JPH09259278A - Image processing device - Google Patents

Abstract

(57) Abstract: When extracting a target object from a natural image, it is an object of the present invention to facilitate the separation of the background and the target object by using illumination and to accurately extract only the target object. An image pickup means (2) picks up an image of a target object and its background illuminated with light and a normal image and stores them in an image storage means (3). The device control means 3 controls the illumination means 1 and the imaging means 2. The image synthesizing unit 5 obtains a difference image between the two images stored in the image storing unit 4, and the object extracting unit 6 extracts the area of the target object from the difference image obtained by the object extracting unit 5 by threshold processing.
At the same time, the control method of the device control means 3 is changed based on the result of the threshold processing, and adjustment is performed so that a better image can be obtained. In this way, by performing the threshold processing, it is possible to accurately extract the target region under the natural background without extracting noise caused by the imaging conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus having a processing function of extracting an object from an image.

[0002]

2. Description of the Related Art Conventionally, in order to extract only a target object from an image (a target image) including a background and a target object, a monochromatic background such as black or blue is used, and threshold processing for luminance information and color information is performed. Alternatively, a method of performing object extraction processing such as edge extraction processing is used (conventional example 1). Further, as a method of extracting a target object without using a special background, there is a method of using a background image that does not include the target object, obtaining a difference between the target image and the background image, and then performing an object extraction process ( Conventional example 2).

[0003]

DISCLOSURE OF THE INVENTION In the conventional example 1,
Since it is necessary to use a special background, there is a problem that the usable place is limited. Further, in the conventional example 2, there is a problem that the influence of the change of the imaging condition when the background image is captured and when the target image is captured is large, and the noise caused by the difference in the imaging condition is extracted together with the target object. .

In order to solve these problems, it is an object of the present invention to facilitate the separation of the background and the target object by using illumination and to accurately extract the target object under the natural background.

[0005]

In order to solve this problem, the present invention provides an illumination means for irradiating a target object and a background with light, and an imaging means for imaging the target object and the background.
A device control means for controlling the illumination means and the image pickup means, an image storage means for storing an image picked up by the image pickup means, and at least two pieces of image information stored in the image storage means are combined. An image synthesizing unit and an object extracting unit for extracting the target object from the image information obtained by the image synthesizing unit are provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram showing an embodiment of the present invention. As shown in FIG.
Illumination means 1 for irradiating the target object and the background with light, imaging means 2 for imaging the target object and the background, device control means 3 for controlling the illumination means 1 and the imaging means 2, and the imaging means 2.
An image storage unit 4 that stores at least two images captured in step S5, an image combination unit 5 that combines the images stored in the image storage unit 4, and a target object is extracted from the combined image obtained by the image combination unit 5. The device control means 3 comprises an object extraction means 6, and the device control means 3 controls the brightness of the lighting means 1 and an imaging control for controlling imaging conditions such as the number of images taken per unit time and the shutter speed. And a part 32.

FIG. 2 is a block diagram showing an embodiment of the illumination control section 31 shown in FIG. In FIG. 2, the illumination control unit 31 includes a switch 311 that performs an on / off switching operation of the illumination unit 1 and a switch control unit 312 that controls the switch 311.

The operation of the image processing apparatus configured as described above will be described. First, the illumination means 1 irradiates the target object and its background with light, and the imaging means 2 images the target object and its background with which the illumination means 1 irradiates light, and sends it to the image storage means 4. As shown in FIG. 4, the illuminating means 1 emits light in a direction substantially the same as the direction in which the imaging means 2 images the target object. An example of an image captured by the image capturing means 2 at this time is shown in FIG.

Since the distance between the image pickup means 2 and the background is larger than the distance between the image pickup means 2 and the target object, the amount of light reaching the background from the illumination means 1 is the same as that of the target object. Is smaller than the amount of light reaching the object, and as a result, the target object is illuminated brighter than the background. Therefore, the image captured while the illumination unit 1 is irradiating light is as shown in FIG.
As compared with the normal image as shown in FIG. 5A, the image has only the brightness of the target object emphasized as shown in FIG.

The illumination control unit 31 controls the illumination unit 1, and the imaging control unit 32 controls the image pickup unit 2.
When configuring the lighting control unit 31 as shown in FIG.
1 switches ON / OFF of the lighting means 1,
The imaging control unit 32 responds to ON / OFF switching of the switch 311 when the illumination emits light (when the switch is ON), that is, only the brightness of the target object as shown in FIG. 5B. Image and the normal image as shown in FIG. 5A are alternately captured when the light is not emitted (when the switch is OFF), and the image storage means 4
Send to

The image storage means 4 stores an image when the light emitted from the image pickup means 2 is emitted and an image when the light is not emitted, and sends it to the image synthesizing means 5. The image synthesizing means 5 obtains a difference image between the two images sent by the image storing means 4, and sends it to the object extracting means 6. Object extracting means 6
Performs threshold processing on the difference image sent by the image synthesizing means 5 using a certain threshold to extract the area of the target object. At the same time, the control methods of the illumination control unit 31 and the imaging control unit 32 are changed based on the threshold processing result, and adjustment is performed so that a better image can be obtained. For example, when the region extracted by the threshold processing is smaller than a certain amount, the illumination light is made stronger. In this way, by extracting the difference between the image in which the brightness of the area of the target object is emphasized by illuminating the target object and the normal image and performing the threshold processing, the noise caused by the imaging conditions can be extracted. It is possible to extract only the target area with high accuracy. Further, since two consecutive images are used, the change in the background image pickup condition is small, and noise can be reduced.

It should be noted that the operation of the switch 311 in the present embodiment is to switch ON / OFF of the power source of the illuminating means 1, but the operation of the switch 311 is the illuminating means 1.
The same effect can be obtained even if the brightness level is switched.

(Second Embodiment) The second embodiment of the present invention will be described below with reference to FIG. In the second embodiment, the image pickup control unit 32 of the first embodiment is configured as shown in the block diagram of FIG.

In FIG. 3, the image pickup control section 32 detects the amount of light (luminous flux) emitted by the illuminating means 1 and a luminous flux sensor 3 for detecting the quantity.
21 and an image capturing instruction unit 322 that determines the timing at which the image capturing unit 2 captures an image of the target object based on the value measured by the light flux sensor 321.

The operation of the image processing apparatus configured as described above will be described. Similar to the first embodiment, the illumination means 1 is
The target object and its background are irradiated with light from the front of the target object, and the imaging unit 2 images the target object and its background illuminated by the illumination unit 1 and sends it to the image storage unit 4. The illumination control unit 31 controls the illumination unit 1 and the imaging control unit 32 controls the imaging unit 2. However, when the illumination control unit 31 is configured as shown in FIG. 3, the illumination control unit 31 controls the illumination unit 1
Controls to always illuminate the target object and the background.
At this time, the illumination unit 1 uses illumination such as a fluorescent lamp whose luminous flux changes with time.

The luminous flux sensor 321 detects the amount of light (luminous flux) emitted by the illuminating means 1, and the image pickup instructing section 322 determines the luminous flux detected by the luminous flux sensor 321.
Determines when to image the target object and background,
The imaging unit 2 is controlled according to the determined timing.
For example, when the light emitted by the illumination unit 1 has the characteristics shown in FIG. 6, the imaging instruction unit 322 captures an image at a time Tmax at which the luminous flux has the maximum value Fmax and a time Tmin at which the luminous flux has the minimum value Fmin. In this way, an instruction is issued to the image pickup means 2.

By thus controlling the image pickup means 2, when the luminous flux of the illuminating means 1 is large, that is, when the image in which the brightness of the target object is particularly emphasized and the illuminating means 1 emits a small amount of light. That is, an image in which the brightness of the target object is not so emphasized is alternately captured, and the image storage means 4 stores these two types of images one by one and sends them to the image synthesis means 5. The subsequent processing and the irradiation direction of the illuminating means 1 (see FIG. 4) are the same as those in the first embodiment.

As described above, an image in which the brightness of the region of the target object is particularly emphasized and an image in which the brightness of the region of the target object is not emphasized are picked up by using the characteristics of the illuminating means 1, and the difference between them is obtained and threshold processing is performed. As a result, only the target area can be accurately extracted without extracting noise caused by the imaging conditions. Further, as in the first embodiment, since two consecutive images are used, changes in the imaging conditions of the background and the target area are small, and noise can be reduced.

As described above, in both the first and second embodiments, since the image in which only the brightness of the target object is emphasized is used, the target object can be accurately extracted even in the natural background. it can. If the target object is a human body,
When the type of light used for the illumination unit 1 is invisible light, the subject does not feel dazzling as in the case of using normal light, and the burden on the subject can be reduced. Furthermore, since the direction of the light emitted by the illumination means is substantially the same as the direction in which the imaging means images the target object, there is an advantage that the shadow of the target object by the illumination means 1 is unlikely to occur and the adverse effect of using the illumination is not exerted. is there.

[0020]

As described above, according to the present invention, the target object is irradiated with light and the brightness of the area of the target object is emphasized, so that the target object and the background are easily separated, and the natural background The target object can be accurately extracted.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a first embodiment of the device control means 3 of FIG.

FIG. 3 is a block diagram showing a second embodiment of the device control means 3 of FIG.

FIG. 4 is a diagram showing an example of an implementation environment of the present invention.

5A and 5B are views showing an example of an image captured by the image capturing means 2.

FIG. 6 is a diagram showing an example of a temporal change in the amount of light emitted by the illumination means 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination means 2 Imaging means 3 Device control means 4 Image storage means 5 Image composition means 6 Object extraction means 31 Illumination control section 32 Imaging control section 311 switch 312 switch control section 321 Light intensity sensor 322 Imaging instruction section

Claims (8)

[Claims] 1. Illuminating means for irradiating a target object and a background with light, and imaging means for imaging the target object and the background.
A device control means for controlling the illumination means and the image pickup means, an image storage means for storing an image picked up by the image pickup means, and at least two pieces of image information stored in the image storage means are combined. An image processing apparatus comprising: an image synthesizing unit; and an object extracting unit that extracts the target object from the image information obtained by the image synthesizing unit. 2. The image processing apparatus according to claim 1, wherein the device control means sequentially updates the device control method based on the image information obtained by the image synthesizing means. 3. The image according to claim 1, wherein the device control means comprises an image pickup control section for controlling the image pickup means and an illumination control section for controlling the brightness of the illumination means. Processing equipment. 4. The image processing apparatus according to claim 3, wherein the illumination control unit includes a switch of the illumination unit and a switch control unit that controls the switch. 5. A switch control unit controls to repeat switching on and off according to the number of images taken by the imaging means per unit time, and displays an image of a state in which the switch is turned on and an image in a state of not turned on. The image processing apparatus according to claim 4, wherein the image processing means sends the image to the image storage means. 6. An image pickup control section, a light flux sensor for detecting an amount of light emitted by the illumination means, and an image pickup instruction section for deciding a timing at which the image pickup means picks up an image of a target object based on a value measured by the light flux sensor. The image processing apparatus according to claim 3, wherein the image processing apparatus is configured by: 7. The image processing apparatus according to claim 1, wherein the image storage means stores the image sent by the image pickup means and the background image picked up in advance. 8. The image processing apparatus according to claim 1, wherein the light beam used by the illumination means is a non-visible light beam.