JP2003199052A - Image data transferring device, its method, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize a memory. <P>SOLUTION: An image data transferring device comprises a fifth transfer unit 26' for inputting image data compressed its data quantity by a JPEG processing unit 21, transferring the image data to a memory 17 to be stored therein, measuring quantity of the image data inputted from the JPEG processing unit 21, having the image data stop to be transferred to the memory 17 when the quantity of the image data is decided to exceed a predetermined limit value before informing the fact of exceeding of the predetermined limit value to a system controller (28), and having the JPEG processing unit 21 change its compression rate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data transfer device, an image data transfer method and an image pickup device suitable for, for example, a digital still camera.

[0002]

2. Description of the Related Art Recently, with the spread of personal computers, a silver salt camera using a silver salt film has been replaced by
Digital still cameras that record image data of digital values obtained by shooting on a memory card are also becoming widespread.

FIG. 5 illustrates a partial circuit configuration of a digital still camera of this type. In the figure, an optical image of a subject obtained by the optical lens system 11 is formed on the CCD 12 which is an image pickup device.

The CCD 12 has, for example, color filters of primary color Bayer array formed integrally on the image pickup surface,
The color image data (hereinafter abbreviated as “Bayer data”) obtained by the image pickup is stored in the sample hold circuit (S / S).
H) 13 is sequentially sampled and held, then digitized by the A / D converter 14 and sent to the line processing unit 15.

The line processing unit 15 collects sequentially transmitted Bayer data on a line-by-line basis, and the collected Bayer data on a line-by-line basis is transferred to the first transfer unit 16.
Is transferred to the memory 17, which is a buffer memory, and expanded and stored.

When the Bayer data for the required number of lines have been developed on the memory 17, the second transfer unit 18 reads the Bayer data into the YUV conversion unit 19 in block units.

The YUV conversion unit 19 performs interpolation processing and color space processing to convert the Bayer data of the primary color system into YUV data which is color image data of the luminance color difference system. The YUV data thus obtained is Switch (S
W) is sent to the JPEG processing unit 21 via the switch 20 and is expanded and stored in the memory 17 by the third transfer unit 23 via the switch 22.

The YUV data expanded and stored in the memory 17 is transferred to the display control unit 25 by the fourth transfer unit 24, and an analog video output signal is created by the display control unit 25. Signals are created and output respectively.

Further, in the JPEG processing section 21, the YUV transmitted from the YUV conversion section 19 via the switch 20.
Data compression processing such as ADCT (Differential Discrete Cosine Transform) processing and Huffman coding is performed on the data to obtain coded JPEG data with a significantly reduced data amount. The JPEG data thus obtained is 5 is transferred to and stored in the memory 17 by the transfer unit 26.

The JPEG data expanded and stored in the memory 17 is recorded on a memory card as a recording medium.

On the other hand, the JPEG data read from the memory card in the reproduction mode is stored in the memory 17 and then read by the sixth transfer unit 27, and the JP data is read again.
The YUV data is transferred to the EG processing unit 21, restored to the original YUV data, transferred to the memory 17 by the third transfer unit 23 via the switch 22 and stored therein, and then transferred to the display control unit 25 by the fourth transfer unit 24. Be served.

However, the operation of each of the above circuits is CP
The system controller 28 including U controls the operation of the system controller 28 in response to a key operation signal directly input from a key input unit 29 including a shutter switch, a mode key, and the like. .

[0013]

In the configuration as shown in FIG. 5, the JPEG processing section 21 has the YUV sent from the YUV conversion section 19 via the switch 20.
When JPEG data encoded by performing data compression processing on the data is obtained and the obtained JPEG data is expanded and stored in the memory 17 by the fifth transfer unit 26, all the JPEG data corresponding to one image is stored in the memory. Only after being expanded and stored in 17 can the total capacity of the JPEG data be known.

Therefore, the quantization table used in the JPEG processing section 21 is controlled to generate the JPEG after generation.
When it is attempted to suppress the amount of data to a certain target data amount or less, conventionally, data compression processing is performed once to obtain coded JPEG data, and the obtained JPEG data is passed to the memory 17 by the fifth transfer unit 26. After expanding and storing, the total data amount was measured, and when the measured data amount exceeded the target data amount, such as when the high-frequency component of the image was larger than expected, the quantization table was variably set again. After that, the data compression process was redone.

Therefore, not only the data compression process may take a long time, but also the JPE of the memory 17 may be required.
As an area for storing the G data, it is necessary to secure a capacity having a margin of, for example, about 1.5 to 2 times the target data amount, and the capacity of the memory 17 can be effectively used. There was also a problem in that it did.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an image data transfer device, an image data transfer method, and an image pickup device which can effectively utilize a memory. Especially.

[0017]

The invention according to claim 1 is
Transfer means for transferring to the memory the image data compressed from the processing circuit and having a compressed data amount, and determining whether or not the amount of the image data transferred to the memory by the transfer means exceeds a preset limit value. And a stop means for stopping the transfer of the image data to the memory by the transfer means when it is determined that the limit value is exceeded.
When the determination means determines that the limit value is exceeded, a notification means for notifying the fact is provided.

With such a configuration, when it is determined that the amount of image data to be transferred to the memory exceeds the limit value, the transfer to the memory is immediately stopped, and to that effect a control system governing the operation of the processing circuit. Therefore, the data compression processing by the processing circuit can be started at an early timing with a new compression rate, and the data compression can be surely performed in the memory having only the capacity of the limit value without wasting the processing time unnecessarily. It is possible to transfer the applied image data.

According to a second aspect of the present invention, in the first aspect of the invention, there is provided a measuring means for measuring the total amount of image data input from the processing circuit, and the notifying means is:
Further, it is characterized by including means for notifying the total amount of image data measured by the above-mentioned measuring means.

According to this structure, in addition to the operation of the invention described in claim 1, by measuring the total amount of the image data determined to have exceeded the limit value and notifying the processing circuit, the processing is performed. The circuit can accurately calculate the compression rate when the image data is compressed so that the data amount will not exceed the limit value.

According to a third aspect of the present invention, in the first aspect of the present invention, the determining means determines whether or not the designated address of the image data transferred to the memory and stored therein exceeds a preset limit address. It is characterized by doing.

With such a configuration, in addition to the operation of the invention described in claim 1, it is possible to determine whether or not the limited data amount is exceeded by the address designating the storage destination at the time of transfer. Therefore, it is possible to easily determine the excess of the data amount.

According to a fourth aspect of the invention, in the first aspect of the invention, there is provided counting means for counting the amount of image data transferred to the memory by the transferring means,
The determination means is characterized by determining whether or not the count value counted by the counting means exceeds a preset limit count value.

According to this structure, in addition to the operation of the invention described in claim 1, it is determined whether or not the limited data amount is exceeded by directly counting the amount of image data to be transferred. By doing so, it is possible to easily determine the excess of the data amount.

According to a fifth aspect of the present invention, in the first aspect of the present invention, there is provided measuring means for measuring the amount of image data input from the processing circuit, and the determining means is measured by the measuring means. It is characterized by determining whether or not the amount of image data to be stored exceeds a preset limit value.

With such a configuration, in addition to the operation of the invention described in claim 1, whether the amount of image data input from the processing circuit is directly measured to exceed the limited data amount. By determining whether or not the data amount is exceeded, it is possible to easily determine.

According to a sixth aspect of the present invention, the transfer step of transferring the image data compressed from the processing circuit to the memory and the amount of the image data transferred to the memory in this transfer step are set in advance. A determination step of determining whether or not the limit value is exceeded, a stop step of stopping the transfer of the image data to the memory by the transfer step when it is determined that the limit value is exceeded in the determination step, and the determination step. When it is determined that the limit value is exceeded, a notification step of notifying the fact is provided.

With this method, the transfer to the memory is stopped immediately when it is determined that the amount of image data to be transferred to the memory has exceeded the limit value, and to that effect a control system governing the operation of the processing circuit. Therefore, the data compression processing by the processing circuit can be started at an early timing with a new compression rate, and the data compression can be surely performed in the memory having only the capacity of the limit value without wasting the processing time unnecessarily. It is possible to transfer the applied image data.

According to a seventh aspect of the present invention, image pickup means for picking up a subject image and outputting the image data, compression means for compressing the image data output from the image pickup means, and image data compressed by the compression means. Means for transferring and storing the data in a memory, a determining means for determining whether or not the amount of image data transferred by the transferring means to the memory exceeds a preset limit value, and the determining means exceeds the limit value. And a control means for changing the compression ratio of the compression means when it is determined that the limit value is exceeded by the determination means. It is characterized by having done.

With such a configuration, at the time when it is determined that the amount of image data to be transferred to the memory for buffer storage of the image data obtained by imaging before recording the image data on the recording medium exceeds the limit value. Immediately stop the transfer to the memory, you can start the data compression process with a new compression rate at an early timing by the compression means, without wasting the processing time wastefully, and ensure the memory with only the capacity of the limit value. It is possible to transfer image data that has undergone data compression.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a digital still camera will be described below with reference to the drawings.

The basic circuit structure of the whole is almost the same as that described with reference to FIG. 5, the same parts are designated by the same reference numerals, and the illustration and description thereof will be omitted.

FIG. 1 specifically shows only the JPEG processing section 21, the fifth transfer section 26 ', and the memory 17 as extracted. In the figure, the fifth transfer unit 26 'composed of a DMA controller (DMAC) is a JPEG processing unit 2 at the time of shooting.
When transferring the JPEG data sent from the memory 1 to the memory 17, the memory 17 sends and receives data together with control signals such as address designation and write enable signal. Transfer base address register and limit address register described later. , A transfer address register, an all data input counter, a data output counter, and a data over flag register.

Next, the operation of the above embodiment will be described.

FIG. 2 mainly shows the system controller 2.
8'shows the general processing contents when a still image is photographed by 8 '. At the beginning, the system controller 28 '
By repeatedly determining whether or not the shutter switch of the key input unit 29 is turned on, the operation is awaited (step A01).

Then, when it is determined that the shutter switch is turned on, one screen of image (Bayer) data is captured by the CCD 12 as photographic processing subsequent to AE (automatic exposure) processing) and AF (automatic focusing) processing. Capture (Step A0
2).

The acquired Bayer data is digitized via the sample hold circuit 13 and the A / D converter 14, and is collected in line units by the line processing unit 15 to obtain the first data.
The data is expanded and stored in the memory 17 by the transfer unit 16 (step A03).

Here, the system controller 28 'is set to 1
It is determined whether or not the Bayer data for the screen has been expanded and stored in the memory 17 (step A04), and if not yet, the processing from step A02 is repeatedly executed.

Then, in step A04, when the Bayer data for one screen is expanded and stored in the memory 17, the system controller 28 'judges this, and this time, the second transfer unit 18 shifts the memory 17 to the YUV conversion unit 19. The Bayer data read / transfer process is executed in block units (step A05) to sequentially convert the Bayer data into YUV data.

At this time, the YUV conversion unit 19 converts the sequentially sent Bayer data into YUV data and sends it to the JPEG processing unit 21 via the switch 20, and the JPEG processing unit 21 converts the YUV data into system data. Immediate data compression is performed at a compression rate based on the quantized data provided from the controller 28 'to generate JPEG data, which is transferred to the memory 17 by the fifth transfer unit 26' and stored therein.

However, the system controller 28 'is
The second transfer unit 18 determines whether or not all the Bayer data for one screen has been read from the memory 17 and transferred to the YUV conversion unit 19 (step A06), and if not yet, the processing from step A05 is repeatedly executed. .

Thus, at step A06, when it is determined that all the Bayer data for one screen is read from the memory 17 by the second transfer section 18 and transferred to the YUV conversion section 19 to be converted into YUV data, the system controller 28 '. Next reads the data over flag from the fifth transfer unit 26 (step A07).

This is because the last block of the YUV data for one screen is sent through the switch 20 to the JPEG processing unit 2.
The data is compressed at 1 to generate the corresponding JPEG data, and is executed at a timing after being appropriately read to the fifth transfer unit 26 ', and the content of the read data over flag is "1". Depending on whether or not there is JPEG
One screen worth of J generated by the processing unit 21 by data compression
It is determined whether or not all the PEG data has been transferred to the memory 17 without exceeding a predetermined data amount prepared in advance in the memory 17 (step A08).

This is executed by the system controller 28 'corresponding to the detailed processing contents of the fifth transfer unit 26' which will be described later, and the data over flag read from the fifth transfer unit 26 'is "1". If it is "0" instead of ", it is determined that the JPEG data for one screen generated by the data compression in the JPEG processing unit 21 has been transferred to the memory 17 without exceeding the predetermined data amount. Then, the JPEG data stored in the memory 17 is transferred as it is to the memory card which is a recording medium and recorded (step A09).

Further, in step A08, the fifth transfer unit 26 '
If the data over flag read from is “1”, J
One screen of JPEG data generated by data compression in the PEG processing unit 21 exceeds a predetermined data amount and is stored in a transfer area for storing a predetermined amount of JPEG data provided in the memory 17. If it is determined that the data cannot be delivered, then the count values of all data input counters, which will also be described later, are read from the fifth transfer unit 26 '(step A10), and J for one screen represented by the count value is read.
A quantization table for instructing a new data compression rate is determined based on the total amount of PEG data, and this is determined by JPEG.
After setting in the processing unit 21 (step A11), the process returns to step A05 again.

FIG. 3 mainly illustrates processing contents when the JPEG data is read from the JPEG processing unit 21 and transferred and stored in the memory 17 by the fifth transfer unit 26 'shown in FIG.

At the beginning, step A05 in FIG. 2 above.
The system controller 28 'synchronizes with the start of the Bayer data reading in the fifth transfer unit 26'.
On the other hand, a transfer base address setting process that represents the start address when the JPEG data is transferred and stored in the memory 17 is executed (step B01), and then the same memory 1 is used.
After executing the setting process of the limit address indicating the end address when the JPEG data is transferred and stored on the device 7 (step B02), the start of the transfer process is instructed (step B03). In this case, each address is in 1-byte units.

Upon receiving this instruction, the fifth transfer unit 26 'first designates, as an initial setting, the transfer base address which is the above-mentioned start address as the transfer address (step B04), and then the JPEG processing unit. The value of the total data input counter that counts the data amount of all the JPEG data for one screen input from 21 is cleared to "0" (step B05), and the data over flag is also notified to the system controller 28 '. "0" is set (step B06).

Thereafter, the JPEG processing unit 21 sends JPEG
Input 1 byte of data (step B07), update the count value of all data input counter by "+1" (step B08), and output to the memory 17 depending on whether the transfer address exceeds the limit address. It is determined whether the total amount of JPEG data to be processed exceeds a preset amount (step B09).

If it is determined that the transfer address does not exceed the limit address and the total amount of JPEG data to be output to the memory 17 does not exceed the preset amount, the data is input from the JPEG processing unit 21 in step B07. One byte of the JPEG data is output to the address position designated by the transfer address of the memory 17 and stored (step B10), after which the transfer address is updated and set to "+1" (step B11), and then the JPEG processing unit 21 Confirms that the JPEG data is still input (step B12) and returns to the processing from step B07.

By repeatedly executing the processing of steps B07 to B12 in this way, the fifth transfer unit 26 'is set to the JPE.
JPEG data is input from the G processing unit 21 byte by byte, transferred to the memory 17, and stored therein. During this period, the transfer address and the count value of the all data input counter are sequentially updated and set by "+1".

However, when it is determined in step B12 that there is no more JPEG data to be input from the JPEG processing unit 21 before the value of the transfer address exceeds the value of the limit address, that is, the JPE set in the memory 17 in advance.
When all the JPEG data for one screen can be transferred and stored within the range of the G data transfer area, the series of processing in FIG.
To prepare for the transfer of PEG data, the above step B0 is performed again.
Return to processing from 1.

In this case, since the data over flag notified to the system controller 28 'remains "0", this is judged at step A08 in the processing of FIG. 2 and is transferred and stored in the memory 17 at step A09. One screen of JPEG data is recorded as it is on the memory card, which is a recording medium.

In step B12, the JPEG processing unit 2
If it is determined in step B09 that the value of the transfer address exceeds the value of the limit address before it is determined that there is no more JPEG data to be input from 1, that is, the range of the transfer area of the JPEG data set in the memory 17 in advance. If it is determined that it is not possible to transfer and store all the JPEG data for one screen within the memory, the transfer output of the JPEG data to the memory 17 and the update setting of the transfer address are stopped, and the system controller 28 Until the data over flag notified to ′ is set to “1” (step B13), it is determined in step B12 that there is no more JPEG data to be input from the JPEG processing unit 21.
The processes of steps B07 to B09, B13 and B12 are repeatedly executed.

As a result, while the transfer and storage of the JPEG data to the memory 17 is stopped, the input of the JPEG data from the JPEG processing unit 21 and the counting operation of the all data input counter accompanying it are continued.

When it is determined in step B12 that there is no more JPEG data to be input from the switch 20, the series of processes shown in FIG. 3 are once ended, and the compression rate is changed again for the same screen. In order to transfer and store the JPEG data of 1 to the memory 17 from the beginning, the process returns to step B01.

In this case, since the data over flag notified to the system controller 28 'is "1", this is judged in step A08 in the processing of FIG. 2, and the count of all data input counters in steps A10 and A11. The value is read by the system controller 28 ', a quantization table of a new data compression rate corresponding to the data amount is set, and the data compression processing in the JPEG processing unit 21 is re-executed.

As described above, when it is determined that the amount of JPEG data to be transferred to and stored in the memory 17 exceeds the preset limit value, the transfer to the memory 17 is stopped and a message to that effect is indicated by the data over flag. Notify the system controller 28 '.

Therefore, while suppressing the memory usage and eliminating the process of writing the JPEG data to the memory 17 after determining that the limit value has been exceeded, the quantization table is rewritten and the JPEG data is written at a new compression rate. The JPEG processing by the processing unit 21 can be started, and the JP that surely compresses the data in the memory 17 having only the capacity of the limit value is used.
It becomes possible to transfer and store the EG data.

At this time, JPEG input from the JPEG processing unit 21 regardless of the determination result as to whether or not the amount of JPEG data transferred and stored in the memory 17 exceeds the limit value.
The total amount of data is counted by the all data input counter.

Therefore, the JPEG processing unit 21 accurately recognizes the data amount of the JPEG data determined to have exceeded the limit value that can be stored in the memory 17, and the JPEG processing unit 21 next determines the data amount. It is possible to accurately calculate the compression rate when the JPEG processing is performed on the YUV data so as not to exceed the limit.

In addition, in the above embodiment, the memory 17
Whether the amount of JPEG data transferred to and stored in the memory exceeds a preset limit amount is determined by whether the specified address of the JPEG data transferred to and stored in the memory 17 exceeds the limit address. Therefore, it is possible to easily determine the excess of the data amount.

In FIG. 3, it is determined whether or not the amount of JPEG data transferred and stored in the memory 17 by the fifth transfer unit 26 'exceeds the limit value based on the relationship between the transfer address and the limit address. However, the present invention is not limited to this, and the J input from the JPEG processing unit 21 is not limited to this.
In addition to the total data input counter that counts the amount of PEG data, an output counter that outputs to the memory 17 may be used to determine whether or not the limit value has been reached.

FIG. 4 is thus mainly shown in FIG.
5 illustrates another processing content when the JPEG data is read from the JPEG processing unit 21 by the fifth transfer unit 26 ′ shown in FIG.

At the beginning, step A05 in FIG.
The system controller 28 'synchronizes with the start of the Bayer data reading in the fifth transfer unit 26'.
On the other hand, a transfer base address setting process that represents the start address when transferring and storing the JPEG data to the memory 17 is executed (step C01), and then the data amount when transferring and storing the JPEG data to the memory 17 is counted. After setting the limit count value of the output counter (step C02), the start of the transfer process is instructed (step C03). Even in this case, each address is 1
It shall be in bytes.

Upon receiving this instruction, the fifth transfer unit 26 'first designates the transfer base address, which is the above-mentioned start address, as the transfer address as the transfer destination address as an initial setting (step C04), and then outputs the output counter. Value is cleared to "0" (step C05), and JP
The value of the total data input counter that counts the data amount of all the JPEG data for one screen input from the EG processing unit 21 is also cleared to "0" (step C06), and the data over is notified to the system controller 28 '. The flag "0" is set in the flag (step C0
7).

Thereafter, the JPEG processing unit 21 sends JPEG
Input 1 byte of data (step C08), update the count value of all data input counters by "+1" (step C09), and check if the count value of the output counter is smaller than the limit count value. Depending on this, it is determined whether the total amount of JPEG data output to the memory 17 is less than a preset amount (step C10).

Here, if it is determined that the count value of the output counter has not reached the limit count value and the total amount of JPEG data output to the memory 17 is less than the preset amount, the JPEG processing unit in step C08 described above. 21
1 byte of the JPEG data input from is output to an address position designated by the transfer address of the memory 17 and stored (step C11), and then the transfer address is set to "+".
1 "is updated and set (step C12), and at the same time, the count value of the output counter is also updated and set to" +1 "(step C13), and it is confirmed that JPEG data is still input from the JPEG processing unit 21 (step C14). ), And the process returns from step C08 again.

By repeatedly executing the processing of steps C08 to C14 in this way, the fifth transfer unit 26 'is set to the JPE.
JPEG data is input from the G processing unit 21 byte by byte, transferred to the memory 17, and stored therein. During this period, the transfer address and the count values of all data input counters and output counters are sequentially updated and set by "+1".

However, before the count value of the output counter becomes equal to the limit count value, in step C14 J
If it is determined that there is no more JPEG data to be input from the PEG processing unit 21, that is, one screen worth of J is set within the range of the JPEG data transfer area preset in the memory 17.
When all of the PEG data can be transferred and stored, the series of processing shown in FIG.
To prepare for the transfer of the JPEG data for the screen, the processing is returned to step C01.

In this case, since the data over flag notified to the system controller 28 'remains "0", this is judged at step A08 in the processing of FIG. 2 and is transferred and stored in the memory 17 at step A09. One screen of JPEG data is recorded as it is on the memory card, which is a recording medium.

In step C14, the JPEG processing unit 2
If it is determined in step C10 that the count value of the output counter becomes equal to the limit count value before it is determined that there is no more JPEG data input from 1, that is, in the transfer area of the JPEG data set in the memory 17 in advance. If it is determined that the entire JPEG data for one screen cannot be transferred and stored within the range, the transfer output of the JPEG data to the memory 17, the transfer address and the update setting of the output counter are stopped here. , "1" is set to the data over flag notified to the system controller 28 '(step C15), and then step C
Until it is determined that there is no more JPEG data input from the JPEG processing unit 21 in step 14, steps C08 to C10,
The processing of C15 and C14 is repeatedly executed.

As a result, while the transfer and storage of the JPEG data to the memory 17 is stopped, the input of the JPEG data from the JPEG processing unit 21 and the counting operation of the all data input counter accompanying it are continued.

When it is determined in step C14 that there is no more JPEG data to be input from the switch 20, the series of processes shown in FIG. 4 is temporarily terminated, and the compression rate is changed again for the same screen. In order to transfer and store the JPEG data of 1 to the memory 17 from the beginning, the process returns to the processing from step C01.

In this case, since the data over flag notified to the system controller 28 'is "1", this is judged in step A08 in the processing of FIG. 2, and the count of all data input counters in steps A10 and A11. The system controller 28 'reads the value, a new quantization table of the data compression rate corresponding to the data amount is set, and the data compression processing in the JPEG processing unit 21 is re-executed.

As described above, whether or not the amount of JPEG data transferred to and stored in the memory 17 exceeds a preset limit amount is directly counted, and the count value of the JPEG data transferred to and stored in the memory 17 is directly counted. Since it is determined whether or not exceeds the preset limit count value, it is possible to easily determine that the data amount is exceeded.

In FIG. 4, an output counter is provided,
Although it is determined whether or not this count value exceeds a preset limit count value, it is determined whether or not the count value of all data input counters exceeds a preset limit count value without providing an output counter. By doing so, it may be determined whether or not the amount of JPEG data transferred to and stored in the memory 17 exceeds a preset limit amount.

In addition, in FIGS. 2 to 4 described above, the fifth transfer unit 2
A data over flag is provided in 6'to allow the system controller 28 'to read it. However, if the data over flag is not provided and the amount of JPEG data to be transferred to and stored in the memory 17 exceeds a preset limit amount. At the time of determination, a signal indicating that fact may be actively output to the system controller 28 '.

Further, steps A10 and A11 in FIG.
Then, the count value of the all-data input counter is read from the fifth transfer unit 26 'to calculate the compression ratio of the JPEG data to be transferred and stored in the memory 17 next. If a quantization table based on the data compression rate of is prepared, and it is determined that the data amount of one screen of JPEG data compressed by the JPEG processing unit 21 exceeds the limit value stored in the memory 17, The JPEG processing unit 21 may again perform data compression using a quantization table based on a higher data compression rate.

In this case, as shown in FIG. 3, if it is determined whether the specified address of the transfer destination memory 17 exceeds the limit address, it is determined whether the memory 17 exceeds the limit value of FIG. It is not necessary to use the all data input counter as described with reference to FIG. 4, and the configuration of the fifth transfer unit 26 'can be further simplified.

Further, when it is determined that the limit value of the memory 17 is exceeded, the processing shown in FIGS. 3 and 4, the Bayer data read / transfer processing, and the data compression processing by the JPEG processing unit 21 are interrupted, and a higher data Since the recompression process based on the compression rate can be started, the image data processing time can be significantly shortened.

In the above embodiment, the digital still camera uses the JPE for the image data obtained by imaging.
The case where the fifth transfer unit 26 ′ transfers and stores the JPEG data compressed by the G processing unit 21 to the memory 17 is described, but the present invention is not limited to this, and the compression rate can be changed. For example, a digital video (movie) camera or a simple digital camera should be built in or connected if it is an image data transfer system or similar device that transfers and stores image data that has undergone data compression in a memory. It is needless to say that the present invention can be applied to an image data processing circuit system provided in a mobile phone capable of performing the above.

In addition, the present invention is not limited to the above-described embodiment, and various modifications can be carried out without departing from the scope of the invention.

Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, at least one of the problems described in the section of the problem to be solved by the invention can be solved, and it is described in the section of the effect of the invention. When at least one of the effects described above is obtained, a configuration in which this constituent element is deleted can be extracted as an invention.

[0085]

According to the first aspect of the present invention, when it is determined that the amount of image data to be transferred to the memory exceeds the limit value, the transfer to the memory is immediately stopped, and to that effect the operation of the processing circuit is performed. The data compression processing by the processing circuit can be started at an early timing with a new compression rate because it is notified to the control system that controls, and the memory that has only the capacity of the limit value can be saved without wasting processing time. It is possible to transfer image data that has undergone data compression.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, by measuring the total amount of the image data determined to exceed the limit value and notifying the processing circuit, The processing circuit can accurately calculate the compression rate when compressing the image data so that the data amount will not exceed the limit value next time.

According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, it is determined whether or not the limited data amount is exceeded by the address designating the storage destination at the time of transfer. Therefore, it is possible to easily determine the excess of the data amount.

According to the fourth aspect of the invention, in addition to the effect of the first aspect of the invention, by directly counting the amount of image data to be transferred, it is determined whether or not the limited data amount is exceeded. By determining, it is possible to easily determine the excess of the data amount.

According to the invention of claim 5, in addition to the effect of the invention of claim 1, the amount of image data input from the processing circuit is directly measured to determine the limited data amount. By determining whether or not the data amount is exceeded, it is possible to easily determine that the data amount is exceeded.

According to the sixth aspect of the invention, when it is determined that the amount of image data to be transferred to the memory exceeds the limit value, the transfer to the memory is immediately stopped, and to that effect the operation of the processing circuit is governed. Since the control system is notified, the data compression processing by the processing circuit can be started at an early timing with a new compression rate, and the data can be reliably stored in the memory having only the capacity of the limit value without wasting processing time. It is possible to transfer the compressed image data.

According to the seventh aspect of the present invention, it is determined that the amount of image data to be transferred to the memory for buffering the image data obtained by imaging has exceeded the limit value before being recorded on the recording medium. At this point, the transfer to the memory can be immediately stopped, and the data compression processing by the new compression rate can be started at an early timing by the compression means, without wasting the processing time unnecessarily, and having only the capacity of the limit value. It is possible to reliably transfer image data that has been subjected to data compression.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the overall processing contents during image capturing according to the same embodiment.

FIG. 3 is a flowchart mainly showing processing contents in a fifth transfer unit according to the embodiment.

FIG. 4 is a flowchart mainly showing another processing content in the fifth transfer unit according to the embodiment.

FIG. 5 is a block diagram showing a partial circuit configuration of a general digital still camera.

[Explanation of symbols]

11 ... Optical lens system 12 ... CCD 13 ... Sample hold circuit (S / H) 14 ... A / D converter (A / D) 15 ... Line processing unit 16 ... First transfer unit 17 ... Memory 18 ... Second transfer unit 19 ... YUV converter 20 ... Switch (SW) 21 ... JPEG processing unit 22 ... Switch (SW) 23 ... Third transfer unit 24 ... Fourth transfer unit 25 ... Display control unit 26, 26 '... Fifth transfer unit 27 ... sixth transfer unit 28, 28 '... System controller 29 ... Key input section

Continued front page    F-term (reference) 5B060 DA08                 5C052 AA17 AB02 AB09 CC01 DD02                       GA02 GB06 GC05 GE04 GF06                 5C053 FA08 GB28 GB36 KA01 LA01                 5C059 KK35 MA00 MA23 MC14 MC38                       ME02 PP01 PP16 SS15 TA00                       TA46 TB04 TC20 TD07 TD12                       UA02 UA30 UA36 UA38                 5C073 BC04 CE02

Claims (7)

[Claims] 1. A transfer means for transferring image data compressed from the processing circuit to the memory, and an amount of image data transferred to the memory by the transfer means exceeds a preset limit value. Determining means for determining whether or not the limit value is exceeded, stop means for stopping the transfer of the image data to the memory by the transferring means when the limit value is determined by the determining means, and the limit value being exceeded by the determining means. An image data transfer device, comprising: a notifying means for notifying that effect when a determination is made. 2. A measuring means for measuring the total amount of image data input from the processing circuit, wherein the notifying means further comprises means for notifying the total amount of image data measured by the measuring means. The image data transfer device according to claim 1. 3. The image data transfer device according to claim 1, wherein the determination means determines whether or not the designated address of the image data to be transferred and stored in the memory exceeds a preset limit address. .. 4. A counting means for counting the amount of image data transferred to the memory by the transferring means, wherein the judging means determines whether the count value counted by the counting means exceeds a preset limit count value. The image data transfer apparatus according to claim 1, wherein it is determined whether or not it is. 5. A measuring means for measuring the amount of image data input from said processing circuit is provided, and said determining means determines whether or not the amount of image data measured by said measuring means exceeds a preset limit value. The image data transfer apparatus according to claim 1, wherein the image data transfer apparatus determines whether or not it is. 6. A transfer step of transferring image data compressed from a processing circuit to a memory, and whether the amount of image data transferred to the memory in this transfer step exceeds a preset limit value. A determination step of determining whether or not the limit value is exceeded, a stop step of stopping the transfer of the image data to the memory by the transfer step when it is determined that the limit value is exceeded in the determination step, and a determination step of determining that the limit value is exceeded in the determination step. And a notification step of notifying that effect. 7. An image pickup means for picking up a subject image and outputting the image data, a compression means for compressing the image data output from the image pickup means, and the image data compressed by the compression means is transferred to a memory. Transferring means for storing, judging means for judging whether or not the amount of image data transferred to the memory by the transferring means exceeds a preset limit value, and the above-mentioned method when the judging means decides that the limit value is exceeded. The present invention is characterized by comprising stop means for stopping the transfer of the image data to the memory by the transfer means, and control means for changing the compression ratio of the compression means when the judgment means judges that the limit value is exceeded. Imaging device.