JPH11261952A - Electronic camera provided with consecutive photographing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate a consecutive photographing speed by allowing a measurement means to omit the updating operation of an operation parameter in one or more frames during consecutive photographing in the case that a consecutive photographing means performs consecutive photographing. SOLUTION: An image processing circuit 15 judges whether or not a high compression mode is set, and in the case of judging as the high compression mode, the image processing circuit 15 judges whether or not it is the first frame of the consecutive photographing. In this case, in the case of the first frame of consecutive photographing, the image processing circuit 15 tries image compression by using a quantization table set for the high compression mode and predicts the compression code amount of image data. The image processing circuit 15 updates the quantization table for the high compression mode to the one capable of obtaining appropriate high compressibility based on the compression code amount predicted in such a manner. Also, in the case of the second or succeeding frame of consecutive photographing, the image processing circuit 15 omits the predicting operation of the compression code amount at all. That is, in one or more frames during consecutive photographing, the updating operation of the operation parameter is omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera having a continuous shooting function. In particular, the present invention relates to an electronic camera that increases the continuous shooting speed.

[0002]

2. Description of the Related Art Heretofore, the following contents have been known for a technique for increasing a continuous shooting speed in an electronic camera. JP 6
Japanese Patent Application Laid-Open No. 54252/1990 describes a technique for simultaneously increasing the continuous shooting speed by simultaneously performing exposure of a succeeding frame on the image sensor side during image compression of the preceding frame.

Further, Japanese Patent Application Laid-Open No. 5-191700 describes a technique for reading an image signal every several lines from an image sensor to shorten the image reading time and increase the continuous shooting speed. Further, Japanese Unexamined Patent Application Publication No. 7-13
Japanese Patent Application Laid-Open No. 5589 discloses a technique for shortening the image recording time by dividing the captured image data on a plurality of recording media and recording the divided data, and increasing the continuous shooting speed.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 6-5 / 1994
According to the technology described in Japanese Patent No. 4252, when the exposure time is longer than the compression processing time, the exposure operation and the compression processing operation can be efficiently performed without interruption. In this case, the best effect can be obtained in increasing the continuous shooting speed.

However, if the compression processing time is longer than the exposure time, the image sensor must wait for the image reading of the subsequent frame until the compression processing of the preceding frame is completed. The continuous shooting speed is reduced by the waiting time. Further, in the technique described in Japanese Patent Application Laid-Open No. 5-191700, it is necessary to use a special image sensor capable of designating and reading out horizontal lines for each line, and it is not possible to use a general-purpose image sensor. There was a point.

Furthermore, in the technique described in Japanese Patent Application Laid-Open No. Hei 7-135589, it is necessary to provide a plurality of mechanisms and recording circuits for mounting a recording medium, and it is difficult to reduce the size and cost of an electronic camera. There was a problem. Therefore, an object of the present invention is to provide an electronic camera capable of increasing the continuous shooting speed from a different viewpoint from the above-described conventional technology.

[0007]

According to a first aspect of the present invention, there is provided an image pickup device which forms an image by imaging light from a subject and generates image data. An electronic camera having a continuous shooting function including a measuring unit that updates an operation parameter on shooting used by the imaging unit and a continuous shooting unit that continuously drives the imaging unit to continuously shoot a subject image. When the continuous shooting means performs continuous shooting,
The measurement unit may omit the operation of updating the operation parameter described above in at least one frame during continuous shooting.

Usually, in continuous photographing, almost the same scene is repeatedly photographed in many cases. Therefore, during continuous shooting, the value of the operation parameter itself rarely changes significantly. Utilizing such circumstances of continuous shooting, the invention according to claim 1 omits the operation of updating the operation parameters by the measuring means in some frames during continuous shooting. As a result, the operation of measuring the object field by the measuring means and the related control operations can be omitted, and the continuous shooting speed can be reliably increased by that much.

The invention described in claim 1 also includes a case in which the measuring means updates the operation parameters only for the first frame of the continuous shooting and omits the updating operation for the second and subsequent frames. Such a photographing function is a photographing function suitable for a photographing object that does not change so much, such as a case where many photographs are taken in order to capture the instantaneous facial expression of a person. Further, the invention described in claim 1 includes an embodiment in which the measuring means updates the operation parameter at a predetermined frame interval during the continuous shooting, and omits the update operation during that. Such a photographing function is a photographing function suitable for a photographing subject that is expected to change to some extent, such as a moving subject or panning photographing.

[0010] Further, the invention according to claim 1 includes a measuring means for increasing (or shortening) a frame interval for updating an operation parameter with time. With such a function, the update interval of the operation parameter can be appropriately and automatically adjusted in accordance with the lapse of time of the continuous shooting. Therefore, the shooting function is suitable for a shooting target that changes at an accelerated rate, such as an approaching subject.

According to a second aspect of the present invention, in the electronic camera having the continuous shooting function according to the first aspect,
The measurement means is means for updating at least one of an appropriate exposure value, a focus adjustment state detection value, and a white balance adjustment value used by the imaging means based on the measurement of the object scene.

According to a third aspect of the present invention, there is provided an image capturing means for capturing an image of a subject to generate image data, and predicting a compression code amount for the image data generated by the image capturing means. Compression prediction means for updating the compression level of data, image compression means for performing image compression based on the compression level obtained from the compression prediction means, and continuous shooting for continuously driving the imaging means to continuously photograph the subject image In the electronic camera having the continuous shooting function provided with the means, when the continuous shooting means performs continuous shooting, the compression prediction means omits the operation of predicting the compression code amount in at least one frame during continuous shooting. It is characterized by.

Usually, in continuous shooting, almost the same scene is repeatedly shot in many cases. For this reason, during continuous shooting, the correlation between image data between frames is high, and the prediction result of the compression code amount rarely fluctuates greatly. Using the circumstances of such continuous shooting, a method according to claim 3
In the invention described in the above, in some frames during continuous shooting,
The operation of predicting the compression code amount is omitted. Therefore, it is possible to surely increase the continuous shooting speed for continuous shooting.

According to the third aspect of the present invention, the compression predicting means performs a predicting operation only for the first frame of the continuous shooting, and
In some cases, the prediction operation is omitted after the frame. Such a photographing function is a photographing function suitable for a photographing object that does not change so much, such as a case where many photographs are taken in order to capture the instantaneous facial expression of a person. Further, the invention according to claim 3 includes a compression predicting unit that performs a prediction operation at a predetermined frame interval during continuous shooting, and omits the prediction operation during that period. Such a photographing function is a photographing function suitable for a photographing subject that is expected to change to some extent, such as a moving subject or panning photographing.

Further, the invention according to claim 3 includes a compression predicting means for increasing (or shortening) a frame interval for performing a prediction operation with time. With such a function, it is possible to appropriately and automatically adjust the interval of the prediction operation in accordance with the lapse of time of the continuous shooting. Therefore, the shooting function is suitable for a shooting target that changes at an accelerated rate, such as an approaching subject.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electronic camera according to the first to third aspects of the present invention. In FIG. 1, a photographing optical system 11 is provided in a main body of an electronic camera. On the image space side of the photographing optical system 11, an imaging surface of the CCD imaging device 13 is arranged. This C
The CD imaging device 13 is driven by a control pulse from the CCD driving circuit 13a. An analog image signal from the CCD 13 is supplied to an image processing circuit 15 as digital image data after passing through an A / D conversion circuit 14. The image processing circuit 15 is in charge of image processing by hardware, such as image compression processing and information synthesis processing for monitor display.

The monitor display image data from the image processing circuit 15 is displayed on a liquid crystal monitor 15a via a liquid crystal drive circuit (not shown). The image processing circuit 15
A timing signal for notifying the readout timing of the CCD image sensor 13 is transmitted to the CCD drive circuit 13a. Further, the image processing circuit 15 includes a CPU
A control signal is provided from 16.

The CPU 16 exchanges image data (including image files) with the image data bus of the image processing circuit 15, the memory 18, and the flash memory card 19 via the system bus 17.
Further, a group of operation buttons 21 such as a release button 22, a menu button 23, and a zoom button 24 are connected to the CPU 16.
Note that the CPU 16 is a multi-processor composed of an image processing processor that performs overall image processing by software and a system control processor that monitors operation buttons and the like of an electronic camera on an actual circuit. Processor.

(Correspondence between the present invention and the present embodiment) Here, the correspondence between the invention described in each claim and the present embodiment will be described. First, regarding the correspondence between the inventions described in the first and second aspects and the present embodiment, the image pickup means corresponds to the white balance adjustment function of the photographing optical system 11, the CCD image pickup device 13, and the image processing circuit 15, and the measurement means Is CPU
16 corresponds to a function of performing a photometric operation, a colorimetric operation, and a contrast amount detection operation based on image data to obtain an appropriate exposure value, a white balance adjustment value, and a contrast amount. Function of continuously driving the element 13 and the like to perform continuous shooting ".

Regarding the correspondence between the invention described in claim 3 and the present embodiment, the image pickup means corresponds to the CCD image pickup device 13 and the compression prediction means has the function of predicting the compression code amount of the image processing circuit 15. The image compression means corresponds to the "function of performing image compression" of the image processing circuit 15, and the continuous shooting means corresponds to the "function of continuously driving the CCD image sensor 13 and the like for continuous shooting" of the CPU 16. I do.

(Main Routine of this Embodiment) The operation of this embodiment will be described below. FIG. 2 is a flowchart showing a main routine at the time of shooting in the present embodiment.
First, the CPU 16 determines whether or not an input operation for mode setting has been performed via the operation button group 21 (see FIG. 2).
S1).

Here, an input operation for mode setting (for example, when the menu button 23 which is one of the operation button groups 21 is set to 0.
When an operation such as pressing for 2 seconds or more is performed, the CPU 1
6 shifts the execution to the mode setting operation shown in FIG. 3 (FIG. 2S
2). Subsequently, the CPU 16 determines whether or not the release button 22 has been pressed (S3 in FIG. 2).

Here, during a period until the release button 22 is pressed, the CPU 16 returns the operation to step S1, and accepts a mode setting operation as needed. On the other hand, the release button 22
Is pressed once (YES side of S3 in FIG. 2), the CPU 16
Determines the setting state of the shooting mode (S4 in FIG. 2). If the single shooting mode has been set as the shooting mode, the CPU 16 shifts the execution to the single shooting operation shown in FIG. 4 (S5 in FIG. 2).

When the low-speed continuous shooting mode is set as the photographing mode, the CPU 16 shifts the execution to the low-speed continuous shooting operation shown in FIG. 5 (S6 in FIG. 2). On the other hand, if the medium-speed continuous shooting mode is set as the shooting mode, the CPU 16
Shifts the execution to the middle-speed continuous shooting operation shown in FIG. 6 (FIG. 2S
7). If the high-speed continuous shooting mode has been set as the shooting mode, the CPU 16 shifts the execution to the high-speed continuous shooting operation shown in FIG. 7 (S8 in FIG. 2). After completing these individual operation routines, the CPU 16 returns the operation to step S1 in preparation for the next mode setting operation and operation of the release button 22. Next, the individual operation routines described above will be described one by one.

(Explanation of Mode Setting Operation) FIG. 3 is a flowchart for explaining the mode setting operation. First, when the mode setting operation is started, the CPU 16 displays a screen in which menu items are arranged on the liquid crystal monitor 15a via the image processing circuit 15. In this state, the operator operates the zoom button 24 to move the cursor position on the screen, and operates the release button 22 to appropriately select the menu item at the cursor position.
By repeating such an interactive operation, various mode setting operations are performed. Hereinafter, three of the mode setting operations, namely, “resolution setting”, “compression ratio setting”, and “continuous shooting setting” will be described.

(1) Description of Operation of Resolution Setting First, when a menu item of “resolution setting” is selected (YES side of S11 in FIG. 3), the CPU 16 selects an option of “high resolution mode” and “low resolution mode”. A menu is displayed (S12 in FIG. 3). Here, when the “high resolution mode” is selected from the menu, the CPU 16 sets the state of the internal flag to the high resolution mode (S13 in FIG. 3), and then returns to the main routine shown in FIG. On the other hand, when the “low resolution mode” is selected from the menu, the CPU 16 sets the state of the internal flag to the low resolution mode (S1 in FIG. 3).
4) Return the operation to the main routine shown in FIG. With the above operation, the setting of the resolution mode is completed.

(2) Description of Operation for Setting Compression Ratio On the other hand, when the menu item “compression ratio setting” is selected (YES in S15 in FIG. 3), the CPU 16 sets the “low compression mode” and the “high compression mode”. The options are displayed on a menu (S16 in FIG. 3). Here, when the "low compression mode" is selected from the menu, the CPU 16 sets the state of the internal flag to the low compression mode (S17 in FIG. 3), and then returns to the main routine shown in FIG. On the other hand, when the "high compression mode" is selected from the menu, the CPU 16 sets the state of the internal flag to the high compression mode (S18 in FIG. 3), and then returns to the main routine shown in FIG. With the above operation, the setting of the compression mode is completed.

(3) Description of Operation of Continuous Shooting Setting On the other hand, when the menu item of “continuous shooting setting” is selected (YES side in S19 of FIG. 3), the CPU 16 sets “high-speed continuous shooting mode” and “medium-speed continuous shooting”. A menu consisting of options of "shooting mode" and "low-speed continuous shooting mode" is displayed (S21 in FIG. 3).
(If any of the continuous shooting modes is set, a menu of “single shooting mode” is also displayed.) When “high-speed continuous shooting mode” is selected from the menu,
After setting the state of the internal flag to the high-speed continuous shooting mode (S22 in FIG. 3), the PU 16 returns the operation to the main routine shown in FIG.

When the "medium speed continuous shooting mode" is selected from the menu, the CPU 16 sets the state of the internal flag to the medium speed continuous shooting mode (S23 in FIG. 3), and then returns to the main routine shown in FIG. . On the other hand, when the "low-speed continuous shooting mode" is selected from the menu, the CPU 16 sets the state of the internal flag to the low-speed continuous shooting mode (S24 in FIG. 3), and then returns to the main routine shown in FIG. With the above operation, the setting of the continuous shooting mode is completed.

(Explanation of Single Shooting Operation) FIG. 4 is a flowchart for explaining the single shooting operation. When the single shooting operation is started, the CPU
16 checks the battery state, the charged amount of the strobe, the remaining capacity of the flash memory card 19, and the like, and determines whether or not shooting is possible (S31 in FIG. 4).

If it is determined that photographing is not possible (NO in S31 in FIG. 4), the CPU 16 displays a warning on the LCD monitor 15a and returns to the main routine shown in FIG. On the other hand, when it is determined that shooting is possible (YES side in S31 in FIG. 4), the CPU 16 determines the appropriate aperture value, the appropriate exposure time, the white balance adjustment value, and the contrast amount based on the image data from the CCD image sensor 13. Each is calculated (S32 in FIG. 4).

The CPU 16 moves the photographing optical system 11 forward and backward based on the contrast amount, and performs a hill-climbing AF.
The control is executed (S33 in FIG. 4). After completion of AF control, C
The PU 16 adjusts the aperture diameter (also used as a lens shutter) of the photographing optical system 11 in accordance with the appropriate aperture value (S3 in FIG. 4).
4). After such preparation, the CPU 16 sweeps out all unnecessary charges of the CCD image sensor 13 via the CCD drive circuit 13a, and newly starts photoelectric storage of the subject image (S35 in FIG. 4).

When the proper exposure time elapses in this state, C
PU 16 closes the lens shutter of the photographing optical system 11,
The photoelectric accumulation of the subject image is terminated (S36 in FIG. 4). Subsequently, the CPU 16 sends the CC through the CCD drive circuit 13a.
The image data is sequentially read from the D imaging device 13 (see FIG. 4).
S37). The read image data is digitized via an A / D conversion circuit 14, and then digitized.
It is taken in. The image processing circuit 15 performs white balance adjustment on the image data based on the white balance adjustment value described above, and then temporarily stores the white balance in the memory 18 (FIG. 4).
S38).

Here, the image processing circuit 15 determines whether or not the low resolution mode is set (S3 in FIG. 4).
9). If the high-resolution mode has been set at this point (NO in S39 in FIG. 4), the image processing circuit 15 does not execute the resolution conversion because the captured image data is used as it is. On the other hand, when the low resolution mode is set (YES in S39 in FIG. 4), the image processing circuit 15 reduces the resolution by thinning out pixels from the image data in the memory 18 (S40 in FIG. 4).

Next, the image processing circuit 15 determines whether or not the high compression mode is set (S41 in FIG. 4). At this time, when the high compression mode is set (S4 in FIG. 4)
(YES side of No. 1), the image processing circuit 15 performs the image compression using the quantization table set for the high compression mode, and predicts the compression code amount of the image data (S4 in FIG. 4).
2). The image processing circuit 15 updates the quantization table for the high compression mode to one that can obtain an appropriate high compression ratio based on the compression code amount predicted in this way. (In the image processing circuit 15, quantization tables are prepared in advance for several stages from a high compression level to a low compression level.) Using the quantization table for the high compression mode updated in this way, The processing circuit 15 executes compression of the image data (S43 in FIG. 4).

On the other hand, if the low compression mode has been set in advance (NO in S41 in FIG. 4), the image processing circuit 15 performs image compression using the quantization table set for the low compression mode, and performs image compression. The compression code amount of the data is predicted (S44 in FIG. 4). The image processing circuit 15 updates the quantization table for the low-compression mode to one that can obtain an appropriate low-compression rate based on the predicted compression code amount.

Using the updated low-compression quantization table, the image processing circuit 15 compresses the image data (S45 in FIG. 4). After completing the image compression according to the compression mode in this way, the CPU 16 converts the compressed image data into a file and records it on the flash memory card 19 (S46 in FIG. 4). With the above series of operations, the single shooting operation is completed.

(Description of Low-Speed Continuous Shooting Operation) FIG. 5 is a flowchart for explaining the low-speed continuous shooting operation. Note that S51 shown in FIG.
The operations of S66 to S66 are the same as those of the single shooting operation (S31 to S4 in FIG.
This is the same operation as 6). In the present embodiment, the CPU 16
Repeats the same operation (S52 to S66 in FIG. 5) as the single shooting operation, whereby the low-speed continuous shooting operation is executed.

If the CPU 16 detects the release of the release button 22 during such a continuous shooting period (S68 in FIG. 5),
The CPU 16 ends the continuous shooting operation and returns to the main routine shown in FIG. On the other hand, during such a continuous shooting period,
When the CPU 16 detects the shortage of the remaining capacity of the flash memory card 19 (S67 in FIG. 5), the CPU 16 suspends the continuous shooting operation at that point and returns to the main routine shown in FIG.

(Explanation of Medium Speed Continuous Shooting Operation) FIG. 6 is a flowchart for explaining the medium speed continuous shooting operation. When the medium-speed continuous shooting operation is started, the CPU 16 checks the battery state, the charged amount of the strobe, the remaining capacity of the flash memory card 19, and determines whether or not shooting is possible (S71 in FIG. 6).

Here, when it is determined that the photographing is impossible (NO side in S71 in FIG. 6), the CPU 16 displays a warning to that effect on the liquid crystal monitor 15a, and then returns to the main routine shown in FIG. On the other hand, when it is determined that shooting is possible (YES in S71 in FIG. 6), the CPU 16 initializes a count value N for periodically counting the number of shot frames to zero (S72 in FIG. 6).

Next, the CPU 16 controls the CCD image pickup device 13.
The calculation is performed on the basis of the image data from (1), and the appropriate aperture value, the appropriate exposure time, the white balance adjustment value, and the contrast amount are updated (S73 in FIG. 6). CPU16
Moves the photographing optical system 11 back and forth based on this contrast amount, and executes hill-climbing AF control (FIG. 6S
74).

After the completion of the AF control, the CPU 16 adjusts the aperture diameter (also used as a lens shutter) of the photographing optical system 11 in accordance with the appropriate aperture value (S75 in FIG. 6). Next, the CPU 16
Is a CCD image pickup device 13 via a CCD drive circuit 13a.
All unnecessary charges are discharged, and photoelectric storage of the subject image is newly started (S76 in FIG. 6). After the proper exposure time has elapsed in this state, the CPU 16 closes the lens shutter of the photographing optical system 11 and ends the photoelectric accumulation of the subject image (S77 in FIG. 6).

Subsequently, the CPU 16 controls the CCD driving circuit 1
Image data is sequentially read from the CCD image pickup device 13 via 3a (S78 in FIG. 6). The read image data is digitized via the A / D conversion circuit 14 and then taken into the image processing circuit 15. Image processing circuit 1
Reference numeral 5 denotes a memory 18 which performs white balance adjustment on the image data based on the white balance adjustment value described above,
(S79 in FIG. 6).

Here, the image processing circuit 15 determines whether or not the low resolution mode is set (S8 in FIG. 6).
0). If the high-resolution mode has been set at this point (NO in S80 in FIG. 6), the image processing circuit 15 does not execute the resolution conversion because the captured image data is used as it is. On the other hand, if the low-resolution mode has been set (YES in S80 in FIG. 6), the image processing circuit 15 reduces the resolution by thinning out pixels from the image data in the memory 18 (S81 in FIG. 6).

Next, the image processing circuit 15 determines whether the high compression mode is set (S82 in FIG. 6). If it is determined in step S82 that the mode is the high compression mode, the image processing circuit 15 determines whether the count value N is zero (S83 in FIG. 6). Here, when the count value N is zero (YES side of S83 in FIG. 6), the image processing circuit 15
Predicts image compression using a quantization table set for the high compression mode, and predicts the compression code amount of image data. The image processing circuit 15 updates the quantization table for the high compression mode to one that can obtain an appropriate high compression ratio based on the compression code amount predicted in this manner (S8 in FIG. 6).
4). If the count value N is not zero (NO in S83 in FIG. 6), the image processing circuit 15 proceeds to step S83.
The prediction calculation of the compression code amount in 84 is omitted at all.

Using the quantization table updated at the timing of (N = 0), the image processing circuit 15 executes compression of the image data (S85 in FIG. 6). On the other hand, if it is determined in step S82 that the mode is the low compression mode, the image processing circuit 15 determines whether the count value N is zero (S86 in FIG. 6). Here, when the count value N is zero (YES side of S86 in FIG. 6), the image processing circuit 1
Reference numeral 5 pre-executes image compression using the quantization table set for the low compression mode, and predicts the compression code amount of the image data. The image processing circuit 15 updates the quantization table for the low compression mode to one that can obtain an appropriate low compression rate based on the compression code amount predicted in this manner (S8 in FIG. 6).
7). If the count value N is not zero (NO in S86 in FIG. 6), the image processing circuit 15 proceeds to step S86.
The prediction calculation of the compression code amount in 84 is omitted at all.

Using the quantization table updated at the timing of (N = 0), the image processing circuit 15 executes the compression of the image data (S88 in FIG. 6). After the image compression is completed in accordance with the compression mode in this manner, C
The PU 16 converts the compressed image data into a file,
Temporary recording in the buffer area of the memory 18 (S8 in FIG. 6)
9).

Here, the CPU 16 checks the remaining capacity of the flash memory card 19 and the buffer capacity of the memory 18 to determine whether or not the continuous shooting operation can be continued (FIG. 6).
S90). At this point, if the remaining capacity of the flash memory card 19 is expected to be insufficient, or if the buffer capacity of the memory 18 is insufficient (NO in S90 in FIG. 6), the CPU 16
After the image files in the buffer area are collectively transferred and recorded on the flash memory card 19 (S94 in FIG. 6), the continuous shooting operation is interrupted and the operation returns to the main routine shown in FIG.

On the other hand, when the remaining capacity of the flash memory card 19 is sufficient and the buffer capacity of the memory 18 is sufficient (YES in S90 in FIG. 6), the CPU 16 determines whether or not the release button 22 is continuously pressed. (Fig. 6
S91). Here, when the release state of the release button 22 is released (NO side in S91 in FIG. 6), the CPU 16 collectively transfers and records the image files in the buffer area to the flash memory card 19 (S92 in FIG. 6), and then performs continuous shooting. The operation is terminated and the operation returns to the main routine shown in FIG.

When the release button 22 is continuously pressed (YES in S91 in FIG. 6), the CPU 16 increments the count value N by 1 (S93 in FIG. 6). next,
The CPU 16 determines whether or not the count value N has reached “3” (S94 in FIG. 6). Here, when the count value N has reached “3” (YES side of S94 in FIG. 6),
The CPU 16 returns the operation to step S72 and repeats the continuous shooting operation from the beginning. On the other hand, when the count value N has not reached “3” (NO in S94 in FIG. 6), the CPU 1
6 returns the operation to step S76 and repeats the continuous shooting operation from the middle. By the series of operations described above, the medium-speed continuous shooting operation is performed.

(Explanation of High-Speed Continuous Shooting Operation) FIG. 7 is a flowchart for explaining the high-speed continuous shooting operation. When the high-speed continuous shooting operation is started, the CPU 16 checks the battery state, the charged amount of the strobe, the remaining capacity of the flash memory card 19, and determines whether or not shooting is possible (S101 in FIG. 7).

If it is determined that photographing is not possible (NO in S101 in FIG. 7), the CPU 16 displays a warning on the LCD monitor 15a to that effect, and then returns to the main routine shown in FIG. On the other hand, if it is determined that shooting is possible (YES side of S101 in FIG. 7), the CPU 16
Perform an operation based on the image data from the image sensor 13,
The appropriate aperture value, the appropriate exposure time, the white balance adjustment value, and the contrast amount are updated (S10 in FIG. 7).
2).

The CPU 16 moves the photographing optical system 11 forward and backward based on this contrast amount, and performs a hill-climbing AF.
The control is executed (S103 in FIG. 7). After the completion of AF control,
The CPU 16 adjusts the aperture diameter (also used as the lens shutter) of the photographing optical system 11 in accordance with the appropriate aperture value (S10 in FIG. 7).
4). Next, the CPU 16 sweeps out all unnecessary charges of the CCD image sensor 13 via the CCD drive circuit 13a, and newly starts photoelectric storage of the subject image (S10 in FIG. 7).
5).

When the proper exposure time elapses in this state, C
PU 16 closes the lens shutter of the photographing optical system 11,
The photoelectric accumulation of the subject image is terminated (S106 in FIG. 7). Subsequently, the CPU 16 outputs C through the CCD drive circuit 13a.
Image data is sequentially read from the CD image pickup device 13 (S107 in FIG. 7). The read image data is digitized via the A / D conversion circuit 14 and then taken into the image processing circuit 15. The image processing circuit 15 performs white balance adjustment on the image data based on the white balance adjustment value described above, and then temporarily stores it in the memory 18 (S108 in FIG. 7).

Here, the image processing circuit 15 determines whether or not the low resolution mode is set (S10 in FIG. 7).
9). If the high-resolution mode has been set at this point (NO in S109 in FIG. 7), the image processing circuit 15 does not execute the resolution conversion because the captured image data is used as it is. On the other hand, if the low-resolution mode has been set (YES in S109 in FIG. 7), the image processing circuit 15
Reduces the resolution by thinning out the pixels from the image data in the memory 18 (S110 in FIG. 7).

Next, the image processing circuit 15 determines whether or not the high compression mode is set (S111 in FIG. 7).
If it is determined in step S111 that the mode is the high compression mode, the image processing circuit 15 determines whether or not it is the first frame of continuous shooting (S112 in FIG. 7). If it is the first frame in continuous shooting (YES in S112 in FIG. 7), the image processing circuit 15
Predicts image compression using a quantization table set for the high compression mode, and predicts the compression code amount of image data. The image processing circuit 15 updates the quantization table for the high compression mode to one that can obtain an appropriate high compression rate based on the compression code amount predicted in this manner (S11 in FIG. 7).
3). Further, in the case of the second and subsequent frames of continuous shooting (NO side in S112 in FIG. 7), the image processing circuit 15 omits the prediction calculation of the compression code amount in step S114 at all.

As described above, the image processing circuit 15 executes image compression during the continuous shooting period by continuously using the quantization table updated in the first continuous shooting frame (S114 in FIG. 7). On the other hand, if it is determined in step S111 that the mode is the low compression mode, the image processing circuit 15 determines whether or not it is the first frame of continuous shooting (S115 in FIG. 7). Here, if it is the first frame of the continuous shooting (YES side of S115 in FIG. 7), the image processing circuit 15
Predicts image compression using a quantization table set for the low compression mode, and predicts the compression code amount of image data. The image processing circuit 15 updates the quantization table for the low compression mode to one that can obtain an appropriate low compression ratio based on the compression code amount predicted in this manner (S11 in FIG. 7).
6). In the case of the second and subsequent frames of continuous shooting (NO in S115 in FIG. 7), the image processing circuit 15 omits the prediction calculation of the compression code amount in step S116 at all.

As described above, the image processing circuit 15 executes the image compression during the continuous shooting period by continuously using the quantization table updated in the first continuous shooting frame (S117 in FIG. 7). After completing the image compression in accordance with the compression mode in this way, the CPU 16 converts the compressed image data into a file and temporarily records it in the buffer area of the memory 18 (FIG. 7).
S118).

Here, the CPU 16 checks the remaining capacity of the flash memory card 19 and the buffer capacity of the memory 18 to determine whether or not the continuous shooting operation can be continued (FIG. 7).
S119). At this point, the flash memory card 19
If the remaining capacity is expected to be insufficient or the buffer capacity of the memory 18 is insufficient (NO in S119 in FIG. 7), the CPU
16 after transferring and recording the image files in the buffer area collectively to the flash memory card 19 (S12 in FIG. 7).
1) The continuous shooting operation is interrupted and the operation returns to the main routine shown in FIG.

On the other hand, when the remaining capacity of the flash memory card 19 is sufficient and the buffer capacity of the memory 18 is sufficient (YES in S119 in FIG. 7), the CPU 16 determines whether or not the release state of the release button 22 is continued. (S120 in FIG. 7). Here, if the release state of the release button 22 is released (NO in S120 in FIG. 7), the CPU 1
No. 6 after transferring and recording the image files in the buffer area collectively to the flash memory card 19 (S12 in FIG. 7).
1) End the continuous shooting operation and return to the main routine shown in FIG. When the release button 22 is continuously pressed (YES in S120 in FIG. 7), the CPU 16
Returns the operation to step S105, and repeats the continuous shooting operation. The high-speed continuous shooting operation is performed by a series of operations as described above.

(Effects of this Embodiment, etc.) By the operation of this embodiment described above, in the medium-speed continuous shooting operation, the following operations (a) to (d) are performed at a rate of three frames per four continuous shots. Is omitted.

(A) Update operation of appropriate exposure value and adjustment operation of aperture diameter accordingly (b) Update operation of contrast amount (detected value of focus adjustment state) and hill-climbing AF operation accordingly (c) White balance adjustment Value updating operation (d) Compressed code amount prediction operation Therefore, the operations of (a) to (d) are omitted,
The continuous shooting speed can be reliably increased.

The operations (a) to (d) are sampled at a rate of one frame for every four consecutive shots. Therefore, it is possible to accurately follow an operation parameter such as an exposure value even for a shooting target that gradually changes during a continuous shooting period, and to obtain almost appropriate image data over the continuous shooting period. It becomes possible. In the present embodiment, the operations (a) to (d) described above are omitted at all in the second and subsequent frames of the high-speed continuous shooting operation. for that reason,
In the high-speed continuous shooting operation, the continuous shooting speed can be further increased.

In such a high-speed continuous shooting mode, the subject itself does not change much and a fast continuous shooting speed is required, as in the case where the instantaneous expression of a person is to be reliably captured at a high continuous shooting speed. This is a continuous shooting mode suitable for a shooting situation where Further, in the present embodiment, the compressed image data is sequentially stored in the buffer area of the memory 18 in the medium-speed and high-speed continuous shooting operations. Therefore, it is not necessary to write the image data to the flash memory card 19 which is slow to write for each frame of continuous shooting, and the continuous shooting speed can be reliably increased.

In this embodiment, the compressed image data is stored in the buffer area of the memory 18. for that reason,
The use efficiency of the buffer area is much higher than the case where the image data before compression is stored in the buffer area, and it is possible to store image data of several times to several tens times in the buffer area. In the above-described embodiment, the appropriate aperture value and the appropriate aperture value are set based on the image data from the CCD image sensor 13.
Although the appropriate exposure time and white balance adjustment value are calculated, the present invention is not limited thereto. For example, a light receiving mechanism such as a photometric unit or a colorimetric unit may be separately provided to obtain these operation parameters.

In the above embodiment, the hill-climbing AF control is performed based on the contrast amount of the image data. However, the present invention is not limited to this method. For example, active ranging, passive ranging,
AF control such as a pupil division phase difference detection method may be performed.
Also in these AF controls, the continuous shooting speed can be reliably increased by omitting the operation of updating the distance measurement value and the defocus amount in at least one frame during continuous shooting.

Further, in the above-described embodiment, in the middle-speed continuous shooting operation, the operation of updating the operation parameters in photographing and the operation of predicting the compression code amount are executed at a rate of one frame per four continuous shots. Of course, the present invention is not limited to such design numerical values. Further, in the above-described embodiment, the continuous shooting is started by pressing the release button 22 in a state where any one of the continuous shooting modes is set. However, the starting operation of the continuous shooting in the present invention is not limited to this. Not something. For example, continuous shooting may be started in accordance with the continuation of the pressing operation of the release button 22.

[0069]

According to the first and second aspects of the present invention, the operation of updating the operation parameters is omitted for one or more frames during continuous shooting. Normally, the value of the operation parameter rarely changes significantly during continuous shooting. Therefore, even if the omission is performed as described above, the imaging unit is likely to generate almost appropriate image data. Also, by omitting the operation of updating the operation parameters, it becomes possible to omit the measurement operation of the object scene by the measuring means and the related control operation, etc., and it is possible to surely increase the continuous shooting speed by that much. It becomes possible.

(Claim 3) In the invention according to claim 3,
In one or more frames during continuous shooting, the operation of estimating the compression code amount is omitted. Normally, the image correlation between frames is high during continuous shooting, and the prediction result of the compression code amount does not greatly fluctuate greatly. Therefore, even if omitted as described above,
The image compression means is likely to perform image compression at a substantially appropriate compression ratio.

Further, by omitting the operation of estimating the amount of compressed code, it is possible to omit the operation time required for the estimating operation, and it is possible to reliably increase the continuous shooting speed for continuous shooting. Become. According to the third aspect of the invention, it is possible to reduce the total time required for image compression. Therefore, the time lag between the compression processing time and the exposure time can be reduced and the continuous shooting speed can be made more efficient by using the “technology for simultaneously performing the image compression processing and the exposure processing” described in the conventional example and the present invention in combination. And it becomes possible to increase synergistically.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic camera corresponding to the first to third aspects of the present invention.

FIG. 2 is a flowchart showing a main routine during photographing.

FIG. 3 is a flowchart illustrating a mode setting operation.

FIG. 4 is a flowchart illustrating a single shooting operation.

FIG. 5 is a flowchart illustrating a low-speed continuous shooting operation.

FIG. 6 is a flowchart illustrating a medium-speed continuous shooting operation.

FIG. 7 is a flowchart illustrating a high-speed continuous shooting operation.

[Explanation of symbols]

 Reference Signs List 11 shooting optical system 13 CCD image pickup device 13a CCD drive circuit 14 A / D conversion circuit 15 image processing circuit 15a liquid crystal monitor 16 CPU 17 system bus 18 memory 19 flash memory card 21 operation button group 22 release button 23 menu button 24 zoom button

Claims (3)

[Claims] 1. An imaging unit that forms an image by imaging light from a subject to generate image data, and a measurement that updates an operation parameter in imaging used by the imaging unit based on a measurement of an object scene. Means, and an electronic camera having a continuous shooting function including a continuous shooting means for continuously driving the imaging means and continuously shooting the subject image, wherein when the continuous shooting means performs continuous shooting, the measurement is performed. An electronic camera having a continuous shooting function, wherein the operation of updating the operation parameter is omitted in at least one frame during continuous shooting. 2. The electronic camera having a continuous shooting function according to claim 1, wherein the measuring unit is configured to detect an appropriate exposure value and a focus adjustment state used by the imaging unit based on a measurement of an object scene. An electronic camera having a continuous shooting function, wherein the electronic camera is means for updating at least one of white balance adjustment values. 3. An image capturing means for capturing an object image to generate image data, a compression predicting means for predicting a compression code amount of the image data generated by the image capturing means and updating a compression level of the image data. A continuous shooting function including: an image compression unit that performs image compression according to a compression level obtained from the compression prediction unit; and a continuous shooting unit that continuously drives the imaging unit to continuously shoot the subject image. In the electronic camera, when the continuous shooting unit performs continuous shooting, the compression prediction unit includes at least one frame during continuous shooting,
An electronic camera having a continuous shooting function, wherein a prediction operation of a compression code amount is omitted.