JP2015028547A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a photographer from using erroneous information because a leveling instrument malfunctions when the camera shake and pan operation are applied to hand-held photographing using an imaging apparatus mounted with the leveling instrument.SOLUTION: An imaging apparatus includes angular velocity detection means which detects shaking, acceleration detection means which detects that external acceleration is applied to a camera, attitude detection means which detects the attitude of the camera from the acceleration detected by the acceleration detection means, attitude information notification means which notifies of attitude information of the camera obtained from the attitude detection means, reliability determination means which determines the reliability of the attitude information of the camera obtained from the attitude detection means, and notification content change means which changes the notification content by the attitude information notification means when the reliability determination means determines that the reliability of the attitude information of the camera is low.

Description

  The present invention relates to an attitude detection of an imaging apparatus having an angular velocity detection means and an acceleration detection means.

  In recent years, when taking a picture with a camera, an imaging apparatus equipped with a level function has been proposed as a means for notifying the photographer of the level of the picture to be taken now, in order to keep the composition horizontal. . Patent Document 1 discloses a method of detecting gravity from an acceleration detection unit and calculating the tilt angle of the camera from the information in order to realize this level function. Further, a method for trimming an image in a correction direction and correcting it to a horizontal image when it is determined that the camera is tilted at the time of shooting based on the detected posture information is disclosed.

JP 2006-129391 A

  However, in the method of detecting how gravity is applied to the camera using the acceleration detection unit as described above and using it in a spirit level, if you ride on a vehicle such as a train or move the camera itself in a panning shot, etc. Even the acceleration of the motion is detected, and the horizontal detection is mistaken.

  Even when shooting using a tripod, when shooting with a tripod platform shaken, there may be cases where the level cannot be maintained correctly due to camera shake or panning.

  Since the output of the acceleration detection unit changes according to the change in acceleration, a shake that changes in direction with a scalar such as camera shake, or a pan operation with a change in direction because it includes a stop even at a constant speed, etc. The acceleration detector detects components other than gravity. For this reason, the level may not be able to determine the correct level due to camera shake and panning.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging apparatus capable of performing high-accuracy determination of horizontality even when camera shake or panning is applied to an imaging apparatus having a level. That is.

In order to achieve the above object, the present invention provides:
Angular velocity detection means for detecting shaking;
Acceleration detecting means for detecting that external acceleration is applied to the camera;
Posture detection means for detecting the posture of the camera from the acceleration detected by the acceleration detection means;
Posture information notifying means for notifying camera posture information obtained from the posture detecting means;
Having reliability determination means for determining the reliability of the posture information of the camera obtained from the posture detection means;
When the reliability determination unit determines that the reliability of the posture information of the camera is low, it includes a notification content changing unit that changes a notification content by the posture information notification unit.

  According to the present invention, in an imaging apparatus provided with a means for determining the level by the acceleration detection unit, an erroneous determination of the level is caused by the influence of shaking accompanied by a change in acceleration caused by camera shake or panning applied to the imaging apparatus. In such a case, by notifying the photographer of this fact, it is possible to prevent photographing based on incorrect information.

Block diagram of the horizontal judgment unit Block diagram of the entire camera How to apply force to the camera Flow chart explaining the embodiment

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 2 is a block diagram for explaining an imaging apparatus which is an example of the embodiment. Reference numeral 201 denotes a first group lens, which is a zoom lens that performs zooming that can change the position in the optical axis direction. (Hereinafter referred to as zoom lens) 209 is a zoom drive control unit that controls the drive of the zoom lens. Reference numeral 202 denotes a shutter / aperture unit. Reference numeral 210 denotes a shutter / aperture unit drive control unit, which controls the drive of the shutter / aperture unit 202. Reference numeral 203 denotes a second group lens, which is a shift lens as a shake correction optical system capable of changing the position on a plane substantially perpendicular to the optical axis. (Hereinafter referred to as shift lens) 211 is a shift lens drive control unit, and drives and controls the shift lens.

  Reference numeral 204 denotes a third group lens, which is a focus lens that performs focus adjustment that can be changed in position in the optical axis direction. (Hereinafter referred to as a focus lens) 212 is a focus drive control unit, and controls the drive of the focus lens. Reference numeral 205 denotes an image sensor that converts a light image that has passed through each lens group into an electrical signal. Reference numeral 206 denotes an imaging signal processing unit that converts an electrical signal output from the imaging element 205 into a video signal. Reference numeral 207 denotes a video signal processing unit that processes the video signal output from the imaging signal processing unit 406 in accordance with the application. Reference numeral 208 denotes a display unit that displays an image as necessary based on the signal output from the video signal processing unit 407.

  A control unit 213 controls the entire system. A zoom switch 214 is an operation unit for operating the zoom lens. An external input / output terminal unit 215 inputs / outputs communication signals and video signals to / from the outside. Reference numeral 216 denotes a shutter release switch. A storage unit 217 stores various data such as video information. Reference numeral 218 denotes a power supply unit that supplies power to the entire system according to the application. An acceleration detection unit 219 detects acceleration applied to the camera. An angular velocity detection unit 220 detects the angular velocity when the camera rotates. In this patent, it is possible to detect the angular velocity when rotated along the optical axis (hereinafter referred to as roll shake).

  Next, the operation of the imaging apparatus having the above configuration will be described. The release switch 216 is configured such that a first switch (hereinafter referred to as SW1) and a second switch (hereinafter referred to as SW2) are sequentially input in accordance with the pushing amount. SW1 is input when the release switch 216 is depressed approximately half, and SW2 is input when the shutter release switch is fully depressed. When SW1 of the release switch 216 is input, the focus drive control unit 212 drives the focus lens 204 based on the AUTO FOCUS function (hereinafter referred to as AF) to adjust the focus, and the AUTO EXPOSURE function (hereinafter referred to as AE). The shutter / aperture unit drive control unit 210 drives the shutter / aperture 22 to set an appropriate exposure amount.

  When SW2 is further input, the electrical signal obtained from the optical image exposed to the imaging 205 is converted into an image signal by the imaging signal processing unit 206, and further processed by the video signal processing unit 207, and then controlled. The data is stored in the storage unit 217 under the control of the unit 213. When the photographer operates the zoom switch 214, the zoom drive control unit 209 that has received an instruction via the control unit 413 of the entire system drives the zoom lens 201 and moves the zoom lens to the instructed zoom position.

  FIG. 1 is a block diagram for calculating an acceleration for determining a level according to an embodiment of the present invention. Reference numeral 100 denotes an angular velocity detection unit. The angular velocity detection unit detects a shake component (however, a detection noise component is also included). Reference numeral 101 denotes AD conversion, which converts analog data detected by the angular velocity detection unit 100 into digital data. Reference numeral 102 denotes a BPF, which is called a band pass filter or a band transmission filter. Generally, the camera shake component is 1 Hz to 10 Hz. The BPF 102 is a filter that transmits the components of the required camera shake frequency band without transmitting the noise components of the low frequency lower than 1 Hz and the high frequency higher than 10 Hz. Here, the above-described noise component can be removed by cutting frequencies other than the hand shake component band.

Reference numeral 103 denotes an integral, which is an angle obtained by integrating the angular velocity. Reference numeral 104 denotes a shaking cancel calculation unit, which is a shaking angle.

The shift lens 303 is moved in the direction opposite to the shaking for canceling the above. Reference numeral 105 denotes a PID control unit that performs feedback control of the shift lens 303. Reference numeral 106 denotes an acceleration detection unit. Reference numeral 100 denotes an angular velocity detection unit. The acceleration detection unit detects an acceleration component (including a detection noise component) applied to the camera. First, gravity is given as an acceleration component applied to the camera. In addition, camera shake of the photographer is also detected as acceleration.

  Reference numeral 107 denotes AD conversion, which converts analog data detected by the acceleration detection unit 106 into digital data. Reference numeral 108 denotes a BPF. The description of the BPF 108 is the same as that of the BPF 102. Reference numeral 109 denotes an attitude detection unit that detects an attitude from an acceleration applied to the camera by an angle. The detection method will be described later. Reference numeral 110 denotes a differentiator, which obtains the amount of change in the rotation angle by differentiating the camera angle detected at 109. Reference numeral 111 denotes a level level reliability determination unit that compares the amount of change in the rotation angle of the camera obtained from the angular velocity detection unit 100 with the amount of change in the rotation angle obtained from the acceleration detection unit, and trusts the detection result as a level. Determine the degree.

  A level unit 112 determines the level when the horizontal detection reliability determination unit 111 determines that there is reliability for horizontal detection. The level of the output of the acceleration detection unit 106 changes due to a change in the level of the imaging apparatus. This is because, when the level is changed, the gravity applied by the acceleration detection unit 106 is always changed. Reference numeral 113 denotes a frequency determination unit, which counts the waveform of the angular velocity detection unit 100 to determine the frequency of shaking.

FIG. 3 is an explanatory diagram of a calculation method for performing horizontal detection from the acceleration detection unit 106 according to the embodiment of the present invention. FIG. 3 is a view of the camera as viewed from the front. The horizontal direction of the camera is the x axis, the vertical direction is the y axis, and the optical axis direction of the camera is the z axis. Further, accelerations on the x-axis and the y-axis that can be detected by the acceleration detection unit 106 are a _x and a _y , respectively. The camera posture is derived from the following equation based on the information obtained from the acceleration detection unit 106.

  FIG. 3A shows how the force is applied when an external force other than gravity is not applied to the camera and the camera is kept horizontal. Here, when the gravitational acceleration is g and the weight of the camera is m, the camera only applies g × m force in the y-axis direction, and the acceleration detection unit 106 is 0 in the x-axis direction and g in the y-axis direction. The acceleration of is detected. In addition, since the camera is kept horizontal, the angular velocity detection unit 100 detects nothing.

  FIG. 3B shows how the force is applied when no external force other than gravity is applied to the camera and the camera is tilted in the roll direction. At this time, the camera is applied with g × m force decomposed in both the x-axis direction and the y-axis direction, and the acceleration detection unit 106 also detects an acceleration that is g from both the x-axis direction and the y-axis direction. . Since the camera rotates in the roll direction, the angular velocity detection unit 100 detects the movement.

  FIG. 3C shows how the force is applied when an external force is applied at an acceleration α in the x-axis direction with the camera kept in a horizontal state. At this time, the camera applies α × m force in the x-axis direction and g × m force in the y-axis direction, and the acceleration detector 106 detects α in the x-axis direction and g acceleration in the y-axis direction. If an attempt is made to obtain the camera posture from equation (1), it is erroneously determined that the camera is tilted even though it is actually horizontal. In addition, since the camera is kept horizontal, the angular velocity detection unit 100 detects nothing.

  As described above, if the force applied to the camera does not change (for example, if it is always subjected to gravity), the angular velocities of the cameras detected by the acceleration detection unit 106 and the angular velocity detection unit 100 coincide with each other. However, when some other force is applied, a difference occurs in the angular velocity of the camera detected by each.

[Example 1]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flowchart for comparing the data detected by the acceleration detection unit 106 with the data detected by the angular velocity detection unit 100 and determining the reliability of the level based on the result. Note that the angular velocity detection unit 100 can detect vertical (also referred to as PITCH) and horizontal (also referred to as YAW) vibration, but this time, particularly, detection of roll blur will be considered. Step S401 declares the start of the level function.

  In step S <b> 402, a value obtained by converting analog data, which is shake information detected by the angular velocity detection unit 100, into digital data through the AD conversion 101 is acquired. In step S403, the BPF 102 is applied to the shaking data acquired in step S402. The initial value of the cut-off frequency of the BPF 102 is normally set to transmit 1 Hz to 10 Hz, which is a camera shake band, but is finely adjusted by tuning. In general, the angular velocity detection unit and the acceleration detection unit include white noise at the time of detection. Therefore, a BPF that transmits only a frequency component that is necessary for removing the influence of the subsequent calculation is widely used. The angular velocity acquired here is assumed to be A.

  In step S404, a value obtained by converting analog data, which is information detected by the acceleration detection unit 106, into digital data through the AD conversion 107 is acquired. In step S405, the data acquired in step S404 is multiplied by the BPF 108. Here, the initial value of the cutoff frequency of the BPF 108 is basically the same as in step S403. In step S406, the posture (angle) of the camera is calculated based on the data acquired in step 403. The calculation is performed according to the above formula (1). In step S407, the posture (angle) of the camera calculated in step 406 is differentiated by the differentiator 110 to be converted into an angular velocity. The angular velocity calculated here is B.

  In step S408, the difference between the angular velocity A of the camera calculated from the data detected by the angular velocity detection unit 100 and the angular velocity B of the camera calculated from the data detected by the acceleration detection unit 106 is obtained. As described above, as long as the external force applied to the camera does not change, the respective detection results coincide with each other. However, when some other external force is applied, a difference occurs in each detection result.

  In step S409, it is determined whether a difference has occurred in S408, and the reliability of the level function is determined. As described above, if they match, the level function is reliable and the process proceeds to S410. On the other hand, if they do not match, the level function is not reliable and the process proceeds to S411. Here, the reliability is determined based on whether or not the speeds A and B match each other. However, a range may be given to the condition that the speeds A and B match. That is, if a certain threshold value is provided and the value obtained in S408 is within the threshold value, it is determined that the angular velocity A and the angular velocity B coincide with each other, and the level function is reliable, and the process proceeds to S410. On the other hand, if the difference obtained in S409 seems to exceed a certain threshold value, it is determined that the angular velocity A and the angular velocity B do not coincide with each other, and the level function is not reliable, so the processing proceeds to S411.

  Step S410 performs processing when it is determined that the level function is reliable. For example, the camera angle is displayed on the display unit 208 so that the photographer can refer to the shooting. Step S411 performs processing when it is determined that the level function is not reliable. For example, an error message is displayed on the display unit 208 so that the user does not perform shooting based on incorrect information.

  Here, the display unit 208 is used for information notification by the level function, but other methods such as sound, vibration, and light may be used. When the image is taken, the camera posture information calculated in step S406 and the level function reliability information determined in step S410 may be loaded on the image. Step S412 declares the end of the level function determination.

  As described above, the image pickup apparatus has been described as an example. However, the present invention is not limited to the image pickup apparatus, and the present invention can be applied to a portable device having the image pickup apparatus.

100 Angular velocity detector 101 and 107 AD conversion 102 and 108 BPF
103 Integration 106 Acceleration Detection Unit 109 Attitude Detection Unit 110 Differential 111 Level Level Reliability Determination Unit 112 Level Level

Claims (11)

Angular velocity detection means for detecting shaking;
Acceleration detecting means for detecting that external acceleration is applied to the camera;
Posture detection means for detecting the posture of the camera from the acceleration detected by the acceleration detection means;
Posture information notifying means for notifying camera posture information obtained from the posture detecting means;
Having reliability determination means for determining the reliability of the posture information of the camera obtained from the posture detection means;
An imaging apparatus comprising: notification content changing means for changing notification content by the posture information notification means when the reliability determination means determines that the reliability of the posture information of the camera is low. First angular velocity detection means for differentiating the output signal from the attitude detection means;
A second angular velocity detection means for directly detecting the shaking;
A difference calculating means for calculating an output from the first angular velocity detecting means and a difference from the second angular velocity detecting means;
The imaging apparatus according to claim 1, wherein the reliability determination unit determines the reliability based on whether the result obtained from the difference calculation unit is within a certain range. When the reliability determination means determines that the reliability of the posture information of the camera is low,
The imaging apparatus according to claim 1, wherein the immediately preceding information is notified by the posture information notification unit. When the reliability determination means determines that the reliability of the posture information of the camera is low,
Along with camera posture information obtained from the posture detection means,
The imaging apparatus according to claim 1, wherein the attitude information notification unit notifies that the reliability of the attitude information is low. When the reliability determination means determines that the reliability of the posture information of the camera is low,
The imaging apparatus according to claim 1, wherein the attitude information notifying unit notifies camera reference attitude information. When the reliability determination means determines that the reliability of the posture information of the camera is low,
The imaging apparatus according to claim 1, wherein the operation of the posture information notification unit is stopped. The imaging apparatus according to claim 1, wherein the posture information notifying unit is notified by being displayed by a display unit. The imaging apparatus according to claim 1, wherein the posture information notifying unit is notified by emitting light from a light generating unit. The imaging apparatus according to claim 1, wherein the posture information notifying unit is notified by generating a vibration by a vibration generating unit. The imaging apparatus according to claim 1, wherein the posture information notifying unit is notified by generating a sound from a sound generating unit.   The imaging apparatus according to claim 1, wherein the posture information and the reliability of the posture information of the camera determined by the reliability determination unit are recorded in an image.