JP3952254B2 - Method and apparatus for generating focused sound - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-focus sound generation method and apparatus for informing a photographer of an in-focus state in conjunction with automatic focus adjustment (AF) control of a camera.
[0002]
[Prior art]
In many digital cameras, the subject is imaged while moving the focus adjustment lens (hereinafter referred to as the focus lens) of the photographic lens, and a high-frequency component is extracted from the output video signal to calculate an evaluation value for focusing. Then, an AF method is used in which the focus lens is driven to focus at a position where the evaluation value is maximized.
[0003]
In this way, as a means for notifying the photographer that the subject is in focus, a notification method using a sound generator mounted on the camera or a display method using a light emitter such as an LED is used. In Japanese Patent Laid-Open No. 6-201983, in order to prevent the notification from becoming harsh, the focus notification method using sound is frequently repeated when the camera shake is large. A method for controlling the intensity of sound is proposed.
[0004]
[Problems to be solved by the invention]
However, there is no one that informs the photographer that the in-focus state can be obtained more quickly or that the photographer can focus in a time when the photographer can easily photograph. To avoid recording a blurred image, it is desirable to start shooting after confirming that the in-focus state has actually been obtained. If it is confirmed that it has been made, there is a risk that the timing will be delayed and a photo opportunity will be missed. Therefore, it is desirable to notify the photographer that the in-focus state is as fast as possible, or to notify the in-focus state at a timing at which the shutter can be easily released.
[0005]
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an in-focus sound generation method and apparatus that enables a photographer to check whether or not the in-focus state is faster or at a better timing. .
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1 is used for focusing confirmation in conjunction with an automatic focusing device that adjusts the focal position of a lens that forms an image of a subject on the imaging surface of a camera. A focus sound generation method for generating a sound (hereinafter referred to as a focus sound),The automatic focus adjustment device includes a first search means for obtaining an evaluation value at each position while moving within a predetermined focus adjustment area at a relatively large interval, and an evaluation value obtained by the first search means. After moving the lens in the vicinity of the position where the maximum value or the maximum value is detected, each lens is moved in the vicinity of the position where the maximum value or the maximum value is detected at a smaller interval than the first search means. A second search means for acquiring an evaluation value at a position, and the focus sound generation method achieves the in-focus state of the lens based on the evaluation value obtained by the first search means. A determination is made as to whether or not the in-focus state can be achieved, and an in-focus sound is generated. Thereafter, an evaluation value is obtained by the second search means, and the second search means Maximum evaluation value obtained by Providing judges that focus position the position where the maximum value is detected, the focus Aseoto generation method characterized by moving the lens to the focus position.
[0007]
According to the present invention, when the possibility of achieving the in-focus state is confirmed as a result of the AF process, after that time (simultaneously or afterwards), the in-focus sound is generated prior to the completion of the AF operation. Therefore, the photographer can quickly know that the in-focus state can be achieved, and the sensation speed of the AF processing can be improved.
[0008]
  In order to provide an apparatus that embodies the above-described method invention, the invention according to claim 2 is linked to an automatic focus adjustment apparatus that adjusts a focal position of a lens that forms an image of a subject on an imaging surface of a camera. An in-focus sound generating device for generating in-focus confirmation sound (hereinafter referred to as in-focus sound);The automatic focus adjustment device includes a first search means for obtaining an evaluation value at each position while moving within a predetermined focus adjustment area at a relatively large interval, and an evaluation value obtained by the first search means. After moving the lens in the vicinity of the position where the maximum value or the maximum value is detected, each lens is moved in the vicinity of the position where the maximum value or the maximum value is detected at a smaller interval than the first search means. A second search means for obtaining an evaluation value at a position, and the in-focus sound generating device is obtained by the in-focus sound generating means for generating the in-focus sound and the first search means. A determination means for determining whether or not the in-focus state of the lens can be achieved based on the evaluation value, and a focus sound is generated by the in-focus sound generation means when it is determined that the in-focus state can be achieved. And then by the second search means Control for obtaining the evaluation value, determining the position where the maximum value or maximum value of the evaluation value obtained by the second search means is detected as the in-focus position, and moving the lens to the in-focus position And a focusing sound generator characterized by comprising the means.
[0009]
  According to a third aspect of the present invention, in the in-focus sound generating device according to the second aspect, the time required from the time when it is detected that the in-focus state can be achieved until the operation for actually achieving the in-focus state is completed. And a means for controlling the generation timing of the in-focus sound so that the timing at the end of the operation for achieving the in-focus state and the timing at the end of the output of the in-focus sound are matched. Provided is an in-focus sound generating device.
[0010]
By making the in-focus sound end timing coincide with the AF operation end timing, the photographer can perform a shutter operation (recording instruction operation) at a better timing.
[0011]
  According to a fourth aspect of the present invention, in the in-focus sound generating device according to the second aspect, when the in-focus sound generation period and the shutter sound generation period overlap in time, Provided is a focusing sound generating device characterized by comprising means for inhibiting generation.This makes it easier to hear the shutter sound.
[0012]
  According to a fifth aspect of the present invention, in the in-focus sound generating device according to the second, third, or fourth aspect, the automatic focusing device includes an imaging unit that converts an optical image into an electrical signal, and an imaging of the imaging unit. A lens that forms an image of a subject on a surface; a lens moving unit that moves the lens within a focus adjustment region; and an image signal output from the imaging unit for each lens position that is moved by the lens moving unit. An evaluation value calculation means for extracting a contrast component of the subject from the image and calculating an evaluation value according to the contrast component; and a detection means for detecting a lens position at which the maximum value or maximum value of the evaluation values is obtained. There is provided an in-focus sound generating device.
[0013]
  According to a sixth aspect of the present invention, in the in-focus sound generating device according to the second, third, fourth, or fifth aspect, the control unit detects a maximum value or a maximum value of the evaluation value by the first search unit. If not, the second search means obtains an evaluation value while moving the entire focus adjustment region at the small intervals, and the maximum value or maximum value of the evaluation value in the search operation of the second search means. An in-focus sound generating device is provided that generates the in-focus sound at the point of time when the signal is detected.
[0014]
  Regarding the first search operation performed by the first search means and the second search operation performed by the second search meansFirst, a first search operation (rough search) having a large search point interval (search step) is performed, and the vicinity of the obtained peak is searched in detail by a second search operation (detailed search) having a small search step. Thus, an accurate in-focus position is obtained. By adopting such an AF method, the AF processing can be speeded up.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of a focused sound generation method and apparatus according to the present invention will be described below with reference to the accompanying drawings.
[0017]
FIG. 1 is an external view of a digital camera to which the present invention is applied. A photographing lens 12, a viewfinder window 14, and a strobe light emitting unit 16 are provided on the front surface of the digital camera 10, and a shutter button 18 and a power switch 20 are disposed on the upper surface of the camera. A card slot 26 for mounting a memory card 24 is provided on the side of the camera opposite to the grip portion 22.
[0018]
A lens having a variable focal length (for example, a zoom lens) is applied to the photographing lens 12, and a CCD image sensor (not shown in FIG. 1, described as reference numeral 52 in FIG. 3, hereinafter referred to as a CCD) is provided behind the photographing lens 12. Is arranged. The shutter button 18 is configured in a two-stage manner. When the shutter button 18 is lightly pressed and stopped halfway (S1 = ON), automatic focusing (AF) and automatic exposure control (AE) are activated to activate AF and AE. Is locked, and shooting is executed in a state of “full press” (S2 = ON), which is further pressed from “half press”.
[0019]
The power switch 20 is also used as a mode switch, and is an “OFF position” where the power is turned off, a “shooting ON position” where the power is turned on in the still image shooting mode, and a “reproduction ON position” where the power is turned on in the playback mode. 3 positions can be switched. In place of the power switch (hereinafter referred to as a power combined mode switch) 20 as in this example, a power switch only for power ON / OFF and mode switching means such as a mode dial for switching between a still image shooting mode and a playback mode. May be provided.
[0020]
FIG. 2 is an external view of the back side of the digital camera 10. On the back of the digital camera 10, a viewfinder 28, a liquid crystal monitor 30, a zoom switch 32, a cross button 34, a menu key 38, an execution key 40, and a cancel key 42 are provided. The liquid crystal monitor 30 is a display means that can be used as an electronic viewfinder for checking the angle of view at the time of shooting, and can display a preview image of the shot image, a reproduced image read from the memory card 24, and the like. Further, menu selection using the cross button 34 and setting of various items in each menu are also performed using the display screen of the liquid crystal monitor 30.
[0021]
The zoom switch 32 is composed of a lever switch that can be operated in the up / down direction. By operating the switch in the upward direction, the zoom switch 32 is zoomed in the telephoto (TELE) direction, and operated in the downward direction in the wide angle (WIDE) direction. Move the zoom. The cross button 34 is a multi-function button capable of inputting instructions in four directions, up, down, left, and right. The cross button 34 is used as an operation button for instructing selection of various setting items and change of setting contents on the menu screen, and an electronic zoom magnification. It is used as a means for instructing adjustment and playback frame return / return.
[0022]
The menu key 38 is used when transitioning from the normal screen to the menu screen in each mode. The execution key 40 is used for confirming the selection contents and instructing execution (confirmation) of processing. The cancel key 42 is used when canceling (cancelling) an item selected from the menu or returning to the previous operation state.
[0023]
The photographer operates the zoom switch 32 to determine the angle of view while confirming the real-time image (through image) displayed on the finder 28 or the liquid crystal monitor 30, and depresses the shutter button 18 to perform photographing.
[0024]
FIG. 3 is a block diagram showing the internal configuration of the digital camera 10. The photographing lens 12 includes a four-group inner focus zoom lens including a fixed lens 44, a variable power lens 46A, a correction lens 46B, and a focus lens 48.
[0025]
The zoom lens 46A and the correction lens 46B move along the optical axis while the positional relationship between them is regulated by a cam mechanism (not shown) to change the focal length. For convenience of explanation, the variable power optical system including the variable power lens 46A and the correction lens 46B is referred to as a “zoom lens 46”.
[0026]
The light passing through the photographing lens 12 is incident on the CCD 52 after the amount of light is adjusted by the diaphragm 50. Photosensors are arranged in a plane on the light receiving surface of the CCD 52, and a subject image formed on the light receiving surface of the CCD 52 via the photographing lens 12 has an amount of signal charge corresponding to the amount of incident light by each photosensor. Is converted to The CCD 52 has a so-called electronic shutter function that controls the charge accumulation time (shutter speed) of each photosensor according to the timing of the shutter gate pulse.
[0027]
The signal charge accumulated in each photosensor is sequentially read out as a voltage signal (image signal) corresponding to the signal charge based on a pulse given from the CCD driver 54. The image signal output from the CCD 52 is sent to the analog processing unit 56. The analog processing unit 56 includes signal processing circuits such as a sampling hold circuit, a color separation circuit, and a gain adjustment circuit. The analog processing unit 56 performs correlated double sampling (CDS) processing and R, G, B color signals. Color separation processing is performed, and signal level adjustment (pre-white balance processing) of each color signal is performed.
[0028]
The signal output from the analog processing unit 56 is converted into a digital signal by the A / D converter 58 and then stored in the memory 60. The timing generator (TG) 62 gives timing signals to the CCD driver 54, the analog processing unit 56, and the A / D converter 58 in accordance with instructions from the CPU 64, and the circuits are synchronized by this timing signal. .
[0029]
The data stored in the memory 60 is sent to the signal processing unit 68 via the bus 66. The signal processing unit 68 is an image processing unit composed of a digital signal processor (DSP) including a luminance / color difference signal generation circuit, a gamma correction circuit, a sharpness correction circuit, a contrast correction circuit, a white balance correction circuit, and the like. The image signal is processed according to the command.
[0030]
The image data input to the signal processing unit 68 is converted into a luminance signal (Y signal) and a color difference signal (Cr, Cb signal) and is subjected to predetermined processing such as gamma correction and then stored in the memory 60. Is done. When the captured image is displayed and output, the image data is read from the memory 60 and transferred to the display memory 70. The data stored in the display memory 70 is converted into a predetermined display signal (for example, an NTSC color composite video signal), and then the liquid crystal monitor (LCD) 30 via the D / A converter 72. Is output. Thus, the image content of the image data is displayed on the screen of the liquid crystal monitor 30.
[0031]
The image data in the memory 60 is periodically rewritten by the image signal output from the CCD 52, and the video signal generated from the image data is supplied to the liquid crystal monitor 30, whereby the image input via the CCD 52 is real-time. Is displayed on the liquid crystal monitor 30.
[0032]
When the photographer operates the zoom switch 32, the instruction signal is input to the CPU 64, and the CPU 64 controls the zoom drive unit 74 based on the signal from the zoom switch 32 to move the zoom lens 46 in the tele (TELE) direction or wide ( Move in the (WIDE) direction. The zoom driving unit 74 includes a motor (not shown), and the zoom lens 46 is driven by the driving force of the motor. The position (zoom position) of the zoom lens 46 is detected by a zoom position sensor 76, and a detection signal from the sensor 76 is input to the CPU 64.
[0033]
Similarly, the focus driving unit 78 includes a motor (not shown), and the focus lens 48 moves back and forth along the optical axis by the driving force of the motor. The position (focus position) of the focus lens 48 is detected by a focus position sensor 80, and a detection signal from the sensor 80 is input to the CPU 64.
[0034]
When the still image shooting mode is set by the power combined mode switch 20 and the shutter button 18 is “half-pressed” (S1 = ON), AE and AF processing are performed. That is, the CPU 64 controls the focus driving unit 78 based on the result of evaluation value calculation described later to move the focus lens 48 to the in-focus position, and calculates the aperture diameter of the diaphragm 50 and the electronic shutter value of the CCD 52.
[0035]
When focus is obtained by the AF operation, a focus sound is emitted from the buzzer 81 to notify the photographer to that effect. By displaying a focus mark or the like on the screen of the liquid crystal monitor 30 simultaneously with the focus sound, the photographer may be notified that the focus is in focus or not in focus.
[0036]
When the shutter button 18 is “fully pressed”, a shooting start instruction (release ON) signal is issued. The CPU 64 detects the release ON signal and executes a recording imaging operation. That is, the CPU 64 performs exposure control based on the result of the AE calculation, and sends a command to the strobe control circuit 82 as necessary to control the light emission of the strobe light emitting unit 16. During this shutter operation (exposure operation for capturing a recorded image), a shutter sound is output from the speaker 83. The CPU 64 outputs a shutter sound signal during the shutter operation, and this signal is sent to the speaker 83 via the D / A converter 85.
[0037]
In this way, in response to the pressing operation of the shutter button 18, the capture of the image data for recording is started, and the required signal processing is performed. When the mode for compressing and recording image data is selected, the CPU 64 sends a command to the compression / decompression circuit 84. The compression / decompression circuit 84 compresses the image data taken into the memory 60 in accordance with JPEG or another predetermined format.
[0038]
The compressed image data is recorded on the memory card 24 via the card interface 86. When the mode for recording non-compressed image data (non-compression mode) is selected, the compression processing by the compression / decompression circuit 84 is omitted, and the image data is recorded on the memory card 24 without being compressed.
[0039]
In the digital camera 10 of this example, for example, smart media (Solid-State Floppy Disk Card) is applied as means for storing image data. The form of the recording medium is not limited to this, and it may be a PC card, a compact flash, a magnetic disk, an optical disk, a magneto-optical disk, a memory stick, etc., and read / write according to an electronic, magnetic, optical, or a combination thereof. Various possible media can be used. A signal processing means and an interface corresponding to the medium to be used are applied. A configuration in which a plurality of media can be mounted regardless of different types or the same type of recording media may be adopted. Further, the means for storing the image is not limited to the removable medium, but may be a recording medium (internal memory) built in the digital camera 10. In the case of storing an image in the internal memory, a communication interface for transferring data to an external device such as a personal computer is provided.
[0040]
When the playback mode is set by the power mode switch 20, the image file is read from the memory card 24. The read image data is decompressed by the compression / decompression circuit 84 as necessary, and is output to the liquid crystal monitor 30 via the display memory 70.
[0041]
The CPU 64 is a control unit that performs overall control of each circuit of the camera system. The CPU 64 controls the operation of the corresponding circuit based on input signals received from the power mode switch 20, shutter button 18, zoom switch 32, and other operation units, and performs display control and autofocus (AF) on the liquid crystal monitor 30. Control and automatic exposure (AE) control are performed.
[0042]
Here, the autofocus control will be described. The image signal converted into a digital signal by the A / D converter 58 is input to the evaluation value calculation unit 88. The evaluation value calculation unit 88 includes a high-frequency component extraction circuit 90 and an integration circuit 92, samples G component data in the input image signal, is described as an AF detection target area (described as reference numeral 94 in FIG. The high frequency component in the focus area) is extracted and the absolute value thereof is taken, and the value (equivalent to the evaluation value) obtained by integrating the absolute value data in the focus area 94 is provided to the CPU 64.
[0043]
The target area for AF detection does not have to be the entire image area, and a partial area at the center of the image is set as the focus area 94 as shown in FIG. During the AF process, the CPU 64 detects the contrast of the center portion of the image at a plurality of AF detection points (search points) while moving the focus lens 48 from infinity to close (or close to infinity) within the focus adjustment region. The evaluation value is calculated.
[0044]
Note that as the focal length of the photographic lens 12 increases, and as the aperture diameter of the diaphragm 50 increases, the depth of field decreases, and the amount of lens driving from infinity to the closest increases. The detection point interval (search interval) is changed.
[0045]
FIG. 5 shows the relationship between the focal length of the photographic lens 12 and the focus adjustment region 300. The figure shows an example of the photographing lens 12 whose focal length can be changed stepwise from 7 mm to 21 mm. As the focal length of the photographing lens 12 becomes longer, the focus adjustment region 300 by the focus lens 48 becomes wider. For example, when the focal length is 7 mm, the movable range of the focus lens 48 from infinity to the nearest distance is 8.17 μm, and the focus adjustment region 300 when the focal length is 21 mm is 735 μm.
[0046]
The CPU 64 determines the AF step width 302 indicating the width of the lens position (search point) for calculating the evaluation value and the number of step steps (number of detection points) in accordance with the focus adjustment region 300 that varies in accordance with the focal length of the photographing lens 12. Set.
[0047]
As for the number of focus steps, the focus adjustment region 300 at each focal length may be equally divided by the AF step width 302, or the short-distance (closest limit) side AF step width 302 is shorter than the infinity side, The number of search points on the side may be increased to increase the focus accuracy.
[0048]
Thus, by combining the evaluation values calculated at the respective search points, the lens position where the evaluation value is maximized is determined as the in-focus position, and the focus driving unit 78 is moved so as to move the focus lens 48 to the obtained in-focus position. To control.
[0049]
At this time, an in-focus sound is generated by the buzzer 81 or an in-focus mark is displayed on the liquid crystal monitor 30 at the same time to inform the photographer that the in-focus state has been achieved (in practice, the in-focus sound is detected). A prior notice is given by sound before the focus is achieved). The faster the time from the operation of the shutter button 18 (half-press operation), the faster the photographer knows that the in-focus state can be achieved and the AF speed feels faster. It is done.
[0050]
FIG. 6 shows a flowchart of the focus sound generation operation. When AF processing is started by half-pressing the shutter button 18, the CPU 64 first sets the focus area 94 (step S110). For example, the shooting screen is divided into 64 blocks of 8 × 8 with the same area, and a predetermined plurality of blocks in the center portion are set as the focus area 94 for evaluation value calculation.
[0051]
Next, the current value of the focal length of the photographic lens 12, that is, information on the current zoom position (ZOOMPOS) is acquired (step S112). Thereafter, the focus lens 48 is moved to the initial position where the AF search is started (step S114), and the evaluation value at the focus stage (search point) is calculated (step S116). The calculated evaluation value is input to the CPU 64, and the CPU 64 stores the evaluation value at the search point in a memory (not shown).
[0052]
Next, the process proceeds to step S120, and a determination process is performed as to whether or not to interrupt the AF search operation. The interruption determination processing subroutine will be described later with reference to FIG. Based on the result of the interruption determination process in step S120 of FIG. 6, the CPU 64 determines whether or not to continue the AF search operation (step S124). In the case of “continue”, the process proceeds to step S126, and it is determined whether or not the focus lens 48 has reached the final position of the search point.
[0053]
If NO is determined in step S126, the process proceeds to step S128, the focus lens 48 is moved from the current focus stage by one search step (AF step width 302), and the process returns to step S116. Thus, the evaluation value is calculated from the frame image data that is moved to the next search point and has a different focus position. The processing in steps S116 to S128 is repeated for each point in the focus adjustment area 300, and the evaluation value of each point is sequentially acquired.
[0054]
If the focus lens 48 has reached the final position in step S126 (when YES is determined), the process proceeds to step S130. In step S130, a process for determining whether or not the in-focus position can be obtained from the result of the evaluation value obtained at each point is performed. A subroutine of this focus possibility determination process will be described with reference to FIG.
[0055]
Based on the result of the determination process in step S130 shown in FIG. 6, it is determined whether or not focusing is possible (step S132). When it is determined that focusing is possible (YES determination) or “interruption” is determined in step S124. If the determination is obtained, the process proceeds to step S140, and a focusing sound is generated. Next, a lens position (in-focus position) from which the maximum evaluation value can be obtained is obtained, and processing for moving the focus lens 48 to the in-focus position is performed (step S142). When the lens moving operation to the in-focus position is completed, the in-focus state is achieved, and the photographing / recording permission state is set (step S144).
[0056]
On the other hand, when it is determined in step S132 that focusing cannot be performed (NO determination), the process proceeds to step S138, and processing for moving the focus lens 48 to a predetermined pan focus position is performed. In this case, the in-focus sound is not output, and it is possible to record and record (step S144). In addition, when focusing is impossible, it is also preferable to notify the photographer by displaying a warning on the screen of the liquid crystal monitor 30. Thus, the automatic focus adjustment process ends.
[0057]
When the photographing / recording permission state is obtained in step S144, the state of the shutter button 18 is monitored by the CPU 64, and the subject is imaged in response to the full depression of the shutter button 18. The captured image is recorded on the memory card 24 together with the attached information through predetermined signal processing.
[0058]
Next, the interruption determination process for the AF search operation will be described. FIG. 7 shows a flowchart of the interruption determination process shown in step S120 of FIG. When the interruption determination process starts, first, a table value “C_TABLE” corresponding to the current focal length [ZOOMPOS] is set in the register C (step S210). This is a process of setting an interruption determination value C that is a determination criterion for determining that the AF search is interrupted when the evaluation values calculated at the respective focus stages (search points) continuously decrease. .
[0059]
The interruption determination value C is set to the same numerical value as the focus step number (“4” in the example of FIG. 5) or a value close thereto on the short focus side (wide side), and is set so as not to perform the interruption process substantially. ing. Further, the interruption determination value C increases as it approaches the long focus side (tele side), and is set to an integer value of about 50% to 30% of the number of focus stages.
[0060]
Next, the process proceeds to step S212, and it is determined whether or not the acquired evaluation value has decreased. If the evaluation value has not decreased (NO determination), the continuation of AF search is determined (step S222), the subroutine is exited, and the process returns to the flowchart of FIG.
[0061]
When it is determined in step S212 in FIG. 7 that the evaluation value is decreasing (YES determination), 1 is added to the value of the register n (initial value is n = 0) (step S214). In subsequent step S216, it is determined whether or not the value of register n exceeds the value of register C. If the value of the register n is equal to or less than the value of the register C (NO determination), the process proceeds to step S222 to decide to continue the AF search, and the process returns to the flowchart of FIG. Thereby, the AF search is continued until the evaluation value continuously decreases C times.
[0062]
If YES is obtained in step S216, that is, if it is detected that the evaluation value continuously decreases C times, the process proceeds to step S218. In step S218, it is determined whether or not the difference between the maximum value (AFmax) and the minimum value (AFmin) of the evaluation values calculated by the AF search operation is greater than a predetermined value K. When the difference between the evaluation values is larger than the predetermined value K (when YES is determined), it indicates that there is a predetermined contrast, so that the interruption of the AF search is determined (step S220). If the difference between the evaluation values is equal to or smaller than the predetermined value K (NO determination), the process proceeds to step S222, and the continuation of the AF search is determined.
[0063]
When the determination of “interruption” or “continuation” is made in step S220 or step S222, this subroutine is terminated, and the process proceeds to step S124 in the flowchart of FIG. The processing contents thereafter are as described in FIG.
[0064]
FIG. 8 shows a flowchart of the focusability determination process shown in step S130 of FIG. As shown in FIG. 8, when the in-focus determination process is started, whether or not the difference between the maximum value (AFmax) and the minimum value (AFmin) of the evaluation values calculated by the AF search operation is larger than a predetermined value K. Is determined (step S310). If YES is determined in step S310, it is determined that “focusing is possible” (step S312). If NO is obtained in step S310, it is determined that “in-focus is impossible” (step S314).
[0065]
After determining whether or not focusing is possible in step S312 or step S314, the process proceeds to step S132 described with reference to FIG. The subsequent processing is as described in FIG.
[0066]
The in-focus sound generation timing in the AF operation described in FIGS. 6 to 8 will be described with reference to FIG. FIG. 9A shows an example of evaluation values acquired by the AF search operation. The horizontal axis indicates the subject distance that can be adjusted by the focus lens 48, and the vertical axis indicates the evaluation value. FIG. 5B conceptually shows the movement of the focus lens 48, and the length of the arrow does not accurately reflect the actual movement amount (the same applies to FIGS. 10 and 18). FIG. 9C shows a driving sequence of the focus lens 48.
[0067]
As shown in FIG. 9, when the AF process starts, first, as shown in FIG. 9B, the focus lens 48 is driven from the current position to the AF search initial position (infinite in FIG. 9). The lens movement (initial position movement) to the AF search initial position is indicated by (1) in the figure.
[0068]
Thereafter, an AF search is executed from this initial position (infinity) toward the closest side, and an evaluation value is acquired at each point. This search operation is indicated by (2) in the figure. In the example of FIG. 9, the evaluation value gradually increases as the lens moves from infinity to the closest distance, and the peak (maximum value) of the evaluation value is detected. After passing the peak of the evaluation value, the evaluation value starts to decrease, and the AF search is interrupted by satisfying the predetermined condition described with reference to FIGS.
[0069]
Then, the focus position corresponding to the detected peak position is determined as the “focus position”, and the focus lens 48 is moved to the focus position to obtain a focused state. After the AF search is completed, the lens movement (focus drive) to the in-focus position is indicated by (3) in FIG. In this example, the focus sound is generated when the AF search is finished and the focus lens 48 starts to be driven to the focus position.
[0070]
Next, an example of control that can achieve a further increase in AF processing speed will be described. As described with reference to FIG. 5, as the focal length of the photographic lens 12 increases, the focus feed amount (number of motor-driven pulses) in the focus adjustment region 300 (from infinity to close) increases, and the AF time increases. Therefore, “rough search” is first performed in which an evaluation value is acquired in an AF search step in which the focus feed amount (search interval) is increased, and when an approximate in-focus position is detected by rough search, the focus feed amount is further reduced in the vicinity region. It is preferable to perform a “detailed search” in which an evaluation value is acquired in the search step.
[0071]
FIG. 10 is a conceptual diagram of rough search and detailed search. For example, it is assumed that the focus feed amount from infinity to the nearest is 240 pulses, the number of focus feed pulses during rough search is set to 20 pulses, and the number of focus feed pulses during detailed search is set to 2 pulses.
[0072]
According to the figure, when the AF process is started, first, the focus lens 48 is driven from the current position to the AF search initial position (infinite in the figure) (initial position moving step (1)). Then, a rough search is started from infinity toward the closest direction. In the rough search step {circle around (2)}, the search point is changed every 20 pulses, the evaluation value is calculated at each point, and the interruption determination (2) process described later in FIG. 16 is performed.
[0073]
When a peak is detected in the rough search and the interruption of the evaluation value acquisition process is determined, the focus lens 48 is moved to the initial position of the detailed search (detailed search initial position moving step (3)). Then, a detailed search is started in the direction of infinity from this initial position. In the detailed search step (4), the search point is changed every two pulses, and the evaluation value is calculated at each point. In the detailed search, if the evaluation value decreases continuously a predetermined number of times after the peak is detected, it is decided to interrupt the evaluation value acquisition process, and the focus lens 48 is driven to the peak position (focus position) (focus drive step (5)). ).
[0074]
As an example of in-focus sound generation timing in this case, for example, the in-focus sound is generated when the rough search is finished and the focus lens 48 starts to be driven near the peak corresponding position of the evaluation value (detail search initial position).
[0075]
FIG. 11 shows a flowchart of AF control in which rough search and detailed search are combined. In FIG. 11, steps S410 to S428 corresponding to the rough search portion are the same as or similar to steps S110 to S128 of the flowchart described with reference to FIG. However, in step S428, the focus lens 48 is driven at a search interval of 20 pulse steps. Further, the interruption determination (2) process shown in step S420 of FIG. 11 will be described later with reference to FIG.
[0076]
If it is determined in step S424 in FIG. 11 that “interruption” is obtained, the process proceeds to step S440, and a focusing sound is generated at this point. That is, when the evaluation value peak is detected by the rough search, it is expected that the focused state will be finally achieved by the subsequent AF operation. Therefore, a focusing sound is generated when the evaluation value peak is detected by the rough search. .
[0077]
After the process of step S440, or when the final position of the focus stage is reached in step S426 (when the peak stage is reached without detecting the peak in the rough search), the process proceeds to step S442. In step S442, an operation for obtaining a detailed search range is performed based on the result of the rough search. The range of the detailed search is, for example, a predetermined range before and after the peak corresponding position of the evaluation value detected by the rough search. Further, when the peak of the evaluation value is not detected by the rough search, the entire range of the focus adjustment region is set as the detailed search range, and the detailed search is started from a predetermined initial position such as the closest (or infinity).
[0078]
Next, in accordance with the detailed search range obtained in step S442, processing for driving the focus lens 48 to the detailed search start position (detailed search initial position) is performed (step S444). Thus, the detailed search is started, and the evaluation value at the search point is calculated (step S446). The obtained evaluation value is input to the CPU 64, and the CPU 64 stores the evaluation value at the search point in a memory (not shown).
[0079]
Next, the process proceeds to step S448, and a process for determining whether or not to stop the AF search (detailed search) is performed. The contents of this “interruption determination” are as described in FIG. Based on the result of the interruption determination process (step S448), the CPU 64 determines whether the AF search is interrupted or continued (step S450). When the determination “continuation” is obtained in step S450, the process proceeds to step S452, and it is determined whether or not the final position of the search point has been reached.
[0080]
If NO is determined in step S452, the process proceeds to step S454, the focus lens 48 is moved from the current focus position by one AF search step (two pulses), and the process returns to step S446. Thus, the evaluation value is calculated from the frame image data that is moved to the next search point and has a different focus position. The processing in steps S446 to S454 is repeated for each point in the detailed search range, and the evaluation value of each search point is acquired.
[0081]
If the focus lens 48 has reached the final position of the search point in step S452, the process proceeds to step S460. In step S460, the focus possibility determination process described in FIG. 8 is performed. Next, based on the result, it is determined whether or not focusing is possible (step S462), and when it is determined that focusing is possible (YES determination) or when the determination of “interruption” is obtained in step S450. The process proceeds to step S464.
[0082]
In step S464, it is determined whether or not a focusing sound has already been generated (step S464). If the in-focus sound has already been output (YES determination), the generation of the in-focus sound is omitted and the process proceeds to step S472.
[0083]
In step S464, if the in-focus sound has not been output yet (NO determination), the process for generating the in-focus sound is executed (step S470), and the process proceeds to step S472.
[0084]
In step S472, a lens position (in-focus position) from which the maximum evaluation value can be obtained is obtained, and processing for moving the focus lens 48 to the in-focus position is performed. When the lens moving operation to the in-focus position is completed, the in-focus state is achieved and the photographing / recording permission state is set (step S474).
[0085]
On the other hand, when it is determined in step S462 that focusing cannot be performed (NO determination), the process proceeds to step S468, and a process of moving the focus lens 48 to a predetermined pan focus position is performed. In this case, the in-focus sound is not output, and the camera can record and record (step S474). Thus, the automatic focus adjustment process ends.
[0086]
Next, the contents of the interruption determination (2) process shown in step S420 of FIG. 11 will be described.
[0087]
FIG. 12 shows an example in which an evaluation value is acquired by AF search. When there is only one main subject in the focus area 94, only one evaluation value peak appears as shown in FIG. In this case, the focus lens 48 may be moved here with the lens position (P) where the peak is detected as the in-focus position. On the other hand, as shown in FIG. 13, when there are a plurality of subjects in the focus area 94, it is not possible to focus on both subjects, and focus is performed on one of the subjects. There is a need.
[0088]
FIG. 14 shows an example of an evaluation value acquisition result when there are a plurality of subjects in the focus area 94. As shown in the figure, when there are a plurality of subjects in the focus area 94, there are a plurality of peaks in the evaluation value curve. When detecting one mountain and ending the AF search, only one mountain can be detected, and a plurality of mountains cannot be detected. For example, in FIG. 14, when the AF search operation is started from the infinity side and the AF search operation is terminated when a peak at the infinity side is detected, another peak on the near side can be detected. Therefore, it is impossible to focus on the closest main subject.
[0089]
As another method, it is possible to focus on the first mountain by always starting the AF search operation from the closest side, but in the case of a high-power zoom lens, a situation where a subject at a long distance is photographed Therefore, it can be said that it is preferable to start the search from the infinity side in consideration of high speed AF processing.
[0090]
Therefore, in the present embodiment, the following measures are taken in order to realize an efficient AF search operation. That is, when FIG. 12 is compared with FIG. 14, in the graph of FIG. 12, when an evaluation value peak is detected by an AF search operation from infinity to the closest position and then the lens is moved in the same direction, When the lens 48 is separated from the peak position P by a certain distance d, the evaluation value decreases to near zero level. On the other hand, when there are a plurality of subjects as shown in FIG. 14, the evaluation is performed after the first peak is detected. The value has started to increase again without falling to near zero level.
[0091]
Focusing on this fact, if the evaluation value at a position that is a fixed distance d away from the lens position where the peak of the evaluation value is detected is equal to or less than a predetermined threshold TH, it is determined that there is no subject ahead, and AF When the search is finished, the focus lens 48 is driven to the detected first peak position.
[0092]
On the other hand, if the evaluation value at a position separated by a certain distance d from the lens position where the peak of the evaluation value is detected is a value larger than a predetermined threshold value TH, there is a possibility that another subject exists ahead. And the AF search operation in the same direction is continued. The distance d from the peak position P is preferably set to about 10 to 20 times the allowable circle of confusion. When a plurality of peaks (maximum values) are detected by the AF search operation, the closest peak position is determined as the focus position.
[0093]
By the way, when the subject is dark, noise of the imaging signal is generated, and as shown in FIG. 15, there may be a situation in which the evaluation value does not fall below the threshold TH even if there is only one peak. However, as apparent from a comparison between FIG. 15 and FIG. 14, when another subject is present on the closest side (FIG. 14), the evaluation value tends to increase from a position a little before the closest distance. On the other hand, when the evaluation value does not decrease due to noise or the like (FIG. 15), the evaluation value does not turn to an increasing tendency even if the distance is more than a certain distance w from the nearest point.
[0094]
Therefore, it is possible to determine whether or not another subject exists on the near side by determining whether or not the evaluation value is increasing in a direction beyond a certain distance w from the closest distance. If the evaluation value beyond a certain distance w from the closest distance is not in the increasing direction, it is determined that there is no subject on the closest side, the AF search operation is terminated, and focus driving is performed at the lens position where the peak is detected. In FIG. 15, the near (NEAR) side is described, but the AF search operation in the infinity (FAR) direction similarly applies to the object on the infinity side if the evaluation value does not tend to increase at a position away from infinity by a fixed distance w. Can be determined to exist.
[0095]
Considering the circumstances shown in FIG. 12 to FIG. 15 described above, a processing program for the AF search interruption determination (2) is configured.
[0096]
FIG. 16 is a flowchart of the interruption determination (2) process. When the interruption determination (2) process is started, it is first determined whether or not a peak at which the evaluation value turns from increasing to decreasing is detected (step S510). This determination is made based on the state of a “peak present flag” described later.
[0097]
If no peak is detected in step S510 (NO determination), the process proceeds to step S512 to determine whether or not the evaluation value has decreased. When NO determination is obtained in step S512, it is determined to continue the evaluation value acquisition process (step S518), this subroutine is terminated, and the process returns to the flowchart of FIG.
[0098]
If it is detected in step S512 that the evaluation value has decreased, the process branches to step S514. In step S514, it is determined whether or not the evaluation value before decreasing tends to increase. If YES is obtained in step S514, it is determined whether or not the difference between the maximum value (AFmax) and the minimum value (AFmin) of the evaluation value calculated by the AF search operation is greater than a predetermined value K ′. (Step S515). If YES is obtained in step S515, the “peak present flag” is set to ON, and the data of the variable P indicating the focus position (peak position) where the peak is detected is updated (step S516). After step S516 or when NO determination is obtained in step S515, the process proceeds to step S518, and the continuation of the evaluation value acquisition process is determined.
[0099]
When the “peak flag” is set to ON, a YES determination is made in step S510. In this case, the process proceeds to step S520, and it is determined whether or not the search direction is the NEAR direction. When the search direction is the NEAR direction (when YES is determined), it is determined whether or not the current focus position (search point) is on the near side beyond a predetermined distance (d) from the peak position P ( Step S522). If the current position is within a predetermined distance d from the peak position P (NO determination), the process proceeds to step S528, and it is determined whether or not the number of remaining detection points in the search direction is smaller than a predetermined value (m). I do. The predetermined value m is a value corresponding to the distance w described in FIG.
[0100]
In step S528, when the number of remaining detection points is equal to or larger than the predetermined value m (NO determination), it is determined to continue the evaluation value acquisition process (step S532), and the process returns to the flowchart of FIG. On the other hand, when a YES determination is obtained in step S528 in FIG. 16, the process proceeds to step S530 to determine whether or not the evaluation value has increased.
[0101]
If an increase in the evaluation value is detected in step S530 (during YES determination), the process proceeds to step S532 to decide to continue the evaluation value acquisition process (step S532), but if the evaluation value has not increased in step S530 ( When the determination is NO, the process proceeds to step S536, where the interruption of the evaluation value acquisition process is determined, and the process returns to the main routine of FIG.
[0102]
Further, when the current focus position is on the near side beyond the predetermined distance d from the peak position P in step S522 in FIG. 16 (YES determination), the process branches to step S524. In step S524, it is determined whether or not the evaluation value at the current focus position is smaller than a predetermined threshold value TH.
[0103]
If the evaluation value is greater than or equal to the threshold TH in step S524 (NO determination), the process proceeds to step S528 in consideration of the possibility that the subject is present closer to the current position. On the other hand, when the evaluation value is smaller than the threshold value TH in step S524 (when YES is determined), it is determined that there is no subject closer to the current position, and interruption of the evaluation value acquisition process is determined ( Step S536).
[0104]
If NO in step S520, that is, if the search direction is the FAR direction, the process proceeds to step S526. In step S526, it is determined whether or not the evaluation value has continuously decreased a predetermined number of times. A reference value serving as a criterion for determining the number of consecutive reductions is appropriately set in consideration of the depth of field.
[0105]
When NO determination is obtained in step S526, the process proceeds to step S528, and interruption or continuation is determined in steps S528 to S536 described above. On the other hand, if YES is obtained in step S526, the process proceeds to step S538, the interruption of the evaluation value acquisition process is determined, and the process returns to the flowchart of FIG. By following the interruption determination (2) process shown in FIG. 16, the peak of the evaluation value corresponding to the subject can be detected accurately and at high speed in both the NEAR direction and the FAR direction. High speed can be realized.
[0106]
Next, another control example in the present embodiment will be described.
[0107]
When the photographer performs an operation of pressing the half-push switch S1 of the shutter button 18 and the full-push switch S2 almost simultaneously, the in-focus sound and the shutter sound (sound notifying the execution of the exposure operation) overlap in time. A situation can occur. That is, in the case of a camera that adopts a control method that accepts an instruction of S2 = ON before the AF operation is completed and can perform an exposure operation immediately after the lens driving to the in-focus position is completed, the in-focus sound and the shutter sound overlap. Can occur.
FIG. 17 shows an example of the situation. FIG. 9 (a) is a sequence diagram shown in FIG. 9 (c) in which descriptions such as the timing of S2 = ON, the in-focus sound duration, and the generation timing of the shutter sound are added. In FIG. 17A, an instruction of S2 = ON is accepted during the search operation (2). When the search operation (2) is completed, a focusing sound is generated at that time, and the lens is moved to the focusing position (focusing driving (3)). The in-focus sound is output for a certain period of time, but before the in-focus sound ends, the in-focus drive (3) ends, and when the exposure operation is performed immediately, the shutter sound and the in-focus sound are temporally It will overlap. In this case, it is preferable to prevent the shutter sound from becoming difficult to hear by restricting the generation of the focusing sound (stopping the focusing sound or prohibiting the generation of the focusing sound).
[0108]
Also, as described in the embodiments of FIGS. 11 to 16, in the case of an AF camera that performs rough search and detailed search, when a focus sound is generated at the time of rough search interruption, there is a possibility that it overlaps with the shutter sound. Almost no. However, when the in-focus sound is generated after the detailed search, there may be a situation in which the generation timing of the shutter sound and the in-focus sound overlaps.
[0109]
FIG. 17B shows an example of the situation. In the figure, the sequence diagram shown in FIG. 10C is added with descriptions such as S2 = ON timing, in-focus sound duration, and shutter sound generation timing. According to FIG. 17B, when the detailed search process (4) is completed, a focusing sound is generated, and the focusing drive process (5) is started. The in-focus sound is output for a certain period of time, but before the in-focus sound ends, the in-focus driving process (5) is completed, and when the exposure operation is performed immediately, the shutter sound and the in-focus sound are temporally Will overlap. Therefore, in order to avoid such a situation, the state determination of S2 is performed during the focus sound generation control after the detailed search, and it is determined whether or not the focus sound is generated according to the determination. FIG. 18 shows a flowchart according to the control example. In the figure, steps that are the same as or similar to those in FIG.
[0110]
In FIG. 18, after the determination of the presence or absence of the in-focus sound in step S464, a determination is made as to whether or not a full press (S2 = ON) operation of the shutter button 18 has been performed (step S466).
[0111]
If it is determined in step S464 that no in-focus sound has been generated (NO determination), the process proceeds to step S466. In step S466, it is determined whether or not S2 is turned on. If YES, the generation of the in-focus sound is prohibited and the process proceeds to step S472. If NO is determined in step S466, the process proceeds to step S470 to execute a process for generating a focused sound, and then proceeds to step S472.
[0112]
As another control example, there is an aspect in which the timing at which the focus lens 48 reaches the in-focus position and the timing at which the in-focus sound ends are matched. FIG. 19 shows an example of in-focus sound generation timing.
[0113]
According to the figure, when the AF process is started, first, the focus lens 48 is driven from the current position to the AF search initial position (infinite in the figure) (initial position moving step (1)). Then, a rough search is started from infinity toward the closest direction. When a peak is detected in the rough search and the possibility of focusing is confirmed, a time T required until the AF ends at the end of the rough search is calculated. In the figure, T = 250 ms. Thereafter, this time T is monitored, and control is performed to generate the in-focus sound when the time T until the AF ends coincides with the in-focus sound generation duration L.
[0114]
After the rough search is completed, the focus is moved to the initial position of the detailed search (detailed search initial position moving step (3)), and the detailed search is started from this initial position in the direction of infinity. When the in-focus position is detected in the detailed search step (4), the focus lens 48 is driven to the in-focus position (in-focus driving step (5)). In the figure, the focusing sound duration L is set to 100 ms, and the focusing sound is generated during the detailed search step (4). Since the in-focus sound end timing and the AF end timing coincide with each other, it is easy for the photographer to set the timing at which the shutter button 18 is fully pressed (S2 = ON).
[0115]
FIG. 20 shows a flowchart in the case where the in-focus sound is matched with the end timing of the AF operation in the AF method in which the rough search and the detailed search are performed. In the figure, steps that are the same as or similar to those in FIG.
[0116]
According to FIG. 20, when it is determined in step S424 that the rough search is interrupted, the process proceeds to step S430. In step S430, a time T until the end of AF is calculated, and thereafter this time T is monitored. Then, a reservation process for generating a focused sound is performed (step S432), and the focused sound is generated when the time T until the end of AF coincides with the length L of the focused sound. After step S432, the process proceeds to step S442. Subsequent processing is as described in FIG. However, in the control example of FIG. 20, the steps S464 and S470 described in FIG. 11 are omitted.
[0117]
The method for determining the in-focus sound generation timing when the in-focus sound and the AF end timing are matched is not limited to the above-described method. As another method, after the AF end time T is calculated, a value (TL) obtained by subtracting the in-focus sound duration L from the obtained time T is set in a timer, for example, when the TL time has elapsed. There is a mode of generating a focusing sound. Also, the time T until the end of AF is calculated when the rough search is interrupted, and the focus sound is generated when the AF search is in a state based on the obtained time T (for example, the focus lens 48 in the detailed search). There is a mode in which the in-focus sound is generated when the three-step driving is determined.
[0118]
Further, the method for matching the end timing of the in-focus sound and the end timing of the AF operation is not limited to the AF method in which the rough search and the detailed search described in FIGS. 19 and 20 are performed. In the AF method described in FIG. Is also applicable.
[0119]
In carrying out the present invention, the AF method is not limited to the above-described contrast AF method, and various methods can be used. In addition to the contrast method, there is a phase method as a focus detection method for analyzing a subject image using a light receiving element and finding a position that connects the best images. Also, as a distance measuring method to measure the distance to the subject, light is emitted from the light projecting unit toward the subject, the reflected light from the subject is received by the light receiving unit, and the principle of triangulation is used from the received light signal There are an active method for measuring the distance to the subject, a passive method for detecting double image coincidence with a pair of split sensors (light receiving elements), a reflection intensity method, a propagation time method, and the like. In-focus sound generation method and apparatus can be applied. For example, after the distance measurement process is completed and the in-focus position can be detected, control is performed to generate an in-focus sound during a period before the in-focus driving is completed.
[0120]
In the above embodiment, the example in which the present invention is applied to a digital camera has been described. However, the scope of the present invention is not limited to this, and an optical image is recorded on a photographic film (such as a silver salt film or a self-developing film). The present invention can also be applied to a camera that performs this.
[0121]
【The invention's effect】
As described above, according to the present invention, since the focus sound is generated before the auto focus adjustment operation is completed at the time of auto focus adjustment, can the photographer focus faster or at a better timing? Can be confirmed. As a result, the sensation speed of AF increases, and it becomes possible to take a picture without missing a photo opportunity.
[Brief description of the drawings]
FIG. 1 is a front external view of a digital camera according to an embodiment of the present invention.
2 is an external view of the back side of the digital camera shown in FIG.
FIG. 3 is a block diagram showing the internal configuration of the digital camera of this example.
FIG. 4 is a diagram showing an example of a focus area set at the center of the screen
FIG. 5 is a diagram illustrating a change in an AF search step width according to a zoom position and a focus position.
FIG. 6 is a flowchart showing a control procedure of automatic focusing in the present example.
FIG. 7 is a flowchart showing a procedure of interruption determination processing shown in FIG. 6;
FIG. 8 is a flowchart showing a procedure of focusability determination processing shown in FIG. 6;
FIG. 9 is an explanatory diagram showing the timing of in-focus sound generation
FIG. 10 is an explanatory diagram showing in-focus sound generation timing in an AF method combining a rough search and a detailed search.
FIG. 11 is a flowchart showing a control procedure of the AF method shown in FIG.
FIG. 12 is a graph showing an example of evaluation values that change as the focus lens moves.
FIG. 13 is a diagram showing a state in which a plurality of subjects exist in the focus area.
FIG. 14 is a graph showing an example of evaluation values that change with the movement of the focus lens when there are a plurality of subjects in the focus area;
FIG. 15 is a graph illustrating a phenomenon in which the evaluation value does not decrease due to the influence of noise or the like.
FIG. 16 is a flowchart showing the contents of interruption determination (2) processing shown in FIG. 11;
FIG. 17 is an explanatory diagram showing a situation where the focusing sound and the shutter sound overlap in time.
FIG. 18 is a flowchart illustrating an example of control for avoiding overlapping of the in-focus sound and the shutter sound.
FIG. 19 is an explanatory diagram showing in-focus sound generation timing when the in-focus sound end timing is matched with the AF operation end timing.
FIG. 20 is a flowchart illustrating a control example for matching the end timing of the in-focus sound with the end timing of the AF operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Digital camera, 12 ... Shooting lens, 18 ... Shutter button, 48 ... Focus lens, 52 ... CCD (imaging means), 64 ... CPU (determination means, audio | voice output control means, means for calculating time, focus sound Means for prohibiting generation, detection means, control means), 78... Focus drive section (lens moving means), 81... Buzzer (sound output means), 88... Evaluation value calculation section (evaluation value calculation means)

Claims (6)

In-focus sound generation that generates sound for in-focus confirmation (hereinafter referred to as in-focus sound) in conjunction with an automatic focus adjustment device that adjusts the focal position of the lens that forms an image of the subject on the imaging surface of the camera A method,
The automatic focus adjustment device includes a first search means for obtaining an evaluation value at each position while moving within a predetermined focus adjustment area at a relatively large interval, and an evaluation value obtained by the first search means. After moving the lens in the vicinity of the position where the maximum value or the maximum value is detected, each lens is moved in the vicinity of the position where the maximum value or the maximum value is detected at a smaller interval than the first search means. Second search means for obtaining an evaluation value at a position,
In this in-focus sound generation method, it is determined whether or not the in-focus state of the lens can be achieved based on the evaluation value obtained by the first search means, and it is determined that the in-focus state can be achieved. In this case, an in-focus sound is generated, and then an evaluation value is obtained by the second search means, and the position where the maximum value or the maximum value of the evaluation values obtained by the second search means is detected is obtained. An in-focus sound generation method characterized by determining a focus position and moving the lens to the focus position . In-focus sound generation that generates in-focus confirmation sound (hereinafter referred to as in-focus sound) in conjunction with an automatic focus adjustment device that adjusts the focal position of the lens that forms an image of the subject on the imaging surface of the camera A device,
The automatic focus adjustment device includes a first search means for obtaining an evaluation value at each position while moving within a predetermined focus adjustment area at a relatively large interval, and an evaluation value obtained by the first search means. After moving the lens in the vicinity of the position where the maximum value or the maximum value is detected, each lens is moved in the vicinity of the position where the maximum value or the maximum value is detected at a smaller interval than the first search means. Second search means for obtaining an evaluation value at a position,
This in-focus sound generator is
A focus sound generating means for generating a focus sound;
Determination means for determining whether or not the in-focus state of the lens can be achieved based on the evaluation value obtained by the first search means;
When it is determined that the in-focus state can be achieved, the in-focus sound generating means generates in-focus sound, and then the evaluation value is obtained by the second search means and obtained by the second search means. A control means for determining the position where the maximum value or the maximum value of the evaluated values is detected as a focus position and moving the lens to the focus position;
An in-focus sound generating device comprising: The in-focus sound generating device according to claim 2,
Means for calculating the time required from the time when it is detected that the in-focus state can be achieved until the operation for actually achieving the in-focus state is completed;
Means for controlling the generation timing of the in-focus sound so that the timing at the end of the operation for achieving the in-focus state and the timing at the end of output of the in-focus sound are matched;
An in-focus sound generating device comprising: The in-focus sound generating device according to claim 2,
An in-focus sound generating device comprising means for prohibiting the in-focus sound from being generated when the in-focus sound generation period and the shutter sound generation period overlap in time . The automatic focusing device is
Imaging means for converting an optical image into an electrical signal;
A lens for forming an image of a subject on the imaging surface of the imaging means;
Lens moving means for moving the lens within a focus adjustment region;
For each lens position moved by the lens moving means, an evaluation value calculating means for extracting a contrast component of the subject from an image signal output from the imaging means and calculating an evaluation value according to the contrast component;
Detection means for detecting a lens position at which a maximum value or a maximum value of the evaluation values is obtained;
The in-focus sound generating device according to claim 2, 3 or 4 . In the in-focus sound generating device according to claim 2, 3, 4, or 5,
If the maximum value or the maximum value of the evaluation value cannot be detected by the first search means, the control means may move the evaluation value while moving the entire focus adjustment area at the small interval by the second search means. An in-focus sound generating apparatus characterized in that the in-focus sound is generated when the maximum value or the maximum value of the evaluation value is detected in the search operation of the second search means .

Images