JPH10275230A - Image emphasizing device and object identifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To emphasize even an image having its space in any specific direction and also to quickly perform this processing. SOLUTION: A lens 7 of a 1st image pickup means 4 is focused on an object 1, and a lens 9 of a 2nd image pickup means 5 is not focused on the subject 1 respectively. The video signals which are outputted from both means 4 and 5 are synchronous with each other and supplied to a difference calculation circuit 10. The circuit 10 calculates the differences among those video signals. A display device 11 displays a relevant image. Thus, an image having an emphasized frequency component is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image enhancing apparatus for capturing biological microscopic images or fluorescent microscopic images of a sample containing particle components, such as blood, urine, and pathological specimens, and for enhancing the captured images. The present invention relates to an object identification device that identifies an irregular-shaped object using the image enhancement device.

[0002]

2. Description of the Related Art As a conventional object identification device, Japanese Patent Laid-Open No.
138417, JP-A-8-29140, JP-A-8-29140
For example, there is an apparatus described in US Pat. Each of these apparatuses detects a power spectrum by performing a two-dimensional Fourier transform on an image obtained by an imaging unit, and identifies an irregular-shaped object based on the power spectrum.

In such an apparatus, when an image is subjected to two-dimensional Fourier transform, if the image is enhanced as preprocessing, the result of the Fourier transform reflects the characteristics of the image better, and the identification accuracy is improved. For example, in the leukocyte classifying apparatus, if the image of the leukocyte is subjected to such a preprocessing and subjected to the Fourier transform, the chromatin structure of the nucleus is better reflected in the result of the Fourier transform.

In the conventional emphasizing method, for example, a video signal of an image of a nucleus of a white blood cell is passed through a high-pass filter circuit or a band-pass filter circuit and then amplified. As a result, the high-frequency region in the video signal was emphasized, and the contrast of the chromatin structure was increased.

However, in this method, since only the high-frequency components of a one-dimensional video signal obtained by scanning the image in the horizontal direction are extracted and emphasized, the vertical high-frequency components of the image are not enhanced at all. Therefore, for example, the chromatin structure of the nucleus characteristic in the vertical direction of the image is not enhanced, and the enhancement is incomplete.

As another method, there is a method using a digital image processing technique. That is, a method of storing an image in a frame memory and performing a neighborhood calculation at each pixel using a differential operation operator. However, according to this method, since the calculation is performed for each pixel, it takes time for the processing.

[0007]

As described above, the method of enhancing a video signal of an image by passing the same through a filter circuit can enhance an image in one direction, but cannot enhance an image in a direction orthogonal thereto. However, the image of the object characteristic in this direction could not be enhanced. Further, the method using the digital image processing method has a drawback that it takes a long time to perform the calculation because the calculation is performed for each pixel.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional drawbacks, and an object of the present invention is to enhance an image having a characteristic in a spatial frequency in any direction and to quickly process the image. It is an object of the present invention to provide an image enhancement device capable of performing such an operation, and further to provide an object identification device provided with such an image enhancement device.

[0009]

According to a first aspect of the present invention, there is provided an image enhancement apparatus which captures an image (hereinafter referred to as an in-focus image) focused on an object and outputs a video signal thereof. Means, an image of an out-of-focus image of the same object (hereinafter, referred to as a defocused image), and a video signal output therefrom; and each of the first and second imaging means. It is characterized by comprising output control means for controlling output video signals to be synchronized, and signal subtraction means for performing subtraction of video signals synchronized with each other by the output control means.

In this apparatus, an image of an object having a Fourier spectrum whose spatial frequency extends to a high frequency is imaged by the first imaging means for imaging the in-focus image, and the high frequency component is increased from the first imaging means. The output video signal is output (see FIG. 3A). Further, an image of an object having a Fourier spectrum from which the high frequency of the spatial frequency has been cut is picked up by a second image pickup means for picking up a defocused image, and a video signal from which high frequency components have been cut off from the second image pickup means Is output (Fig. 3 (b)
reference).

In the signal subtraction means, two video signals of the same object synchronized by the output control means are subtracted, so that the low frequency components of the two video signals cancel each other, and the high frequency components of the video signal remain. Is output. If this signal is displayed on the display device, an image in which the high-frequency component of the object is extracted can be obtained.

According to a second aspect of the present invention, there is provided an image enhancing apparatus for capturing an image of an object and outputting a video signal of the object, and controlling the image capturing means to convert the image captured by the image capturing means from an in-focus image. A switching unit configured to make the focus image or vice versa, and at least an image before switching by the switching unit among images captured by the imaging unit is stored, and an image captured by the imaging unit before and after the switching Output adjusting means for synchronizing and outputting the video signal of
Signal subtraction means for subtracting two video signals.

In this device, the output adjusting means synchronizes the video signals of the images before and after the switching by the switching means and outputs them to the signal difference calculating means. That is, the video signals of the in-focus image having the Fourier spectrum whose spatial frequency has been extended to the high frequency and the defocus image having the Fourier spectrum whose high frequency of the spatial frequency has been cut are synchronized and provided to the signal difference calculating means. .

In the signal subtracting means, the two video signals are subtracted, so that the low frequency components of the two video signals cancel each other out, and the remaining high frequency components of the video signal are output. If this signal is displayed on a display device, an image in which the high-frequency component of the object is emphasized can be obtained.

According to a third aspect of the present invention, there is provided an image enhancing apparatus according to the second aspect.
The switching means includes a piezo element, and moves the optical element or the imaging element in the imaging means in the optical axis direction by expansion and contraction of the piezo element. The optical element or the imaging element in the imaging means moves at high speed and accurately by the piezo element.

According to a fourth aspect of the present invention, there is provided an object identification apparatus.
Or an image enhancement device according to claim 2, two-dimensional Fourier transform means for performing two-dimensional Fourier transform on an image based on the difference video signal output by the image enhancer device, and the video obtained from the conversion result of the two-dimensional Fourier transform means. Power spectrum detecting means for detecting a power spectrum of an image based on a signal, and identification means for identifying an object in an object based on the power spectrum detected by the power spectrum detecting means.

In such a device, the video signal output from the image enhancing device according to claim 1 or 2 is a signal in which a high frequency component is enhanced. The two-dimensional Fourier transform unit performs a two-dimensional Fourier transform on the image based on the signal, and the power spectrum detecting unit detects a power spectrum from the result of the conversion. The identification means performs the identification based on the power spectrum.

According to a fifth aspect of the present invention, there is provided the object identification device.
In the apparatus according to the above, the object in the object is a blood cell. According to this device, since the image in which the high-frequency component of the image of the blood cell is emphasized is analyzed, the blood cell can be accurately identified.

[0019]

FIG. 1 is a diagram showing the overall configuration of a first embodiment of the present invention. This apparatus includes a table 2 on which an object 1 is placed, and a beam splitter 3 at a position separated from the table 2 by a predetermined distance.
1st that respectively captures the image of the object divided by
And the second imaging means 5.

The first image pickup means 4 comprises a CCD 6 and this C
It has a lens 7 for guiding an image of the object 1 provided to the CD 6 via the beam splitter 3. The lens 7 is arranged at a focal position so that an in-focus image of the object 1 is captured. Similarly, the second imaging means 5 includes a CCD 8
And a lens 9 for guiding the image of the object 1 given to the CCD 8 via the beam splitter 3. The focus position of the lens 9 is shifted so that a defocused image of the object 1 is captured. C of the first imaging means 4
The image of the object 1 received by the CD 6 is in focus. The image of the object 1 received by the CCD 8 of the second imaging means 5 is
The image is the same as the image of the object 1 received by the CCD 6 of the first imaging means 4, but is out of focus and blurred.

The subtraction circuit 10 is a circuit for taking the difference between the luminance signals of the output signals of the CCD 6 and the CCD 8 synchronized by the output control means (not shown).
This is a display device that performs display based on the video signal output from the difference circuit 10.

In the device configured as described above, the first
The video signal of the in-focus image is output from the imaging means 4, and the video signal of the defocused image is output from the second imaging means 5. The difference circuit 10 calculates the difference between these signals. For this reason, the display device 11 displays an image obtained by extracting the high frequency component of the image of the target object in real time.

FIG. 2 is a diagram showing the overall configuration of the second embodiment of the present invention. This apparatus includes a table 2 on which the object 1 is mounted, and an imaging unit 15 for imaging the object 1 mounted on the table 2. The imaging means 15 includes a CCD 16
And a lens 17 for guiding the image of the object 1 to the CCD 16
And a lens moving mechanism 18 for moving the lens 17 in the optical axis direction. The output of the CCD 16 reaches a frame memory 19 and a difference circuit 20. The output of the frame memory 19 reaches the other input terminal of the difference circuit 20.

The control section 21 controls the lens moving mechanism 18 and the frame memory 19. This control unit 2
1 may be constituted by a microcomputer, a sequencer or a personal computer, or may be an analog circuit or a digital circuit having the same function as these. The difference circuit 20 is a circuit for calculating the difference between the luminance signal of the output signal of the frame memory 19 and the luminance signal of the output signal of the CCD 16 synchronized by the control unit 21.
Is a display device that performs display based on the video signal output from the difference circuit 20.

Here, the lens moving mechanism 18 and the control section 21 constitute switching means, and the frame memory 19 and the control section 21 constitute output adjustment means.

In the apparatus configured as described above, first, the control unit 21 controls the lens moving mechanism 18 so that the in-focus image is given to the CCD 16.
7 is moved. Next, the control unit 21 stores the output signal for one frame of the CCD 16 in the frame memory 19.
Then, the control unit 21 controls the lens moving mechanism 18 to
The lens 17 is moved so that the defocused image is given to the CCD 16. Next, the control unit 21 synchronizes with the video signal output from the CCD 16 and
Is output to the difference circuit 20. As a result, the video signal of the in-focus image is output from the frame memory 19, and the video signal of the defocus image is output from the CCD 16. The difference circuit 20 calculates the difference between these signals. For this reason, the display device 11 includes:
An image in which the high-frequency component of the image of the object is emphasized is displayed.

In the present embodiment, the movement of the lens 17 of the lens moving mechanism 18 is performed under the control of the control unit 21. However, the movement of the lens 17 may be directly performed by a human to change the position of the lens 17. In addition, the control of the timing of storing and reading the video signal in and from the frame memory 19 is also performed by the control unit 21, but this may also be performed by a human switch operation.

In the present embodiment, the in-focus image is stored in the frame memory. However, the defocus image is stored in the frame memory, and the video signal and the in-focus image directly obtained from the image pickup means are stored. The video signal may be provided to the difference circuit.

In this embodiment, one frame memory is used, but two frame memories are used to store an in-focus image and a defocus image respectively, and when necessary, fetch the both and synchronize them. , May be provided to the difference circuit.

Here, the lens moving mechanism 18 is used as an example of a means for changing the focus to capture an in-focus image and a de-focus image of the object 1, and if it serves the same purpose, The configuration does not matter. For example, instead of this lens moving mechanism, a CCD moving mechanism for moving a CCD, an object moving mechanism for moving an object, a mechanism for changing the type of lens, a lens and a C
A mechanism for moving the CD may be used.

In the above two embodiments, the difference circuit may be an analog circuit using an operational amplifier or a transistor, or may be a circuit that converts a video signal into a digital signal and performs a digital operation using the digital signal. good. In addition, the offset adjustment function of the signal in the difference circuit,
If an amplification function is added, a clearer high-frequency component extracted image can be obtained. Further, although the CCD is used as the imaging means, an imaging tube or the like may be used.

Next, an object identification device according to a third embodiment will be described. This device is a leukocyte classification device that classifies leukocytes. FIG. 4 shows the entire configuration. The microscope 31 has a sample stage on which a sample is placed. The sample stage is movable by a sample stage moving means 32 on a plane orthogonal to the optical axis of the objective lens of the microscope 31. The identification target object position detection unit 33 is a unit that detects that the identification target object has reached a specific position. Sample stage control means 3
Reference numeral 4 denotes a unit that controls the sample stage moving unit 32 based on the detection signal of the identification target object position detecting unit 33. The focus detection means 35 is means for detecting whether or not the microscope 31 is focused on the sample, and the focus adjustment means 36
This is a means for adjusting the focus of the microscope 31. The automatic focus control unit 37 controls the focus adjustment unit 36 based on the detection signal of the focus detection unit 35, and applies the microscope 31 to the sample on the sample stage.
Is a means of focusing.

A piezo element is attached to the objective lens housing of the microscope 31 that houses the objective lens. The piezo element is sandwiched between the objective lens housing and the microscope main body. Therefore, the objective lens is moved relative to the microscope main body in the optical axis direction by a voltage applied to the piezo element. Therefore, the automatic focus control means 37
Adjusts the voltage applied to the piezo element to move the objective lens.

The image pickup means 38 is a means for picking up an in-focus or defocus microscope image of an image to be analyzed, for example, using a CCD camera. The memory 39 stores an image captured by the imaging unit 38.

The first image preprocessing means 41 includes a memory 39
Is a means for extracting an image to be analyzed based on the RGB density information of the image stored in.

The auxiliary parameter detecting means 42 is means for detecting the color and area of the image extracted by the first image preprocessing means 41. The second image preprocessing unit 43 is a unit that emphasizes the image extracted by the first image preprocessing unit 41.
The second image preprocessing means 43 has the configuration shown in FIG.
That is, a frame memory 51 for storing the image extracted by the first image preprocessing means 41 for one frame, and an output signal of the frame memory 51 and the first image preprocessing means 41
And a difference amplifier circuit 52 for taking the difference between the output signals and amplifying the result. The operation timing of the frame memory 51 is controlled by the control unit 48.

Returning to FIG. 4, two-dimensional Fourier transform means 4
Reference numeral 4 denotes a unit for performing a two-dimensional Fourier transform of the image supplied from the second image preprocessing unit 43. The two-dimensional Fourier transform means 44 of the present apparatus is a means for optically transforming, and has a configuration as shown in FIG. That is, the two-dimensional Fourier transforming unit 44 is a liquid crystal display device 5 that displays an image based on a signal given from the second image preprocessing unit 43.
3. A laser diode 54 that emits coherent light to the liquid crystal display device 53, and a light interposed between the laser diode 54 and the liquid crystal display device 53, and the light emitted by the laser diode 54 is converted into parallel light to be displayed on the screen of the liquid crystal display device 53 A lens 55 for guiding the light, a lens 56 for converting the phase of the light transmitted through the liquid crystal display device 53, and a ring detector 57 for receiving the light transmitted through the lens 56 are provided. The ring detector 57 has ring-shaped photodetectors having different diameters arranged concentrically. The ring detector 57 is arranged such that the center of the circle coincides with the focal position of the lens 56.

Returning to FIG. 4, the power spectrum detecting means 45 is a means for obtaining a power spectrum based on the conversion result of the two-dimensional Fourier transform means 44.

The identification judging means 46 identifies the image extracted by the first image preprocessing means 41 based on the power spectrum obtained by the power spectrum detecting means 45 and the color and area data detected by the auxiliary parameter detecting means 42. Is a means for performing The identification determining means 46 has a learning function, and is connected to a learning table 47 for storing a learning result.

The control unit 48 is for overall control of the entire apparatus, and includes an automatic focus control unit 37, a sample stage control unit 34, a first image preprocessing unit 41, a second image preprocessing unit 43, The two-dimensional Fourier transform means 44 is controlled. Among the above units, the memory 39, the first image preprocessing unit 41, the auxiliary parameter detecting unit 42, the power spectrum detecting unit 45, the identification determining unit 46, the learning table 47, and the control unit 48 are one personal computer. It can be realized by the functions of the computer.

Next, the operation of the above-configured apparatus will be described with reference to the flowchart of FIG. First, the operator mounts a sample prepared by applying a sample to a preparation on a sample stage of the microscope 31 (S1). Here, the sample is stained blood, and the amorphous object to be identified is white blood cells. Next, the control unit 48 causes the automatic focus control unit 37 to control the focus position. Thereby, the automatic focus control means 37
Operates the focus adjusting means 36 based on the detection signal of the focus detecting means 35 so that the lens of the microscope 31 is focused on the sample on the sample stage (S2). Next, the control unit 48
Instructs the sample stage control means 34 to start moving the sample stage (S3). As a result, the sample stage moves, and the identification target object position detecting means 33 outputs one identification target object, that is, one identification target object.
When one leukocyte reaches a specific position, it is detected. The sample stage control means 34 determines whether or not the identification object has been detected based on the detection result of the identification object position detection means 33 (S4), and stops the movement of the sample stage if this detection is detected (S4).
5) If there is no such detection, the process returns to step S3.

Next, the image pickup means 38 picks up a microscope image (S6) and outputs this to the memory 39 and the first image preprocessing means 41. Here, the imaging means 38 outputs an image centered on one white blood cell. The memory 39 stores this. Next, the first image pre-processing means 41
An image to be analyzed is extracted based on the RGB density information of the image stored in (7). That is, the control unit 48
The analysis target image extracted by the first image preprocessing means 41 is stored in the frame memory 51 shown in FIG. At this point, since the object is in focus, what is stored in the frame memory 51 is the in-focus image. The analysis target image extracted here is the internal structure of white blood cells.

Next, the auxiliary parameter detecting means 42
The color and area of the image extracted by the image pre-processing means 41 are detected (S8). The control unit 48 determines whether emphasis is necessary based on the detected color and area information (S9). If not, the first image preprocessing unit 41 performs a two-dimensional Fourier transform on the image extracted by the first image preprocessing unit 41 (step S12). Then, if necessary, a defocused microscope image is picked up, and the second image pre-processing means 43 emphasizes the image extracted by the first image pre-processing means 41 (S10, S11).

That is, when the control unit 48 determines that emphasis is necessary, the control unit 48 controls the automatic focus control unit 37 to output a defocused image from the imaging unit 38, and from this image, the first image preprocessing unit. An image to be analyzed is extracted by 41 and a video signal of the image to be analyzed is supplied to one input terminal of a differential amplifier circuit 52 shown in FIG. 5, and an image of the image stored in the frame memory 51 is synchronized with this signal. The video signal is supplied to the other input terminal of the differential amplifier circuit 52. The difference amplification circuit 52 first performs a difference between these two video signals. Therefore, the low frequency components of the two video signals cancel each other, and the high frequency components contained only in the in-focus image remain. Then, the difference amplification circuit 52 amplifies the difference result. The second image pre-processing means 43 shown in FIG. 4 emphasizes the high-frequency components of the image to be analyzed in this way, and outputs a video signal of the image to the two-dimensional Fourier transform means 44.

The two-dimensional Fourier transform means 44 performs a two-dimensional Fourier transform of the image supplied from the second image preprocessing means 43 (S12). That is, in the apparatus shown in FIG. 6, the liquid crystal display 53
Display the image given by. This image is an image in which high-frequency components in the analysis target image extracted by the first image preprocessing unit 41 are emphasized. For example, a type of leukocyte called a monocyte has a fine net-like pattern inside the nucleus of a cell, and the contrast is emphasized and displayed.

The coherent light emitted from the laser diode 54 and converted into parallel light by the lens 55 is incident on the display screen of the liquid crystal display device 53. The transmitted light on the display screen is subjected to a phase conversion action by the lens 56 to form a Fourier transform image on the ring detector 57.
Here, the Fourier transform image is an image corresponding to the spatial frequency of the image, and a low spatial frequency component appears near the focal position of the lens 56 and a high spatial frequency component appears far from the focal position of the lens 56. Therefore, by detecting the amount of light incident on each photodetector of the ring detector 57, the distribution of the spatial frequency of the image displayed on the liquid crystal display device 53, that is, the power spectrum can be obtained.

Next, the power spectrum detector 45 shown in FIG. 4 obtains a power spectrum by detecting the amount of light incident on each photodetector of the ring detector 57 based on the conversion result of the two-dimensional Fourier transformer 44 (S13). ).

Next, the identification determining means 46 determines whether the learning table 4
7, the identification of the target object extracted by the first image preprocessing unit 41 based on the power spectrum obtained by the power spectrum detection unit 45 and the color and area data detected by the auxiliary parameter detection unit 42. Perform (S14).
For example, if the leukocytes are monocytes as described above, the pattern inside the nucleus is a delicate mesh, and the power spectrum contains many high-frequency components. If the leukocyte is a lymphocyte, the pattern inside the nucleus has no fine structure and is spacious, and the power spectrum has few high frequency components. For example, if the power spectrum contains many high-frequency components, the identification determining means 46 determines that the white blood cells are monocytes, and if the power spectrum has few high-frequency components, determines that the white blood cells are lymphocytes. Identification determination means 4
The learning result of No. 6 is stored in the learning table 47.

The sample stage control means 34 stores the process of moving the sample stage, thereby determining whether all the identification target objects, that is, leukocytes have been identified (S15), and all the identification target objects are identified. If it is determined that the process has been completed, the processing of this apparatus is terminated.
Return to the processing of.

The switching between in-focus and de-focus of the microscope image of the apparatus is performed by using a piezo element. For switching between in-focus and defocus, a movement of the lens of about several hundred nm to several μm is sufficient. The position adjustment of this order is optimally performed by a piezo element. Further, according to the piezo element, switching between in-focus and defocus can be performed at high speed, and fine adjustment of the defocus amount can be easily performed by adjusting the applied voltage.

In this apparatus, the image to be analyzed is emphasized using the configuration of the second embodiment described above.
This may be performed using the configuration of the above-described first embodiment.

In the present apparatus, the two-dimensional Fourier transform is performed by using an optical device. However, the image signal may be converted into a digital signal, and the conversion may be performed by a calculation by a digital computer.

In the present apparatus, emphasis is performed after extracting the image to be analyzed. However, the image to be analyzed may be extracted after emphasizing the image.

[0054]

According to the apparatus of the first aspect, an image in which a high frequency component of a spatial frequency is emphasized in any direction of the image can be obtained. Also, according to this device, a circuit such as a high-pass filter is unnecessary,
The configuration is extremely simple. Further, according to this device, the image enhancement processing is performed quickly.

According to the device of the second aspect, in addition to having the same effects as those of the device of the first aspect, the configuration can be further simplified because only one imaging means is required.

According to the device of the third aspect, the switching between in-focus and de-focus using the piezo element can be performed at high speed and accurately.

According to the fourth aspect of the present invention, it is possible to obtain an analysis target image in which a high-frequency component of a spatial frequency is emphasized in any direction of an image, so that object identification with high accuracy can be performed. Can be.

According to the apparatus of claim 5, highly accurate blood cell identification can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall configuration of a second embodiment of the present invention.

FIG. 3 is a diagram showing a spatial frequency distribution of an image containing many high-frequency components and a spatial frequency distribution of an image from which high-frequency components have been cut.

FIG. 4 is a diagram showing an overall configuration of a third embodiment of the present invention.

FIG. 5 shows a second image preprocessing means 43 of the apparatus shown in FIG.
The figure which shows the specific structure of.

FIG. 6 shows a two-dimensional Fourier transform means 4 of the device shown in FIG.
The figure which shows the specific structure of 4 of FIG.

FIG. 7 is a view showing a flowchart for explaining the operation of the apparatus shown in FIG. 4;

[Description of Signs] 4 First imaging means 5 Second imaging means 15 Imaging means 10, 20 Difference circuit 19 Frame memory 21 Control unit 38 Imaging means 41 First image preprocessing means (extraction means) 43 Second Image preprocessing means (enhancing means) 44 two-dimensional Fourier transform means 45 power spectrum detecting means 46 identification determining means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Takemura 585 Tomicho, Funabashi-shi, Chiba Sumitomo Osaka Cement Co., Ltd. (72) Inventor Yutaka Nagai 1-31-4 Nishi-Ochiai, Shinjuku-ku, Tokyo Japan Photovoltaic Industry Co., Ltd. No. Japan photoelectric company

Claims (5)

[Claims] A first imaging unit that captures an in-focus image of an object and outputs a video signal thereof; and an out-of-focus image of the same object and outputs a video signal thereof. A second image pickup unit, an output control unit for controlling a video signal output from each of the first and second image pickup units to be synchronized, and a subtraction of video signals synchronized by the output control unit. An image enhancement device comprising a signal subtraction means for performing the following. 2. An image pickup means for picking up an image of an object and outputting a video signal thereof, and controlling the image pickup means so that an image picked up by the image pickup means is out of focus from a state where the object is in focus. Switching means for setting the state to be reversed or vice versa, and storing at least an image before switching by the switching means among images captured by the imaging means, and images captured by the imaging means before and after the switching. An image enhancement device comprising: an output adjusting unit that synchronizes and outputs the video signals of the above; and a signal subtraction unit that performs a subtraction between two video signals output by the output adjusting unit. 3. The switching device according to claim 2, wherein the switching means includes a piezo element, and moves the optical element or the imaging element in the imaging means in the optical axis direction by expansion and contraction of the piezo element. Image enhancement device. 4. An image enhancement device according to claim 1, wherein said image enhancement device outputs a two-dimensional Fourier transform of an image based on a difference video signal. Power spectrum detection means for detecting a power spectrum of an image based on the video signal from the conversion result of the Fourier transform means; and identification means for identifying an object in an object based on the power spectrum detected by the power spectrum detection means. An object identification device, comprising: 5. The object identification device according to claim 4, wherein the object in the object is a blood cell.