JP2009065248A - Image pickup device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain tilt information for highly precisely matching images horizontally and vertically. <P>SOLUTION: When a mechanical driving part of a digital camera starts operating (S1), control of a spirit level module comprising a G sensor (acceleration sensor), a means for calculating tilt from this output and a means for displaying tilt to an LCD monitor by a frame and an indicator on the basis of the calculated tilt is changed (S2), and when completing operation of the mechanism driving part (S3), the control of the spirit level module is changed again (S4). As processing S2 of the control over the spirit level module, the means for displaying the tilt displayed to the LCD monitor (the frame and the indicator) are deleted, the G sensor (acceleration sensor) is shifted to a power saving mode, or the means for calculating the tilt from the output of the G sensor is stopped. As processing S4, the G sensor is recovered from the power saving mode, the tilt from the G sensor output is calculated, and the frame and the indicator onto the LCD monitor is displayed again. Influences of noise element attributed to operation of the mechanical driving part is mitigated to obtain a correct tilt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a control method using an imaging result, and detects the tilt of the image and the tilt of the imaging apparatus at the time of image acquisition, and the image tilt is post-processed as necessary based on the detected tilt information. The present invention relates to an imaging apparatus capable of correcting and accurately aligning images vertically and horizontally, and a control method thereof.

  In recent years, digital cameras have been configured so that they can be carried and used in various places due to the reduction in size and weight, and the functions of digital cameras are also incorporated into mobile phones and the like.

  In a digital camera, due to the reduction in size and weight, shooting is not always performed in a stable posture, and an arbitrary inclination is generated in an image at the time of shooting because it is held by a person.

  In addition, in a digital camera, there may be a case where an image is taken with an intentionally tilted composition, or a case where a vertically long composition is used.

  Patent Document 1 describes an imaging apparatus that can correct the inclination of an imaging result by correctly reflecting the above-described user's intention. Patent Document 2 describes an imaging device that inputs a planar image by reducing distortion when combining divided images.

There is also a commercially available level that uses air bubbles and can be inserted into a hot shoe to be attached to a digital camera and used to check the posture, for example, to attach an external strobe of the digital camera.
JP 2004-343476 A JP 11-136575 A

  However, in the imaging apparatus having such a configuration, vibration during operation of a mechanical drive unit that drives a lens barrel unit, a camera shake correction mechanism, and the like included in the digital camera is transmitted to the acceleration sensor, and the output of the acceleration sensor is mechanically driven. The noise by the operation of the part gets on. As a result, the accuracy of the angle calculated from the output of the acceleration sensor is reduced, and the angle information also fluctuates and becomes violent, resulting in a deterioration in display quality. Also, a method for increasing the accuracy at this time is not disclosed.

  The present invention is directed to solving the problems of the prior art, and an object thereof is to provide an imaging apparatus capable of obtaining tilt information for aligning images horizontally and vertically with high accuracy, and a control method therefor. .

  In order to achieve the above object, the invention described in claim 1 according to the present invention includes a display unit that displays an acquired image, an acceleration sensor, a unit that calculates the tilt of the apparatus from the output of the acceleration sensor, and a display. In the imaging apparatus having means for displaying the tilt calculated using the unit, one or more control processes of the means for calculating the tilt, the means for displaying the tilt, or the acceleration sensor are changed according to the operation of the mechanical drive unit By changing the control of the acceleration sensor, the means for calculating the inclination, and the means for displaying the inclination before and after the operation of the mechanical drive unit, the noise for the detection signal of the acceleration sensor can be reduced and accurate. By detecting the tilt, the display quality can be prevented from being degraded.

  The invention described in claims 2 to 4 is the imaging apparatus according to claim 1, wherein the means for changing the control process changes the control process when the mechanical drive unit starts and / or ends. In addition, the operation of the mechanical drive unit is the movement or storage of the lens barrel unit, the movement of the focus lens, the operation of holding the camera shake correction mechanism or the camera shake correction unit, and further, the operation of the mechanical drive unit is In addition to the mechanical operation, the power supply unit includes a process with a large electrical variation.

  The imaging apparatus control method described in claims 5 to 8 includes the imaging apparatus according to claims 1 to 4 described in steps, and is a method for controlling the imaging apparatus according to the tilt detection and display of the apparatus. And the features are the same as those of the imaging device according to the first to fourth aspects.

  According to the present invention, it is possible to alleviate the influence of the noise component of the acceleration sensor output caused by the operation of the mechanical drive unit, and it is possible to detect an accurate inclination so as not to deteriorate the display quality.

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

  FIG. 1A is a front view, FIG. 1B is a rear view, and FIG. 1C is a top view showing the appearance of a digital camera according to an embodiment of the present invention. FIG. 2 is a block circuit diagram showing an outline of the system configuration inside the digital camera.

  As shown in FIGS. 1A and 1C, a release switch (release shutter) SW1, a mode dial switch SW2, and a jog dial 1 switch SW3 are disposed on the front and top surfaces of the digital camera body. A flash unit 1, a distance measuring unit 2, an optical viewfinder 3, and a lens barrel unit 4 including a photographing lens are provided.

  On the back of the digital camera shown in FIG. 1B, there is an LCD monitor 5, a jog dial 2 switch SW4, a zoom switch [TELE] SW5, a zoom switch [WIDE] SW6, an upper switch SW7, a right switch SW8, an OK switch SW9, and a left A switch SW10, a lower switch / macro switch SW11, a display switch SW12, a deletion switch SW13, a menu switch SW14, and a power switch SW15 are provided. A battery cover 6 is provided on the side surface of the camera body.

  Since the function and operation of each member of the digital camera are known, the description thereof will be omitted, and the internal system configuration of the camera will be described with reference to FIG. 1 based on FIG.

  As shown in FIG. 2, reference numeral 104 denotes a digital still camera processor (hereinafter referred to as a processor). The processor 104 includes a first CCD signal processing block 1041, a second CCD signal processing block 1042, a CPU block 1043, a local SRAM 1044, a USB block 1045, a serial block 1046, a JPEG / CODEC block (block for performing JPEG compression / decompression) 1047, and a RESIZE. Block (block that enlarges / reduces the size of image data by interpolation processing) 1048, TV signal display block (block that converts image data to a video signal for display on an external display device such as a liquid crystal monitor / TV) 1049, memory A card controller block (block for controlling a memory card that records captured image data) 10410 is included. Each of these blocks is connected to each other via a bus line.

  Further, outside the processor 104, RAW-RGB image data (image data in a state where white balance setting and γ setting are performed), YUV image data (image data in which luminance data and color difference data are converted), An SDRAM 103 for storing JPEG image data (image data in a JPEG compressed state) is disposed, and the SDRAM 103 is connected to the processor 104 via a memory controller (not shown) and a bus line.

  The SDRAM 103 temporarily stores image data when the processor 104 performs various processes on the image data. The image data to be stored is, for example, “RAW-RGB image data” in which the white balance setting and the γ setting are performed from the CCD 101 via the F / E-IC 102 and the first CCD signal processing block 1041 is set. And “YUV image data” in which luminance data / color difference data conversion has been performed in the second CCD signal control block 1042, “JPEG image data” compressed in JPEG in the JPEG / CODEC block 1047, and the like.

  In addition to the processor 104, a built-in memory such as a RAM (a memory for storing captured image data even when a memory card is not installed in the memory card slot) 107, a ROM storing a control program, parameters, and the like (Not shown) are provided and are also connected to the processor 104 by bus lines.

  The control program stored in the ROM is loaded into the main memory (not shown) of the processor 104 when the power switch SW15 of the digital camera is turned on. The processor 104 controls the operation of each unit according to the control program, Parameters and the like are temporarily stored in the built-in memory 107 or the like.

  The lens barrel unit 4 includes a lens barrel including a zoom optical system 41 having a zoom lens 41a, a focus optical system 42 having a focus lens 42a, a diaphragm unit 43 having a diaphragm 43a, and a mechanical shutter unit 44 having a mechanical shutter 44a. ing. Note that the zoom lens 41a, the focus lens 42a, and the aperture 43a constitute a photographing optical system. The optical axis of the photographing optical system is the Z axis, and the plane orthogonal to the Z axis is the XY plane.

  The zoom optical system 41, the focus optical system 42, the aperture unit 43, and the mechanical shutter unit 44 are driven by a zoom motor 41b, a focus motor 42b, an aperture motor 43b, and a mechanical shutter motor 44b, respectively.

  Each motor of the lens barrel unit 4 is driven by a motor driver 45, and the motor driver 45 is controlled by a CPU block 1043 of the processor 104.

  Further, a subject image is formed on a CCD 101 which is a solid-state imaging device that photoelectrically converts an optical image by each lens system of the lens barrel unit 4, and the CCD 101 converts the subject image into an image signal and outputs the image signal to the F / E-IC 102. Is output. The F / E-IC 102 includes a CDS 1021 that performs correlated double sampling for image noise removal, an AGC 1022 for gain adjustment, and an A / D conversion unit 1023 that performs analog-digital conversion. That is, the F / E-IC 102 performs predetermined processing on the image signal, converts the analog image signal into a digital signal, and outputs the digital signal to the first CCD signal processing block 1041 of the processor 104.

  These signal control processes are performed via the TG 1024 by a VD (vertical synchronization) -HD (horizontal synchronization) signal output from the first CCD signal processing block 1041 of the processor 104. The TG 1024 generates a drive timing signal based on the VD-HD signal.

  In addition, the processor 104 supplies a vertical synchronization signal and a horizontal synchronization signal from the first CCD signal control block 1041 to perform white balance setting and γ setting on the output data of the F / E-IC 102 from the CCD 101, and controls the second CCD signal. In block 1042, conversion to luminance data / color difference data is performed as filtering processing. The CPU block 1043 controls the operation of each part of the apparatus and temporarily stores data necessary for control in the local SRAM 1044.

  The CPU block 1043 further controls the strobe circuit 114 to emit illumination light from the strobe light emitting unit 1. In addition to this, the CPU block 1043 also controls the distance measuring unit 2.

  The CPU block 1043 is connected to a sub CPU 109 of the processor 104, and the sub CPU 109 is connected to an operation key unit including operation switches SW1 to SW15. The operation key units (SW1 to SW15) are key circuits operated by the user, and the sub CPU 109 is a CPU in which ROM / RAM is built in one chip, and outputs from the operation key units (SW1 to SW15) and the like. The signal is output to the CPU block 1043 as user operation information.

  The USB block 1045 is connected to an external device such as a personal computer for USB communication with a USB connector (not shown), and the serial block 1046 is connected to the external device and an RS-232C connector via a serial driver circuit (not shown). Connected and performs serial communication. The TV signal display block 1049 is connected to the LCD monitor 5 via the LCD driver 108 and is also a video AMP (AMP (amplifier) for converting the video signal output from the TV signal display block 1049 to 75Ω impedance). 109 is connected to a video jack 110 (a jack for connecting the camera to an external display device such as a TV) 110. The memory card controller block 10410 is connected to a card contact of a memory card slot (not shown).

  The LCD driver 108 functions to drive the LCD monitor 5 and convert the video signal output from the TV signal display block 1049 into a signal to be displayed on the LCD monitor 5. The LCD monitor 5 is used to display the image data recorded in the memory card or the built-in memory 107 in order to monitor the state of the subject before photographing and to confirm the photographed image.

  Further, the acceleration sensor 111 is mounted on any of the printed circuit boards (PCBs) constituting the above-described parts (see FIG. 3), and outputs data of two axes X and Y and temperature T. The tilt (roll angle) of the digital camera is calculated from the data by, for example, the CPU block 1043 and displayed on the LCD monitor 5 or the like.

  Next, a method for calibrating the variation between the individual roll angles of the CCD and the acceleration sensor in the digital camera at the factory will be described.

  First, as shown in FIG. 4A, the digital camera 10 and the chart 20 are set up. The digital camera 10 is installed so as to be substantially horizontal, and as shown in FIG. 4B, a line connecting the center (feature point) of the cross 21a and the cross 21b of the chart 20 is parallel to the gravity direction. Install. Further, the center point of the one side 21a is defined as a feature point A, and the center point of the other side 21b is defined as a feature point B.

  The output of the acceleration sensor (hereinafter referred to as G sensor) of the digital camera 10 is acquired, and the chart after 1 second (X-axis G sensor output at this time is X0, Y-axis G sensor output is Y0, temperature output is T0) 20 is photographed to obtain an image. The coordinates of the feature point A of the chart 20 (referred to as (a, b)) and the coordinates of the feature point B (referred to as (c, d)) are read from the image, and the CCD roll for the chart 20 installed in an absolute vertical direction The angle θc is obtained.

  An image scanning method will be described with reference to FIG. Luminance data is acquired for the image of the cross 21 in order from the upper side in the horizontal direction. The luminance decreases when the black portion of the cross 21 is scanned. The coordinates where the luminance is below the predetermined threshold and the midpoint of the coordinates where the luminance is above the predetermined threshold are set as the center of the cross black belt. The change in brightness is detected twice at first by this horizontal scanning, and further, only once at the feature point, and then twice. By the upper and lower scans that detect twice the luminance change of the X 21 when scanned, a total of four centers of the X black belt are obtained. The coordinates of the intersection are calculated by using these four coordinates as a guide. This is the center (feature point) of the cross 21.

  A method of obtaining the CCD roll angle θc with respect to the chart 20 shown in FIG. From the coordinates of the feature point A (a, b) and the feature point B (c, d), the CCD roll angle θc is expressed by (Equation 1).

It becomes.

  Next, the roll angle θs with respect to the horizontal of the G sensor is obtained. From X-axis output X0, Y-axis output Y0, and temperature output T0 of G sensor (Equation 2)

Here, G0 is an output at the time of zero gravity.

  When the gravity is zero, the gravity of the G sensor is zero when the sensor axis is oriented perpendicular to the gravity, and the gravity is zero when the sensor is free-falling. Incidentally, when the sensor axis is parallel to gravity, the output is 1 G, and when it is 45 degrees, the output is 1 / √2 G.

  The output value of the G sensor is expressed by (C × (gravity) + output at zero gravity) (C is a constant). In order to obtain gravity, it is necessary to calculate the output at zero gravity and subtract from the output value. The output at zero gravity outputs around "2048", but the G sensor has temperature characteristics and is accurate. This is expressed as “G0 = 2048 + 0.4 × t”.

  A difference between the roll angle θc of the CCD obtained from the image and the roll angle θs obtained from the G sensor is obtained. This is θ0 (horizontal shooting), which is the relative roll angle between the CCD and the G sensor. The relative roll angle θ0 is stored in a storage unit (for example, nonvolatile memory: EEPROM).

  Further, the digital camera 10 is installed at a vertical shooting of +90 degrees, the relative roll angle θ90 is obtained by the same method as described above, and the relative roll angle θ90 is stored in the storage unit. Further, the digital camera 10 is installed at a longitudinal shooting of −90 degrees, the relative roll angle θ270 is obtained by the same method as described above, and the relative roll angle θ270 is stored in the storage unit.

  Although the relative roll angle between the CCD and the G sensor does not depend on the posture, the output of the G sensor varies somewhat depending on the posture, and thus the calculated values are different. In order to obtain a higher level of accuracy, the relative roll angles for the three postures of horizontal shooting and vertical shooting (+90 degrees and -90 degrees) that are frequently used are stored.

  The horizontality detection operation when the user uses the digital camera will be described. The output from the G sensor is X-axis output x, Y-axis output y, temperature output t, zero-gravity output g (t), X-axis / Y-axis gravity ratio is R, and the detection roll angle is θ. (Equation 3)

It becomes. In the range of 0 <θ <360, there are two candidates for the detected roll angle θ. Therefore, it is determined whether x−g (t) is positive or negative. θ is determined. Note that θ0 is the horizontal shooting relative roll angle of the storage means.

  If the detected roll angle θ is near +90 degrees, the relative roll angle θ90 is used instead of the relative roll angle θ0,

Then, the detected roll angle θ is recalculated.

  Similarly, if the detected roll angle θ is near −90 degrees, the relative roll angle θ270 is used instead of the relative roll angle θ0,

Then, the detected roll angle θ is recalculated.

  The detected roll angle θ determined by the means for calculating the inclination as described above is displayed on the LCD monitor 5 of the display unit shown in FIG. 1 as shown in the lower part of FIG. It is displayed by means for displaying the inclination of 24). This is a frame 23 and an indicator 24 imitating a level using bubbles, and the indicator 24 (circle) is at the center of the frame 23 when leveling, and the indicator 24 depends on the angle when the digital camera is going up to the right. The indicator 24 is shifted to the right of the frame 23, and when it goes up to the left, the indicator 24 is shifted to the left of the frame 23 according to the angle. The frame 23 and the indicator 24 displayed on the LCD monitor 5 are displayed on the captured image data by OSD (On Screen Display).

  Alternatively, a line segment having a length approximately the same as the rectangle (frame 23) on the LCD monitor 5 and having a round dot at the center is displayed as an indicator indicating the level, and when the digital camera is going up to the right, the indicator is adjusted to the angle. On the LCD monitor 5, the right edge of the line segment is centered on the circle dot, the left edge is up, and conversely when it is going up to the left, the indicator is The display may be swung as described above.

  As shown in FIG. 7, for example, in the lens barrel unit 4 of FIG. 1, when the operation of the mechanical drive unit that drives the lens barrier, the focus lens, etc. is started (S 1), the control of the level module is changed ( S2) After that, when the operation of the mechanical drive unit ends (S3), the control of the level module is changed again (S4).

  The level module uses the above-described G sensor (acceleration sensor), means for calculating a tilt (detected roll angle) based on the output, and the above-described frame 23 and indicator 24 based on the calculated tilt. 5 is composed of means for displaying an inclination on the top.

  Specifically, at the start of the operation of the mechanical drive unit, the frame 23 and the indicator 24 (see FIG. 6) displayed on the LCD monitor 5 are deleted, the G sensor (acceleration sensor) is shifted to the power saving mode, or the G sensor. The process of calculating the tilt (detected roll angle) from the output is stopped. At the end of the operation of the mechanical drive unit, the G sensor is returned from the power saving mode, the inclination is calculated from the G sensor output, and the indicator 24 with the frame 23 is displayed again on the LCD monitor 5. In the above-described plurality of processes performed at the start of operation and at the end of operation, any one or a combination thereof may be performed.

  In the present embodiment, the mechanical drive unit related to the lens barrel unit 4 is described, and a process with a large electrical variation with respect to the power source unit, such as a camera shake correction mechanism and a pop-up light emission preparation in the strobe light emitting unit 1, is described. However, if they can cause mechanical and electrical noise, they are included in the same manner as the operation of the mechanical drive unit.

  By doing so, mechanical and electrical noise caused by the operation of the mechanical drive unit, etc. can be avoided, the influence of noise components that cause malfunction of the digital camera can be mitigated, and the tilt angle can be obtained accurately. In addition, an effect of preventing deterioration of display quality can be obtained.

  Further, at the time of starting the operation of the mechanical drive unit in the flowchart shown in FIG. 7, as another control content of the level module, for example, in the frame 23 and the indicator 24 displayed on the LCD monitor 5 which is a means for displaying the inclination, In order to notify that the tilt detection is not controlled, the movement of the indicator 24 is stopped and blinking is performed. Then, at the end of the operation of the mechanical drive unit, control is performed so that the movement of the indicator 24 is restarted and lit to notify that accurate tilt detection is being controlled.

  Further, at the start of the operation of the mechanical drive unit in the flowchart shown in FIG. 7, as another control content of the level module, for example, in the means for calculating the inclination, the detected roll angle θ calculated from the output of the acceleration sensor The detection roll angle θ obtained from the average of the latest 50 times stored in the storage means is redefined, and the position of the indicator 24 is determined based on the detected roll angle θ as the position in the frame 23. At the end of the operation of the mechanical drive unit, the inclination (detected roll angle θ) output from the acceleration sensor is calculated again, and control for determining the position of the indicator 24 within the frame 23 is performed based on this.

  As described above, the frame 23 and the indicator 24 displayed on the LCD monitor 5 as shown in FIG. 6 reduce the influence of the noise component of the acceleration sensor output caused by the operation of the mechanical drive unit of the digital camera, and accurately By displaying and confirming a proper tilt, it is possible to take a picture without degrading the display quality.

  Although the display positions of the frame 23 and the indicator 24 on the LCD monitor 5 shown in FIG. 6 are displayed at the lower part of the LCD monitor 5, they may be arranged at the upper position and can be set by the user. Also, the display position is changed according to the horizontal shooting and vertical shooting of the digital camera.

  The image pickup apparatus and its control method according to the present invention can accurately display the inclination of the apparatus angle by avoiding, reducing, and invalidating the noise associated with the operation of the mechanical drive unit, thereby reducing the size and weight. This is useful for detecting the tilt of a digital camera or the like.

1A is a front view, FIG. 2B is a rear view, and FIG. 3C is a top view showing the appearance of a digital camera according to an embodiment of the present invention. Block circuit diagram showing the outline of the system configuration inside the digital camera Diagram showing an example of mounting an acceleration sensor inside a digital camera (A) is a layout diagram of a digital camera and a chart, and (b) is a diagram showing a chart. Diagram explaining how to scan a cross on a chart Figure showing a rectangular frame and circle indicator as shown on the LCD monitor Flow chart showing the relationship between the operation of the mechanical drive and the control of the level module

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strobe light emission part 2 Ranging unit 3 Optical finder 4 Lens barrel unit 5 LCD monitor 6 Battery cover 23 Frame 24 Indicator 104 Processor 109 Sub CPU
108 LCD Driver 111 Acceleration Sensor 1043 CPU Block SW1-15 Operation Key

Claims (8)

  In an imaging apparatus comprising: a display unit that displays an acquired image; an acceleration sensor; a unit that calculates an inclination of the apparatus from an output of the acceleration sensor; and a unit that displays the calculated inclination using the display unit. An imaging apparatus comprising: means for calculating the inclination according to the operation of the unit; means for displaying the inclination; or means for changing one or more control processes of the acceleration sensor.   2. The imaging apparatus according to claim 1, wherein the means for changing the control process changes the control process when the operation of the mechanical drive unit starts and / or when the operation ends.   3. The image pickup apparatus according to claim 1, wherein the operation of the mechanical drive unit is an operation of extending or storing the lens barrel unit, moving the focus lens, and holding the camera shake correction mechanism or the camera shake correction unit. .   4. The image pickup apparatus according to claim 3, wherein the operation of the mechanical drive unit includes a process with a large electrical fluctuation with respect to the power supply unit in addition to a mechanical operation.   An imaging apparatus control method comprising: a display unit that displays an acquired image; an acceleration sensor; a unit that calculates an inclination of the apparatus from an output of the acceleration sensor; and a unit that displays the calculated inclination using the display unit. An imaging apparatus comprising: a step of changing any one or a plurality of control processes of the means for calculating the inclination, the means for displaying the inclination, or the acceleration sensor in accordance with the operation of the mechanical drive unit. Control method.   6. The method of controlling an image pickup apparatus according to claim 5, wherein the means for changing the control process changes the control process at the start and / or end of the operation of the mechanical drive unit.   7. The image pickup apparatus according to claim 5, wherein the operation of the mechanical drive unit is an operation of extending or storing the lens barrel unit, moving a focus lens, or holding by a camera shake correction mechanism or a camera shake correction unit. Control method.   8. The method of controlling an image pickup apparatus according to claim 7, wherein the operation of the mechanical drive unit includes a process having a large electrical variation with respect to the power supply unit in addition to a mechanical operation.