JP4684057B2 - Electronic camera - Google Patents

Description

  The present invention relates to an electronic camera such as an electronic still camera having an automatic focus adjustment function and an automatic exposure adjustment function.

Patent Document 1 discloses an electronic camera of this type that displays a frame frame on a display unit that displays a captured video signal in order to notify the user that the operation of the automatic focus adjustment function has been completed. Yes.
JP, 2000-92354, A In addition, as an electronic camera of this type, in order to notify the user that the operation of the automatic exposure adjustment function has been completed, a shutter speed that is an exposure time on a display unit that displays a captured video signal A device for displaying the speed is disclosed in Patent Document 2. JP, 2002-290800, A In recent electronic cameras, what has both an automatic focus adjustment function and an automatic exposure adjustment function is common. In this type of electronic camera in which both focus adjustment and exposure adjustment are performed automatically, focus adjustment and exposure adjustment are performed as adjustments before photographing in response to a half-press of the shutter button. This will be specifically described below.

  When the shutter button that operates the switch that detects the two steps of half-press and full-press is pressed halfway, the aperture is first opened, photometry is performed to know the brightness level of the subject, and exposure is optimal for automatic focus adjustment. Obtain and set time (shutter speed) and sensitivity level. Next, by moving the focus lens stepwise in the direction of the optical axis from the infinite end point to the closest side, the relative position between the imaging surface of the image sensor and the focus lens was changed stepwise, and obtained at the position of each focus lens. From the focus evaluation value that is the high-frequency component level of the captured video signal, automatic focus adjustment is performed by a so-called hill-climbing method that detects the position of the focus lens where the focus evaluation value is the maximum value, and the position of the focus lens is determined and set. Next, using the brightness level obtained by the photometry process or the brightness level obtained by the photometry process performed again after completion of the automatic focus adjustment, an aperture value and an exposure time for obtaining an optimal exposure amount for photographing are calculated, and an actual value is calculated. A so-called automatic exposure adjustment is performed in which the photometric process is performed again in a state where the aperture value used for photographing is set to confirm the exposure amount. When all of these processes are completed, information regarding the automatic focus adjustment function and the automatic exposure adjustment function is displayed to notify the user that the adjustment before photographing has been completed.

  However, as described above, if the user is not notified only after the automatic exposure adjustment is completed even though the automatic focus adjustment is completed, the perceived speed until the completion of the automatic focus adjustment given to the user. There is a problem that will be reduced.

  On the other hand, it is considered that one of the countermeasures is to immediately notify the completion of the automatic focus adjustment regardless of the operation of the automatic exposure adjustment. After both are completed, that is, after it is notified that the automatic exposure adjustment has been completed, if the subject is dark and it takes time to adjust the automatic exposure, it will be possible to take a picture after notifying the completion of the automatic focus adjustment. Takes a long time and causes the user to feel uncomfortable.

  In order to solve the above-described problems, the present invention provides an automatic focus adjustment unit that performs a focusing operation by changing a relative position between an imaging surface of an imaging element and a focus lens in an electronic camera, and the automatic focus adjustment unit. A first notification means for notifying the user that the operation is completed, and an exposure amount adjustment after completion of the operation of the automatic focus adjustment means. An automatic exposure adjusting means for confirming that the exposure amount is obtained, a second notification means for notifying the user that the operation of the automatic exposure adjusting means is completed, and an exposure amount before the operation of the first notification means is started. Discriminating means for discriminating whether or not the exposure time in the confirmation photometry performed by the automatic exposure adjusting means based on the detected exposure amount is longer than a preset reference time; and When the determination means determines that the exposure time in the confirmation photometry performed by the dynamic exposure adjustment means is longer than the reference time, the operation of the first notification means is prohibited until the operation of the automatic exposure adjustment means is completed. And a notification control unit that operates the first notification unit regardless of completion of the operation of the automatic exposure adjustment unit when the determination unit determines that it does not increase.

  According to the present invention, when it is determined that the exposure time in the confirmation metering performed by the automatic exposure adjustment unit is increased, the operation completion notification of the automatic focus adjustment unit is prohibited until the operation of the automatic exposure adjustment unit is completed. It is possible to prevent the user from feeling uncomfortable because it takes a long time from when notification of completion of focus adjustment to when shooting is possible. On the other hand, when it is determined that it does not increase, the completion of the operation of the automatic focus adjustment unit is notified regardless of the completion of the operation of the automatic exposure adjustment unit, so that the sensation speed until the completion of the automatic focus adjustment given to the user can be improved. .

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a functional block diagram of an electronic camera according to an embodiment of the present invention. Referring to FIG. 1, incident light incident through a focus lens 1 and a diaphragm mechanism 2 is photoelectrically converted by an image pickup device 3 such as a CCD, and a photographed image signal is generated by a CDS / AGC circuit 4. The generated captured image signal is converted into a digital signal by the A / D converter 5 and then applied to the signal processing circuit 6.

  The signal processing circuit 6 performs known signal processing such as color separation processing on a given digital photographed image signal, and then performs known automatic white balance adjustment for each field (one screen) of the photographed image signal. The image data is sequentially formed and supplied to the SDRAM 7 which is a buffer memory.

  The SDRAM 7 sequentially stores the input field unit image data from one to the next, and outputs the stored image data for each field to the monitor 8 via the signal processing circuit 6 for display. In the photographing operation performed by operating the shutter button 14, image data for one screen stored in the SDRAM 7 is compressed by the signal processing circuit 6 in terms of software and recorded in the memory card 9.

  The focus lens 1 is driven by a motor 1a driven by a driver 1b, the diaphragm mechanism 2 is driven by a motor 2a driven by a driver 2b, and the image sensor 3 is driven by a TG circuit (timing generator circuit) 3a. . Further, the photographed image signal is input from the signal processing circuit 6 to the focus evaluation circuit 10, and a focus evaluation value that is a high frequency component level of the photographed image signal is calculated and supplied to the control circuit 12. In the control circuit 12, automatic focus adjustment is performed by a so-called hill-climbing method for detecting the position of the focus lens 1 at which the focus evaluation value becomes the maximum value, and the position of the focus lens 1 is detected and the position of the focus lens 1 is set. A captured image signal is input from the signal processing circuit 6 to the exposure evaluation circuit 11, and an exposure evaluation value that is a luminance level of the captured image signal is calculated and supplied to the control circuit 12. The control circuit 12 uses the exposure evaluation value to calculate an aperture value and an exposure time at which an optimum exposure amount for photographing is obtained. The aperture value of the aperture mechanism 2, the exposure time of the image sensor 3, and the CDS / AGC circuit 4 Set the gain.

  The speaker 13 is controlled by the control circuit 12 and functions to convey information to the user with sound. The shutter button 14 operates a switch for detecting two stages of half-press and full-press, and gives the detection result to the control circuit 12.

  Next, an operation when the shutter button 14 of the electronic camera centering on the control circuit 12 is half-pressed will be described with reference to the flowcharts shown in FIGS. When half-pressing of the shutter button 14 is detected, the aperture mechanism 2 is fully opened (S1), and brightness data included in the image data is obtained from the image sensor 3 via the signal processing circuit 6 into the exposure evaluation circuit 11 and obtained. By integrating the luminance data for one screen, an exposure evaluation value that is the luminance level of the subject is calculated (S3). Then, a flag F indicating whether or not it takes time for exposure adjustment performed later is set (S5).

  The flag F setting process is performed according to the flowchart shown in FIG. Based on the exposure evaluation value A calculated from the luminance data obtained in step S3 and the exposure time T at the time of execution of step S3 set by the electronic shutter function in the image sensor 3, the maximum frame rate of the image sensor 3 is obtained. An exposure evaluation value B indicating an exposure amount at an exposure time L (for example, if the frame rate is 30 fps, the exposure time L is 1/30 seconds) is calculated by using Formula 1 (S501).

  Then, the calculated exposure evaluation value B and the optimum exposure evaluation value S indicating the target optimum exposure amount are converted into a 100-percentage rate and defined as a night view rate. Is calculated (S503).

When a sufficient exposure amount can be ensured with the exposure time L, that is, when the subject is bright, the night view rate Y is smaller than 0%. As the subject gradually becomes darker, the amount of exposure that can be secured even with the same exposure time L decreases. The ratio that could not be secured is the night view rate.

  Next, it is determined whether or not the calculated night view rate Y is greater than 0%, that is, whether or not the exposure amount is insufficient in the exposure time L (S505). The fact that the exposure amount is insufficient even in the exposure time L even though the aperture mechanism 2 is fully open means that an exposure time longer than one frame period is required to obtain the optimum exposure, and a long exposure time. If it is necessary, it takes time to confirm the exposure amount before photographing, and the time for exposure adjustment becomes longer. Accordingly, in step S505, if it is determined that the night view rate Y is greater than 0%, the value of the flag F is set to 1 so as to indicate that it takes time to check the exposure before shooting (S507). The value of F is set to 0 (S509). Since the drive period of the image sensor 3 required for one exposure is set in units of frame periods, the image sensor has a two-frame period in order to shoot and output a signal with an exposure time longer than the exposure time L. It requires more time. Even if the exposure time is slightly longer than the exposure time L, the image sensor must be driven for two frame periods.

  Next, returning to the flowchart shown in FIG. 2, the relative position between the imaging surface of the imaging device 3 and the focus lens 1 is changed stepwise by moving the focus lens 1 stepwise from the infinite end point in the optical axis direction. From the focus evaluation value that is the high-frequency component level of the photographed image signal calculated by the focus evaluation circuit 10 at the position of each focus lens, the position of the focus lens 1 at which the focus evaluation value becomes the maximum value, that is, the alignment value. A focal position is detected (S7). If the in-focus position can be detected, the focus lens 1 is set at the in-focus position (S9, S11). If not, the focus lens 1 is set at a predetermined position (S9, S13). . The predetermined position is a position determined in advance as a focal position where there is a high possibility that the subject exists, and the setting to the predetermined position is performed as error processing in step S7.

  Next, it is determined whether or not the value of the flag F is 0 (S15). If it is 0, a frame as shown in FIG. * Is used to notify the user that the automatic focus adjustment in steps S7 to S13 has been completed. 10a is displayed on the monitor 8 and a sound is generated from the speaker 13 (S17). This improves the sensation speed until completion of automatic focus adjustment given to the user. However, if it is not 0, step 17 is not performed.

  Then, the exposure evaluation circuit 11 captures the luminance data from the image sensor 3 via the signal processing circuit 6, and calculates the exposure evaluation value, which is the luminance level of the subject, by integrating the acquired luminance data for one screen ( S19). Based on the calculated exposure evaluation value, a program diagram process known as an electronic camera is performed to determine an aperture value and an exposure time (S21). Then, the aperture mechanism 2 is driven and set so as to achieve the determined aperture value (S23), and exposure is performed by controlling the electronic shutter of the image sensor 3 and the signal readout timing so as to achieve the determined exposure time. Then, the luminance data obtained by the exposure is taken in and an exposure evaluation value is calculated (S25). It is determined whether or not it has been confirmed that the optimum exposure amount has been obtained based on the obtained exposure evaluation value (S27). If it is determined that it has not been obtained, the exposure time is adjusted (S29), and step S25 is performed again. Luminance data is fetched and the confirmation in step S27 is performed.

  When it is confirmed in step S27 that the optimum exposure amount has been obtained, it is next determined whether or not the value of the flag F is 1 (S31), and if it is 1, automatic focus adjustment in steps S7 to S13 is performed. In order to notify the user of completion, a frame 10a is displayed on the monitor 8 as shown in FIG. 5, and a sound is generated from the speaker 13 (S33). If not 1, the notification that the automatic focus adjustment has been completed has already been performed in step S17, and therefore step 33 is not performed.

  Then, the adjusted aperture amount 11a and exposure time (shutter speed) 11b are displayed on the monitor 8 as shown in FIG. 6 to notify the user that automatic exposure adjustment has been completed (S35), and the shutter button 14 The operation when half-pressing is completed. The numerical values indicating the aperture amount 11a and the exposure time 11b shown in FIG. 6 are examples. Steps S15 and S31 to S35 prevent the user from feeling uncomfortable because it takes a long time from when the completion of automatic focus adjustment is notified until shooting is possible.

  Next, the process proceeds to the flowchart shown in FIG. When the full press of the shutter button 14 is detected (S37), the main exposure is performed to obtain the recorded image data with the set aperture amount and the adjusted exposure time (S41). Then, reading from the image pickup device 3 is performed (S43), signal processing and compression for creating a recording signal are performed by the signal processing circuit 6 (S45), and writing and recording on the memory card (S47). On the other hand, if full-pressing of the shutter button 14 is not detected in step S37, the process waits until the half-pressing of the shutter button 14 is released (S39), and ends when the half-pressing of the shutter button 14 is released.

  Although the embodiments of the present invention have been described above, the reference time used for determining whether the exposure time in the confirmation photometry performed by the automatic exposure adjusting means is long or short is limited to the exposure time that is maximum at the frame rate of the image sensor. However, it can be arbitrarily set. For example, a two-frame period may be set as the reference time.

  Furthermore, the frame displayed for notifying the user that the automatic focus adjustment has been completed can be a frame frame indicating a region for extracting a focus evaluation value on the screen. In addition, the display for notifying completion may be performed separately by the light emitter instead of on the monitor.

  In addition to the hill-climbing method that performs focus adjustment by detecting the high-frequency component level of the captured image signal obtained from the image sensor as the focus evaluation value, automatic focus adjustment may employ an infrared or ultrasonic method. Is possible.

  Furthermore, in order to notify the user that the operation of the automatic exposure adjustment means has been completed, it is not necessary to display the exposure time and aperture value set at the time of shooting. You may make it display the attached character, an icon, or a figure.

Further, the completion of the operation of the automatic exposure adjustment means is to determine the exposure time and aperture value to be used during recording photography. In the main exposure performed at the time of recording and shooting, since the image pickup device is driven by a driving method different from the conventional one, even if the exposure time and the aperture value need to be set again at the time of main exposure, the recording and shooting are performed. When the exposure time and aperture value used at times are determined, the operation of the automatic exposure adjusting means is completed. If it is necessary to newly set the exposure time and aperture value during the main exposure, the final setting of the exposure time and aperture amount is performed between step S37 and step S41 in the flowchart shown in FIG. Become.

It is a functional block diagram of the electronic camera which is an Example of this invention. It is a flowchart which shows operation | movement of the electronic camera which is an Example of this invention. It is a flowchart which shows operation | movement of the electronic camera which is an Example of this invention. It is a flowchart which shows operation | movement of the electronic camera which is an Example of this invention. It is explanatory drawing which shows operation | movement of the electronic camera which is an Example of this invention. It is explanatory drawing which shows operation | movement of the electronic camera which is an Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Focus lens 2 Aperture mechanism 3 Image pick-up element 6 Signal processing circuit 8 Monitor 10 Focus evaluation circuit 11 Exposure evaluation circuit 12 Control circuit 13 Speaker 14 Shutter button

Claims (5)

Automatic focus adjustment means for performing a focusing operation by changing the relative position between the imaging surface of the imaging element and the focus lens;
First notification means for notifying a user that the operation of the automatic focus adjustment means has been completed;
Automatic exposure adjustment means for adjusting the exposure amount after completion of the operation of the automatic focus adjustment means and performing photometry using the image sensor as photometry for confirmation before photographing and confirming that a desired exposure amount is obtained at the time of photographing;
Second notification means for notifying a user that the operation of the automatic exposure adjustment means has been completed;
Whether or not the exposure time in the confirmation photometry performed by the automatic exposure adjustment unit based on the detected exposure amount before the start of the operation of the first notification unit is longer than a preset reference time. Determining means for determining whether or not
When the determining means determines that the exposure time in the confirmation metering performed by the automatic exposure adjusting means is longer than the reference time, the operation of the first notification means is prohibited until the operation of the automatic exposure adjusting means is completed. And a notification control means for operating the first notification means regardless of completion of the operation of the automatic exposure adjustment means when the determination means determines that it does not increase,
An electronic camera comprising:   The electronic camera according to claim 1, wherein the automatic focus adjustment unit performs focus adjustment by detecting a high frequency component level of a captured image signal obtained from the image sensor as a focus evaluation value.   2. The first notification means notifies a user that the operation of the automatic focus adjustment means is completed by displaying a character or a graphic on a monitor that displays a photographed image signal. Electronic camera.   The second notifying unit notifies the user that the operation of the automatic exposure adjusting unit has been completed by displaying the exposure time and aperture value set by the automatic exposure adjusting unit at the time of shooting using the display unit. The electronic camera according to claim 1, wherein: 2. The electronic camera according to claim 1, wherein the completion of the operation of the automatic exposure adjustment means is to determine an exposure time and an aperture value used at the time of photographing.

Images