JP2000115605A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve data processing efficiency for attaining electronic zooming function by providing a data storage control means, which stores the data on the zoom magnifying power that is set by a zoom-magnifying power setting means into an image data storage medium. SOLUTION: A access to an image data storage medium (internal memory) 5 is controlled by a memory controller 7. The controller 7 and a magnifying power setting circuit 8 store only the memory data on a partial area that is limited to a visual field area to be magnified with the magnifying power set by a zoom magnifying power setting means (control switch) 9 into the memory 5 foom among those output image data on the image-pickup visual field obtained by an image-pickup device 2. Thus, the access form is controlled to the memory 5, and also the data showing the zoom magnifying power set by the switch 9 are stored in the memory 5 to follow the image data which are stored in the memory 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera having an electronic zooming function for changing the magnification of imaging by performing a specific process on image data obtained by an imaging device, separately from optical zooming. About the camera.

[0002]

2. Description of the Related Art Various electronic cameras having a function of performing zooming electronically without using a zoom lens have already been proposed. For example, in Japanese Patent Publication No. 5-60369, image information from an image sensor is stored in a frame memory.
An electronic camera configured to record the information from the frame memory to a removable medium, wherein a memory trimming circuit limits a partial image reading area from the frame memory in accordance with a zoom magnification command, and There is disclosed an apparatus in which an image data in a read area is reproduced as an image corresponding to one screen to obtain an electronic zooming effect.

In the electronic camera described in the above publication, all image data corresponding to the entire visual field of the imaging lens is once fetched into the frame memory, and then the image data in the partial visual field area is read out by the memory trimming circuit in a limited manner. An electronic zooming effect is obtained by storing the image data in a removable medium and uniformly reproducing the image data stored in the medium as an image corresponding to one screen during reproduction. Therefore, the image data corresponding to the entire field of view of the imaging lens or the entire photoelectric conversion region of the imaging element is always taken into the frame memory functioning as an intermediate buffer memory during this image data processing, so that the image data is finally effectively used. The data that is not used is subjected to the same processing as the data in the effective area to be zoomed, which is not desirable from the viewpoint of data processing efficiency.

On the other hand, most of recent electronic cameras have been commercialized as digital cameras. In these digital cameras, after converting image data obtained by an image pickup device into digital image data, the digital image data is converted to digital image data. It has become commonplace to perform a data compression process such as DCT (Discrete Cosine Transform) or the like and record it on a medium.

In this configuration, the amount of data finally stored in a recording medium such as a memory card or other built-in memory changes significantly depending on the compression ratio in the data compression processing. That is, if the compression ratio is high, the amount of data finally stored on the recording medium is reduced, so that a large number of images can be recorded. However, in the electronic camera disclosed in Japanese Patent Publication No. 5-60369, no special consideration is given to the relationship between the magnification of electronic zooming and the compression ratio in the data compression processing. For this reason, there is no viewpoint of optimizing the data compression ratio to improve the use efficiency of the memory (recording medium).

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has the following technical points. -To improve the efficiency of data processing when implementing the electronic zooming function. -Improving the efficiency of memory (recording medium) utilization by optimizing the data compression ratio by associating the electronic zooming magnification with the compression ratio in the data compression process.

[0007]

In order to solve the above-mentioned problems, one aspect of the present invention is configured as follows. [1] A digital camera configured to store, in an image data storage medium, image data corresponding to an output of an imaging element that photoelectrically converts an image related to an imaging field of view by an optical system, and performs photographing intended by a photographer. Zoom magnification setting means for setting the zoom magnification, and limiting the visual field area to be enlarged by the magnification set by the zoom magnification setting means in the output image data of the imaging visual field by the imaging element. The access mode to the image data storage medium is controlled so that only the image data relating to the partial area is stored in the image data storage medium, and the data of the zoom magnification set by the zoom magnification setting means is stored in the image data storage medium. A data storage system for storing the image data in the image data storage medium along with the image data stored in the medium. Digital camera comprising: the means.

Another invention of the present application is configured as follows. [2] A digital camera configured to store, in an image data storage medium, image data corresponding to an output of an image sensor that photoelectrically converts an image related to an imaging field of view by an optical system, and performs photographing intended by a photographer. Zoom magnification setting means for setting the zoom magnification, and limiting the visual field area to be enlarged by the magnification set by the zoom magnification setting means in the output image data of the imaging visual field by the imaging element. The transfer mode of the image data to the image data storage means is controlled so that only the image data relating to the partial area is stored in the image data storage medium, and the data of the zoom magnification set by the zoom magnification setting means is stored in the image data storage medium. Data to be stored in the image data storage medium along with the image data stored in the image data storage medium. A storage control unit configured to perform data compression processing on the image data to be stored in the image data storage medium at a compression ratio corresponding to a zoom magnification set by the zoom magnification setting unit. A digital camera, comprising: a stored data compression unit.

Still another invention of the present application is configured as follows. [3] The digital camera according to [1] or [2], wherein the image data stored in the image data storage medium is set so as to be reproduced as a one-screen image by electronic zooming. A digital camera further comprising an enlargement processing means for performing enlargement processing corresponding to the zoom magnification.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The technical idea of the present invention will be clarified by describing the embodiments of the present invention in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital camera as one embodiment of the present invention. In FIG. 1, an image related to an imaging visual field of an imaging lens 1 as an optical system is configured to be photoelectrically converted by an imaging element (CCD in this example) 2, and is processed by a process circuit 3 at the next stage of the imaging element 2. Gamma correction for the output of element 2,
After white balance adjustment and other necessary signal processing in a known processing format relating to a color video signal are performed, the output signal of the process circuit 3 is further converted to digital image data by an AD converter 4 in the next stage. Is configured.

An internal memory 5 is fixedly or exchangeably provided in the digital camera so as to temporarily store output image data of the AD converter 4. In the digital camera of the present embodiment, the internal memory 5 is also one image data storage medium, but the image data once stored in the internal memory 5 is read out and stored in an interpolation arithmetic circuit 6 described later. Output via This output is directly supplied to a printer and printed out, supplied to a personal computer and subjected to arbitrary image processing, or displayed on a monitor in a system of the personal computer, or converted into an analog signal through a DA converter. The image is supplied to the monitor and displayed.

Access to the internal memory 5 is controlled by a memory controller 7.
The memory controller 7 operates according to the data supplied from the magnification setting circuit 8. On the other hand, the magnification setting circuit 8 performs photographing intended by the photographer by operation of the user (photographer) of the digital camera. Is configured to output zoom magnification data in response to an operation on an operation switch 9 as a zoom magnification setting means for setting the zoom magnification.

As described below, the memory controller 7 and the magnification setting circuit 8 determine the magnification set by the zoom magnification setting means (operation switch 9) in the output image data relating to the field of view of the image pickup device 2. The access mode to the image data storage medium (internal memory 5) is controlled so that only the image data relating to the partial area limited to the visual field area to be enlarged is stored in the image data storage medium (internal memory 5). The data representing the zoom magnification set by the zoom magnification setting means (operation switch 9) is associated with the image data stored in the image data storage medium (internal memory 5). This constitutes data storage control means for storing the data in the storage device.

Now, the photographer sets the zoom magnification 1 to the operation switch 9 as the zoom magnification setting means so that the photographer sets the zoom magnification to 1 (that is, does not change the magnification while keeping the current field of view). Suppose you went. In this case, the entire image data of the imaging field of view of the imaging lens 1 is recorded, so that an image of the entire imaging field of view, that is, an image at a magnification of 1 can be reproduced.

The above will be described with reference to a block diagram. In accordance with the setting of the zoom magnification 1 for the operation switch 9, data representing the zoom magnification 1 generated by the operation switch 9 is supplied to the magnification setting circuit 8. The magnification setting circuit 8 responds to this by giving a command (data) representing the zoom magnification 1
Is given to the memory controller 7. In response to a given zoom magnification command (in this case, “zoom magnification 1”), the memory controller 7 synchronizes the operation of a trigger switch (not shown) such as an operation for starting a photographing operation with the photoelectric conversion of the image sensor 2. Image data from substantially the entire area of the conversion surface (image data corresponding to the entire imaging field of view of the imaging lens 1) is converted to AD.
The data is temporarily stored in the above-described internal memory 5 via the converter 4.
The memory controller 7 also stores the zoom magnification command (data representing "zoom magnification 1") in a predetermined area of the internal memory 5 along with the image data.

Next, when setting the zoom magnification to 2, first, the operation switch 9 is operated to set the zoom magnification to 2. With this operation, data representing the zoom magnification 2 generated by the operation switch 9 is supplied to the magnification setting circuit 8. In response to this, the magnification setting circuit 8 gives a command (data) indicating the zoom magnification 2 to the memory controller 7 in synchronization with the operation for activating the above-described photographing operation. The memory controller 7 responds to the given zoom magnification command (in this case, “zoom magnification 2”) to obtain image data of the entire imaging field of view of the imaging lens 1 (images from substantially the entire photoelectric conversion surface of the imaging element 2). Instead of the data), the image data of only a limited area which corresponds to the entire reproduction screen when the image is enlarged twice is temporarily stored in the internal memory 5 via the AD converter 4. Also in this case, the memory controller 7 stores a zoom magnification command (in this case, data representing “zoom magnification 2”) in a predetermined area of the internal memory 5 along with the image data.

At the time of reproducing an image, the image data stored in the internal memory 5 as described above is read under the control of the memory controller 7 according to the operation of a reproduction switch (not shown) and the like. 6 is output. In this reproducing operation, data representing the zoom magnification stored in the internal memory 5 is also read out to the magnification setting circuit 8 along with the image data, and the zoom magnification based on this data is recognized by the memory controller 7. You.
Since the memory controller 7 supplies the information on the zoom magnification to the interpolation arithmetic circuit 6, the interpolation arithmetic circuit 6 recognizes the zoom magnification. Based on this recognition, the interpolation calculation circuit 6 performs an interpolation process corresponding to the value of the zoom magnification on the image data read out as described above, and outputs the result.
As described above, this output is supplied to a printer and printed out as an image subjected to electronic zooming, or supplied to a personal computer as image data, or
The data is DA-converted and reproduced by a predetermined monitor or the like.
That is, according to this embodiment, the digital camera itself can reproduce an image having an electronic zooming effect.

FIG. 2 is a conceptual diagram for explaining the operation of electronic zooming. The outer rectangular frame line a is the image sensor 2
And is corresponding to the entire reproduction screen of a monitor or the like.
The inner rectangular frame line b is a limited area that corresponds to the entire reproduction screen when the enlargement processing is performed at the set magnification (two times in the above example). For example, the area of the frame line a is 1280 × 1024, while the area of the frame line b is 640 × 512.
It is. Border line b corresponding to the set magnification of electronic zooming
Are significantly less than the image data in the frame a. Therefore, according to this embodiment, only the limited image data that is effectively used by being enlarged according to the set magnification is to be processed, so that the efficiency of the data processing when the electronic zooming function is realized is improved. I do.

The interpolation processing circuit 6 performs an interpolation process for enlarging the image data within the frame line b to a size corresponding to the entire reproduction screen such as a monitor indicated by the frame line a. For example, a well-known operation of directly assigning one pixel data to data of four pixels as it is, or calculating a weighted average of pixel data to be interpolated from data of neighboring pixels according to a distance may be applied.

FIG. 3 is a block diagram showing a configuration of a digital camera as another embodiment of the present invention. FIG.
In the figure, corresponding parts to those in the embodiment of FIG. 1 described above are denoted by the same reference numerals, and detailed description is omitted. As in the embodiment of FIG. 1, an image related to the imaging field of view of an imaging lens 1 as an optical system is photoelectrically converted by an imaging element (CCD in this example) 2, subjected to the above-described predetermined processing by a process circuit 3, and A
The D converter 4 is configured to convert the digital image data into digital image data.

In the embodiment shown in FIG. 3, in particular, the output of the AD converter 4 is configured to be temporarily stored in the intermediate memory 11. An internal memory 5 similar to that of FIG.
Data is transmitted and received between the internal memory 5 and the intermediate memory 11 via a compression / expansion circuit 12 for compressing / expanding image data.

As in the embodiment shown in FIG. 1, access to the internal memory 5 is controlled by a memory controller 7.
The memory controller 7 operates according to the data supplied from the magnification setting circuit 8, and the magnification setting circuit 8 is used by the user to set the zoom magnification for the photographing intended by the user. It is configured to output zoom magnification data in response to an operation on an operation switch 9 as zoom magnification setting means.

In the embodiment shown in FIG. 3, only the limited image data corresponding to the zoom magnification is stored in the intermediate memory 11, as described with reference to FIG. And
Further, in this example, the image data stored in the intermediate memory 11 is subjected to a compression process such as an operation conforming to JPEG by the compression / expansion circuit 12 and stored in the internal memory 5. Therefore, the amount of data per image finally stored in the internal memory 5 is smaller than that in the embodiment of FIG. 1, and a larger number of images can be stored and held in a memory having the same capacity. Can be done.

In particular, in the embodiment of FIG.
The compression process in the compression / expansion circuit 12 is configured as a type capable of controlling the code amount, that is, a type in which the compression ratio is variable. In FIG. 3, data of the zoom magnification set by the zoom magnification setting means (operation switch 9) is supplied to the compression / expansion circuit 12 as zoom magnification information via the magnification setting circuit 8, the memory controller 7, and the internal memory 5. The compression / expansion circuit 12 is configured to perform compression at a compression ratio corresponding to the value of the zoom magnification.

For example, when the zoom magnification is relatively high, that is, when the degree of enlargement of the image is so large that the image quality may be degraded, the compression / expansion circuit 12 compresses the image data. Performs compression with a relatively low compression ratio.On the other hand, when the zoom magnification is relatively low, that is, when the setting is such that the degree of image enlargement is small and the image quality is not significantly degraded, In the compression processing of the image data in the expansion circuit 12, compression is performed with a relatively high compression ratio.

The embodiment of FIG. 3 is also configured to store the zoom magnification data in the storage medium (internal memory 5) along with the image data in the embodiment of FIG. This is the same as the embodiment.

At the time of the reproducing operation, first, under the control of the memory controller 7, the data of the zoom magnification stored in the internal memory 5 is read out to the magnification setting circuit 8. The zoom magnification based on the data of the zoom magnification thus read is recognized by the memory controller 7. Since the memory controller 7 supplies the information on the zoom magnification to the interpolation arithmetic circuit 6, the interpolation arithmetic circuit 6 recognizes the zoom magnification. Based on this recognition, the interpolation arithmetic circuit 6 reads out the data from the internal memory 5 and expands the data by the compression / expansion circuit 12.
The image data derived via the intermediate memory 11 is subjected to interpolation processing corresponding to the value of the zoom magnification and output.
The output image subjected to electronic zooming is supplied to a printer and printed out, or supplied as image data to a personal computer, or is converted to digital data and converted into a digital signal by a predetermined monitor, as in the case described above. The image is displayed. That is, also in this embodiment, an image having an electronic zooming effect can be reproduced by the digital camera itself.

In the embodiment shown in FIG. 3, the data compression ratio is optimized by associating the electronic zooming magnification with the compression ratio in the data compression process, and the utilization efficiency of the memory (recording medium) is measured. In addition, by optimizing the compression ratio, degradation of image quality due to compression of image data can be minimized.

[0030]

According to the first aspect of the present invention, it is possible to improve the efficiency of data processing when realizing an electronic zooming function. According to the second aspect of the present invention, by associating the magnification of electronic zooming with the compression ratio in the data compression process, it is possible to optimize the data compression ratio and to improve the use efficiency of the memory (recording medium). Can be. According to the third aspect of the invention, in addition to the above, an image having an electronic zooming effect can be reproduced by the digital camera itself.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital camera as one embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining an operation of electronic zooming.

FIG. 3 is a block diagram showing a configuration of a digital camera as another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 imaging lens 2 imaging element 3 process circuit 4 AD converter 5 internal memory 6 complementary arithmetic circuit 7 memory controller 8 magnification setting circuit 9 operation switch 11 intermediate memory 12 compression / expansion circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H04N 7/24

Claims (3)

[Claims] 1. A digital camera configured to store, in an image data storage medium, image data corresponding to an output of an image sensor that photoelectrically converts an image in a field of view captured by an optical system. Zoom magnification setting means for setting a zoom magnification for photographing, and a visual field area to be enlarged by a magnification set by the zoom magnification setting means in output image data of the imaging visual field by the image sensor. The access mode to the image data storage medium is controlled so that only the image data related to the partial area limited to the image data storage medium is stored in the image data storage medium, and the data of the zoom magnification set by the zoom magnification setting means is stored in the image data. Data to be stored in the image data storage medium along with the image data stored in the data storage medium Digital camera comprising: the pay control means. 2. A digital camera configured to store image data corresponding to an output of an image sensor for photoelectrically converting an image in a field of view taken by an optical system into an image data storage medium, the digital camera being intended by a photographer. Zoom magnification setting means for setting a zoom magnification for photographing, and a visual field area to be enlarged by a magnification set by the zoom magnification setting means in output image data of the imaging visual field by the image sensor. In addition to controlling the transfer mode of the image data to the image data storage means so as to store only the image data relating to the partial area limited to the image data storage medium, the data of the zoom magnification set by the zoom magnification setting means Is stored in the image data storage medium along with the image data stored in the image data storage medium. A data storage control unit configured to perform data compression processing on the image data to be stored in the image data storage medium at a compression ratio corresponding to a zoom magnification set by the zoom magnification setting unit; And a stored data compression unit. 3. The digital camera according to claim 1, wherein said image data stored in said image data storage medium is set to be reproduced as one screen image by electronic zooming. A digital camera further comprising enlargement processing means for performing enlargement processing corresponding to a zoom magnification.