JP2006332809A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to confirm the presence or absence of blur in a photographed image easily. <P>SOLUTION: A CPU determines whether shutter speed is faster than 1/focal distance f [second] or not (step S7). When it is true, it is determined whether or not an amplitude angle based on angular velocity detected by an angular velocity sensor is larger than a threshold angle obtained from an angle of view corresponding to focal distance (f) (step S8). When it is not true in the step S8, the CPU displays a captured image on an LCD via an LCD control unit, and displays the alarm of camera shake on the captured image. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus that warns or suppresses the occurrence of blurring in a captured image due to camera shake or the like.

  When camera shake occurs when shooting a subject with a camera, the shot image is blurred and the image quality deteriorates. Therefore, various cameras that perform camera shake correction have been proposed.

Specifically, an imaging apparatus that realizes camera shake detection and camera shake compensation at a low cost in an imaging apparatus such as a digital still camera is disclosed (for example, see Patent Document 1). In this imaging apparatus, the image compression / decompression unit 116 performs two-dimensional wavelet transform in the process of compressing still image captured image data. The system controller 122 calculates horizontal and vertical high-frequency component amounts from the LH and HL subband coefficients obtained by the two-dimensional wavelet transform, and performs horizontal, vertical, or diagonal hand shake detection based on the calculated amount. When a camera shake is detected, a camera shake warning is displayed on the display device 12, and in order to make the influence of the camera shake less noticeable, the image processor 110 performs control such as applying strong edge enhancement in the camera shake direction to the image data. Do.
JP 2004-32135 A

  The imaging apparatus described in Patent Document 1 calculates a high-frequency component amount from still image captured image data, and performs camera shake detection based on the calculated high-frequency component amount. Therefore, there is a problem that subject detection is inevitable and erroneous detection cannot be avoided. It was.

  In general, the number of pixels of an image sensor that captures a subject is 2 million pixels, whereas the number of pixels of an LCD (Liquid Crystal Display) that confirms a captured image is only 100,000 to 200,000 pixels. For this reason, even if the user looks at the image displayed on the LCD, the user cannot accurately confirm the presence or absence of blurring of the captured image.

  The present invention has been proposed to solve the above-described problems, and allows the user to easily check for the presence or absence of blurring of the captured image, to easily restore the blurred image, and to prevent the captured image from blurring. An object of the present invention is to provide an imaging apparatus that sets imaging conditions.

  In order to solve the above-described problems, an imaging apparatus according to the present invention includes an imaging unit that images a subject in accordance with imaging light incident through an optical system, and a focal length calculation unit that calculates a focal length of the optical system. A shutter speed calculating means for calculating the shutter speed of the image pickup means, an angular speed detecting means for detecting an angular speed, and a shutter speed calculated by the shutter speed calculating means is a focal length calculated by the focal distance calculating means. Warning output means for outputting a warning when the amplitude angle is larger than the reciprocal and the amplitude angle based on the angular velocity detected by the angular velocity detection means exceeds a threshold angle corresponding to the focal length.

  If the shutter speed is larger than the reciprocal of the focal length, camera shake may occur. Further, when the amplitude angle based on the angular velocity detected by the angular velocity detecting means exceeds the threshold angle corresponding to the focal length, it means that the apparatus body is largely shaken compared to the angle of view corresponding to the focal length.

  Therefore, in the imaging apparatus, the shutter speed calculated by the shutter speed calculation unit is larger than the reciprocal of the focal length calculated by the focal length calculation unit, and the amplitude angle based on the angular velocity detected by the angular velocity detection unit is a focal length. When the threshold angle corresponding to is exceeded, a warning is output to alert the user.

  An imaging apparatus according to the present invention includes an imaging unit that images a subject in accordance with imaging light incident through an optical system, a focal length calculation unit that calculates a focal length of the optical system, and a shutter speed of the imaging unit. When the shutter speed calculated by the shutter speed calculation means is greater than the reciprocal of the focal length calculated by the focal length calculation means, Angular velocity storage means for storing the angular velocity detected by the angular velocity detection means or information related to the angular velocity.

When there is a blur in the captured image, it is easy to restore the image by following the locus of the blur.
Therefore, when the shutter speed is larger than the reciprocal of the focal length, the image pickup apparatus stores the angular velocity detected by the angular velocity detecting means or information related to the angular velocity, thereby restoring an image deteriorated by the blur. Camera shake trajectory information can be obtained.

  An imaging apparatus according to the present invention includes an imaging unit that images a subject in accordance with imaging light incident through an optical system, a focal length calculation unit that calculates a focal length of the optical system, and a shutter speed of the imaging unit. A shutter speed calculation unit that calculates the angular velocity, an angular velocity detection unit that detects an angular velocity, and a camera shake detected when the shutter speed calculated by the shutter speed calculation unit is greater than the reciprocal of the focal length calculated by the focal length calculation unit And an imaging condition setting unit that sets an imaging condition so as not to cause a shake in the photographed image when a camera shake is detected by the camera shake detection unit.

  It is very complicated for the user to set the imaging condition again when the captured image is blurred. Therefore, the imaging apparatus detects a camera shake when the shutter speed is larger than the reciprocal of the focal length, and sets an imaging condition so that the captured image is not shaken when the camera shake is detected. Imaging conditions can be set without causing troublesome operations.

  The image pickup apparatus according to the present invention can allow the user to easily check for the presence or absence of blurring of the captured image, easily restore the blurred image, or set the imaging condition so that the captured image does not blur.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an imaging apparatus according to the first embodiment of the present invention.

  The imaging apparatus includes an optical unit 10 to which imaging light from a subject is input, an imaging unit 20 that is disposed behind the optical axis of the optical unit 10 and images the subject via the optical unit 10, and performs image processing and overall control. A main control unit 30 is provided, and an output unit 50 that outputs an image processed by the main control unit 30 is provided.

  The optical unit 10 includes a zoom lens 11, a correction lens 12, a diaphragm mechanism, and a focus lens 13. The zoom lens 11 can be moved in the optical axis direction by a zoom motor, and the focus lens 13 can be moved by an auto focus motor. The correction lens 12 is controlled by the correction lens motor so that the incident angle of the imaging light with respect to the imaging surface is always substantially constant. The iris of the iris mechanism is controlled by an iris motor. These motors are controlled by a motor driver 14.

  The imaging unit 20 generates a subject image signal in accordance with imaging light from the optical unit 10 and a correlation unit 2 that removes noise components included in the image signal read from the CCD image sensor 21. A CDS circuit 22 that performs a double sampling (CDS) process, a digital / analog converter (hereinafter referred to as an A / D converter) 23 that converts an analog signal processed by the CDS circuit 22 into a digital signal, And a timing generator (TG) 24 that generates a timing signal for driving the CCD image sensor 21.

  The main control unit 30 includes various circuits connected to each other via a bus 31. Specifically, the main control unit 30 includes an image input control unit 32 that supplies the image data from the A / D converter 23 to the bus 31, and image processing that performs predetermined digital signal processing on the input image data. A circuit 33, a VRAM 34 for storing image data representing an image to be displayed, and an LCD control unit 35 for performing control to display an image based on the image data stored in the VRAM 34 on the LCD 51 are provided.

  Further, the main control unit 30 includes an AF detection circuit 36 that detects a contrast value used to adjust the focus of the focus lens 13, and an AE (Auto Exposure) detection circuit that detects optimal exposure and white balance based on image data. 37, an EEPROM (Electrically Erasable Programmable Read Only Memory) 38 in which information such as various programs and parameters are stored in advance, an SDRAM (Synchronous Dynamic Random Access Memory) 39 used as a work memory, and compression / decompression of image data A compression / decompression circuit 40, a media control unit 41 that reads / writes various information from / to the recording medium 52, and a CPU 42 that reads information from the EEPROM 38 and controls each unit.

  The AF detection circuit 36 detects the contrast value of the image data input from the imaging unit 20 and stored in the VRAM 34. The in-focus position is obtained when the contrast value is maximized.

  The AE / AWB detection circuit 37 detects an exposure value (EV value) representing the brightness of the subject based on the image data. Although the EV value will be described in detail later, it is used as a photometric value for obtaining the aperture and shutter speed.

  In the imaging apparatus configured as described above, the analog signal representing the subject image output from the CCD image sensor 21 is processed by the CDS circuit 22 and converted into a digital image signal by the A / D converter 23. The image data is input from the image input control unit 62 into the main control unit 30. The input image data is temporarily stored in the SDRAM 39 via the bus 31.

  In the main control unit 30, the AF detection circuit 36 calculates the contrast value based on the image data stored in the SDRAM 39, and the AE detection circuit 37 performs the AE calculation. Based on these calculation results, the CPU 42 moves the focus lens 40 to the in-focus position via the motor driver 14, and sets the aperture mechanism and the electronic shutter function of the CCD image sensor 21 to appropriate exposure control values (aperture value and Shutter speed) and an AWB adjustment value.

  Further, the CPU 42 integrates angular velocities detected by the angular velocity sensor 15 for every predetermined sampling time, for example, and calculates amplitude angles in the pitch direction and the yaw direction of the imaging apparatus, respectively.

  In the present embodiment, the AE detection circuit 37 calculates the EV value, aperture value, and the like that are the brightness of the subject based on the image data, but the present invention is not limited to this. For example, an optical sensor or the like that detects the peripheral light amount may be provided, and the calculation may be performed based on the optical sensor output.

  FIG. 2 is a flowchart showing a subject imaging routine. That is, the CPU 42 executes the next step S1 transition process.

  In step S1, after the angle of view is determined by the zoom lens 11, the CPU 42 determines whether or not the shutter button 45 is half-pressed and waits until it is half-pressed. Then, when the CPU 42 detects that the shutter button 22 is half-pressed, the CPU 42 proceeds to step S2.

  In step S2, the CPU 42 reads the position (zoom position) of the zoom lens 11 obtained from an encoder (not shown), calculates the focal length f (for example, 300 [mm] in this embodiment) based on the zoom position, The process proceeds to step S3.

  In step S3, the AE detection circuit 37 calculates an exposure value based on a photometric value (EV value) and a preset ISO sensitivity. The CPU 42 uses these pieces of information to calculate the aperture value and shutter speed (shutter opening time [s]) with reference to the program diagram of the imaging apparatus, and proceeds to step S4.

  In step S4, the CPU 42 executes an autofocus process. Specifically, the CPU 42 detects the position where the contrast detected by the AF detection circuit 36 is maximized while moving the focus lens 13 via the motor driver 14, and sets the focus lens 13 at the position. The process proceeds to step S5.

  In step S5, the CPU 42 determines whether or not the shutter button 45 is fully pressed, and waits until the shutter button 45 is pressed. When the CPU 42 detects that the shutter button 22 has been fully pressed, the process proceeds to step S6.

  In step S6, the CPU 42 controls the CCD image sensor 21 to image the subject at the shutter speed calculated in step S3, and proceeds to step S7. Thereby, the image of the subject generated by the CCD image sensor 21 is converted into a digital signal and stored in the VRAM 34 of the main control unit 30.

  In step S7, the CPU 42 determines whether or not shutter speed> 1 / focal length f [seconds]. If the determination is affirmative, the process proceeds to step S8. If the determination is negative, the processing of this routine is performed. finish. The reason for determining whether or not the shutter speed> 1 / focal length f [seconds] is that there is a high possibility that camera shake will occur when this equation is satisfied.

  In step S8, the CPU 42 determines whether or not the amplitude angle based on the angular velocity detected by the angular velocity sensor 15 is larger than the threshold angle obtained from the angle of view corresponding to the focal length f calculated in step S2. Here, the threshold angle is set as follows according to the angle of view corresponding to the focal length f calculated in step S2.

  FIG. 3 is a diagram showing the relationship between the focal length f and the angle of view. In the figure, the upper row shows the angle of view [degree], and the lower row shows the focal length [mm]. For example, when the focal length f is 300 [mm] and 400 [mm], the angles of view are 8.2 [degrees] and 6.2 [degrees], respectively. In the present embodiment, the CPU 42 sets 1/100 of the angle of view corresponding to the focal length f as the threshold angle. For example, when the focal length f is 300 and 400 [mm], the threshold angles are 0.08 [degree] and 0.06 [degree], respectively.

  Therefore, the CPU 42 sets the threshold angle 0.08 degrees from the angle of view 8.2 [degrees] corresponding to the focal length f = 300 [mm] calculated in step S2, and within the exposure time corresponding to the shutter speed. It is determined whether or not the amplitude angle based on the angular velocity detected by the angular velocity sensor 15 exceeds a threshold angle of 0.08 degrees. If it exceeds, the process proceeds to step S9, and if not, the processing of this routine is terminated. .

In this embodiment, the threshold angle is set to 1/100 of the angle of view. The reason is as follows. For example, when the focal length f = 400 mm (view angle 6.2 degrees), if the correction range by the correction lens 12 is ± 0.3 degrees, good camera shake correction is performed. here,
Correction angle 0.6 degrees / field angle 6.2 degrees = 1/10
It is. This represents the maximum correction amount. Note that, when a shake larger than the maximum correction amount occurs during the exposure time, the camera shake cannot be corrected.

  The camera shake correction is a technique for improving the shake of a photographed image by 2 to 3 steps (−6 to −18 dB) based on 1 / f [second] in terms of shutter speed, and is practically −20 dB (1/10). The camera shake is suppressed in the following). Therefore, since the blur corresponding to 1/10 of the angle of view is suppressed to 1/10 or less, the shake of the photographed image after the camera shake correction is 1/100 or less of the angle of view.

  On the other hand, if a shake greater than the maximum correction amount occurs, the shake of the captured image after the camera shake correction exceeds 1/100 of the angle of view. Therefore, in the present embodiment, the threshold angle for determining whether there is camera shake is set to 1/100 of the angle of view.

  In the present embodiment, the threshold angle is 1/100 of the angle of view, but the present invention is not limited to this. The threshold angle may be 1/1000 to 1/100 of the angle of view.

  In step S9, the CPU 42 displays a captured image on the LCD 51 via the LCD control unit 35 and displays a handshake warning on it, and ends the processing of this routine. Thereby, the user can confirm the presence or absence of blurring of the captured image. Thereafter, when the user presses an OK button (not shown), the image data stored in the VRAM 34 is compressed by the compression / decompression circuit 40 and then recorded on the recording medium 52 via the media control unit 41. Note that when the user presses an NG button (not shown), the image data stored in the VRAM 34 is deleted.

  As described above, in the imaging apparatus according to the first embodiment, the shutter time is longer than 1 / focal length f, and the amplitude angle based on the angular velocity detected by the angular velocity sensor 15 within the shutter time is the focal length f. When the angle is larger than the threshold angle obtained from the corresponding angle of view, a camera shake warning is automatically displayed. As a result, the user can confirm the captured image without performing complicated operations, and can easily retake the image thereafter.

  When the CPU 42 makes an affirmative determination in step S 7, instead of performing the processes in steps S 8 and S 9, the CPU 42 displays (previews) a warning image together with the captured image on the LCD 51 for a few seconds, and then displays it on the LCD 51. The image may be enlarged. Thereby, the user can confirm whether or not the camera shake of the captured image is within the allowable range.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the circuit similar to 1st Embodiment, and the detailed description is abbreviate | omitted. The imaging apparatus according to the second embodiment is configured as shown in FIG. 1, and further executes the following camera shake correction routine.

  FIG. 4 is a flowchart illustrating a subject imaging routine according to the second embodiment. That is, the CPU 42 executes a process for the next step S11.

  Steps S11 to S15 of this routine are the same as steps S1 to S5 of the subject imaging routine shown in FIG. Therefore, step S16 and subsequent steps in FIG. 4 will be described.

  In step S16, the CPU 42 determines whether or not the shutter speed> 1 / focal length f [second]. If the determination is affirmative, the process proceeds to step S18. If the determination is negative, the process proceeds to step S18. .

  In step S17, the CPU 42 integrates the angular velocity detected by the angular velocity sensor 15 every predetermined sampling time, and starts recording the integrated value (the angle in the pitch direction and the yaw direction) in the VRAM 34 as a blur locus, and then in step S18. Migrate to Note that the recording of the angles in the pitch direction and the yaw direction is continued at least until the imaging period (shutter period) in the next step S18 ends. Further, instead of the integrated value, the angular velocity itself detected by the angular velocity sensor 15 may be recorded on the recording medium 52.

  FIG. 5 is a diagram showing a camera shake waveform when the shutter speed is 1/8 [second]. The maximum value of the waveform for 1/8 second, which is the shutter period, that is, the shutter period, is the range of blur. In step S17, at least the blur range is recorded.

  In step S18, the CPU 42 controls the CCD image sensor 21 to image the subject at the shutter speed calculated in step S13, and ends the processing of this routine. Thereby, the image of the subject generated by the CCD image sensor 21 is converted into a digital signal and stored in the VRAM 34 of the main control unit 30.

  Thereafter, when the user presses an OK button (not shown), the image data and angle information stored in the VRAM 34 are compressed by the compression / expansion circuit 40 and then recorded on the recording medium 52 via the media control unit 41. As a result, the pitch angle and the yaw direction angle are recorded on the recording medium 52 as the accompanying information together with the captured image. Note that when the user presses an NG button (not shown), the image data stored in the VRAM 34 is deleted.

  As described above, the imaging apparatus according to the second embodiment calculates the focal length f and the shutter speed, and when [shutter speed> n / (focal length f)] holds, not only the captured image, The vibration locus during the shutter period, that is, the angles in the pitch direction and the yaw direction are recorded. Thereby, when the captured image is blurred, the captured image can be restored by using the angles in the pitch direction and the yaw direction by the application software.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the circuit similar to embodiment mentioned above, and the detailed description is abbreviate | omitted. The imaging apparatus according to the third embodiment is configured as shown in FIG.

(First process)
When detecting a camera shake, the CPU 42 of the main control unit 30 of the present embodiment performs a first process after giving a camera shake warning to the LCD 51 as shown in FIG. As described in the first and second embodiments, the case of “detecting camera shake” means that (1) the shutter speed is greater than 1 / focal length f, and (2) the shutter speed is 1 / focus. Any of cases where the amplitude angle is larger than the distance f and the amplitude angle based on the detection value of the angular velocity sensor 15 within the shutter time is larger than the threshold angle obtained by the angle of view corresponding to the focal length f.

  After detecting the camera shake, the CPU 42 automatically sets the maximum aperture and the maximum sensitivity when an operation for instructing reshooting is performed by the user as shown in FIG. Specifically, the CPU 42 controls the aperture mechanism so as to have the maximum aperture via the motor driver 14, and further controls the CCD image sensor 21 so that the shutter speed becomes longer. Accordingly, the re-shooting condition can be set so that the ISO sensitivity is maximized and the camera shake is difficult. For example, regardless of whether the ISO sensitivity is ISO 100, 400, or 800, the re-shooting condition may be set to ISO 1600.

(Second process)
The CPU 42 executes the first process and picks up the subject. Then, as shown in FIG. 7, the CPU 42 executes the pixel mixing process in the horizontal direction or the vertical direction when an operation for instructing reshooting is performed again by the user as shown in FIG. Thus, the CCD image sensor 21 is controlled.

  For example, when the pixel mixing process is not performed, the image obtained from the CCD image sensor 21 is 2816 pixels × 2120 pixels. On the other hand, when the pixel mixing process is performed, the image obtained from the CCD image sensor 21 is 1280 pixels × 960 pixels. By reducing the number of pixels in this way, image blurring can be made difficult to occur.

(Third process)
Even if the CPU 42 executes the second process, as shown in FIG. 7, when an operation for instructing reshooting is performed again by the user, the CPU 42 sets the focal length f to the widest side. That is, the CPU 42 may bring the position of the zoom lens 11 closest to the imaging surface of the CCD image sensor 21 via the motor driver 14. For example, in any case of the focal length f = 400, 200, 100, 50 [mm], the re-shooting condition may be set to the focal length f = 28 [mm]. Thus, by setting the angle of view to the wide angle side, the captured image is less likely to be blurred.

  As described above, the image pickup apparatus according to the third embodiment performs the sensitivity improvement process when the camera shake is detected, and performs the pixel mixing process when the shake still occurs in the shot image, and still shakes the shot image. When this occurs, a process of setting the focal length f to the wide angle side is performed. Thereby, the blurring of the photographed image can be surely eliminated by performing the process of eliminating the blur on the photographed image in stages.

  In addition, this invention is not limited to embodiment mentioned above, It can apply also to what was changed in the design within the range of the matter described in the claim. For example, the imaging apparatus of the present invention is not limited to the configuration shown in FIG. 1 and is not limited to the processing procedures shown in FIGS. 2 and 4.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. It is a flowchart which shows a to-be-photographed object routine. It is a figure which shows the relationship between the focal distance f and a field angle. It is a flowchart which shows the to-be-photographed object routine of 2nd Embodiment. It is a figure which shows the waveform of a camera shake when a shutter speed is 1/8 [second]. It is a figure which shows a camera shake warning. It is a figure which shows re-taking operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical unit 11 Zoom lens 12 Correction lens 13 Focus lens 14 Motor driver 15 Angular velocity sensor 21 CCD image sensor 36 AF detection circuit 37 AE detection circuit 42 CPU
45 Shutter button

Claims (4)

Imaging means for imaging a subject in accordance with imaging light incident via an optical system;
A focal length calculating means for calculating a focal length of the optical system;
Shutter speed calculating means for calculating the shutter speed of the imaging means;
Angular velocity detecting means for detecting angular velocity;
The shutter speed calculated by the shutter speed calculating means is larger than the reciprocal of the focal distance calculated by the focal distance calculating means, and the amplitude angle based on the angular speed detected by the angular speed detecting means is in accordance with the focal distance. Warning output means for outputting a warning when the threshold angle is exceeded;
An imaging apparatus comprising: Imaging means for imaging a subject in accordance with imaging light incident via an optical system;
A focal length calculating means for calculating a focal length of the optical system;
Shutter speed calculating means for calculating the shutter speed of the imaging means;
Angular velocity detecting means for detecting angular velocity;
When the shutter speed calculated by the shutter speed calculation unit is larger than the reciprocal of the focal length calculated by the focal length calculation unit, the angular velocity detected by the angular velocity detection unit or information related to the angular velocity is stored. Angular velocity storage means;
An imaging apparatus comprising: Imaging means for imaging a subject in accordance with imaging light incident via an optical system;
A focal length calculating means for calculating a focal length of the optical system;
Shutter speed calculating means for calculating the shutter speed of the imaging means;
Angular velocity detecting means for detecting angular velocity;
Camera shake detection means for detecting camera shake when the shutter speed calculated by the shutter speed calculation means is greater than the reciprocal of the focal length calculated by the focal distance calculation means;
An imaging condition setting unit configured to set an imaging condition so that a captured image is not shaken when a camera shake is detected by the camera shake detection unit;
An imaging apparatus comprising: The camera shake detection means has a shutter speed calculated by the shutter speed calculation means larger than the reciprocal of the focal distance calculated by the focal distance calculation means, and an amplitude angle based on the angular speed detected by the angular speed detection means. The imaging apparatus according to claim 1, wherein camera shake is detected when a threshold angle corresponding to the focal length is exceeded.

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