JP5290700B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to imaging control of an imaging apparatus.

  In digital cameras, there is a time lag, the so-called release time lag, between the moment when the photographer presses the release button and the shooting time of the actually shot image.

  FIG. 4 is a timing chart for explaining the release time lag of the digital camera.

  When the user of the digital camera presses the release button halfway and the first release signal rises (ON), the shooting preparation operation is started. When the user further presses the release button, the second release signal is turned on, and the V reset signal that resets the vertical synchronization signal VSYNC is turned on. Note that before the V reset signal is turned on, the vertical synchronization signal VSYNC is repeatedly turned on and off at a constant cycle.

  In synchronization with the timing when the V reset signal falls (off), the vertical synchronization signal VSYNC is turned on ignoring the previous period. Then, in accordance with the timing of the vertical synchronization signal VSYNC, a sweep pulse is generated to sweep out the charge of the imaging device.

  After the sweep pulse is stopped, the charge accumulation of the imaging device is started. Then, after the mechanical shutter is closed so that a predetermined exposure time is reached, a readout pulse is generated and the charge of the imaging device is read out. The analog signal obtained by reading the charge is subjected to predetermined signal processing and recorded in a storage medium, and one shooting operation is completed.

  That is, the actual photographing operation corresponds to a period from when the sweep pulse is stopped until the mechanical shutter is closed. Accordingly, the time from when the second release signal is turned on, the sweep pulse is stopped, and the actual shooting operation is started is the release time lag.

  The release time lag can be shortened by improving the apparatus. However, the time from when the user of the digital camera starts pressing the release button until the second release signal is turned on, or the time from when the release button is pressed until the actual shooting operation starts (hereinafter referred to as shutter time lag). ) Cannot be shortened.

JP 2002-199288

  An object of the present invention is to reduce a shutter time lag felt by a user.

  The present invention has the following configuration as one means for achieving the above object.

Imaging device according to the present invention comprises a first release signal instructing the start of the photographic preparation operation, and a second release signal generating means for Ru is generated to instruct the start of the photographing operation of the imaging means, the first release signal set the predicted capturing start time based on the generation, the prediction and prediction photographing means for starting the shooting operation of the imaging means to imaging start time, the second before the predicted capturing start time from a predetermined determination time has elapsed A determination unit that determines whether or not a release signal has been generated, and a prediction release unit that generates the second release signal after the predicted shooting start time has elapsed and before the determination time has elapsed. and control means for acquiring imaging data captured by the initiated photographing operation, and having a.

Control method according to the present invention, the imaging means, and a first release signal instructing the start of the photographic preparation operation, the generating means Ru is generated and a second release signal instructing the start of image capturing operation of the imaging means An imaging apparatus control method comprising: setting a predicted shooting start time based on generation of the first release signal, starting a shooting operation of the imaging unit at the predicted shooting start time, and starting from the predicted shooting start time It is determined whether or not the second release signal is generated before a predetermined determination time has elapsed, and the second release signal is output after the predicted imaging start time has elapsed and before the determination time has elapsed. When it occurs, the imaging data acquired by the imaging operation started at the predicted imaging start time is acquired.

  According to the present invention, the shutter time lag felt by the user can be reduced.

  Hereinafter, an imaging device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Device configuration]
FIG. 1 is a block diagram illustrating a configuration example of a digital camera that is an imaging apparatus according to the embodiment.

  In FIG. 4, a CPU 26 is a one-chip microcontroller that controls the overall operation of the digital camera by using a built-in RAM as a work memory and executing a control program stored in a built-in ROM or the like.

  The reflected light of the subject forms an image on the imaging device 12 that is a photoelectric conversion device such as a CCD or a CMOS sensor via the photographing lens 11.

  The control signal generator (TG) 13 generates a vertical synchronization signal VSYNC, a sweep signal, a readout signal, and the like, which are control signals for controlling the operation of the imaging device 12. The V reset unit 15 changes the generation timing of the vertical synchronization signal VSYNC of TG 13 to an arbitrary timing.

  The imaging circuit 14 generates data in a predetermined format from an analog signal corresponding to the electric charge read from the imaging device 12. The CPU 26 displays an image on the display unit 19 based on the data generated by the imaging circuit 14, and when the release button 21 is pressed, acquires the data generated by the imaging circuit 14 and acquires an image memory 18 such as a memory card. To store. The data generated by the imaging circuit 14 includes imaging data (RAW data) obtained by analog / digital conversion of the analog signal output from the imaging device 12, image data obtained by demosaicing the imaging data, and, for example, JPEG obtained by compressing the image data. There is data.

An automatic focus unit (AF) 17 controls the focus of the taking lens 11 to focus on the subject. Automatic Exposure unit (AE) 16 controls the aperture of the taking lens 11 is controlled to a proper amount of light incident on the image pickup device 12. The posture detection unit 20 detects the direction and amount of vibration of the digital camera. The CPU 26 displaces a part of the photographing lens 11 or the imaging device 12 according to the direction and amount of vibration detected by the posture detection unit 20, cancels the vibration, and corrects or reduces camera shake.

  The CPU 26 displays an image captured by the imaging device 12, an operation menu of the digital camera, and the like on the display unit 19, sets the operation of the digital camera according to a user instruction input from the operation unit 22, and controls the operation To do. The operation unit 22 includes, for example, a mode dial, a switch, a touch panel, and the like.

  The release button 21 generates a first release signal and then a second release signal in accordance with the stroke for pressing the button. That is, the first release signal and the second release signal are sequentially generated according to the stroke. The timer 23 measures various timings from when the first release signal is generated until the second release signal is generated, and stores the timed data (hereinafter, timed data) in the data memory 24.

  The time counting unit 23 starts from the time when the first release signal is turned on, the time when the second release signal is turned on, the time when the vibration frequency detected by the posture detection unit 20 changes, the operation of the AE16 and AF17 The time when (shooting preparation) is completed is recorded in the data memory 24. The second release prediction unit 25 calculates a time during which the second release signal is turned on (hereinafter, “predicted photographing time”) from the data stored in the data memory 24.

[Operation]
FIG. 2 is a timing chart showing the photographing operation of the digital camera, and FIG. 3 is a flowchart for explaining the photographing operation of the digital camera.

When the digital camera is ready to shoot, the CPU 26 waits until the release button 21 is operated and the first release signal is turned on (S101). When the first release signal is turned on, CPU 26 causes the start clocking the clock unit 23, AE16, AF17 to execute the photographing preparation (focus and exposure will control), the detection of the vibration of the digital camera attitude detection unit 20 Is started (S102). The posture detection unit 20 detects the vibration of the digital camera caused by the user operating the release button 21, and detects the time when the vibration frequency changes.

  Next, the CPU 26 causes the second release prediction unit 25 to set the predicted shooting time t1 (S103). Initially, the second release prediction unit 25 sets the time when a predetermined time has elapsed after the first release signal is turned on as the predicted shooting time t1.

  Next, the CPU 26 resets the generation of the vertical synchronization signal VSYNC of the TG 13 by the V reset unit 15 so that shooting is started at the predicted shooting time t1, and immediately after the reset, generates the vertical synchronization signal VSYNC (S104). . The TG 13 generates a vertical synchronization signal VSYNC and generates a sweep pulse for removing unnecessary charges accumulated in the imaging device 12 for a predetermined time. The sweep pulse stops at the predicted imaging time t1.

  Next, the CPU 26 determines whether or not the second release signal is turned on before the determination time S elapses (t1 + S) after the sweep pulse is stopped (S105). Note that the determination time S is a fixed value set to a time (for example, less than 0.1 second) that the user cannot recognize the release time lag. If the second release signal is turned on before the determination time S elapses (t1 ≦ t <t1 + S), the process proceeds to step S106 on the assumption that the predictive imaging has succeeded. If the second release signal is not turned on within the determination time, the process proceeds to step S112 assuming that the predictive shooting has failed.

  If the second release signal is not turned on within the determination time (t1 ≦ t <t1 + S), the normal shooting mode shown in FIG. 4 is executed (S112). That is, the CPU 26 generates a sweep pulse when the second release signal is turned on, and then performs imaging for the exposure time T determined by the AE 16, and returns the processing to step S101 after the imaging is completed.

  On the other hand, if the second release signal is turned on within the judgment time (t1 ≤ t <t1 + S), the CPU 26 determines whether the exposure time T has elapsed (t1 + T) after the sweep pulse has stopped. Is determined (S106). When the exposure time T has elapsed, the mechanical shutter of the photographic lens 11 is closed (S107). Then, the TG 13 generates a readout signal, reads out the electric charge accumulated in the imaging device 12 (S108), converts the analog signal corresponding to the electric charge read out into the imaging circuit 14 into image data (S109), and Is stored in the image memory 18 (S110). In the example of FIG. 2, since the photographing is started earlier by time t4 than when the second release signal is turned on, the shutter time lag can be reduced by time t4.

  Next, based on the time data recorded in the data memory 24, the CPU 26 turns on the difference t2, t1 between the completion time of t1 and shooting preparation, the difference t3 between the change time of the vibration frequency, t1, and the second release signal. Calculate the difference in time (t4). Then, the difference time and the predicted shooting time t1 are recorded in the data memory 24 (S111). Then, the process returns to step S101.

  The CPU 26 repeats the operations from the above steps S101 to S112. Then, the predicted shooting time t1 and the above difference time are recorded in the data memory 24 for each shooting. After these time data are accumulated, the second release predicting unit 25 sums up the time (t1 + t4) when the second release signal is turned on every time after photographing, and calculates the average value or median value of the subsequent predicted photographing. It may be used at time t1. Then, it is possible to set the predicted shooting time t1 that matches the shooting style of the user.

  Further, the starting point of the predicted shooting time t1 is not limited to the time when the first release signal is turned on. For example, after the time data is accumulated in the data memory 24, the predicted shooting time t1 may be set based on the average value of the difference t2 in the shooting preparation completion time, starting from the time when the shooting preparation is completed. By doing this, it is possible to cancel the time variation of the shooting preparation such as AF and AE, so that the accuracy of the predicted shooting time t1 can be improved.

  Alternatively, the predicted imaging time t1 may be set based on the difference t3 in the change time of the vibration frequency, starting from the time when the vibration frequency is changed after the time data is accumulated in the data memory 24. In this way, since the predicted shooting time t1 can be set from the user's operation of the release button 21, the accuracy of the predicted shooting time t1 can be improved.

  Further, although the determination time S has been described as a fixed value, it can be changed according to the shooting mode and user preference. Of course, the starting point of the estimated shooting time t1 can be changed according to the shooting mode and user preference.

  Thus, the shutter time lag felt by the user can be reduced with a certain probability. Furthermore, if the predicted shooting time t1 is determined using the time data stored in the data memory 24, the probability that the user feels the shutter time lag small can be increased.

[Other embodiments]
Note that the present invention can be applied to a system composed of a plurality of devices (for example, a computer, an interface device, a reader, a printer, etc.), or a device (for example, a copier, a facsimile machine, a control device) composed of a single device. Etc.).

  Another object of the present invention is to supply a recording medium or a recording medium recording a computer program for realizing the functions of the above embodiments to a system or apparatus. This can also be achieved by the computer (CPU or MPU) of the system or apparatus executing the computer program. In this case, the software read from the recording medium itself realizes the functions of the above embodiments, and the computer program and the computer-readable recording medium storing the computer program constitute the present invention. .

  Further, the above functions are not only realized by the execution of the computer program. That is, according to the instruction of the computer program, the operating system (OS) and / or the first, second, third,... This includes the case where the above function is realized.

  The computer program may be written in a memory of a device such as a function expansion card or unit connected to the computer. That is, it includes the case where the CPU of the first, second, third,... Device performs part or all of the actual processing according to the instructions of the computer program, thereby realizing the above functions.

  When the present invention is applied to the recording medium, the recording medium stores a computer program corresponding to or related to the flowchart described above.

FIG. 1 is a block diagram illustrating a configuration example of a digital camera that is an imaging apparatus according to an embodiment. A timing chart showing the shooting operation of the digital camera, A flowchart for explaining a photographing operation of the digital camera; It is a timing chart explaining the release time lag of a digital camera.

Claims (11)

A first release signal instructing the start of the photographic preparation operation, and a second release signal generating means for Ru is generated to instruct the start of the photographing operation of the imaging means,
A predictive photographing unit configured to set a predicted photographing start time based on the generation of the first release signal and to start a photographing operation of the photographing unit at the predicted photographing start time;
Determination means for determining whether or not the second release signal is generated before a predetermined determination time has elapsed from the predicted photographing start time;
Control for obtaining imaging data photographed by the photographing operation started by the predictive photographing means when the second release signal is generated after the predicted photographing start time has elapsed and before the determination time has elapsed. imaging apparatus characterized by comprising a means. 2. The imaging apparatus according to claim 1, wherein the predictive photographing unit sets a time when a predetermined time has elapsed from a generation time of the first release signal as the predictive photographing start time. For each shooting operation, the predicted time to start shooting, and are described in claim 1, characterized in that it comprises a recording means for recording the time difference generation time of the predicted capturing start time and the second release signal to the memory Imaging device. The prediction photographing means, the photographing operation for each of the on the basis of the predicted capturing start time and the difference time, and the imaging apparatus according to claim 3, characterized in that setting the predicted capturing start time. For each shooting operation, the predicted time to start shooting, and, according to claim 1, characterized in that it comprises a recording means for recording the difference time of the shooting preparation completion time of operation and the predicted imaging start time in the memory Imaging device. The prediction photographing means, the photographing operation for each of the based on the shooting preparation completion time of operation and the difference time, the imaging apparatus according to claim 5, characterized in that setting the predicted Start Time. Detecting means for detecting vibration of the imaging device;
2. The imaging apparatus according to claim 1 , further comprising: a recording unit configured to record the predicted imaging start time and a difference time between the predicted imaging time and a time when the vibration frequency is changed. The prediction photographing means, on the basis of the time frequency changes of the vibration and the differential time, and the imaging apparatus according to claim 7, characterized in that setting the predicted Start Time. Imaging means, and, a the first release signal and a control method for an imaging apparatus having a generating means for Ru to generate a second release signal instructing the start of image capturing operation of the imaging means for instructing the start of the photographic preparation operation And
Set the predicted capturing start time based on the occurrence of the first release signal, to start the imaging operation of the imaging means to the predicted capturing start time,
Determining whether the second release signal has occurred before a predetermined determination time has elapsed from the predicted shooting start time;
When the second release signal is generated after the predicted shooting start time has elapsed and before the determination time has elapsed, the imaging data captured by the shooting operation started at the predicted shooting start time is acquired. A control method characterized by the above. A program for causing an imaging device to execute the control according to claim 9.   11. A computer-readable recording medium on which the program according to claim 10 is recorded.

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