JPH0795458A - Still video camera - Google Patents

Abstract

PURPOSE:To provide a still video system that can select a desired TV signal system and a desired picture quality level by means of a single camera by using an optional image pickup unit and then freely attaching/detaching this pickup unit to/from a common camera main body. CONSTITUTION:A control means 14 of a camera main body 3 reads the characteristic information out of a characteristic storing circuit 11 of an image pickup unit 2 and grasps the type and the number of pixels of a solid state image pickup element 5 of the unit 2, the capacity, etc., of a frame memory buffer 8 of the unit 2, and the characteristic of an optical system. These grasped information are used as the basic information in a photographing state, for example, for segmentation of data out of the buffer 8 and processing of these data, for data compression processing required for improvement of the recording density of an external memory 18, and for lens error correction processing. Therefore it is just required to add the unit 2 later when the change of using purpose is desired. Thus various variations can be enjoyed at low cost by a still video camera.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a still video camera, and more particularly to a digital still video camera for recording an electronic image taken by an image pickup device such as a CCD in an external memory such as an IC memory card.

[0002]

2. Description of the Related Art A still video camera usually has an image pickup device according to a television signal system and a desired image quality inside the camera body (Japanese Patent Laid-Open No. 64-174214, etc.).

For example, when the television system is different, such as the NTSC system and the HDTV (high-definition television) system, an image pickup device having an aspect ratio and a pixel number corresponding to this is used. That is, as shown in FIGS. 14 (a) and 14 (b),
The display screen of the NTSC system has a height-to-width ratio of 3: 4 and the number of scanning lines is 525, whereas the HDTV display screen has a height-to-width ratio of 9:16. The number of lines is 1
The number of pixels is 125, and an image pickup device having an aspect ratio and a pixel number suitable for each characteristic is indispensable.

Even if the television system is the same, the number of pixels of the image pickup device may be different depending on the application. That is, as shown in FIGS. 14C and 14D, there is a large level difference in image quality required between the image quality of the professional camera and the image quality of the consumer camera. 300,000 pixels for consumer use and 400,000 pixels for business use) are used.

[0005]

A still video camera having an image pickup device compatible with a television signal system and an image quality level has been developed as a dedicated machine, and is not suitable for use other than its intended purpose. Therefore, if the user wants to reproduce a still image using different methods, or if he wants to select the image quality according to the application, he has to purchase a dedicated still video camera each time, which is troublesome and costly. This will be the case.

The present invention has been made in view of the drawbacks of the prior art, and its object is a still video system in which a desired television signal system and image quality level can be selected by a single camera. Is to be realized at low cost.

[0007]

A camera body and an image pickup system are separated from each other, and the image pickup system is optionalized as a dedicated part to be used appropriately according to the purpose. Then, the user selects an imaging system according to the intended use, and attaches it to the common camera body each time to use it.

In order to achieve this structure, the following measures are taken, for example. In the optional imaging system (imaging unit),
At least one frame (one frame corresponds to two field scans in a television scan, and is used herein to mean the total amount of data necessary to form one complete screen. Provided with a frame memory buffer that can store image data of
The imaging data digitized by the A / D converter is
Be sure to store it once in this frame memory buffer.

The image pickup system can read out information indicating its own characteristics (pixel arrangement of the solid-state image pickup element, information of the number of pixels, information of the capacity of the frame memory buffer, etc.) in response to a request from the camera body. It is held in the form. That is, the image pickup device, the buffer memory, and information of these image pickup systems are stored in the ROM or the like.

The camera body is provided with a control unit (system controller) that totally controls the entire system including the attached imaging system. The control means provided in the camera body reads the characteristic information of the image pickup system and grasps the characteristic of the image pickup system while the image pickup system is connected.

Then, when the release switch is pressed, the control means instructs the imaging system to perform a shooting operation, and the imaging system automatically executes the shooting as programmed in advance, The video data is stored in the frame memory buffer.

Next, the control means cuts out the data from the frame memory buffer of the image pickup system to the camera body based on the characteristic information read in advance, transfers the data, adds necessary processing to the data, and records the data. It is recorded in an external memory such as a flash memory by a circuit.

The transfer of data from the frame memory buffer in the imaging system to the camera body is actually data communication between memories. In this case, the camera body also has a memory equivalent to the frame buffer memory. However, it is not impossible to carry out the processing after transferring all the data, but in this case, the data has to be cut out from the memory again in a necessary unit at the time of processing, which is wasteful.
Therefore, the camera body is provided with a register that can temporarily hold a unit (predetermined amount) of data required for processing, and when reading data from the frame memory buffer in the imaging system, the unit of data required It is desirable to perform a so-called pipeline-like process of efficiently reading data one after another and connecting it to the next process.

The process performed by the camera body is, for example,
These are process processing, color space processing, and data compression processing. When data and control information are communicated between the image pickup system and the camera body, using a dedicated interface circuit reduces the load on the communication of the control means and the internal circuit, which is convenient. Further, if the information of the imaging system being used is displayed on the camera body, the usability for the user is improved.

[0015]

By simply replacing the image pickup system (image pickup unit), the desired television signal system and the desired image quality level can be met, and the expandability and flexibility of the still video system are significantly improved as compared with the conventional ones. Further, since the camera main body is common and only the dedicated imaging system (imaging unit) needs to be replaced, the cost can be suppressed as compared with the case where the entire system is replaced.

As a result, the user can enjoy variations such as purchasing an optional image pickup system (image pickup unit) little by little and improving the system.

The reason why such a function is realized by the present invention is as follows. That is, the conventional still video camera has only an analog type, and its basic configuration is as shown in FIG.
The video signal obtained by the image pickup of (1) passes through the processing circuits 102 to 104 without interruption in time and is finally recorded in the video floppy 105. Therefore, in the analog system, it is not possible to provide a break in the flow of the video signal.

The present invention firstly digitizes a still video camera based on such knowledge, and utilizes the merit of the digital system to provide a still video system.
It introduced the concept of clear division.

That is, digital data can be electrically stored very easily by using an IC memory, and arbitrary data can be read by addressing. Moreover, since high-speed synchronized processing using a timing clock is possible, high-speed pipeline flow processing is also possible by devising memory communication and processing stages.

From the above consideration, the present inventor has found that before and after process processing, that is, a portion of data as imaged by the solid-state image pickup device and a portion of processing the data to obtain a color difference signal and the like. I noticed that I could distinguish and understand.

The data obtained in the first half differs depending on the type of solid-state image pickup device used. If this difference can be absorbed in some way, the image pickup system can be made independent as an image pickup unit having a dedicated image pickup function. No problem.

In the latter half of the signal processing system, the basic processing contents are the same regardless of the image pickup method, and if the data handled according to the image pickup method can be changed appropriately, a common signal can be obtained. It is also possible to use a processing circuit to support various imaging systems.

Therefore, in the present invention, first, a frame memory is prepared at the final stage on the side of the image pickup unit, and the data necessary for displaying a still image is temporarily stored. Even if it is a method, it is possible to concentrate on a common operation that can be freely addressed, that is, access to the memory space, and absorb the differences in pixel arrangement and number of pixels (differences in resolution, etc.) of the solid-state image sensor here. Resulting in.

However, since the unique information such as the pixel arrangement and the number of pixels of the solid-state image pickup element for each image pickup unit is necessary for the subsequent processing, it is easy to identify the identity of the image pickup unit by storing it in ROM beforehand. To be able to recognize.

Next, a system controller is provided on the signal processing side (camera body). Regarding the imaging of the subject, this system controller only entrusts the dedicated imaging unit to instruct the start of the operation, and focuses on the subsequent processing (that is, performing the processing that matches each method and resolution accurately). In charge of.

The basis of such processing is to read information indicating the characteristics of the image pickup unit, and based on the information, retrieve data from the frame memory according to a procedure matching each system and resolution, and the content of the retrieved data. Is given to the signal circuit as prior knowledge. As a result, it becomes possible to perform processing according to a difference in television signal system and resolution using the common camera body.

As described above, according to the present invention, the still video camera is digitized, and the data to be handled can be controlled by using the memory control. Utilizing this, synchronous pipeline data processing can be performed. By making a flow, it is possible to realize efficient and high-speed processing adapted to the difference in the television signal system and the resolution based on the characteristic information of the image pickup unit.

[0028]

(Embodiment 1) Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a first embodiment of a still video camera of the present invention. The still video camera 1 of the present embodiment is a digital camera, and includes an optional imaging unit 2, a camera body 3 commonly used for each imaging unit, and an external device for storing shooting data. A memory (for example, a card-type IC memory such as a flash memory) 18 and the like.

As shown in FIGS. 2A and 2B, the image pickup unit 2 and the camera body 3 are detachable, and the user can attach and use a dedicated image pickup unit according to the purpose of use. It is like this.

As shown in FIG. 1, the image pickup unit 2
Is an optical system (lens) 4, a CCD 5 selected according to the use of the image pickup unit, a drive circuit 6 for driving the CCD 5, an A / D converter 7, and digitized image data. It has a frame memory buffer 8 for temporary storage and a ROM 11 for recording characteristic information of the image pickup unit (image pickup system). The AWB sensor (auto white balance sensor) 10 is provided as needed. Further, the starting circuit 9 for giving a starting command to each circuit is shown independently for convenience of description,
If it is built in as an input interface function of each circuit such as the drive circuit 6, it does not need to be provided independently.

On the other hand, the camera body 3 receives the data from the frame memory buffer 8 of the image pickup unit 2, temporarily stores the data, the data processing circuit 13 for executing a predetermined process, and the external memory 18. External memory interface (recording circuit) 15 for recording and control means (system controller) for controlling the system as a whole
14 and a release switch 17. In addition,
The AWB sensor (auto white balance sensor) 16 is provided as needed, and is unnecessary when the sensor 10 is provided on the imaging unit side.

Next, the operation of this embodiment will be described. The control means 14 in the camera body 3 reads the characteristic information from the characteristic storage circuit (ROM) 11 in the image pickup unit 2 at any time when the image pickup unit 2 is connected, and the characteristic of the attached image pickup unit is read. Understand.

The content of the characteristic information of the image pickup system is, for example, as shown in FIG.
As shown in the upper left of FIG. 1, information about the type of solid-state image sensor, the number of pixels, the capacity of the frame memory buffer, and the like, and information about the characteristics of the optical system (lens). Then, such information is, for example, in FIG.
As shown on the right side of FIG. 1, data cut-out processing from the frame memory buffer 8, process processing, data compression processing performed to improve the recording density in the external memory 18,
Also, it will be used as basic information in lens error correction processing.

When the release is turned on, the AWB sensor (1
The information obtained from 0, 16) is used in the color space conversion process. Next, when the release switch is pressed by the user, the control means 14 commands the image pickup unit side to start up,
In response to this, each circuit in the image pickup unit 2 automatically operates to perform shooting and store shooting data in the frame memory buffer 8.

When the storage of the photographed data in the frame memory buffer 8 is completed, the control means 14 executes a data cutting process to transfer a predetermined amount of data from the frame memory buffer 8 to the register 12.

As shown in FIG. 4, this cutout process is a process of accessing a memory area in which desired data is stored and reading out the data. At this time, the control means 1
4 is the capacity of the frame memory that has been read in advance,
The read address is controlled by using the information such as the size of the imaged data stored therein.

The cut-out data group is a unit of data in the subsequent processing, and therefore the minimum amount necessary for the processing must be ensured. In particular, it is necessary to cut out the amount of data necessary for the data compression processing described later. For example, if 8-bit data is required for data compression, it is necessary to cut out 8 bits.

Subsequently, the control means 14 instructs the data processing means to perform predetermined processing such as process processing, color space conversion processing and data compression processing. The contents of each process will be described below.

(Process Processing) An example of the content of the process processing is shown in FIG. FIG. 5 shows a case where a color difference line sequential CCD in which Ye (yellow), Cy (cyan), Mg (magenta), and G (green) pixels are arrayed according to a predetermined rule is used as the CCD 5. A method of processing for obtaining the luminance signal Y and the color difference signals Cr and Cb from respective pixel values is shown (in this case, the color difference signal is obtained for each line).

That is, in the data processing circuit 13,
By performing the processing shown on the lower side of FIG. 5, it is possible to obtain a luminance signal and a color difference signal in a predetermined line (line n or line n + 1).

Normally, in an analog circuit, a delay circuit must be used to realize a required combination of data, and the arithmetic circuit must perform the calculation shown in FIG. However, in the present invention, since the control means 14 knows the arrangement of the pixels of the CCD from the characteristic information of the image pickup unit, which address in the frame memory should read the data and transfer it to the data processing circuit 13. Has become clear in advance. Therefore, necessary data is read out from the frame memory one after another and transferred to the register 12 once.
After storing, it is only necessary to collectively pass the data to the data processing circuit 13, and a delay circuit or the like is unnecessary, and the configuration can be simplified.

(Color Space Conversion Process) FIG. 6 is a diagram for explaining the contents of the color space conversion process. The color space conversion process is a process for surely performing optimum color reproduction under any light source, and is based on information from the AWB sensor (10, 16) having RGB color filters arranged on the sensor surface. Process.

Also in this case, the pixel arrangement of each color of the CCD,
Information such as at which address in the frame memory the pixel data of each color is stored is required. Based on this information, the control means 14 uses the coefficient generation means 21 shown in FIG. ) Is generated, the signal of the pixel of the color to be changed, which is output from the memory 20 in the data processing circuit 13, is multiplied by a coefficient to change the color.

(Data compression processing) In order to compactly record a huge amount of video data in the external memory 18 having a limited capacity such as an IC memory, data compression is required. The principle of the compression is shown in FIG.

That is, the image data (luminance signal / chroma signal) is subjected to discrete cosine transform, the energy distribution with respect to the spatial frequency is investigated, and the distribution state is recorded as data. This compression is performed by, for example, 8 pixels adjacent to each other.
Since the process is performed in units of a pixel group of 8 pixels, the process shown in FIG.
The data is cut out, and then the compression is executed.

After the above processing, the external memory interface 15 transfers the video data to the external memory 18.
Recorded in. (Embodiment 2) FIG. 8 is a diagram showing a configuration of a second embodiment of the present invention. The basic configuration of this embodiment is similar to that of the above-mentioned embodiment. However, in the present embodiment, the interface circuit 40 for exchanging various signals between the image pickup unit 2 and the camera body 3 is provided, and the detailed configuration is further embodied. Is different from the embodiment described above.

The interface circuit 40 is provided for smoothly exchanging information with each other without imposing a burden on the internal circuits of the image pickup unit and the camera body.

In this embodiment, optical system information such as the number of image sensor pixels, buffer memory capacity, and optical blur information, which the imaging system information recording unit 11 has as recording information, is passed through the interface circuit 40. Then, the control means 14 in the camera body reads it and prepares for control and signal processing based on it.

After that, the control means 14 and the clock generation circuit 5
1 issues a processing instruction and an operation clock suitable for the image pickup system. When a processing command such as a shooting command is issued from the camera body side, the interface circuit 40 interprets this and
In order to operate the image pickup unit side, the image pickup element drive unit 6
Alternatively, a signal is issued to the pre-process circuit 30 and the like. The pre-process circuit 30 is a circuit for pre-processing that performs γ correction of signals, amplitude limit, and the like.

When the processing on the image pickup unit side is completed, the interface circuit 40 detects the end and notifies the control means 14 on the camera body side of this. This is a rough operation on the image pickup unit side of the present embodiment.

Next, the operation of the image pickup unit will be described more specifically. That is, when the release switch 17 is pressed, in the image pickup unit 14, an optical image of the subject is given to the image pickup element (CCD) 5 via the optical system 4 including a lens, a diaphragm, a shutter and the like.

The analog image signal photoelectrically converted by the image pickup device 5 by the transfer pulse from the image pickup device driving section 6 is transferred to the preprocess circuit 30 including a clamp circuit, a γ correction circuit and the like. The analog image signal processed by the preprocessing circuit 30 is transferred to the A / D converter 7. In the A / D converter 7, the analog image signal is converted into a digital image signal, and the digital image signal is once held in a frame memory buffer (data holding means) composed of, for example, a FIFO memory.

Generation timing of a transfer pulse for driving the image pickup device 5, data transfer timing from the preprocessing circuit 30 to the A / D converter 7, data conversion timing in the A / D converter 7, A / D The timing of data transfer from the converter 7 to the frame memory buffer 8 is controlled by the control means 14 and the clock generation circuit 51 in the camera body 3 via the interface circuit 40.

Here, what is important about the image pickup unit 2 is, for example, the image pickup element 5 in the case of an NTSC image pickup unit.
Is for NTSC, and in the case of an HDTV image pickup unit, the image pickup element 5 is provided for HDTV.

Further, the frame memory buffer 8 also has a capacity commensurate with the number of pixels of the image pickup device 5, and the image pickup device driving section 6 also has a speed and accuracy suitable for driving the image pickup device 5, It is important for the D converter 7 to have speed and accuracy suitable for converting an analog image signal output from the image sensor 5 into a digital image signal.

Next, the processing on the camera body side will be described. The digital image data from the frame memory buffer 8 is sent to the data processing circuit 13 via the interface circuit 40 and the register 12. Data processing circuit 1
In 3, processing such as data compression is performed. The signal-processed digital image signal is transferred to the external memory interface 15
Via an external memory (in this embodiment, a flash memory card of 2 to 4 Mbytes) 13 which is detachably attached to the camera body.

As shown in FIG. 9, the data processing circuit 13 is configured by connecting a process processing stage 60, a color space processing stage 61, and a data compression processing stage 62 in a pipeline.

An external view of the case where the above system is realized is shown in FIG. FIG. 4A shows a state in which the image pickup unit 2 and the camera body 3 are separated from each other, and FIG. 4B shows a form in which the image pickup unit is attached to the camera body via the interface circuit 40.

The interface circuit 40 may be provided on the side of the image pickup unit 2 as shown in FIG. 10 or may be provided on the side of the camera body 3 as shown in FIG. Also, FIG.
2, the display unit 70 may be provided on the camera body 3 to display the information of the attached imaging unit so that the user can confirm the information. For example, when a high-definition image pickup unit is attached, a display as shown in FIG. 12A appears to clearly indicate that the high-definition unit is attached, and the remaining shooting frame number and other system information are displayed. indicate. Similarly, when the NTSC / high resolution image pickup unit is attached, the display as shown in (b) appears.

As described above, when the image pickup unit 2 is connected to the camera body 3, the processing is performed according to the information of the unit. By changing the image pickup unit, the desired television signal system and The system is capable of handling image quality levels.

[0062]

As described above, according to the present invention, when the user wants to change the intended use by making the image pickup unit optional and constructing a system in which the user can select it according to the desired television signal system and image quality level, It is sufficient to add only the image pickup unit later, and there is an effect that a high-performance still video camera that can enjoy various variations can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a still video camera of the present invention.

FIG. 2A and FIG. 2B are views showing the external appearance of the still video camera of the present invention.

FIG. 3 is a diagram showing information relating to characteristics and the like of an imaging system used in the embodiment of FIG. 1 and their uses in association with each other.

FIG. 4 is a diagram showing an example of contents of data cutout processing executed in a data processing circuit 13 of FIG.

5 is a diagram showing an example of the contents of process processing executed in the data processing circuit 13 of FIG.

6 is a diagram showing an example of contents of color space processing executed in the data processing circuit 13 of FIG.

7 is a diagram showing an example of contents of data compression processing executed in the data processing circuit 13 of FIG.

FIG. 8 is a diagram showing a configuration of a second embodiment of a still video camera of the present invention.

9 is a diagram showing a configuration example of a data processing circuit 13 in FIG.

10 is a diagram showing an example of the layout of the interface circuit 40 used in the embodiment of FIG.

FIG. 11 is a diagram showing another example of arrangement of the interface circuit 40 used in the embodiment of FIG.

12A and 12B are diagrams showing a display example in the case where a display section for displaying the characteristics of the image pickup unit is provided on the camera body in the embodiment of FIG.

FIG. 13 is a diagram showing a configuration example of a conventional analog still video camera.

FIGS. 14A to 14D are views for explaining the problems of the conventional technique.

[Explanation of symbols]

 1 still video camera 2 image pickup unit 3 camera body 4 optical system 5 CCD (image pickup device) 6 CCD drive circuit 7 A / D conversion circuit 8 frame memory buffer 10, 16 AWB sensor 11 image pickup system information recording means (ROM) 12 register 13 data processing circuit 14 control means (system controller) 15 external memory interface 17 release switch 18 external memory (flash memory etc.)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Keiichi Kawazu 2970 Ishikawacho, Hachioji City, Tokyo Konica Stock Company

Claims (7)

[Claims] 1. A still video camera constructed by detachably attaching an image pickup unit to a camera body, wherein the image pickup unit comprises an image pickup unit dedicated to the image pickup unit and a digital image picked up by the image pickup unit. And a characteristic information storage unit that stores information indicating the characteristic of the image pickup unit, and the camera body includes the data holding unit. A data processing unit that receives the video data output from the image processing unit and performs a predetermined process, and reads the characteristic information of the imaging unit from the characteristic information storage unit, and controls the operation of the data processing unit based on the characteristic information. A still video camera, comprising: a control unit that executes the predetermined process. 2. The information indicating the characteristics of the image pickup unit stored in the characteristic information storage means is information on the number of pixels of the image pickup means and information on the capacity of the data holding means. Still video camera. 3. The still video camera according to claim 1, wherein an interface for exchanging signals with each other is provided between the imaging unit and the camera body. 4. A still video camera comprising a camera body, to which a dedicated image pickup unit, which is selectively used according to a user's request, is detachably attached, wherein the image pickup unit is the image pickup unit. A dedicated image pickup unit including an optical system, a solid-state image pickup device, and a drive circuit for the solid-state image pickup device, an A / D converter for digitizing an analog video signal photographed by the image pickup unit, and an A / D converter A frame memory buffer capable of storing at least one frame of video data digitized by a D converter, information relating to the characteristics of the optical system, information relating to the pixel arrangement and the number of pixels of a solid-state image sensor, and the capacity of the frame memory buffer. And characteristic information storage means of the imaging unit that stores information, and The camera body receives the video data output from the data holding unit and stores the data, and uses a memory having a smaller capacity than that of the frame memory buffer and data output from the small capacity memory. Data processing means for performing the processing, recording means for recording the data processed by the data processing means in an external memory, and when the camera body and the imaging unit are in an electrically connected state, When information is read from the characteristic information storage means and the characteristics of the image pickup unit are grasped, and the release switch on the camera body is operated, an operation start command is issued to the image pickup unit, and a predetermined peculiarity of the image pickup unit is given. The operation is executed to store the video data in the frame memory buffer, and then the stored video data is stored in the above-mentioned location. The data is cut out in a unit of the amount necessary for a fixed process and transferred to the small capacity memory, and further, the data processing unit is instructed to use the data transferred to the small capacity memory to match the characteristics of the imaging unit. A still video camera, comprising: a system control unit that causes the recording circuit to perform the predetermined processing described above and perform recording in an external memory by the recording circuit. 5. The still video camera according to claim 4, wherein the predetermined processing by the data processing means is at least one of color signal processing (process processing), color space conversion processing, and data compression processing. 6. The still video camera according to claim 4, wherein interface means for exchanging signals with each other is provided between the image pickup unit and the camera body. 7. The still video camera according to claim 1, wherein display means for displaying information of the image pickup unit being used is provided on the camera body.