JP2004140879A - Digital camera and image processing method in digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the commercial value of a digital camera by adding a snap shot photographing function with which a photographing error hardly occurs. <P>SOLUTION: When an ON signal is sent from a still picture recording button 15a when recording a moving picture, a control core circuit 14 judges that still photographing for a snap shot is instructed from the outside, and a moving picture under photographing at present and a still picture desired to be recorded as the snap shot are parallel displayed on a display 9. During five seconds parallel displaying the still picture, a user can confirm whether or not the desired snap shot can be photographed on the display 9. Besides, photographed moving picture data and still picture data are filtered by a common image data correcting circuit 4. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a digital camera such as an electronic still camera and an image processing method that can be used in the digital camera. For example, the present invention relates to encoding and decoding of image data in accordance with MPEG (Moving Picture Expert Group) and JPEG (Joint Photographic Coding Expert Group) standards. It relates to the one provided with the function to perform.

In recent years, the demand for electronic still cameras has been growing more and more in place of cameras using silver halide photographic technology since the 19th century. In electronic still cameras, when transmitting and storing image data, the "JPEG" method is used as a data compression / expansion technique in order to compress the image data and reduce the amount of data for efficient processing. ing. This JPEG system is standardized by the JPEG committee (ISO / IEC 10918-1) under the umbrella of the ISO (International Organization for Standardization) / IEC (International Electro-technical Commission).

The JPEG method is also called a JPEG algorithm, and the core of the technology is a discrete cosine transform (DCT). The JPEG method is widely used not only for electronic still cameras but also for processing image data in a CD-ROM (CD-Read Only Memory) system or the like. In addition, since the moving image data can be compressed and expanded according to the JPEG method, some electronic still cameras using the JPEG method have a moving image photographing function. Such a technique of compressing and expanding moving image data using the JPEG method is called M-JPEG (Motion-JPEG).

By the way, the information handled in multimedia is enormous and diverse, and it is necessary to process such information at high speed in order to put multimedia into practical use. In order to process information at high speed, data compression / decompression technology is indispensable. As such a data compression / decompression technique, there is the “MPEG” method. This MPEG system is standardized by the MPEG Committee (ISO / IECJTC1 / SC29 / WG11) under the umbrella of ISO / IEC.

The core of the technology used in the MPEG video part is motion compensated prediction (MC) and DCT. An encoding technique using both MC and DCT is called a hybrid encoding technique. In other words, the MPEG system can be said to be a technology in which the MC is combined with the JPEG system. The MPEG system uses various storage media (video CD (Compact Disc), CD-ROM, DVD, video tape, memory card using nonvolatile semiconductor memory, etc.), various communication media such as LAN (Local Area Network), various It supports all transmission media including broadcast media (terrestrial broadcasting, satellite broadcasting, CATV (Community Antenna Television)).

In a digital camera such as an electronic still camera using the MPEG method, it is desired that a still image corresponding to one frame of a moving image can be recorded as a snapshot during the shooting of the moving image. For example, Patent Document 1 discloses a similar technique.
JP-A-11-75148

(4) In the conventional example, the result of the snapshot is confirmed after the end of the moving image shooting, and if there is a mistake in the shooting of the snapshot, it often cannot be retaken in terms of time. Even if two shooting modes, that is, a moving image and a snapshot, are provided, this is not a user-friendly design.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a digital camera capable of taking a snapshot with few errors and an image processing method in the digital camera.

The digital camera according to claim 1, further comprising: a still image encoding unit that encodes the image data as a still image; a moving image encoding unit that encodes the image data as a series of moving images; An image correction unit provided in an input path of the image data to a moving image encoding unit, for performing a filtering process on the image data, and a display unit for generating an image signal for displaying captured image data on a display; Control means for controlling the operation of each of the means, wherein the image correction means filters the image data for the still image coding means and the image data filtering processing for the moving image coding means. The control means displays the captured image data as a moving image on the display. That during a still image corresponding to a part of the moving image, and its gist to instruct the display means to be displayed on said display.

The digital camera according to claim 2, further comprising: a still image encoding unit that encodes the image data as a still image; a moving image encoding unit that encodes the image data as a series of moving images; An image correction unit provided in an input path of the image data to a moving image encoding unit, for performing a filtering process on the image data, and a display unit for generating an image signal for displaying captured image data on a display; Control means for controlling the operation of each of the means, wherein the image correction means filters the image data for the still image coding means and the image data filtering processing for the moving image coding means. The control means displays the captured image data as a moving image on the display. That while the image data captured at the timing corresponding to the shooting instruction signal of a still image, and its gist to instruct the display means to be displayed on said display.

According to a third aspect of the present invention, in the digital camera according to the first or second aspect, the image correction unit is configured to select a plurality of types of filtering processing of the image data for the still image encoding unit, and the plurality of types of filtering processing are performed. The gist is that a selection means for selecting a function is provided.

According to a fourth aspect of the present invention, in the digital camera according to any one of the first to third aspects, the image correction unit includes a filter unit and a storage unit that stores a coefficient for determining a filter function of the filter unit. Is the gist.

According to a fifth aspect of the present invention, in the digital camera according to any one of the first to fourth aspects, an image for one frame is provided in response to a still image shooting instruction signal while a moving image is displayed on the display. The gist of the present invention is to provide storage means for temporarily storing data.

7. The digital camera according to claim 6, further comprising: a still image encoding unit that encodes the image data as a still image; a moving image encoding unit that encodes the image data as a series of moving images; and the still image encoding unit. And an image correction means provided in an input path of the image data to the moving image encoding means for filtering the image data, and a display means for generating an image signal for displaying photographed image data on a display Storage means for temporarily storing one frame of image data in response to a still image recording instruction signal during the encoding processing by the moving picture encoding means, and control means for controlling the operation of each means The control means, while displaying the captured image data as a moving image on the display, a static image corresponding to a part of the moving image. Images, and its gist to instruct the display means to be displayed on said display.

In a digital camera according to a seventh aspect of the present invention, in the invention according to the sixth aspect, the image correction unit performs a filtering process of the image data for the still image encoding unit and a filtering process of the image data for the moving image encoding unit. The gist is that they differ from each other.

The gist of the digital camera of claim 8 is that, in the invention of claim 6 or 7, the image data of one frame stored in the storage means is image data before processing by the image correction means. .

According to a ninth aspect of the present invention, in the digital camera according to the eighth aspect, the control unit generates the image data stored in the storage unit as a still image after the end of the encoding process by the moving image encoding unit. The gist is to send the image data to the image correction means.

According to a tenth aspect of the present invention, in the invention of the sixth or seventh aspect, the image data for one frame stored in the storage unit is image data processed by the image correction unit. .

In the digital camera according to the eleventh aspect, in the invention according to any one of the first to tenth aspects, the control unit may display a still image displayed during display of a moving image on the display instead of the moving image. The gist of the present invention is to control the display means so that the display is performed.

In the digital camera according to the twelfth aspect, in the invention according to any one of the first to tenth aspects, in the still image and the moving image displayed in parallel, the still image is set and displayed on a main screen on the display. The gist of the present invention is to control the display means so as to cause the display.

A digital camera according to a thirteenth aspect of the present invention is the digital camera according to any one of the first to tenth aspects, wherein controlling the display means to set and display the moving image on a main screen on the display. I do.

According to a fourteenth aspect of the present invention, in the digital camera according to any one of the first to tenth aspects, one of the still image and the moving image is switchably selected, set on the main screen on the display, and displayed. The gist is to control the display means as described above.

According to a fifteenth aspect of the present invention, in the digital camera according to any one of the first to thirteenth aspects, the control means controls the display means to display the still image for a predetermined time. .

In a digital camera according to a sixteenth aspect, in the invention according to any one of the first to thirteenth aspects, the control unit sets the display unit to allow or prohibit display of the still image to be switchable. Make a summary.

According to a seventeenth aspect of the present invention, in the digital camera according to any one of the first to thirteenth aspects, the control unit controls the display unit to display the still image for a time according to a user's instruction. This is the gist.

The digital camera according to claim 18 is the digital camera according to any one of claims 5 to 17, wherein the control unit is configured to store the image stored in the storage unit after the end of the encoding processing by the moving image encoding unit. The gist of the present invention is to transmit data to the still image encoding means to record the data in the recording means.

The gist of the nineteenth aspect of the present invention is that, in the invention of any one of the first to eighteenth aspects, the encoding units of the still image encoding unit and the moving image encoding unit are shared.

An image processing method in a digital camera according to claim 20, wherein both of the image data to be encoded as a still image and the image data to be encoded as a moving image are subjected to filtering processing by a common image correcting means, A process for capturing a still image during capturing of a moving image; and a process for displaying the captured still image. The image correction unit performs filtering on image data to be encoded as the still image. The gist is that the processing and the filtering processing for the image data to be encoded as the moving image are different, and the display of the moving image and the display of the still image are performed in such a manner that they can be visually recognized simultaneously by a digital camera.

An image processing method for a digital camera according to a twenty-first aspect is characterized in that, in the invention according to the twentieth aspect, the image correcting means is configured to be capable of selecting a plurality of types of filtering processing for image data to be encoded as the still image. The gist is to perform a filtering process according to the selection signal.

An image processing method for a digital camera according to a twenty-second aspect is the image processing method according to the twentieth or twenty-first aspect, wherein the image correction unit includes a filter unit and a storage unit that stores coefficients for determining a filter function of the filter unit. This is the gist.

An image processing method in a digital camera according to claim 23, wherein both of the image data to be encoded as a still image and the image data to be encoded as a moving image are subjected to filtering processing by a common image correcting unit, In accordance with a still image encoding instruction signal during a moving image encoding process, the method includes a process of photographing, a process of photographing a still image during photographing of a moving image, and a process of displaying the photographed still image. One frame of image data is temporarily saved in a storage unit as image data to be encoded as a still image, and the display of the moving image and the display of the still image are performed in such a form that they can be visually recognized simultaneously by a digital camera. The main point is that

An image processing method for a digital camera according to a twenty-fourth aspect of the present invention is the image processing device according to the twenty-third aspect, wherein the image correcting means performs filtering on image data to be encoded as the still image and filtering on image data to be encoded as the moving image. The gist is that the processing is different from the processing.

According to a twenty-fifth aspect of the present invention, in the image processing method for a digital camera according to any one of the twentieth to twenty-fourth aspects, the simultaneously visible state is generated only for a predetermined time.

According to a twenty-sixth aspect of the present invention, in the image processing method for a digital camera according to the twenty-third aspect, the image data before being processed by the image correcting means is saved in the storage means.

According to a twenty-seventh aspect of the present invention, in the image processing method of the digital camera according to the twenty-third aspect, the image data processed by the image correcting unit is saved in the storage unit.

According to a twenty-eighth aspect of the present invention, in the image processing method for a digital camera according to the twenty-sixth or twenty-seventh aspect, after the moving image encoding processing, the filtering processing is performed on the image data saved in the storage unit.

According to a twenty-ninth aspect of the present invention, in the digital camera according to the twenty-sixth or twenty-seventh aspect, after recording a moving image, the image data saved in the storage unit is encoded as a still image. .

According to the present invention, the commercial value as a digital camera can be increased by adding a snapshot shooting function that is less likely to cause a shooting error.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block circuit diagram of an electronic still camera 1 using the JPEG and MPEG systems. The electronic still camera 1 includes an imaging device 2, a signal processing circuit 3, an image data correction circuit 4, a JPEG core circuit 5, an MPEG core circuit 6, a frame buffer 7, a display circuit 8, a display 9, a memory card 10, and an input / output circuit 11. , Data buses 12 and 13, a control core circuit 14, and a group of operation buttons 15.

The control core circuit 14 controls each of the components 2 to 13 of the electronic still camera 1 according to the ON / OFF signal of the operation button group 15. The operation button group 15 has a still image recording button 15a, a moving image recording button 15b, and other operation buttons 15c.

(4) The imaging device 2 is composed of a CCD (Charge Coupled Device) or the like, and captures a subject image to generate an output signal. The signal processing circuit 3 includes an A / D conversion circuit, performs A / D conversion on an output signal of the imaging device 2, and then performs white balance adjustment, gamma correction, and the like, so that, for example, the number of pixels is 1200 × The horizontal 1600 original image data is generated. The digital original image data generated by the signal processing circuit 3 is transferred to at least one of the frame buffer 7 and the display circuit 8 via the data bus 12.

(4) The display circuit 8 generates an image signal from the image data of each screen transferred via the data bus 12. The display 9 displays the image signal generated by the display circuit 8 as a subject image. The frame buffer 7 is composed of a rewritable semiconductor memory (for example, an SDRAM (Synchronous Dynamic RAM), a DRAM, a Rambus DRAM, etc.), and stores image data transferred via the data bus 12, that is, image data in frame units. At the same time, the stored image data is read out one screen at a time. In the frame buffer 7, a storage area 7a (hereinafter, referred to as a storage area) for temporarily saving the corresponding one frame of still image data according to the ON signal of the still image recording button 15a during the recording of the moving image. (Also referred to as an evacuation storage area 7a). Incidentally, the storage area 7a is an example of the "storage means" in the present invention.

The image data of each screen read from the frame buffer 7 is transferred to the image data correction circuit 4 via the data bus 12. The image data correction circuit 4 performs a later-described correction process on the image data input from the signal processing circuit 3. The image data for each screen after the correction processing generated by the image data correction circuit 4 is transferred to the JPEG core circuit 5 or the MPEG core circuit 6 via the data bus 12.

The memory card 10 is detachably mounted on the electronic still camera 1, and a flash memory 10a is provided in the memory card 10. The flash memory 10 a writes and stores the compressed image data of each screen transferred via the data bus 13, reads the stored compressed image data one screen at a time, and transfers the data to the data bus 13. The flash memory 10a is an example of the “recording unit” in the present invention.

The input / output circuit 11 outputs the image data for each screen transferred via the data bus 13 to an external device (for example, an external display, a personal computer, a printer, etc.) connected to the electronic still camera 1. At the same time, the image data input from the external device is transferred to the data bus 13. Image data read from the memory card 10 or image data input via the input / output circuit 11 is transferred to the JPEG core circuit 5 or the MPEG core circuit 6 via the data bus 13.

As shown in FIG. 2, the JPEG core circuit 5 includes a DCT circuit 16, a quantization circuit 17, a Huffman encoding circuit 18, a Huffman decoding circuit 19, an inverse quantization circuit 20, and an inverse DCT (Inverse DCT) circuit 21. Have been. In the JPEG core circuit 5, image data of one screen is divided into a plurality of macroblocks defined by the JPEG standard, and compression / expansion processing is performed for each block. Here, the DCT circuit 16, the quantization circuit 17, and the Huffman coding circuit 18 constitute a JPEG encoder, perform compression and coding processing of still image data, and perform a Huffman decoding circuit 19, an inverse quantization circuit 20, and an inverse DCT circuit. Reference numeral 21 denotes a JPEG decoder. The JPEG core circuit 5 (JPEG encoder) is an example of the “still image encoding unit” in the present invention.

The DCT circuit 16 captures image data of one screen in units of one block with respect to image data of one screen read from the frame buffer 7, and performs two-dimensional discrete cosine transform (DCT: DCT coefficients are generated by performing Discrete Cosine Transform. The quantization circuit 17 quantizes the DCT coefficient supplied from the DCT circuit 16 with reference to a quantization threshold stored in a quantization table stored in a RAM (not shown).

The Huffman encoding circuit 18 compresses the DCT coefficients quantized by the quantization circuit 17 by performing variable length encoding with reference to a Huffman code stored in a Huffman table stored in a RAM (not shown). The generated image data is generated one screen at a time. The compressed image data generated by the Huffman encoding circuit 18 is transferred to at least one of the memory card 10 and the input / output circuit 11 via the data bus 13.

The MPEG core circuit 6 is configured by adding first and second MC (prediction with motion compensation) circuits 22a and 22b to the JPEG core circuit 5. Therefore, the DCT circuit 16, the quantization circuit 17, the Huffman encoding circuit 18, the Huffman decoding circuit 19, the inverse quantization circuit 20, and the inverse DCT circuit 21 are shared by the JPEG core circuit 5 and the MPEG core circuit 6, and The switching signal from the core circuit 14 selects whether to use the JPEG core circuit 5 or to use the MPEG core circuit 6 to which the first and second MC circuits 22a and 22b are added. However, the quantization table and the Huffman table described above are separately provided in JPEG and MPEG.

In the MPEG core circuit 6, one screen of image data is divided into a plurality of macroblocks defined by the MPEG standard, and compression / expansion processing is performed for each block. Here, the DCT circuit 16, the quantization circuit 17, the Huffman encoding circuit 18, and the MC circuit 22a constitute an MPEG encoder, perform compression encoding of moving image data, and perform a Huffman decoding circuit 19, an inverse quantization circuit 20, The inverse DCT circuit 21 and the MC circuit 22b constitute an MPEG decoder. The MPEG core circuit 6 (MPEG encoder) is an example of the “moving image encoding unit” in the present invention.

Then, the compressed image data generated by the MPEG encoder is also transferred to at least one of the memory card 10 and the input / output circuit 11 via the data bus 13. In the JPEG core circuit 5 or the MPEG core circuit 6, the Huffman decoding circuit 19 decompresses the compressed image data of each screen transferred via the data bus 13 by performing variable length decoding with reference to the Huffman code. The generated image data is generated one screen at a time.

The inverse quantization circuit 20 generates DCT coefficients by inversely quantizing the decompressed image data for each screen generated by the Huffman decoding circuit 19 with reference to the quantization threshold. The inverse DCT circuit 21 performs a two-dimensional inverse discrete cosine transform (IDCT: Inverse DCT) on the DCT coefficient generated by the inverse quantization circuit 20. Here, in the MPEG core circuit 6, MC processing is performed by the second MC circuit 22b on the decompressed image data of each screen subjected to the inverse discrete cosine transform in the inverse DCT circuit 21.

The decompressed image data from the JPEG core circuit 5 or the MPEG core circuit 6 is transferred to the frame buffer 7 via the data bus 12. Then, the frame buffer 7 writes and stores the image data for each screen transferred from the JPEG core circuit 5 or the MPEG core circuit 6 via the data bus 12. Further, the display circuit 8 generates an image signal from image data of each screen transferred from the frame buffer 7 via the data bus 12, and the image signal is displayed on the display 9 as a subject image.

The image data correction circuit 4 includes a digital filter unit 23, a ROM 24, and a timing control unit 25, as shown in FIG. The digital filter unit 23 includes a spatial filter that is a non-circulating type digital filter, for example, a FIR (Finite Impulse Response) filter, and as shown in FIG. 4, converts an n-bit input signal input from the signal processing circuit 3 at each sampling period. , N + 1 multipliers 27..., And an adder 28 for convolving the signals from the multipliers 27. The coefficients an, an-1... A2, a1 of the multipliers 27 are coefficients for determining the characteristics of the filter, and are coefficients for filtering the moving image data and filtering the still image data. Are written in the ROM 24 in advance. The coefficient stored in the ROM 24 is set to an appropriate value by simulation at the manufacturing stage in advance.

For example, when filtering moving image data, a good low-pixel-density image is obtained by changing the value of each coefficient for each sampling cycle using a concept such as linear interpolation. As an example, consider the case where the number of pixels in the horizontal direction is reduced to 2/3. Now, tentatively, three pixels p1 to p3 are arranged horizontally in the original image, and these pixels are converted into two pixels q1 and q2 by a filtering process on moving image data. For this purpose, q1 and q2 are represented by first-order linear sums of p1, p2, and p3, respectively. In other words, the filtering process for reducing the data amount is realized by determining how much the number of pixels is reduced, the ratio thereof, and determining each coefficient of the linear sum by experiments or the like. As an example, the number of pixels may be reduced to, for example, 480 × 720. On the other hand, when filtering the still image data, a high-pass filter may be formed by setting the value of each coefficient so as to emphasize a high-frequency region. By doing so, it is possible to obtain a sharp image without deterioration of the edge portion, while keeping the number of pixels constant.

In the present embodiment, n is set to 8, but this naturally has a degree of freedom in design. The timing control unit 25 controls the timing of reading coefficients from the ROM 24, the timing of latching input / output data, the timing of filter operation, and the like, under the control of the control core circuit 14. Based on such a configuration, the recording operation of the image data will be described with reference to the flowcharts shown in FIGS.

In FIG. 5, when the still image recording button 15a is turned on, the still image processing shown in FIG. 6 is performed, and when the moving image recording button 15b is turned on, the moving image processing shown in FIG. 7 is performed.

(Still image recording)
In FIG. 6, an original image signal captured from the imaging device 2 is input to the signal processing circuit 3 at a timing corresponding to the ON signal of the still image recording button 15a, where it is converted into one screen of digital original image data. Then, it is taken into the frame buffer 7 (S1). Then, the original image data of one screen is sent from the frame buffer 7 to the image data correction circuit 4 and also sent to the display circuit 8 to display a still image on the display 9 (S2).

The data fetched by the image data correction circuit 4 is subjected to the above-described correction processing for a still image in the image data correction circuit 4 (S3), and the corrected data is input to the JPEG core circuit 5 and is subjected to predetermined compression. -After the encoding process is performed (S4), it is recorded in the flash memory 10a (S5).

(Moving image recording)
7, an original image signal captured from the imaging device 2 is input to the signal processing circuit 3 at a timing corresponding to the ON signal of the moving image recording button 15b, where it is converted into digital original image data for each screen. Then, the data is sequentially taken into the frame buffer 7 (S11). Then, the original image data for each screen is sent from the frame buffer 7 to the image data correction circuit 4 and also sent to the display circuit 8 to display the moving image on the display 9 (S12).

The data sequentially captured by the image data correction circuit 4 is subjected to the above-described correction processing corresponding to the moving image in the image data correction circuit 4 (S13), and the corrected data is input to the MPEG core circuit 6, and the predetermined data is output. After the compression / encoding process is performed (S14), it is recorded in the flash memory 10a (S15). This operation is continued until the ON signal is transmitted again from the moving image recording button 15b (S16).

(Snapshot recording)
In FIG. 7, when the ON signal is transmitted from the still image recording button 15a during the recording period of the moving image, the control core circuit 14 determines that the still photography for the snapshot has been instructed from the outside, and FIG. (S17).

8, when an ON signal is transmitted from the still image recording button 15a during the recording period of a moving image, one frame of image data is temporarily saved and stored in the saving storage area 7a of the frame buffer 7. (S21). During this evacuation operation, the moving image recording operation is continued as it is. That is, the original image signal captured from the imaging device 2 is input to the signal processing circuit 3, where it is converted into digital original image data for each screen and sequentially captured by the frame buffer 7 (S22). Then, the original image data for each screen is sent from the frame buffer 7 to the image data correction circuit 4 and also sent to the display circuit 8.

The data sequentially captured by the image data correction circuit 4 is subjected to the above-described correction processing corresponding to the moving image in the image data correction circuit 4 (S23), and the corrected data is input to the MPEG core circuit 6, where After the compression / encoding processing is performed (S24), the data is recorded in the flash memory 10a (S25). Here, in the present embodiment, the original image data for each screen is sent from the frame buffer 7 to the display circuit, and the image data for one frame saved in the save storage area 7a is also sent. By doing so, the moving image currently being photographed and the still image to be recorded as a snapshot are displayed in parallel on the display 9 (S26).

FIG. 9 shows an example in which a moving image and a still image are displayed in parallel on the display 9. A still image 100 is used as a main screen, and a moving image 200 is displayed at the upper right of the screen with a size of 1/16 of the screen. Let it.

Display of a still image is performed for a predetermined time (for example, 5 seconds), and after 5 seconds, the display is switched to display of only a moving image (S27), and the process returns to the normal moving image processing shown in FIG. 7 (S28). The user can confirm on the display 9 whether or not a desired snapshot has been taken within 5 seconds during which the still images are displayed in parallel.

{Circle over (5)} When the ON signal is transmitted again from the still image recording button 15a before the lapse of 5 seconds, the processing of S21 to S27 is performed based on the data taken in at the timing corresponding to the ON signal (S29). In this case, the contents of the save storage area 7a are replaced with new data. FIG. 10 is a diagram for explaining the use state of the frame buffer 7 in the moving image processing and the snapshot processing. In FIG. 1, the frame buffer 7 includes four normal storage areas A to D, and each of the storage areas A to D stores data for one screen (one frame). Of course, the number of storage areas is appropriately changed according to the specifications of the camera 1.

10, in the normal moving image processing shown in FIG. 7, as shown in FIG. 10A, digital original image data of each screen from the signal processing circuit 3 is sequentially arranged in the order of A → B → C → D. The data is stored and output to the data bus 12 in order from the first one (First-In First-Out). Then, when data is stored in the last storage area D, the storage area A is used again. That is, the storage areas A to D are used cyclically. For cyclic use of the frame buffer 7, an LRU (Least Recently Used) algorithm or another page memory control method may be employed.

During processing of a moving image, when an ON signal is transmitted from the still image recording button 15a for a snapshot, data captured at a timing corresponding to the ON signal is stored in a certain storage area, and the area is left as it is. It is used as a save area 7a for saving still image data. For example, when the data captured at the snapshot recording timing is stored in the third storage area C, the storage area C is used as the evacuation storage area 7a as shown in FIG. In the subsequent moving image processing, the storage areas A, B, and D are used cyclically. Thereafter, when the data captured again at the snapshot recording timing is stored in the second storage area B, the data in the third storage area C is canceled, that is, protected as shown in FIG. , The second storage area B is used as the evacuation storage area 7a, and the remaining storage areas A, C, and D are used cyclically in the subsequent moving image processing.

When the moving image recording ends, in FIG. 7, the control core circuit 14 determines whether or not the above-described still image saving operation has been performed during the moving image recording operation (S18), and the saving operation is performed. If so, the data for one frame stored in the save storage area 7a is transferred to the image data correction circuit 4 via the data bus 12, and the same processing as the above-described still image recording is performed (S19).

電子 The electronic still camera 1 of the present embodiment described above has the following functions and effects.

(1) Since a still image can be extracted as a snapshot during shooting of a moving image, the function as an electronic still camera is improved.

(2) Since the still image taken as a snapshot is displayed on the display 9, the user can easily confirm the shooting condition of the snapshot, and if he does not like it, he can take the snapshot again immediately. The degree of occurrence of mistakes can be reduced. Therefore, the commercial value of the electronic still camera can be increased.

(3) In addition to the above (2), since the moving image currently being photographed is displayed in parallel, the photographing state of the moving image can be checked in real time.

(4) In addition to the above (2) and (3), on the display 9, a still image to be recorded as a snapshot is used as the main screen, and the moving image is displayed in a small size of, for example, 1/16 of the screen. Can be checked very easily.

(5) In addition to the above (2), since a still image to be recorded as a snapshot is only temporarily displayed on the display 9, the work of confirming the recording of a moving image on the display 9 is hindered for a long time. There is no.

(6) As shown in FIG. 10, the evacuation storage area 7a is not provided until the still photography for the snapshot is instructed, and all are used as normal storage areas, so that the utilization efficiency of the frame buffer 7 is improved.

(7) The still image data can be corrected to a more optimal image by using the data correction circuit 4.

(8) Since the still image data as well as the moving image data are configured to pass through the data correction circuit 4, even if it is desired to perform a separate correction process on the still image, only the coefficients need to be stored in the ROM 24. Function can be improved at cost.

In addition, since it is not necessary to separately provide a correction circuit dedicated to a still image, it is possible to prevent an increase in the size of the device and an increase in power consumption.

(9) In the JPEG core circuit 5 and the MPEG core circuit 6, the DCT circuit 16, the quantization circuit 17, the Huffman encoding circuit 18, the Huffman decoding circuit 19, the inverse quantization circuit 20, and the inverse DCT (IDCT; Inverse DCT) circuit 21 Are shared, the configuration of the electronic still camera 1 and the arithmetic processing algorithm can be simplified.

(10) Since the evacuation storage area 7a is provided for the snapshot, the still image and the moving image can be easily classified and searched, and the reproduction can be performed more quickly.

(11) When still photography for a snapshot is instructed, one frame of image data before being input to the image data correction circuit 4 is temporarily saved and stored in the storage area 7a. When performing the filtering process in the data correction circuit 4, it is easy to perform the filtering process and the zoom process in the vertical direction, and it is possible to perform the moving image recording without interruption.

The present invention is not limited to the above-described embodiment, and may be modified as described below. Even in such a case, the same or more action and effect can be obtained.

(A) In S26 of FIG. 8, only a still image is displayed on the display 9.

(B) In S26 of FIG. 8, the sizes of the still image and the moving image to be displayed in parallel on the display 9 are reversed (the moving image is used as the main screen). In addition, the configuration is such that the user can specify whether to display a still image with a button or the like.

(C) In S29 of FIG. 8, image data for a newly shot snapshot is stored in parallel without replacing old data. That is, as shown in FIG. 11, in the normal moving image processing, the storage areas A to D of the frame buffer 7 are cyclically used (FIG. 11A).

Next, when the data captured at the timing of the first snapshot recording is stored in the third storage area C, the storage area C is used as the save storage area 7a (see FIG. 11B )), In the subsequent moving image processing, the other three storage areas A, B, and D are cyclically used.

When the data captured at the timing of recording the second snapshot is stored in the second storage area B, the second and third storage areas B and C are used as the evacuation storage area 7a. Then, in the subsequent moving image processing, the two storage areas A and D are used cyclically (alternately).

す る By doing so, a plurality of snapshots can be recorded. It should be noted that the more the number of snapshots that can be recorded, the more the area in which the frame buffer 7 can be used in moving image processing decreases as the number of snapshots increases, so that overflow of the frame buffer 7 does not occur during moving image processing. Must be set. Further, in this case, the control core circuit 14 may select any one of the recorded multiple snapshots and finally save the snapshot according to the operation of the selection button 15c or the like by the user. Good.

(D) In S29 of FIG. 8, the area for storing the image data for the newly captured snapshot is used by overwriting the area for storing the old data.

(E) Instead of the memory card 10, a magneto-optical disk, an optical disk, a magnetic disk, or the like is used.

(F) When still photography for a snapshot is instructed, the image data after the processing is completed by the image data correction circuit 4 is temporarily saved and stored in the save storage area 7a. In this way, when the JPEG core circuit 5 performs a predetermined compression process thereafter, the data extraction process can be easily performed.

(G) M-JPEG technology is used for compression / decompression of moving image data.

(H) For compression / expansion of still image data, in addition to JPEG, compression using difference YUV based on difference processing, block-based Hadamard transformation, slant transformation, and Haar transformation method -Use extension technology.

(Re) Although it has been described that one of the snapshot and the moving image is displayed on the main screen, a user may be able to select which is set on the main screen. The control core circuit 14 may switch which one is displayed on the main screen in accordance with the operation of the selection button 15c or the like by the user. Further, in accordance with the user's instruction, the control core circuit 14 may have a mode for prohibiting the display of the snapshot, or may display the snapshot only for the time when the user instructs the display.

FIG. 1 is a block circuit diagram of an electronic still camera according to an embodiment of the invention. FIG. 2 is a block diagram schematically illustrating a JPEG core circuit and an MPEG core circuit according to the embodiment. FIG. 2 is a block diagram schematically illustrating an image data correction circuit according to the embodiment. FIG. 3 is a circuit diagram illustrating a filter unit of the image data correction circuit according to the embodiment. 5 is a flowchart illustrating an operation of the electronic still camera according to the embodiment. 5 is a flowchart illustrating an operation of the electronic still camera according to the embodiment. 5 is a flowchart illustrating an operation of the electronic still camera according to the embodiment. 5 is a flowchart illustrating an operation of the electronic still camera according to the embodiment. FIG. 5 is a diagram showing a display screen when recording a snapshot of the electronic still camera according to the embodiment. FIG. 5 is a diagram for describing a use form of a frame buffer in the present embodiment. FIG. 11 is a diagram for describing another example of a usage pattern of the frame buffer in the present embodiment.

Explanation of reference numerals

Reference Signs List 1 electronic still camera 2 imaging device 3 signal processing circuit 4 image data correction circuit 5 JPEG core circuit 6 MPEG core circuit 7 frame buffer 8 display circuit 9 display 10 memory card 10a flash memory 11 input / output circuit 12, 13 data bus 14 control core Circuit 15a Still image recording button 15b Video recording button 15c Selection button 16 DCT circuit 17 Quantization circuit 18 Huffman encoding circuit 19 Huffman decoding circuit 20 Inverse quantization circuit 21 Inverse DCT circuit 22a, 22b MC circuit 23 Digital filter unit 24 ROM
25 timing control unit 26 delay unit 27 multiplier 28 adder

Claims (29)

A still image encoding unit that encodes image data as a still image, a moving image encoding unit that encodes the image data as a series of moving images, and a still image encoding unit and a moving image encoding unit. Image correction means provided in an input path of image data for filtering the image data, display means for generating an image signal for displaying photographed image data on a display, and controlling operations of the respective means The image correction means, wherein the image data filtering processing for the still image coding means and the image data filtering processing for the moving image coding means are different. Corresponds to a part of the moving image while displaying the captured image data as a moving image on the display. Digital camera still images, and characterized by instructing the display means to be displayed on the display that. A still image encoding unit that encodes image data as a still image, a moving image encoding unit that encodes the image data as a series of moving images, and a still image encoding unit and a moving image encoding unit. Image correction means provided in an input path of image data for filtering the image data, display means for generating an image signal for displaying photographed image data on a display, and controlling operations of the respective means The image correction means, wherein the image data filtering processing for the still image coding means and the image data filtering processing for the moving image coding means are different. Is a still image shooting instruction signal while displaying the shot image data as a moving image on the display. Digital camera wherein the image data photographed by corresponding timing, instructing said display means to be displayed on said display. A plurality of types of filtering processing of the image data for the still image encoding unit can be selected in the image correction unit, and a selection unit for selecting the plurality of types of filtering functions is provided. Item 3. The digital camera according to item 1 or 2. 4. The digital camera according to claim 1, wherein the image correction unit includes a filter unit and a storage unit that stores a coefficient that determines a filter function of the filter unit. 5. 5. A storage device according to claim 1, further comprising a storage unit for temporarily storing one frame of image data in response to a still image shooting instruction signal while a moving image is displayed on the display. The digital camera according to claim 1. Still image encoding means for encoding image data as a still image; moving image encoding means for encoding the image data as a series of moving images; and still image encoding means and moving image encoding means. An image correction unit provided in an input path of the image data, for performing a filtering process on the image data, a display unit for generating an image signal for displaying photographed image data on a display, and the moving image encoding unit Storage means for temporarily storing image data for one frame in accordance with a still image recording instruction signal during encoding processing by the CPU, and control means for controlling the operation of each means, wherein the control means While the captured image data is displayed as a moving image on the display, a still image corresponding to a part of the moving image is displayed on the display. Digital camera characterized by instructing the display means to cause shown. 7. The image correction unit according to claim 6, wherein a filtering process of the image data for the still image encoding unit is different from a filtering process of the image data for the moving image encoding unit. Digital camera. 8. The digital camera according to claim 6, wherein the image data for one frame stored in the storage unit is image data before being processed by the image correction unit. 2. The image processing apparatus according to claim 1, wherein the control unit sends the image data stored in the storage unit to the image correction unit to generate a still image after the encoding process by the moving image encoding unit is completed. 9. The digital camera according to 8. 8. The digital camera according to claim 6, wherein the image data for one frame stored in the storage unit is image data processed by the image correction unit. 11. The control device according to claim 1, wherein the control unit controls the display unit to display a still image displayed during display of a moving image on the display instead of the moving image. 2. The digital camera according to item 1. The control means controls the display means so as to set and display the still image on the main screen on the display, in the still image and the moving image displayed in parallel. The digital camera according to any one of items 10 to 10. The control unit controls the display unit to set and display the moving image on a main screen on the display, in the still image and the moving image displayed in parallel. The digital camera according to any one of items 10 to 10. The display means is configured to select one of the still image and the moving image so that the still image and the moving image can be switched between the still image and the moving image that are displayed in parallel and set and display the main image on the main screen on the display. The digital camera according to claim 1, wherein the digital camera is controlled. 14. The digital camera according to claim 1, wherein the control unit controls the display unit to display the still image for a predetermined time. 14. The digital camera according to claim 1, wherein the control unit sets the display unit to allow or prohibit display of the still image. 15. 14. The digital camera according to claim 1, wherein the control unit controls the display unit to display the still image for a time according to a user's instruction. The control means sends the image data stored in the storage means to the still image coding means in order to record the image data stored in the storage means after completion of the coding processing by the moving image coding means. The digital camera according to any one of claims 5 to 17, wherein: 19. The digital camera according to claim 1, wherein an encoding unit of the still image encoding unit and an encoding unit of the moving image encoding unit are shared. A common image correction unit filters both image data to be encoded as a still image and image data to be encoded as a moving image. A process of capturing an image and a process of displaying the captured still image, wherein the image correction unit performs filtering on image data to be encoded as the still image, and image data to be encoded as the moving image. And an image processing method in the digital camera, wherein the display of the moving image and the display of the still image are performed in such a manner that they can be visually recognized simultaneously by the digital camera. 21. The image correction unit according to claim 20, wherein a plurality of types of filtering processes for the image data to be encoded as the still image are configured to be selectable, and the filtering process is performed according to a selection signal from the selection unit. Image processing method in a digital camera. 22. The image processing method according to claim 20, wherein the image correction unit includes a filter unit and a storage unit that stores a coefficient for determining a filter function of the filter unit. A common image correction unit filters both image data to be encoded as a still image and image data to be encoded as a moving image. A process of photographing an image and a process of displaying the photographed still image, wherein one frame of image data is taken as a still image according to a still image encoding instruction signal during the moving image encoding process. An image processing method in a digital camera, wherein image data to be encoded is temporarily saved in storage means, and the display of the moving image and the display of the still image are performed in a form that can be visually recognized simultaneously by the digital camera. . 24. The digital camera according to claim 23, wherein in the image correction unit, a filtering process for image data to be encoded as the still image and a filtering process for image data to be encoded as the moving image are different. Image processing method. 25. The image processing method according to claim 20, wherein the simultaneously visible state is generated only for a predetermined time. 25. The image processing method according to claim 23, wherein the image data before being processed by the image correction unit is saved in the storage unit. 25. The image processing method according to claim 23, wherein the image data processed by the image correction unit is saved in the storage unit. 28. The image processing method in a digital camera according to claim 26, wherein the filtering process is performed on the image data saved in the storage unit after the moving image encoding process. 28. The image processing method according to claim 26, wherein the image data saved in the storage unit is encoded as a still image after recording the moving image.

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