JP2000307935A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust subject depth while preventing the occurrence of deficiency to be an image that cannot be generated in an optical system by deciding the priority relation of partial area mutual processing, performing respectively different filter processing of partial areas according to decided results, also generating a record image to be a final record object and adjusting the apparent subject depth. SOLUTION: A system controller 12 controls a digital process circuit 8 and performs all of the discrimination of a priority area, filter processing, image cutting, the generation of a record image, etc. The controller 12 controls an exposure control driver 17 as necessary and performs exposure operations including stroboscope light emission. Further, in this case, a normal mode and a portrait mode whose execution form is unique are provided in a switchable way. This switching is selectable by an operation switching system 13 before photographing. The control of a camera is entirely carried out by such a manner that the controller 12 appropriately controls each part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an imaging device having an image processing function.

[0002]

2. Description of the Related Art An image pickup device such as an electronic still camera mainly constituted as a still image recording device, typically a digital camera using a memory card or the like as a recording medium, not to mention a so-called video camera. 2. Description of the Related Art An electronic image pickup apparatus that captures a subject image using an image and records the image in the form of an electric signal is widely known.

In an electronic image pickup apparatus, various signals are processed to improve the image quality when a recorded image is generated because the signal can be processed by an electric circuit. It only compensates for the image quality that is often still inferior to the image quality of film camera systems.

On the other hand, when performing image processing for improving image quality, various possibilities are widened if different processing is performed for each region. Several techniques have been tried from such a viewpoint. For example, JP-A-8-51
Japanese Unexamined Patent Publication No. 632 discloses an area-compatible white balance processing technique that performs white balance control of a strobe photographed image on a block basis based on a luminance comparison between a strobe photographed image and an image photographed only with external light. I have. Also, Japanese Patent Application Laid-Open No. 5-292524 discloses a method of detecting a skin color portion and lowering the degree of contour emphasis from other portions to smoothly express the skin. Also, JP-A-7-466.
Japanese Patent Laid-Open No. 21 discloses a tone correction means for detecting a flesh color portion and improving the brightness of the portion to reduce dullness. The technologies disclosed in these publications are for solving individual technical problems, and in solving the problems, an area correspondence type process is performed as needed.

[0005]

By the way, the image area of the image pickup device used in the electronic image pickup device is not limited to a Leica plate (double frame) which is a typical frame format of a silver halide film, but also a half size (single frame) or a single frame. Usually, the size is extremely small as compared with APS (Advanced Photo System). This is an inevitable situation that arises from the demand for improved yield in semiconductor manufacturing. Since the vertical magnification of the imaging optical system is proportional to the square of the horizontal magnification, the depth of field at the same angle of view becomes larger as the image area size becomes smaller under the same other conditions. For this reason, there is a problem that an image obtained by the electronic imaging apparatus becomes an image having a very pan-focus impression compared to an image obtained by a silver halide camera, and is likely to be unsuitable for so-called portrait photography or the like. .

In order to address this problem, it is conceivable to use an image processing technique. In other words, portrait photography with a film camera is achieved by using a medium telephoto lens to greatly blur the background of a person. There is a possibility that an image having a portrait effect will be obtained.

[0007] However, a technique that can specifically realize such a method has not been proposed. As a slightly related example, Japanese Patent Application Laid-Open No. Hei 5-292524 describes a process for changing the frequency characteristic adaptively in a region. This is completely different from the problem of obtaining an effect, and the technology disclosed in this publication cannot obtain a portrait effect similar to that of a film camera as described above.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the conventional image pickup apparatus, and adjusts the apparent depth of field of a picked-up image by image processing, for example, a portrait effect similar to a film camera. It is an object of the present invention to provide an imaging device capable of easily obtaining the above. To describe the purpose of each claim, the invention according to claim 1 reduces the apparent depth of field of a recorded image by image processing while preventing the occurrence of a problem that results in an image that cannot be generated by an optical system. An object of the present invention is to provide an imaging device that can be adjusted. It is another object of the present invention to provide an imaging apparatus which can prevent a problem that an image cannot be generated by an optical system and causes an image to be generated, and which is extremely simple in processing and operation. A third aspect of the present invention is directed to the imaging apparatus according to the second aspect, wherein the main subject area and the background area can be easily set.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 relates to a method in which each partial area, which is a part of an entire image area set for a captured image, is mutually related. Priority relationship determining means for determining a priority relationship of processing; and performing one or more different filtering processes on each of the partial areas based on the determination of the priority relationship determining means for one or a plurality of captured images obtained by subject imaging. And a depth-of-field adjusting means for adjusting the apparent depth of field of the recorded image by generating a final recorded image to be recorded based on the judgment of the priority relation judging means. It constitutes an imaging device.

With this configuration, when processing an image, filter processing is performed based on the priority of processing of each partial area, and a final recorded image to be recorded is generated. The apparent depth of field of the recorded image can be adjusted by image processing while preventing the occurrence of a problem that results in an image that cannot be generated. That is, by adopting the above configuration,
A different blur can be given to an arbitrary part of the subject after shooting, and, for example, only the background can be largely blurred while the person who is the main subject remains as it is. At this time, if this is simply executed, the image is expanded by blurring, and the phenomenon that the blur of the background image overlaps with the human image occurs, which results in an image that cannot be generated by the optical system. Since the filter processing is performed based on the priority relationship between the areas and the recorded image is generated, the occurrence of such a problem is prevented by disposing the blurred image only in the background area other than the main subject area. be able to.

According to a second aspect of the present invention, there is provided an area setting means for setting an area by discriminating a main subject area and a background area from an entire image area set in a captured image; Recording image generating means for generating one final image to be recorded from a plurality of captured images, wherein the recorded image generating means extracts a main subject area image from the captured image as a main subject image Image extracting means, and image processing means for extracting an image of the background area from the captured image as a background image, and then performing a predetermined defocus process and outputting the image as a defocused background image, wherein the main subject area To generate the main subject image and a defocused background image in the background area as the recorded image. And it constitutes an image device.

[0012] In the imaging apparatus configured as described above,
Since the area setting processing is performed by discriminating the main subject area from the background area, there is no problem that an image that cannot be generated by the optical system is generated similarly to the invention according to claim 1 and the processing is performed. And an imaging device whose operation is extremely simple can be realized.

According to a third aspect of the present invention, in the imaging apparatus according to the second aspect, the area setting means sets the area based on information of a captured image captured by illuminating a subject with an illumination device. It is characterized by being constituted. As described above, the discrimination setting of the subject region is performed using the illumination device, so that the region setting can be performed extremely easily.

[0014]

Next, an embodiment will be described. FIG. 1 is a block diagram showing an embodiment of an imaging apparatus (digital camera) according to the present invention. In FIG. 1, 1 is a lens system, 2 is a lens driving mechanism, 3 is an exposure control mechanism, 4 is a filter system, 5 is a CCD image sensor, 6 is a CCD driver, 7 is a pre-processing circuit including an A / D converter, Reference numeral 8 denotes a digital process circuit which includes a memory as hardware and performs all digital process processing. 9 is a memory card interface, 10 is a memory card, 11 is an LCD image display system, 12 is a system controller including a microcomputer as a main configuration, 13 is an operation switch system, 14 is an operation display system including a display LCD and a sounding buzzer, 15 Is a flash, 16 is a lens driver, and 17 is an exposure control driver. In addition, the imaging device is provided with a release button (not shown) and the like.

In the digital camera configured as described above, the system controller 12 controls the digital process circuit 8 for the main operations such as determination of a priority area, filter processing, image cutting, and generation of a recorded image. The system controller 12 controls the exposure control driver 17 as necessary,
Exposure operation including flash emission is performed. Further, the digital camera according to the present embodiment has a normal mode corresponding to the conventional shooting as a shooting mode,
A portrait mode, which is unique to the embodiment of the present invention, is switchable, and the operation switch 13 can be used to switch and select this prior to photographing. Further, the camera control in the following description is all executed by the system controller 12 appropriately controlling each unit.

Next, the operation of the embodiment configured as described above will be described. FIG. 2A is an example of a photographed image captured by photographing, in which a person as a main subject, and a house and a flower located in the rear as a background are almost clearly captured. On the contrary,
FIG. 2B is an example of a final target image processed in the portrait mode of the digital camera according to the present embodiment, and is the same as an image captured using a medium telephoto lens in a conventional film camera. The background is greatly blurred.

When the photographer operates the release button in the portrait mode, the first exposure is performed together with strobe irradiation. At this time, the aperture and the shutter may be controlled in several ways depending on the method of the area discrimination processing. In the present embodiment, the aperture is opened regardless of the exposure value of the main photographing, and the exposure time is determined by the flash emission time. It is set to the shortest time within the range that does not fall below. The amount of light emitted from the strobe is appropriately adjusted by a known technique such as flashmatic or photometry.
By opening the aperture, it is possible to extend the reaching limit of the strobe light, and to shorten the exposure time to reduce the influence of external light. The image obtained at this time is defined as a first image. In the following, it is assumed that the background is sufficiently far from the main subject. Therefore, the strobe light reaching the background is sufficiently smaller than the main subject.

The second exposure is performed immediately after the first exposure under the originally intended exposure conditions (exposure conditions including whether or not a strobe is used). The image obtained at this time is defined as a second image. In normal portrait photography, if the time difference between the two exposures is set sufficiently small, the change in the subject can be ignored.
The second image will be described on the assumption that an image having the same composition in practical use has been obtained.

Here, if the second image is an image as shown in FIG. 2A, the first image is an image in which the background portion is almost dark as shown in FIG. 2C. become that way.
Note that, in FIG. 2C, the background portion is represented by a bright portion for convenience of illustration. That is, since the exposure time is set to the shortest in the first image as described above, the exposure by the external light can be almost ignored. Since the background is far away, the exposure level by the strobe is low. The first image is subjected to level comparison with respect to a predetermined level on a pixel-by-pixel basis, and a pixel position at or above the predetermined level is registered as a main subject area, and a pixel position at or below another predetermined level is registered as a background area. As mentioned earlier, external light exposure is almost negligible, but in reality there may be some exposure, and there is also background exposure using a strobe, so this level comparison process will definitely remove this effect. is there. If the strobe light control level at the time of the first exposure is set higher than that at the time of normal photographing, the possibility of erroneous determination of a low reflectance portion in the main subject can be reduced. Area setting in the processing can be made more reliable.

Subsequently, only the image of the background area is extracted from the second image, and a predetermined amount of defocus processing is performed.
Specifically, the defocus process is a process in which a two-dimensional Gaussian low-pass filter process is performed by known digital filtering. Although the above-described filter processing is employed in order to bring the blur of the optical system closer, any filter processing can be employed in consideration of the load on the processing system. For simplicity, one-dimensional processing may be used. FIG. 2D shows an intermediate image obtained at the time of this defocus processing.
(The main subject portion is shown as a bright portion for the sake of illustration). Here, extracting only the background image has a significant meaning. When the defocus processing is performed on the entire image, the blur of the image of the main subject is widened and a part of the image is overlapped with the background area. If a recorded image is generated using such an image as described below, the image becomes an image that cannot be obtained by the optical system (not shown), and cannot be a portrait image.

Next, image composition for recording image generation is performed. That is, the image of the main subject area of the first image is combined with the image obtained by extracting only the background area from the intermediate background image subjected to the defocus processing, to form one final recorded image. As a result, FIG.
The image shown in FIG. Also in this image synthesis, if the image of the main subject area and the intermediate background image are simply added, as shown in FIG. 2E in which the blur of the background image has spread to the main subject area. Since the image cannot be obtained by the optical system, the image cannot be formed as a portrait image. (Note that the processing technique for differentiating the frequency characteristic adaptively in the region described in the conventional example (Japanese Patent Laid-Open No. 5-292524) having a different problem from the present invention is simply applied to solve the problem of the present invention. In this case, the obtained image is as shown in FIG. 2 (E).)

Finally, the generated recording image is recorded on the memory card 10 after being subjected to appropriate processing such as compression.
As described above, according to the present embodiment, the main subject area and the background area can be reliably set in a very simple manner by effectively using the strobe, and the photographer can release the camera in the same manner as in the conventional camera operation. By simply operating the button, an image suitable for portrait photography similar to a desired silver halide camera can be recorded.

Although the present invention has been described based on the above embodiment, various modifications can be considered in the above embodiment. For example, instead of using a strobe as in the above-described embodiment, for example, individual distance measurement may be performed on the entire subject area, and the main subject area and the background area may be set based on the distance data.

The subject area can be expanded not only into a main subject area and a background area but also into an arbitrary number of areas. For example, 3
It is possible to set one or more appropriate areas, and if three areas of foreground, middle and background are set, "the other two views are for the foreground and the background is for the middle. If the defocus degree of the foreground is made larger than that of the middle view by performing the same processing as in the above-described embodiment and the foreground is the background, A more favorable image is obtained at the rate. That is, the relationship between the main subject and the background is an example of the priority relationship considered in the processing of the above embodiment.

[0025]

As described above with reference to the embodiments, according to the present invention, the apparent depth of field of a photographed image is adjusted by image processing, and for example, a portrait effect similar to a film camera is obtained. An imaging device that can be easily obtained can be realized. In particular, according to the first aspect of the present invention, it is possible to adjust the apparent depth of field of a recorded image by image processing while preventing a problem that an image cannot be generated by the optical system. Further, according to the second aspect of the present invention, it is possible to prevent the occurrence of a problem that an image cannot be generated by the optical system and to realize an image pickup apparatus whose processing and operation are extremely simple. According to the third aspect of the present invention, since the discrimination setting of the subject area is performed using the illumination device, the area setting can be made extremely easily.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing a captured image, a processed image, and a reference image according to the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lens system 2 Lens drive mechanism 3 Exposure control mechanism 4 Filter system 5 CCD image sensor 6 CCD driver 7 Preprocess circuit 8 Digital process circuit 9 Memory card interface 10 Memory card 11 LCD image display system 12 System controller 13 Operation switch system 14 Operation Display system 15 Strobe 16 Lens driver 17 Exposure control driver

Claims (3)

[Claims] And a priority determination unit configured to determine a priority relationship between processing of the partial regions with respect to each partial region which is a part of an entire image region set for a captured image, and a method for determining a priority relationship between the partial regions. One or a plurality of photographed images are subjected to different filter processing for each of the partial areas based on the determination by the priority relation determining means, and the final recording target recording is performed based on the determination by the priority relation determining means. An imaging apparatus comprising: a depth-of-field adjusting unit that adjusts an apparent depth of field of a recorded image by generating an image. 2. An area setting means for setting an area by discriminating a main subject area and a background area from an entire image area set in a captured image, and a final setting from one or a plurality of captured images obtained by subject imaging. Recording image generating means for generating one image to be a general recording target, the recording image generating means extracting the image of the main subject area from the captured image as a main subject image, a main subject image extracting means, Image processing means for extracting the image of the background area from the captured image as a background image, and then performing a predetermined defocusing process and outputting the image as a defocused background image, wherein the main subject area includes the main subject image Wherein the background area is configured to generate an arrangement of a defocused background image as the recorded image. Imaging device. 3. The apparatus according to claim 2, wherein the area setting means is configured to perform the area setting based on information of a captured image captured by illuminating a subject with an illumination device. Imaging device.