON AF is performed, AE is performed in advance in an AF image area, and AF is performed in an exposure state optimal for AF. Then, after AF is completed, AE is performed on a wide image area of the entire area, and main exposure shooting is performed with appropriate exposure. By changing the evaluation image area of AE according to cases, AF accuracy is improved. High-quality images with proper exposure can be obtained.

  Also, when SW1: ON AWB, by measuring a plurality of locations on a screen with a relatively small image area, an effective area can be selectively obtained as subject white balance data, and white balance with good accuracy is performed. be able to.

  Further, by simultaneously executing the AE and AWB after the AF described above, the shooting operation is accelerated and the release time lag in shooting can be improved.

  Furthermore, after shooting with SW1: ON after SW1: ON (after signal processing), if only SW2 is released and SW2 is turned on again, AF / AE / AWB is not re-executed, and the previous AF / AE / AWB state is maintained. The next shooting (main exposure and signal processing) can be performed immediately. Thereby, it is possible to reduce the shooting time when shooting repeatedly, and to perform different framing and different subject shooting under the same shooting conditions such as AF, AE, and AWB. This is effective when a panoramic image is created later.

  Also, in the SW1 shooting preparation stage (including AF, AE, and AWB), the image data of a part of the area is read in the movie state without reading out all the pixels of the CCD, so that the SW1 of AF, AE, AWB, etc. You can speed up each action and improve the release time lag.

  Also, in the state where only SW1: ON, user cancellation by camera operation is accepted, and the user cannot cancel during SW2: ON signal processing. This makes it possible to create a complete image file without interrupting signal processing in an incomplete state. Further, it can be checked whether or not the user cancellation has been generated immediately before the signal processing, so that the user cancellation is not missed.

1 is a block diagram showing a system configuration of a camera according to the present invention. The block diagram which shows the internal structure of the digital signal processing part of FIG. The figure which shows the main flow of the imaging sequence of an Example The figure which shows the detailed flow of imaging / optical power-on of FIG. 3, and imaging operation preparation The figure which shows the detailed flow of the imaging | photography book exposure of FIG. Block diagram showing the configuration of a conventional digital camera system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical block 2 Imaging block 3 MPU (control means)
4 A / D converter
5 Digital signal processor 6 Memory (storage means)
7 Built-in recording unit 10 Strobe unit 13 Operation unit 14 Battery (built-in power supply)
15 Power supply circuit

Claims (2)

Imaging means for converting the photographed subject image into an electrical image signal;
An A / D converter for converting an analog image signal from the imaging means into a digital signal;
Signal processing means for performing predetermined signal processing on the digital signal,
An information acquisition operation for obtaining predetermined information for photographing by processing of the signal processing means, and a main photographing operation for performing a main photographing after obtaining the predetermined information and generating a digital image signal by the signal processing means. An imaging device ,
During the execution of the information acquisition operation, a detection operation is performed to detect a low battery state in which a power supply voltage has dropped below a predetermined voltage, and when the low battery state is detected, the power supply is shut off.
Just before the main shooting operation, the remaining battery level is checked so that the main shooting operation can be completed. Even if the power supply voltage drops below the predetermined voltage during the main shooting, the low battery state is recognized. without an imaging apparatus characterized by comprising a control means for so that control to complete the present photographing operation. Converting the captured subject image into an electrical image signal;
Converting the image signal into a digital signal;
Applying predetermined signal processing to the digital signal;
Obtaining predetermined information for photographing by the signal processing;
Performing a main shooting after obtaining the predetermined information to generate a digital image signal;
During the execution of the step of obtaining the predetermined information, a detection operation is performed to detect a low battery state in which the power supply voltage has dropped below the predetermined voltage, and the power supply is shut off when the low battery state is detected. And
A step of checking a remaining battery level sufficient to complete the main photographing operation immediately before the main photographing operation, and the low battery state even if the power supply voltage drops below the predetermined voltage during the main photographing. And a control step of controlling to complete the step of generating the digital image signal by performing the main photographing without recognizing the image pickup apparatus .

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