JP4175729B2 - Electronic imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to an electronic imaging apparatus having a continuous shooting function and a camera shake correction function.
[0002]
[Prior art]
In recent years, an electronic camera that converts a subject into image data using an electronic imaging function and records the image data on a recording medium has become widespread. Electronic cameras include digital video cameras in addition to electronic still cameras, also called digital cameras. However, an electronic still camera is assumed as a specific example.
[0003]
With recent electronic cameras, products with a so-called continuous shooting function capable of continuous shooting have been realized as the image processing speed required for shooting operations has increased and the memory capacity of the buffer memory for storing image data has increased. is doing. The continuous shooting function of an electronic camera is a function that stores image data corresponding to the release time from the start to the end (for example, image data for four screens per second) in a buffer memory so that temporally continuous still images can be captured. Is to get.
[0004]
By the way, when the user takes a picture with the camera in hand, a so-called camera shake phenomenon occurs. In particular, in continuous shooting, the influence (variation of the reproduced image) due to the camera shake phenomenon is large. For this reason, an electronic camera also needs a camera shake correction function.
[0005]
Conventionally, as a camera shake correction method adopted in a video camera, a silver salt film camera, or the like, a method of moving an output pixel range of a CCD as an image sensor according to a camera shake state, or a lens optical system according to a camera shake state. A method of driving the device itself with respect to the optical axis is well known.
[0006]
[Problems to be solved by the invention]
As described above, the continuous shooting function of the electronic camera actually requires a camera shake correction function. However, the conventional camera shake correction method described above is not necessarily suitable for an electronic camera. In other words, the former method of moving the output pixel range of the CCD cannot effectively use all the constituent pixels of the CCD, and is not suitable for an electronic camera that particularly requires high image quality. Further, the latter method of driving the lens optical system itself with respect to the optical axis complicates the structure of the lens optical system, leading to an increase in manufacturing cost and an increase in size of the camera itself. Furthermore, this method is difficult to cope with the high frequency camera shake phenomenon.
[0007]
Accordingly, an object of the present invention is to improve a continuous shooting function particularly in an electronic camera by realizing a camera shake correction function that can maintain a high image quality without requiring a complicated mechanism.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention , there are provided release means for instructing shooting of continuous shot images composed of temporally continuous still images, camera shake detection means for detecting a camera shake state at the time of continuous shooting by the release means, Recording means for adding and recording hand-shake information obtained by the hand-shake detection means together with continuous-shot image data obtained at the time of continuous shooting, and the continuous-shot image data recorded on the recording means. When reproducing a captured image, each still image data constituting the continuous image data is set by setting an output range of an image necessary for reproducing the continuous image based on camera shake information recorded in the recording means. And an output unit that outputs continuous-shot image data corrected by the correction unit .
[0009]
With such a configuration, the electronic camera of the present invention accumulates camera shake information together with continuous shot image data during continuous shooting. Then, when the continuous shot image is reproduced by the continuous shot image data, the camera shake correction can be performed using the stored camera shake information. Therefore, it is possible to realize a camera shake correction function by software using hand shake information without requiring a mechanism having a complicated structure such as a method of driving the lens optical system to shift with respect to the optical axis. In addition, by restricting the output pixel range of the CCD, it is possible to perform a camera shake correction process that changes (limits) the display output range of an image according to, for example, a camera shake state when reproducing a continuous shot image. The number of output pixels of the CCD can be used effectively.
[0010]
According to a second aspect of the present invention, there is an instruction means for instructing pause of reproduction output at the time of reproduction output of continuous shot images, and in response to the instruction, all of the corresponding still image data among the continuous image data is provided. An electronic camera having a function of outputting pixels. That is, at the time of reproduction of continuously shot images, the display output range is limited according to the camera shake state by the camera shake correction function as described above. In this case, in response to the pause instruction, the reproduction of the continuous shot image is paused, and the restriction by the camera shake correction is released, so that all pixels of the still image data at the timing of the instruction are output. Therefore, in still image reproduction other than during continuous image reproduction, high-quality output in the design specification can be obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
(Configuration of electronic camera)
The electronic camera of the present embodiment has a continuous shooting function, and is roughly composed of an imaging system 1, a control system 2, a recording system 3, and an output system 4, as shown in FIG. First, the imaging system 1 includes a photographing lens 10, a CCD (Charge Coupled Device) 11, an A / D converter 12, and an image processing circuit 13. In addition to this, although not shown, an actuator for the lens 10 and an actuator drive circuit are also provided.
[0013]
The CCD 11 photoelectrically converts a subject image incident through the photographing lens 10. The taking lens 10 is attached to the actuator and is configured to be zoomed or focused according to the driving of the actuator driving circuit. The A / D converter 12 converts the image analog signal for each pixel obtained by the CCD 11 into a digital signal. The image processing circuit 13 executes various signal processing (image correction processing) such as gamma correction and white balance adjustment.
[0014]
The control system 2 includes a system controller (hereinafter referred to as a CPU) 20 including a microprocessor (CPU) as a main element, and includes a key input unit 21, a buffer memory 22, an image compression processing unit 23, an image expansion processing unit 24, and a RAM 25. Have
[0015]
The CPU 20 has a function (including power supply control) for controlling the entire electronic camera, as well as a continuous shooting function and a camera shake correction function for continuous shooting described later. The CPU 20 is connected to the key input unit 21 and controls various input operations corresponding to operations such as a continuous shooting start / end (S / E) switch 21A, a still image release switch 21B, and a mode switch 21C. The continuous shooting start / end (S / E) switch 21A is a switch for instructing the start and end of continuous shooting. The still image release switch 21B is a switch for instructing a still image taken at a so-called shutter timing. The mode switch 21C is used for instructing a selection setting between a continuous shooting mode (continuous shooting) and a single mode (normal still image shooting), and a selection setting of presence / absence of a camera shake correction mode related to the embodiment. It is a switch.
[0016]
The buffer memory 22 is image data obtained by photographing by the photographing system 1, and normally stores image data for a plurality of screens (for example, five screens). The image compression processing unit 23 performs image compression processing on the image data stored in the buffer memory 22 during an image recording operation. The image expansion processing unit 24 executes image expansion processing on image data read from the memory card 30 as a recording medium during an image reproduction operation. Note that the image compression processing unit 23 and the image expansion processing unit 24 correspond to functional units realized by software executed by the CPU 20 or another CPU. Further, the RAM 25 is a work memory for holding data necessary for various control operations of the CPU 20, and stores camera shake information as will be described later.
[0017]
Further, the control system 2 is provided with an angular velocity sensor 26 related to the camera shake correction function of the embodiment. The angular velocity sensor 26 detects a camera shake in three axial directions that occurs during a shooting operation (especially during continuous shooting in the same embodiment), and sends the detection result to the CPU 20 as camera shake information that is a digital value.
[0018]
The recording system 3 uses, for example, an exchangeable memory card 30 formed of a flash memory, which is an IC memory, as a recording medium, and has a memory controller 31 for controlling recording and reproduction of the memory card 30.
[0019]
The output system 4 includes a TFT panel 40 and a display control unit 41 including a TFT liquid crystal driving circuit. The display control unit 41 displays the image data for one screen output from the buffer memory 22 on the TFT panel 40 under the control of the CPU 20. As an output system, although not shown, the image data output from the buffer memory 22 is converted into a video signal and output via an output terminal that can be connected to an external device such as a television receiver. A video output unit is also provided.
[0020]
(Recording operation of the continuous shooting function)
First, the operation of continuous shooting (continuous shooting recording) will be described with reference to the flowchart of FIG. 2 together with FIG.
[0021]
First, it is assumed that the electronic camera is turned on and the continuous shooting mode and the camera shake correction mode are selected and set by the mode switch 21C. The CPU 20 executes imaging processing by continuous shooting according to the operation of the continuous shooting start (S) switch 21A of the key input unit 21 by the user (steps S1 and S2). That is, the subject is imaged by the photographing system 1 described above, and still image data for a plurality of temporally continuous screens are sequentially stored in the buffer memory 22 under the control of the CPU 20 (step S4). The image data stored in the buffer memory 22 is displayed on the TFT panel 40 of the output system 4.
[0022]
At the time of continuous shooting, the CPU 20 inputs camera shake information corresponding to the camera shake state detected by the angular velocity sensor 26, and stores it in the RAM 25 (step S3). That is, the CPU 20 causes the angular velocity sensor 26 to function during continuous shooting, monitors the occurrence of a camera shake phenomenon during the shooting period, and always acquires camera shake information corresponding to the camera shake state (the degree of camera shake).
[0023]
In continuous shooting, until the continuous shooting end (E) switch 21A is operated, the CPU 20 proceeds to the next imaging timing, and when the next still image data continuous in time is obtained by the imaging system 1, the buffer 20 The operation of storing in the memory 22 is repeated (YES in step S5, NO in S6). In the continuous shooting function of the electronic camera, the CPU 20 cyclically and repeatedly uses each storage area of the buffer memory 22, and still image data (continuous shot images) for a plurality of continuous screens corresponding to the continuous shooting time. Data). Here, the camera shake information is information indicating a camera shake direction, a speed, and an amplitude value for each still image data constituting the continuous shot image data.
[0024]
When the user operates the continuous shooting end (E) switch 21A, the CPU 20 performs image compression processing in the stored order (oldest order) from the temporally continuous still image data stored in the buffer memory 22. After the image is compressed by the unit 23, it is recorded in the memory card 30 (YES in step S6, S7). The CPU 20 records the continuous shot image data obtained by the continuous shooting on the memory card 30 by the image compression processing unit 23 as, for example, a file according to the motion JPEG standard (denoted as a motion JPEG file). At this time, the CPU 20 reads camera shake information stored in the RAM 25, adds it to the motion JPEG file, and records it in the memory card 30 (step S8).
[0025]
(Sequential shooting function playback operation)
Through the continuous shooting operation described above, a motion JPEG file (compressed continuous shooting image data file) to which camera shake information is added is recorded in the memory card 30. The CPU 20 reads a specified file from the memory card 30 in accordance with an image playback instruction by operating the key input unit 21 and executes a playback process (which means display output on the TFT panel 40 here). This will be described below with reference to the flowcharts of FIGS.
[0026]
When a file to be played is selected by the user's operation of the key input unit 21, the CPU 20 reads a designated file from the memory card 30 (step S10). If the file is a motion JPEG file, the CPU 20 executes a continuous image reproduction process (YES in step S11). If the camera shake information is added to the read motion JPEG file, the CPU 20 executes a reproduction process including a camera shake correction process as described later (YES in step S12).
[0027]
When camera shake information is not added, the CPU 20 executes normal continuous image reproduction processing (NO in step S12, S13). That is, the CPU 20 decompresses the continuous shot image data constituting the motion JPEG file by the image decompression processing unit 24, and displays and outputs it on the TFT panel 40 (steps S13 to S15).
[0028]
Here, when the pause of the reproduction process is instructed by the user's operation of the key input unit 21, the CPU 20 reproduces the continuous shot image data (that is, the display output process of each still image data continuous in time). ) Is stopped, and still image data is displayed according to the timing of the instruction (YES in steps S14, S16, and S17). That is, among the still images displayed continuously in time, a still image corresponding to a pause instruction is displayed. When the suspension is canceled, the CPU 20 returns to the continuous shot image reproduction process again (YES in step S18, S13).
[0029]
(Playback operation including image stabilization processing)
Next, with reference to the flowchart of FIG. 4, the case where the reproduction | regeneration processing containing a camera shake correction process is performed is demonstrated (refer YES of step S12).
[0030]
When camera shake information is added to the motion JPEG file read from the memory card 30, the CPU 20 executes the camera shake correction process using the camera shake information. Specifically, the CPU 20 obtains the average value of the amplitude values of the camera shake included in the camera shake information to identify the camera shake state. When the camera shake state has a relatively large amplitude value, the CPU 20 sets the display range of the continuous shot image. Change to make it smaller. Further, in the case of a hand shake state having a relatively small amplitude value, the display range of the continuous shot image is changed to be enlarged. That is, the CPU 20 executes a calculation process that limits the reproduction display range of the continuous shot image according to the hand shake state (step S20). Here, the CPU 20 may be a method of changing (limiting) the display range in a stepwise manner according to the hand movement state as a method of calculating the display range. Then, based on the calculated display range, the CPU 20 displays a continuous shot image in a range (window) limited to the central portion of the TFT panel 40 (step S21). That is, a different display range is set in the central portion of the TFT panel 40 according to the camera shake state of each still image, and each still image continuous in time is displayed.
[0031]
When the reproduction processing for each still image data of the motion JPEG file is completed, the CPU 20 stops the continuous-shot image reproduction operation (YES in step S23). Here, when a pause of the playback process is instructed by the user's operation of the key input unit 21, the CPU 20 stops the continuous image data playback process including the camera shake correction process, and according to the timing of the instruction. Still image data is displayed (YES in step S22, S24). At this time, the CPU 20 validates the total number of pixels of the still image data according to the pause instruction and displays it on the entire surface of the TFT panel 40 (step S25). When the suspension is canceled, the CPU 20 returns to the continuous shot image reproduction process again (YES in step S26, S21).
[0032]
As described above, according to the camera shake correction function of the embodiment, camera shake information indicating the camera shake state detected by the angular velocity sensor 26 during continuous shooting is stored in the RAM, so that the CPU 20 continuously captures image data as necessary. Can be obtained for each still image data continuous in time. Further, the CPU 20 adds and records the camera shake information when the continuous shot image data is recorded on the memory card 30 as, for example, a motion JPEG file.
[0033]
The CPU 20 executes a camera shake correction process using the camera shake information added to the file of the continuous shot image data when the continuous shot image is reproduced. Specifically, the camera shake correction process restricts the display range of the continuous shot image according to the degree of the camera shake state, and visually suppresses the display variation of the image due to the camera shake. Also, when playback of still images is stopped temporarily and still images are played back, the display range restriction is released and display output is performed using all the pixels effectively. realizable. Therefore, the camera shake correction method of the embodiment does not require a mechanism having a complicated structure like the method of driving the lens optical system itself with respect to the optical axis, and uses camera shake information, that is, software shake correction by software. Processing can be realized. In addition, when reproducing continuous shot images, camera shake correction processing is performed to change the display output range of the image according to the state of camera shake. Therefore, the number of output pixels of the CCD is set without limiting the output pixel range of the CCD of the imaging system 1. It can be used effectively.
[0034]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to realize a camera shake correction function related to the continuous shooting function of an electronic camera without requiring a lens optical system mechanism having a complicated structure or a limitation on the output pixel range of the CCD. Can do. Accordingly, it is possible to provide a camera shake correction function that enables a high-quality reproduction output with a simple configuration, and as a result, an electronic camera having a high-performance continuous shooting function can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main part of an electronic camera related to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining an operation at the time of continuous shooting related to the embodiment;
FIG. 3 is a flowchart for explaining a continuous-shot image reproduction operation related to the embodiment;
FIG. 4 is a flowchart for explaining camera shake correction processing related to the embodiment;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Imaging system 2 ... Control system 3 ... Recording system 4 ... Output system 10 ... Shooting lens 11 ... CCD
12 ... A / D converter 20 ... System controller (CPU)
21 ... Key input unit 21A ... Continuous shooting start / end (S / E) switch 21B ... Still image release switch 21C ... Mode switch 22 ... Buffer memory 23 ... Image compression processing unit 24 ... Image expansion processing unit 25 ... RAM
26. Angular velocity sensor (camera shake detection means)
30 ... Memory card 31 ... Memory controller 40 ... TFT panel 41 ... Display control unit

Claims (3)

Release means for instructing to shoot continuous shot images consisting of temporally continuous still images;
Camera shake detecting means for detecting a camera shake state during continuous shooting by the release means;
A recording means for adding and recording the camera shake information obtained by the camera shake detection means together with the continuous shot image data obtained by the continuous shooting.
When reproducing the continuous shot image based on the continuous shot image data recorded in the recording means, the output range of the image necessary for reproducing the continuous shot image based on the camera shake information recorded in the recording means Correction means for executing camera shake correction processing for changing the output range of each still image data constituting the continuous shot image data ,
An electronic imaging apparatus comprising: output means for outputting continuous shot image data corrected by the correction means. The electronic imaging apparatus according to claim 1 , wherein the correction unit includes a unit that limits an output range of an image necessary for reproducing the continuous shot image in a stepwise manner based on the camera shake information. Instructing means for instructing pause of reproduction output at the time of reproduction output of the continuous shot image by the output means
And the output means, any one of claim 1 or 2, characterized in that outputs all the pixels of the corresponding still image data among the continuously shot image data in accordance with an instruction from said instruction means The electronic imaging device according to item .

Images