JP2001128109A - Method and device for picture processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a thumbnail picture with which contents of an original picture is easily confirmed. SOLUTION: A specific area (ROI) of the original picture is designated by an ROI designation part 19, and the designated ROI of the original picture is reduced by a reduction circuit 18 and is displayed, and the picture of the ROI is compressed by a compression circuit 8 at a compression rate lower than that of the other picture areas of the original picture. The compressed picture corresponding to the ROI is stored in a CF(compact flash) 11 as a thumbnail picture of the original picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing method and apparatus for compressing and storing an image or reading and displaying a stored image.

[0002]

2. Description of the Related Art Conventionally, in digital cameras and the like,
The captured images are sequentially compressed and stored in a storage medium such as a memory card, and when a desired image is designated, the image is decoded and displayed on a monitor. When selecting a desired image from these multiple images,
A thumbnail image obtained by reducing each image can be created, and a plurality of thumbnail images can be simultaneously displayed as an image index on a monitor of a digital camera or on a screen of a PC or the like connected to the digital camera. It is configured as follows.

[0003] In a printer or the like for printing an image photographed by a digital camera or the like, an index print function for reducing a plurality of images and printing the reduced images on one sheet is provided.

[0004]

However, since a thumbnail image of such a digital camera is created by reducing the original image, it is necessary to confirm the content of the original image taken from the thumbnail image. There was a problem that it was difficult. Therefore, it is conceivable to cut out only the area including the subject from the picked-up image and create a thumbnail image based on the cut-out area to confirm the content of the shot image. However, it is difficult for the digital camera to automatically determine which part of the captured image is the subject, and a user's instruction is required to cut out the subject area.

[0005] Even when index printing is performed by a printer, since individual thumbnail images are printed in a reduced size, it may be difficult for the user to check the contents of each image from the index printing. .

At present, as a next-generation compression method,
The so-called JPEG2000 system is under study. A detailed description of this JPEG2000 will be omitted here, but as a characteristic function, a certain range of interest (Regi
on Interest (hereinafter abbreviated as ROI), and has a function of compressing an image in the specified range with a compression coefficient (compression ratio) different from other ranges of the image. Here, R compressed with a compression coefficient that results in a lower compression ratio than other ranges
It is conceivable that the OI includes a notable subject in the image.

The present invention has been made in view of the above conventional example, and has as its object to provide an image processing method and apparatus capable of creating a thumbnail image in which the contents of an original image can be easily confirmed.

It is another object of the present invention to provide an image processing method and apparatus capable of creating a reduced image from an original image in which the contents of the original image can be easily confirmed.

[0009]

In order to achieve the above object, an image processing apparatus according to the present invention has the following arrangement.
That is, a detection unit that detects a specific region of the original image, and a compression unit that compresses the specific region of the original image detected by the detection unit at a lower compression ratio than other image regions of the original image, Storage means for storing an image corresponding to the specific area compressed by the compression means as a thumbnail image of the original image.

[0010] To achieve the above object, the image processing apparatus of the present invention has the following configuration. That is, specifying means for specifying a specific area of the original image, compression means for compressing the specific area of the original image specified by the specifying means at a lower compression rate than the other image areas of the original image, Storage means for storing an image corresponding to the specific area compressed by the compression means as a thumbnail image of the original image.

To achieve the above object, the image processing method of the present invention comprises the following steps. That is, a detection step of detecting a specific area of the original image, and a compression step of compressing the specific area of the original image detected in the detection step at a lower compression ratio than other image areas of the original image, A storage step of storing an image corresponding to the specific area compressed in the compression step as a thumbnail image of the original image.

In order to achieve the above object, the image processing method of the present invention comprises the following steps. That is, a specifying step of specifying a specific area of the original image, and a compression step of compressing the specific area of the original image specified in the specifying step at a lower compression ratio than other image areas of the original image, A storage step of storing an image corresponding to the specific area compressed in the compression step as a thumbnail image of the original image.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[First Embodiment] FIG. 1 is a block diagram showing a configuration of a digital camera according to a first embodiment of the present invention.

In FIG. 1, reference numerals 1 and 3 denote photographing lenses, which are shown as two lenses for convenience, but are actually housed in a lens unit composed of a larger number of lenses and the like. Reference numeral 2 denotes an aperture, which is provided in the lens unit and adjusts the amount of light incident on the taking lens 3. 4
Denotes an image sensor, which is composed of a CCD, a CMOS, or the like. Reference numeral 17 denotes a focus adjustment circuit arranged in the lens unit, which realizes an autofocus function by adjusting the focal length in accordance with an instruction from the CPU 12 or in the case of a manual operation. Reference numeral 16 denotes an aperture drive circuit arranged in the lens unit, which adjusts the aperture of the lens in accordance with an instruction from the CPU 12 or in the case of manual operation. 5 is a drive circuit of the image sensor 4;
Reference numeral 6 denotes an A / D converter, which converts an imaging signal, which is an analog signal output from the image sensor 4, into a digital signal.
Reference numeral 7 denotes a signal processing circuit that performs signal processing on the photographing signal digitally converted by the A / D converter 6. The signal processing circuit 7 includes a reduction circuit 18 for reducing an image.

Reference numeral 8 denotes a compression / expansion circuit which performs compression processing on the digital image signal processed by the signal processing circuit 7 and decompresses the compressed digital image signal to restore the original image signal. ing. Reference numeral 19 denotes an ROI designation unit, which is included in the compression / decompression circuit 8 and has a function of designating a region of interest in an image.

9 is a RAM for temporarily storing digital image signals and the like, 10 is a ROM for storing programs executed by the CPU 12, and 11 is a compact flash (final flash) for finally storing the digital image signals. C
F) and other storage media, 12 is a central processing unit (CPU) such as a microcomputer, and 13 is a display unit such as a liquid crystal monitor for displaying a video or the like that has been shot or is about to be shot.

Reference numeral 15 denotes a release switch. When the switch 15 is turned on by a user, the image pickup device 4 is turned on.
Is subject to photoelectric conversion, and an image pickup signal as an output signal thereof is A / D converted by the A / D converter 6. Further, the A / D-converted digital signal is subjected to signal processing in a signal processing circuit 7 and temporarily stored in a RAM 9 as a digital image signal. The digital image signal temporarily stored in the RAM 9 is subjected to compression processing by the compression / expansion circuit 8 and stored as a file in the storage medium 11 such as a compact flash.

The digital image signal temporarily stored in the RAM 9 is reduced by the reduction circuit 18 to generate a thumbnail image having, for example, 160 pixels horizontally and 120 pixels vertically. The created thumbnail image is temporarily stored in the RAM 9. Further, the thumbnail image is subjected to compression processing by the compression / expansion circuit 8 and stored in the storage medium 11 as a file, thereby completing the photographing operation.

Reference numeral 14 denotes a switch input circuit for detecting the state of various switches such as a release switch and a switch dial such as a mode dial for switching a shooting mode not shown in the figure.

FIG. 2 is a flowchart showing the operation of the digital camera according to the first embodiment at the time of photographing. A program for executing this processing is stored in the ROM 10. FIG. 3 is a diagram illustrating an example of an image captured by the digital camera according to the first embodiment and an example of a thumbnail image corresponding to the image.

Hereinafter, the first embodiment will be described with reference to these figures.
The control operation of the digital camera according to the first embodiment will be described.

First, in step S100, the user turns on the release switch 15, and the digital camera starts photographing. Next, the process proceeds to step S101, in which an AF (autofocus) operation is performed in step S10.
In step 2, an AE (automatic aperture adjustment) operation is performed. In the AF operation and the AE operation, a charge signal is read from the image sensor 4 and a digital image signal is sequentially read into the signal processing circuit 7 via the A / D converter 6. The signal processing circuit 7 performs a calculation based on the image signals sequentially read in this way, and outputs a control signal to the focus adjustment circuit 17 using the calculation result to control the photographing lenses 1 and 3 so that the lenses are in focus. Control or outputs a control signal to the aperture driving circuit 16 to control the aperture 2.
This is done by controlling

Next, in step S103, exposure for photographing is performed by the image sensor 4, and in step S104,
The charge stored in the image sensor 4 by the exposure is read out, and the image signal, which is the output signal, is A / D converted by the A / D converter 6. Next, the process proceeds to step S105, in which the signal processing circuit 7 performs signal processing, and temporarily stores the signal processing result in the RAM 9 as a digital image signal.
The digital image signal temporarily stored in the RAM 9 is subjected to compression processing by the compression / expansion circuit 8 in step S106, and the compressed image data is stored as an image file in a storage medium 11 such as a compact flash.

In the compression processing in step S106, as represented by the JPEG2000 compression method,
A method of designating a certain range of interest (ROI) in an image and compressing the image in the designated range with a compression coefficient (compression rate) different from that of another image range is adopted. In the digital camera according to the first embodiment, the ROI designation section 19 of the compression / decompression circuit 8
In this case, the ROI (region of interest) is determined in advance, and assuming that the ROI includes a notable subject in the image, the ROI has a lower compression ratio than other ranges. Compress with compression factor.

FIG. 3 shows a photographed original image and its ROI.
3A is a diagram showing an example of a thumbnail image, and FIG. 3A shows an example of a captured image, and a rectangular area 3 indicated by a dotted line in FIG.
01 is the ROI. FIG. 3B shows the ROI 301.
3 shows an example of a thumbnail image.

Next, the flow advances to step S108 to set the ROI as an area for creating a thumbnail image. For example, if the captured original image is 1280 pixels horizontally and 960 pixels vertically, and the entire image is used as an ROI to create a thumbnail image of 160 pixels horizontally and 120 pixels vertically, the reduction rate is 1/8 (12.5%) Becomes On the other hand, if the size of the ROI in the original image is 800 pixels horizontally and 600 pixels vertically and the ROI is an original image for creating a thumbnail image of 160 pixels horizontally and 120 pixels vertically, the reduction ratio is 1 / 5 (20.0%). By doing so, by obtaining a thumbnail image from the ROI,
Rather than obtaining a thumbnail image from the entire original image. A thumbnail image with a lower reduction ratio is obtained, and it becomes easier to confirm the contents of the original image captured from the thumbnail image.

For this reason, the process first proceeds to step S108, in which a thumbnail area for the original image is set, and step S10
In step 9, the reduction circuit 18 performs a reduction process on the digital image signal in the set thumbnail area to create a thumbnail image.
Store temporarily in M9.

FIG. 3B shows a thumbnail image created by reducing the ROI 301 of the image shown in FIG. 3A as a thumbnail area.

Next, the process proceeds to step S110,
The compression / expansion circuit 8 performs compression processing on the thumbnail image created in 109. Next, the process proceeds to step S111, in which the compressed image data is stored in the storage medium 11 as an image file, and the photographing operation is completed (S112).

In this image compression processing, RO
For the compression method of the I part and the non-ROI part, for example, J
Various methods have been proposed and studied in PEG2000 and the like, and may be based on these methods, and detailed description is omitted here, but will be briefly described as follows.

First, an ROI portion in an original image is created as a bit plane image, and this is used as an ROI mask. Next, when encoding the coefficients after the discrete wavelet transform when encoding the original image, if a certain coefficient in the image belongs to the ROI, the coefficient
A code indicating that it belongs to the OI (ROI / MASK code) is added. Then, the ROI part and the non-ROI part are compression-encoded as separate code strings. Thus, when the compressed image data is decompressed, the decoder (decoder) looks as if there is an ROI image and a non-ROI image.

Another method has been proposed. this is,
After generating an ROI mask and performing discrete wavelet transform on the original image in the same manner as described above, when coding the coefficients, if a certain coefficient in the image belongs to the ROI, the coefficient is set to a predetermined value. Level up. That is, in JPEG2000, the upper bit plane is preferentially encoded at the time of encoding, and the lower bits are omitted according to the situation. Therefore, the shifted up portion, that is, the ROI portion, is relatively encoded to the lower bits, and Image quality will be higher.

In the first embodiment, the ROI portion of an image is used as a reference when setting an area for creating a thumbnail image of the image, and encoding and decoding of the ROI portion are performed. Is not limited to a particular scheme.

In the first embodiment, the ROI portion of an image has been described as an area for creating a thumbnail image of the image. However, the ROI portion has a shape other than a rectangle, or has a rectangular shape. It is also conceivable that the vertical and horizontal ratios are different from the thumbnail image to be created.

FIG. 4 is a view for explaining an example of setting a thumbnail image area for an ROI.

FIG. 4A shows a portion of the rectangle including the entire ROI portion 401, such as the rectangular region indicated by the dotted line 402, with respect to the dotted elliptical ROI portion indicated by the portion 401. The smallest one may be set as the thumbnail area.

Further, as shown in FIG. 4B, a rectangle which fits in the ROI portion 403 as shown by a dotted rectangle region 404 with respect to the dotted elliptical ROI portion indicated by 403. There is also a method of setting the largest one among the areas as a thumbnail area.

In the first embodiment, R
Although the OI portion is unconditionally used as an original image for creating a thumbnail image, a specific switch of the digital camera is used to make the ROI portion an original image for creating a thumbnail image, or the entire image is It is possible to switch whether the range is the original image for creating the thumbnail image, and switch the switch before the user executes the shooting so that the area of the thumbnail image can be changed according to the shooting scene Is also good.

[Second Embodiment] A second embodiment of the present invention will be described. In the second embodiment, a description will be given of the case of a personal computer or an image processing apparatus instead of the digital camera of the first embodiment.

FIG. 5 is a block diagram showing a configuration of an image display apparatus according to Embodiment 2 of the present invention.
In the image display device described above, a compressed digital image signal stored in a memory such as a compact flash can be decompressed and displayed on a screen of a display unit such as a liquid crystal display.

In FIG. 5, reference numeral 21 denotes a compression / expansion circuit for decompressing (expanding) a compressed digital image signal. An ROI determination unit 28 included in the compression / expansion circuit 21 determines the ROI portion of an image when decompressing a digital image signal. 24 is an R for temporarily storing digital image signals and the like.
AM and 25 denote ROMs storing programs and the like of a CPU 27, 26 denotes a storage medium such as a compact flash in which digital image signals are stored, and 27 denotes a central processing unit (CPU) such as a microcomputer. 22
A display unit such as a liquid crystal is used to display a photographed or decompressed digital image. A switch input circuit 23 detects various switches and dials not shown in FIG. By operating these switches, the user can instruct display of an image, display the next image, or display the previous image.

FIG. 6 shows an example of an image displayed on the image display device according to the second embodiment, an example in which only one image is displayed on the screen of the display unit 22, and four images including the image. Is displayed on the display unit 22.

An image displayed by the image display device of the present embodiment specifies a certain range of interest (ROI) in the image, as represented by the JPEG2000 compression method, and the image in the specified range is Compression is performed with a compression coefficient (compression ratio) different from the other ranges. This ROI is compressed with a compression coefficient that provides a lower compression ratio than other ranges, assuming that a notable subject in the image is included.

FIG. 6A shows an example of an image displayed on the image display device according to the second embodiment. A rectangular area 601 indicated by a dotted line in the figure is an ROI.

In the image display device according to the second embodiment,
As shown in FIG. 6B, the compact flash (C
F) The image read out from 26 and decompressed is displayed on the display unit 22 as 1
When only a single image is displayed, the entire area of the image is displayed.

When four or more decompressed images are displayed on the display unit 22, as shown in FIG.
The OI (for example, 601 in FIG. 6A) is set as an original image area for display, and this area is subjected to reduction processing by the CPU 27, and the reduced image is displayed. Here, the ROI portion of the decompressed image is determined by the ROI determination unit 2
8 is detected.

FIG. 7 is a flowchart showing image display processing in the image processing apparatus according to the second embodiment of the present invention. A program for executing this processing is stored in ROM 25 and executed under the control of CPU 27. You.

First, in step S201, the compressed image data stored in the storage medium such as the CF 26 is read, and in step S202,
The compressed image data is decompressed (expanded). Next, in step S203, when the digital image data is decompressed, the ROI of the image is determined by the ROI unit 28. The ROI determination process may be realized by a program executed by the CPU 27. Next, in step S204, when displaying the decompressed (decompressed) image, it is checked whether or not a mode for displaying one image on the screen of the display unit 22 is determined.
Then, the decompressed image is displayed on the screen of the display unit 22 (see FIG. 6B).

On the other hand, if the mode is not the mode for displaying one image on one screen in step S204, the process proceeds to step S206, where the ROI is extracted from the entire answered image.
The ROI image is reduced and displayed (see FIG. 6C).

According to the second embodiment as described above, RO
Since the region I is considered to include a remarkable subject in the image, the ROI portion is reduced by reducing only the ROI portion instead of reducing the entire decompressed image.
It is easy to confirm the contents of the image even when the image is displayed in a reduced size as shown in FIG.

In the second embodiment, the ROI portion of the decompressed image is unconditionally used as the original image area when the image is reduced and displayed. For example, the ROI portion is displayed by using a specific switch of the image display device. The user can switch between the original image area when the part is reduced and displayed or the original image area when the entire range of the decompressed image is reduced and displayed. It is also possible to change the display screen.

Further, in the second embodiment, the case where the image is read from the storage medium and displayed in a reduced size in the image display apparatus has been described. When printing at a size smaller than the reduction ratio of
By reducing only the I portion, it is easy to confirm the content of the image from the printed result.

Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), a single device (for example, a copying machine, a facsimile machine, etc.) ) May be applied.

Another object of the present invention is to supply a storage medium (or storage medium) storing program codes of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide the system or the apparatus with the storage medium. It is also achieved by a computer (or CPU or MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. In addition, by the computer executing the read program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instructions of the program code. Performs some or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. This also includes the case where the CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

As described above, according to the present embodiment, a rectangular area calculated based on a specified range in an image is used as an original image for creating a thumbnail image, so that the captured contents can be obtained from the image. A thumbnail image that can be easily confirmed can be created.

Further, according to the present embodiment, it is possible to create a thumbnail image in which the captured image can be easily checked.

Further, according to the present embodiment, when displaying the decompressed image with an image size smaller than a predetermined reduction ratio, calculation is performed based on the specific range compressed at a lower compression ratio than other regions. By displaying the reduced image of the rectangular area in place of the original image, a reduced image whose contents can be easily checked is created.

[0060]

As described above, according to the present invention, a thumbnail image in which the contents of an original image can be easily confirmed can be created.

Further, according to the present invention, there is an effect that a reduced image from which the contents of the original image can be easily confirmed can be created from the original image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a digital camera according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing a photographing operation of the digital camera according to the first embodiment.

FIG. 3 is a diagram showing an example of an image shot by the digital camera according to the first embodiment and an example of a thumbnail image of the image.

FIG. 4 is a diagram illustrating a method for setting an area for creating a thumbnail image from an ROI according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of an image display device according to Embodiment 2 of the present invention.

FIG. 6 is a diagram illustrating an example of an image displayed on the image display device according to the second embodiment, a display example in which one image is displayed, and a display example in which four images including the image are displayed. is there.

FIG. 7 is a flowchart showing an image display process in the image display device according to Embodiment 2 of the present invention.

[Explanation of symbols]

 1, 3 shooting lens 2 pattern 4 image sensor 5 image sensor driving circuit 6 A / D converter 7 signal processing circuit 8, 21 compression / expansion circuit 11, 26 storage medium 13, 22 display unit (LCD monitor) 14, 23 switch Input circuit 15 Release switch 16 Aperture drive circuit 17 Focus adjustment circuit 18 Reduction circuit 19 ROI designation section 28 ROI determination section

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat ゛ (Reference) G06F 15/66 355A F-term (Reference) 5B057 CA12 CA16 CB12 CB16 CD05 CE09 DB02 5B075 ND08 NR16 PQ02 PQ46 PQ48 QP05 5C052 AA11 AA17 DD02 EE03 EE08 GA02 GA03 GA05 GA06 GA09 GB06 GC03 GC05 GD03 GD09 GE08 5C053 FA04 FA05 FA06 FA08 FA27 GB28 GB36 HA30 KA03 KA05 KA08 KA24 LA06 5C076 AA02 AA19 AA21 AA22 BB01

Claims (15)

[Claims] 1. A detecting means for detecting a specific area of an original image, and compression for compressing a specific area of the original image detected by the detecting means at a lower compression rate than other image areas of the original image. Means for storing an image corresponding to the specific area compressed by the compression means as a thumbnail image of the original image. 2. The image processing apparatus according to claim 1, further comprising a selection unit that selects one of a mode in which an original image for creating the thumbnail image is set to the specific area and a mode in which the entire area of the image is set. Item 2. The image processing device according to Item 1. 3. The apparatus according to claim 1, wherein, when the specific area is an area having a shape other than a rectangle, the detection unit detects a maximum rectangular area included in the area as the specific area. The image processing apparatus according to any one of the preceding claims. 4. The apparatus according to claim 1, wherein, when the specific area is an area having a shape other than a rectangle, the detection unit detects a maximum rectangular area including the area as the specific area. Image processing device. 5. The image processing apparatus according to claim 1, further comprising a restoration unit that expands and restores the thumbnail image stored in the storage unit. 6. The image processing apparatus according to claim 1, wherein the restoring unit identifies and decompresses an image area in which the compression rate of the compressed image data stored in the storage unit is lower than that of another part, as the thumbnail image. Item 6. The image processing device according to Item 5. 7. A detecting step of detecting a specific area of an original image, and compression for compressing the specific area of the original image detected in the detecting step at a lower compression ratio than other image areas of the original image. An image processing method, comprising: storing an image corresponding to the specific area compressed in the compression step as a thumbnail image of the original image. 8. The method according to claim 1, further comprising a selection step of selecting one of a mode in which an original image for creating the thumbnail image is set to the specific area and a mode in which the entire area of the image is set. Item 8. The image processing method according to Item 7. 9. The method according to claim 7, wherein, in the detecting step, when the specific area is an area having a shape other than a rectangle, a maximum rectangular area included in the area is detected as the specific area. The image processing method described in the above. 10. The method according to claim 7, wherein, in the detection step, when the specific area is an area having a shape other than a rectangle, a maximum rectangular area including the area is detected as the specific area. Image processing method. 11. The image processing method according to claim 7, further comprising a restoration step of decompressing and restoring the thumbnail image stored in the storage step. 12. In the restoration step, an image area in which the compression rate of the compressed image data stored in the storage step is lower than that of another part is identified and decompressed as the thumbnail image. Item 12. The image processing method according to Item 11. 13. A specifying step of specifying a specific area of an original image, and compression for compressing the specific area of the original image specified in the specifying step at a lower compression ratio than other image areas of the original image. An image processing method, comprising: storing an image corresponding to the specific area compressed in the compression step as a thumbnail image of the original image. 14. A computer-readable storage medium storing a control program for executing the image processing method according to claim 7. Description: 15. A designating means for designating a specific area of an original image, and compression for compressing a specific area of the original image specified by the designating means at a lower compression ratio than other image areas of the original image. Means for storing an image corresponding to the specific area compressed by the compression means as a thumbnail image of the original image.