JP4309622B2 - Electronic imaging apparatus and electronic imaging apparatus for microscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic imaging device that electronically records an image taken by a solid-state imaging device or the like, and an electronic imaging device for a microscope.
[0002]
[Prior art]
In recent years, an image of a subject image formed by a photographing lens is picked up by an image pickup device such as an image pickup device (CCD), and an electronic camera or the like that electronically records an image signal obtained as an electric signal from the image pickup device. Many electronic imaging devices are used.
[0003]
In such an electronic imaging device, it is important to display a better image on the display unit. For this reason, conventionally, appropriate signal processing is performed on an image signal output as an electrical signal from the imaging unit. Things are being done.
[0004]
Japanese Patent Application Laid-Open No. 11-112837 is based on such a concept, and the contour enhancement degree by the contour enhancement unit is variably controlled according to the gain value by the gain control unit during the imaging operation.
[0005]
On the other hand, the subject image that has recently been imaged on the image sensor is optically shifted with a parallel plate provided in the optical path of the photographic lens, or the photographic lens is shifted in a plane perpendicular to the optical axis. A method of reading a plurality of images and synthesizing the plurality of images to obtain a high-definition still image has been put into practical use.
[0006]
Even in this method, in order to display a better image on the display means, appropriate signal processing is performed on the image signal. For example, it is disclosed in Japanese Patent Application Laid-Open No. 07-123424. As described above, it is known that the edge enhancement intensity is varied based on the relative positional relationship of the shifted image, and the image quality is controlled so that a stable resolution can be felt in any state.
[0007]
[Problems to be solved by the invention]
In this Japanese Patent Application Laid-Open No. 07-123424, the spatial frequency characteristics are shifted to the right as shown in FIG. 4 as the relative positional relationship between the shifted images becomes finer. That is, the spatial frequency characteristic is shifted in the direction in which the Nyquist frequency is increased to increase the edge emphasis level, thereby ensuring stable resolution.
[0008]
However, if the degree of edge enhancement is increased in this way, it will be emphasized up to an extra frequency, causing extra noise, jaggedness due to edge enhancement, and so on, resulting in an unsightly image. This causes a problem.
[0009]
The present invention has been made in view of the above circumstances, and provides an electronic imaging device and an electronic imaging device for a microscope that can obtain a high-quality image with reduced noise and jaggedness enhanced by contour enhancement while maintaining a sense of resolution. The purpose is to do.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 is an image sensor that captures a subject image, and a displacement unit that periodically displaces the image sensor and outputs an image signal of the subject image from the image sensor for each displacement position; Image processing means for rearranging the image signals of the image sensor for each displacement position by the displacement means and synthesizing the image, and a contour enhancement frequency for performing contour signal processing on the image rearranged by the image processing means A contour emphasizing means that can be varied, and The contour emphasizing unit sets the contour emphasizing frequency so as to emphasize a frequency range up to a resolution limit point determined according to the shape of the opening of the image sensor. It is characterized by that.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the contour emphasizing unit may change the contour emphasizing frequency before and after the periodic displacement operation of the image sensor by the displacement unit. It is a feature.
[0012]
According to a third aspect of the invention, there is provided a lens system according to the first aspect, wherein the subject image is projected onto the image sensor, and the contour emphasis frequency by the contour emphasizing means is set according to the type of the lens system. It is characterized by being variable.
[0013]
According to a fourth aspect of the present invention, in the first aspect of the invention, there is provided gain adjustment means for adjusting a signal level of an image output from the image pickup device to a predetermined gain, and the gain adjustment means according to the gain value of the gain adjustment means. Thus, the contour emphasis frequency by the contour emphasizing means can be varied.
[0014]
The invention according to claim 5 is connected to a microscope having an aperture stop for adjusting the numerical aperture of illumination light and an objective lens, and having at least one port for outputting an image from the objective lens, and is output from the port. In the electronic imaging device for a microscope for picking up a captured image, there is provided contour enhancement means capable of varying contour enhancement strength for performing contour signal processing on the image output from the port and captured, and the aperture stop The contour emphasis intensity by the contour emphasizing means is varied according to the state change.
[0016]
Claim 6 The invention described is connected to a microscope having an aperture stop for adjusting the numerical aperture of illumination light and an objective lens, and having at least one port for outputting an image from the objective lens. In an electronic imaging device for a microscope for imaging,
An image pickup device for picking up a subject image, a displacement means for periodically displacing the image pickup device and outputting an image signal of the subject image from the image pickup device for each displacement position, and for each displacement position by the displacement means Image processing means for rearranging the image signals of the image sensor and synthesizing the images, According to the state change of the aperture stop Contour emphasizing means capable of varying the contour emphasis frequency for performing the contour signal processing on the image rearranged by the image processing means, The contour emphasizing unit sets the contour emphasizing frequency so as to emphasize a frequency range up to a resolution limit point determined according to the shape of the opening of the image sensor. It is characterized by doing.
[0017]
As a result, according to the present invention, while maintaining a sense of resolution in both cases before and after the displacement of the image sensor by the displacement means, it is possible to suppress the occurrence of extraneous noise emphasized by edge emphasis or oblique jaggedness due to edge emphasis. it can.
[0018]
Further, according to the present invention, it is possible to suppress the occurrence of extra noise that is emphasized by edge emphasis while maintaining a sense of resolution, or burrs caused by edge emphasis, regardless of the MTF of the lens system.
[0019]
Furthermore, according to the present invention, it is not necessary to perform edge enhancement more than necessary in a region with a large amount of noise, and a high-quality image can be acquired.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
(First embodiment)
FIG. 1 shows a schematic configuration of an electronic imaging apparatus to which the first embodiment of the present invention is applied. In the figure, reference numeral 1 denotes a photographic optical system, which includes a photographic lens, a drive motor and a drive mechanism for driving the photographic lens. An optical subject image is formed on a solid-state imaging device (hereinafter simply referred to as a CCD) 2 such as a CCD through the photographing optical system 1.
[0022]
The CCD 2 photoelectrically converts an optical subject image to be formed and generates an image signal of the subject image.
[0023]
In this case, a timing generator (TG) 3 and a signal generator (SG) 4 for generating a synchronizing signal such as a driving pulse are connected to the CCD 2 and are driven by a predetermined timing signal. The CCD 2 has an electronic shutter function (means) (not shown) so that the exposure time can be controlled.
[0024]
A piezoelectric driver 5 is connected to the CCD 2 as a displacement means. The piezoelectric driver 5 has a piezoelectric element such as a piezoelectric element, and the CCD 2 is periodically displaced by the piezoelectric element to output an image signal in which the subject image is shifted from each other at each displacement position. ing.
[0025]
The CCD 2 is connected to a CDS circuit (Correlated Double Sampling). This CDS circuit extracts an image signal component from the output signal of the CCD 2.
[0026]
An amplifier (AMP) 7 is connected to the CDS circuit 6 as a gain adjusting means. The amplifier (AMP) 7 includes gain control means including an AGC circuit for adjusting the output signal level from the CDS circuit 6 to a predetermined gain value.
[0027]
A frame memory 9 as an image memory is connected to the amplifier (AMP) 7 via an A / D converter 8. The A / D converter 8 converts the analog image signal output from the amplifier (AMP) 7 into a digital image signal in synchronization with the timing signal of the timing generator (TG) 3. The frame memory 9 stores the digital signal output from the A / D converter 8. The frame memory 9 is controlled by the memory controller 10 to read and write data. The frame memory 9 includes a memory corresponding to a plurality of images acquired by pixel shifting, and stores each image in these memories. Then, based on the control of the CPU 28 to be described later, the plurality of images are rearranged (pixel shift) into one image (image processing means).
[0028]
A color separation circuit 11 and a γ correction circuit 12 are connected to the frame memory 9.
The color separation circuit 11 separates the image signal read from the frame memory 9 into the three primary color signals of the RL signal, the GL signal, and the BL signal. The γ correction circuit 12 performs a gamma (γ) correction process on the color signal.
[0029]
A WB (white balance) circuit 13 for adjusting the white balance of the image signal is connected to the color separation circuit 11. A color correction circuit 16 is connected to the WB (white balance) circuit 13 via a white clip 14 and a clip level detection circuit 15. The color correction circuit 16 performs color correction for improving color reproducibility.
[0030]
A color difference matrix circuit 18 is connected to the color correction circuit 16 via a color γ correction circuit 17. The color γ correction circuit 17 performs γ (γ) correction processing of the color signal corrected by the color correction circuit 16. The color difference matrix circuit 18 converts the color signals of R, G, and B into a luminance signal YL and two color difference signals (RY signal and BY signal) to adjust the hue and color saturation. is there.
[0031]
On the other hand, a Y signal generation unit 19 is connected to the γ correction circuit 12. The Y signal generation unit 19 extracts and generates only a luminance signal (Y signal) from the image signal that has been subjected to γ correction processing by the γ correction circuit 12.
[0032]
A band pass filter (BPF) 20 is connected to the Y signal generation unit 19. The band pass filter (BPF) 20 forms part of the contour emphasizing means, and extracts a contour signal (hereinafter referred to as an edge signal) by removing low frequency components from the Y signal.
[0033]
A coring unit 21 is connected to the band pass filter (BPF) 20. The coring unit 21 also forms part of the contour emphasizing means, and suppresses or removes the noise component of the edge signal generated by the bandpass filter (BPF) 20 to perform coring processing for improving the S / N ratio. It is something to apply.
[0034]
An edge enhancement integrator 22 is connected to the coring unit 21. The edge enhancement degree integrator 22 performs edge enhancement processing by multiplying a Y coefficient that has been subjected to coring processing by the coring unit 21 by a predetermined coefficient, and constitutes part of the contour enhancement means. .
[0035]
The edge-enhanced Y signal output from the edge enhancement integrator 22 is input to the adder 23 together with the luminance signal YL output from the color difference matrix circuit 18. The adder 23 adds these signals and outputs a luminance signal YH.
[0036]
The luminance signal YH from the adder is input as an image signal to the liquid crystal display (LCD) 24 and the DRAM 25 as an image signal together with the color difference signals (RY signal and BY signal) from the color difference matrix circuit 18. . The liquid crystal display (LCD) 24 has a signal processing circuit for processing an image signal into a displayable form, and displays the signal-processed image here. The DRAM 25 is a camera built-in storage unit including a memory or the like that temporarily stores an image signal.
[0037]
Connected to the DRAM 25 are a compression / decompression circuit 26 that performs compression processing and decompression processing on the image signal, and a recording medium 27 such as a memory card that stores the image signal.
[0038]
Each component described above is electrically connected to the CPU 28 which is a control means. The CPU 28 comprehensively controls the entire electronic imaging apparatus. An operation unit 29 is connected to the CPU 28. The operation unit 29 has a plurality of switches such as a trigger switch that can start an AF operation at the time of photographing and generate a trigger signal for starting an exposure operation.
[0039]
An operation performed at the time of shooting in the electronic imaging apparatus configured as described above will be described. Here, only the portion related to the present invention is described among the actions performed at the time of photographing.
[0040]
In this case, the CCD 2 is vibrated at a constant period by a piezoelectric driver 5 having a piezoelectric element such as a piezo element, and generates an imaging output in synchronization with this vibration. For example, in the pixel arrangement shown in FIG. 2A, (1) → (2) → (3) → (4) at 2/3 pixel intervals with respect to the reference pixel position (1) shown in FIG. 2 (b). In order of ▼ → ▲ 5 ▼ → ▲ 6 ▼ → ▲ 7 ▼ → ▲ 8 ▼ → ▲ 9 ▼, pixel shift is performed in 9 locations in total, 3 in each of the horizontal and vertical directions, and each displacement position is imaged. Generate output. As a result, as shown in FIG. 6C, the number of pixels is tripled in the X and Y directions without changing the color arrangement of R, G, and B, and the resolution can be improved accordingly.
[0041]
The image signal component obtained from the CCD 2 is extracted by the CDS circuit 6 and the output signal level is adjusted to a predetermined gain value by the amplifier (AMP) 7, and then converted into a digital signal by the A / D converter 8. Converted. The image signal converted into the digital signal is temporarily stored in the frame memory 9.
[0042]
The frame memory 9 includes memories corresponding to nine images (1) to (9) acquired by pixel shifting, and stores nine images in these memories. Then, under the control of the CPU 28, these nine images are rearranged (pixel shift) into one image.
[0043]
Thereafter, the image signal of the rearranged image is branched into a main signal output to the color separation circuit 11 and a sub signal output to the γ correction circuit 12. Here, the main signal is subjected to signal processing such as predetermined color correction processing in each circuit after the color separation circuit 11. On the other hand, after the γ correction processing is performed by the γ correction circuit 12, the sub signal is generated by extracting only the luminance signal (Y signal) in the Y signal generation unit 19. This Y signal is input to a band pass filter (BPF) 20. The band pass filter (BPF) 20 generates an edge signal from the Y signal and outputs it to the coring unit 21.
[0044]
The coring unit 21 performs a predetermined coring process on the edge signal, and then outputs it to the edge enhancement integrator 22. After the edge enhancement processing is performed in the edge enhancement integrator 22, the edge-enhanced Y signal is added to the luminance signal YL of the main signal in the adder 23, and is output to the LCD 24 for image reproduction display. Processing is done.
[0045]
By the way, the edge enhancement processing performed by the bandpass filter (BPF) 20 usually uses a 4 × 4 BPF, and emphasizes the vicinity of the Nyquist frequency. That is, for the image signal before pixel shift shown in FIG. 2A, edge enhancement is performed near the Nyquist frequency by using a 4 × 4 BPF as shown in FIG. (Contrast reproducibility) can be secured. .
[0046]
On the other hand, the image signal after pixel shift shown in FIG. 2C is expected to improve resolution and reduce moire due to aliasing by increasing the Nyquist frequency.
[0047]
However, in actuality, when the shape of the opening of the CCD 2 (PD (photodiode) for converting light into an electrical signal) is large as shown in FIG. 4A, (1) as shown in FIG. 4B. The pixel shift of (9) causes an overlap portion with the pixel position before the pixel shift, and this overlap portion makes it difficult to improve the resolution, and the MTF cannot be secured up to the Nyquist frequency after the pixel shift. In other words, the resolution limit of the image signal after pixel shift is determined by the shape of the opening of the CCD 2, and thereafter, the Nyquist frequency only shifts even if pixel shift is performed. FIG. 5 shows the MTF with respect to the resolution frequency in the case of the CCD 2 having an aperture ratio of 85%. With respect to the Nyquist frequency F1 before pixel shift, the MTF can be secured without any problem. However, the Nyquist frequency F2 after the pixel shift has already reached the limit of resolution, and therefore no further improvement in resolution can be expected.
[0048]
When a 4 × 4 BPF is applied as the bandpass filter (BPF) 20 to the image signal after such pixel shift, as shown in FIG. 6, the frequency characteristic B of the 4 × 4 BPF is as shown in FIG. As described above, the vicinity of the Nyquist frequency after pixel shift is emphasized with respect to the MTF of the CCD 2 described above, so that an extra frequency region (portion indicated by hatching in the figure) D where improvement in resolution cannot be expected is emphasized. It will be. In other words, the Nyquist frequency after pixel shifting has already reached the limit of resolution, and even though no further improvement in resolution can be expected, extra enhancement will be performed, which causes noise and edge enhancement. There arises a problem of causing oblique burrs and the like.
[0049]
Therefore, in the first embodiment, after pixel shifting, a 6 × 6 BPF as shown in FIG. 3B is used instead of the 4 × 4 BPF. The frequency characteristics of the 6 × 6 BPF are set so as to emphasize the frequency range up to the resolution limit including the vicinity of the Nyquist frequency before pixel shift, as indicated by C in FIG. As a result, an unnecessary frequency region that cannot be expected to improve the resolution is not emphasized, and only necessary edge enhancement can be performed. Therefore, it is possible to suppress the occurrence of noise and slanting due to edge enhancement.
[0050]
For this reason, the band pass filter (BPF) 20 for edge enhancement switches between 4 × 4 BPF and 6 × 6 BPF without using pixel shifting.
[0051]
A timing chart during the photographing operation in this case is as shown in FIG. In this case, the vertical synchronizing signal VD shown in FIG. 6A is output in a frame period, and the pixel shift voltages x and y shown in FIGS. 5E and 5F are controlled based on the vertical synchronizing signal VD. Shifting is performed. Further, the image signal shown in FIG. 5G is read out by the exposure shown in FIG. 5B for each pixel shift. Also, the band pass filter (BPF) 20 shown in FIG. 4D uses a 4 × 4 BPF when shooting in a state before shifting the image signal by pixel, and after shifting the image signal by pixel. 6 × 6 BPF is used instead of 4 × 4 BPF. That is, the edge enhancement processing is executed in a state where a predetermined S / N ratio is secured by variably controlling the contour intensity frequency by the band pass filter (BPF) 20.
[0052]
In this way, with respect to the image signal before the pixel shifting operation shown in FIG. 2A, by using the 4 × 4 BPF, the vicinity of the Nyquist frequency can be emphasized and the MTF can be secured without any problem. . In addition, with respect to the image signal after the pixel shifting operation shown in FIG. 2C, an extra frequency region that cannot be expected to improve the resolution is emphasized by using a 6 × 6 BPF instead of the 4 × 4 BPF. Thus, only necessary edge enhancement can be performed. As a result, it is possible to obtain a high-quality image that can suppress the occurrence of extraneous noise emphasized by contour emphasis or oblique jaggedness due to edge emphasis while maintaining a sense of resolution in both cases before and after pixel shifting.
[0053]
(Second Embodiment)
Next, a second embodiment of the present invention will be described.
[0054]
Since the schematic configuration of the electronic imaging apparatus according to the second embodiment is the same as that of FIG. 1 described in the first embodiment, the same figure is used.
[0055]
The second embodiment is characterized in that the contour intensity frequency is varied by the band pass filter (BPF) 20 according to the tendency of the MTF of the lens system including the optical system such as the photographing optical system 1 and the objective lens on the microscope side. Yes.
[0056]
FIG. 8 shows an example of the MTF of the CCD 2. When a lens system having a relatively high MTF is used for such a CCD 2 as shown in FIG. 9A, the CCD 2 and the lens system are combined. The MTF at that time is as shown in FIG. 10A, and a high MTF can be obtained over the entire resolution frequency.
[0057]
In such a case, a 4 × 4 BPF having frequency characteristics as shown in FIG. 11A is used as the bandpass filter (BPF) 20. Thereby, necessary edge emphasis can be performed over the whole region including a high frequency.
[0058]
On the other hand, when a lens system having a relatively low MTF as shown in FIG. 9B is used for the MTF CCD 2 as shown in FIG. 8, the MTF when the CCD 2 and the lens system are combined is shown in FIG. As shown in FIG. 10 (b), in particular, in a high frequency region, the MTF is low, and the improvement of the resolution is hardly expected.
[0059]
In such a case, the band pass filter (BPF) 20 uses a 6 × 6 BPF instead of the 4 × 4 BPF. The frequency characteristics of the 6 × 6 BPF are set so as to emphasize frequencies in a range excluding a high frequency region where an improvement in resolution cannot be expected as shown in FIG.
[0060]
As a result, an unnecessary frequency region that cannot be expected to improve the resolution is not emphasized, and only necessary edge enhancement can be performed, so that generation of noise and the like due to edge enhancement can be suppressed.
[0061]
Therefore, in this case, the resolution can be improved by switching between 4 × 4 BPF and 6 × 6 BPF in the band pass filter (BPF) 20 according to the MTF of the lens system. No unnecessary frequency band is emphasized, and only necessary edge emphasis can be performed. Thereby, regardless of the MTF of the lens system, it is possible to acquire a high-quality image that can suppress the occurrence of extra noise enhanced by contour enhancement and the occurrence of jaggedness due to edge enhancement while maintaining a sense of resolution.
[0062]
(Third embodiment)
Next, a third embodiment of the present invention will be described.
[0063]
Since the schematic configuration of the electronic imaging apparatus according to the third embodiment is the same as that of FIG. 1 described in the first embodiment, the same figure is used.
[0064]
In the first embodiment described above, the output signal level of the CDS circuit 6 that extracts the image signal component from the output signal of the CCD 2 is adjusted to a predetermined gain by the amplifier (AMP) 7. This embodiment is characterized in that the contour intensity frequency is varied by the band-pass filter (BPF) 20 in accordance with the gain value of the amplifier (AMP) 7.
[0065]
FIG. 12 shows the relationship between the gain value of the amplifier (AMP) 7 and the amount of noise. In this figure, for example, when the gain value of the amplifier (AMP) 7 is increased because the captured image is dark, it is included from the beginning. It shows how the amount of noise increases.
[0066]
From this state, when the gain region A in which the gain value is relatively small and the noise amount is not so large is used in the amplifier (AMP) 7, the bandpass filter (BPF) 20 is shown in FIG. A 4 × 4 BPF having such frequency characteristics is used.
[0067]
In this case, when the gain region A of the amplifier (AMP) 7 and the 4 × 4 BPF shown in FIG. 13A are combined with the MTF of the CCD 2 shown in FIG. 14, FIG. The MTF as shown can be obtained and the necessary edge enhancement can be performed under high resolution.
[0068]
On the other hand, in the amplifier (AMP) 7, when the gain region B having a large gain value and a large amount of noise is used, the bandpass filter (BPF) 20 uses 6 × 6 instead of 4 × 4 BPF. The BPF is used. As this 6 × 6 BPF, one having frequency characteristics as shown in FIG. 13B is used.
[0069]
Then, also in this case, when the gain region B of the amplifier (AMP) 7 and the 6 × 6 BPF shown in FIG. 13B are combined with the MTF of the CCD 2 shown in FIG. 14, FIG. The MTF as shown can be obtained and the necessary edge enhancement can be performed under low resolution.
[0070]
Therefore, in this way, by switching the 4 × 4 BPF and the 6 × 6 BPF in the band pass filter (BPF) 20 according to the gain value in the amplifier (AMP) 7, Edge enhancement more than necessary is not required in a region with a large amount of noise, and a high-quality image can be acquired.
[0071]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
[0072]
FIG. 16 shows a schematic configuration of a microscope to which the electronic imaging apparatus for a microscope according to the present invention is applied. In addition, since the schematic structure of the electronic imaging device for microscopes connected to such a microscope is the same as that of FIG. 1 described in the first embodiment, this figure is incorporated.
[0073]
In FIG. 16, reference numeral 31 denotes a light source. Light emitted from the light source 31 is collected by a collector lens 32, an FS (field stop) 33 for adjusting the illumination range, and an AS for adjusting the numerical aperture of the illumination light. The sample 36 is irradiated through the (aperture stop) 34 and the condenser lens 35. Further, the transmitted light from the sample 36 is imaged by the CCD 39 via the objective lens 37 and the imaging lens 38. In this case, the CCD 39 corresponds to the CCD 2 of the electronic imaging device for a microscope (see FIG. 1) connected to a port (not shown).
[0074]
By the way, it is known that the MTF of the objective lens 37 changes between when the AS (aperture stop) 34 is closed and when the microscope is configured as described above.
[0075]
FIG. 17 illustrates this state. FIG. 17A shows the respective objective lenses when the AS (aperture stop) 34 is closed, and FIG. 17B shows the respective objective lenses when the AS (aperture stop) 34 is open. 37 MTFs are shown. As can be seen from the figure, when the AS (aperture stop) 34 is closed, the resolution in the middle region is higher than when the AS (aperture stop) 34 is open. On the other hand, when the AS (aperture stop) 34 shown in the figure (B) is open, the limit resolution greatly extends in the high frequency direction compared to when the AS (aperture stop) 34 shown in the figure (A) is closed.
[0076]
As a result, when the MTF of the image acquired with the AS (aperture stop) 34 in the open state is in the state of FIG. 18C, the AS (aperture stop) 3 is adjusted to the closed state, and thus acquired. As shown in FIG. 4D, the MTF of the image to be displayed becomes an extremely unnatural image due to an excessive increase in the MTF in the middle range, and noise is generated due to unnecessary high frequency MTF enhancement. Will be invited.
[0077]
Therefore, in the fourth embodiment, the edge enhancement degree in the edge enhancement degree integrator 22 shown in FIG. 1 is varied according to the state change of the AS (aperture stop) 34. In this case, the edge enhancement integrator 22 can vary the level of edge enhancement as shown in FIGS. 19A and 19B by a gain value control command from the CPU 28.
[0078]
In such a configuration, when the AS (aperture stop) 34 is open, the edge enhancement integrator 22 selects the normal edge enhancement shown in FIG. As a result, the MTF of the image acquired with the AS (aperture stop) 34 opened is maintained in the state shown in FIG. 18C, and a natural and high-quality image can be acquired. On the other hand, when the AS (aperture stop) 34 is closed, the resolution in the middle region is high as shown in FIG. 18D, so that the edge enhancement integrator 22 has the level shown in FIG. A small edge enhancement is selected. Thereby, it is suppressed that the resolution in the middle range becomes too high, and the MTF of the image acquired with the AS (aperture stop) 34 closed is also in the state shown in FIG. A good quality image can be acquired.
[0079]
On the other hand, in the fourth embodiment, the contour intensity frequency is varied by the band pass filter (BPF) 20 in accordance with the state change of the AS (aperture stop) 34.
[0080]
In this case, when the AS (aperture stop) 34 shown in FIG. 17A is closed and the limit resolution does not extend in the high frequency direction, the bandpass filter (BPF) 20 is shown in FIG. A 6 × 6 BPF having frequency characteristics as shown is used. The frequency characteristics of the 6 × 6 BPF are set so as to emphasize frequencies in a range excluding a high frequency region where improvement in resolution cannot be expected. As a result, an unnecessary frequency region that cannot be expected to improve the resolution is not emphasized, and only necessary edge enhancement can be performed, so that the generation of noise can be suppressed.
[0081]
In addition, when the AS (aperture stop) 34 shown in FIG. 17B is in an open state and the limit resolution greatly extends in the high frequency direction, a 6 × 6 BPF is used as the band pass filter (BPF) 20. Instead, 4 × 4 BPF having frequency characteristics as shown in FIG. Thereby, necessary edge emphasis can be performed over the whole region including a high frequency.
[0082]
Accordingly, by changing the contour enhancement degree and the contour strength frequency in accordance with the state change of the AS (aperture stop) 34, a high-quality image in which noise is suppressed can be acquired.
[0083]
In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary.
[0084]
Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.
[0085]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electronic image pickup apparatus and a microscope electronic image pickup apparatus that can obtain a high-quality image with reduced noise and oblique burrs while maintaining a sense of resolution. .
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an electronic imaging apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining pixel shift according to the first embodiment;
FIG. 3 is a diagram showing a 4 × 4, 6 × 6 BPF used in the first embodiment;
FIG. 4 is a diagram illustrating an opening of a CCD used in the first embodiment.
FIG. 5 is a view for explaining an MTF of a CCD used in the first embodiment.
FIG. 6 is a diagram illustrating a state in which 4 × 4 and 6 × 6 BPFs are switched according to the first embodiment.
FIG. 7 is a timing chart at the time of shooting operation according to the first embodiment.
FIG. 8 is a diagram for explaining an MTF of a CCD used in the second embodiment of the present invention.
FIG. 9 is a diagram for explaining an MTF of a lens system used in the second embodiment.
FIG. 10 is a diagram for explaining a second embodiment;
FIG. 11 is a diagram illustrating frequency characteristics of 4 × 4 and 6 × 6 BPFs according to the second embodiment.
FIG. 12 is a diagram showing a relationship between an amplifier (AMP) gain value and a noise amount used in the third embodiment of the present invention.
FIG. 13 is a diagram illustrating frequency characteristics of 4 × 4 and 6 × 6 BPFs according to the third embodiment.
FIG. 14 is a diagram for explaining an MTF of a CCD used in the third embodiment.
FIG. 15 is a diagram for explaining a third embodiment;
FIG. 16 is a diagram showing a schematic configuration of a microscope applied to a fourth embodiment of the present invention.
FIG. 17 is a diagram for explaining an MTF according to a state change of an aperture stop according to the fourth embodiment.
FIG. 18 is a diagram for explaining an MTF of an image acquired according to a state change of an aperture stop according to the fourth embodiment.
FIG. 19 is a diagram for explaining the edge enhancement degree of the edge enhancement degree integrator used in the fourth embodiment.
FIG. 20 is a diagram illustrating frequency characteristics of 4 × 4 and 6 × 6 BPFs according to the fourth embodiment.
[Explanation of symbols]
1 ... Photography optical system
2 ... CCD
3. Timing generator (TG)
4 ... Signal generator (SG) 4
5 ... Piezoelectric driver
6 ... CDS circuit
7: Amplifier (AMP)
8 ... A / D converter
9 ... Frame memory
10 ... Memory controller
11. Color separation circuit
12 ... γ correction circuit
13 ... WB (white balance) circuit
14 ... White clip
15 ... Clip level detection circuit
16 Color correction circuit
17 ... γ correction circuit
18. Color difference matrix circuit
19 ... Y signal generator
21 ... Coring part
22 ... Edge enhancement integrator
23 ... Adder
24 ... LCD
25 ... DRAM
26: Compression / decompression circuit
27 ... Recording medium
28 ... CPU
29 ... operation unit
31 ... Light source
32 ... Collector lens
33 ... FS (field stop)
34 ... AS (aperture stop)
35 ... Condenser lens
36 ... Sample
37 ... Objective lens
38 ... Imaging lens
39 ... CCD

Claims (6)

An image sensor for capturing a subject image;
Displacement means for periodically displacing the image sensor and outputting an image signal of the subject image from the image sensor for each displacement position;
Image processing means for rearranging the image signals of the image sensor for each displacement position by the displacement means and combining the images;
Contour emphasizing means capable of varying the contour emphasizing frequency for performing contour signal processing on the image rearranged by the image processing means, and
The electronic image pickup apparatus , wherein the contour emphasizing unit sets the contour emphasis frequency so as to emphasize a frequency range up to a resolution limit point determined according to a shape of an opening of the image sensor .   2. The electronic image pickup apparatus according to claim 1, wherein the contour emphasizing unit makes the contour emphasis frequency variable before and after the periodic displacement operation of the image sensor by the displacement unit. A lens system for projecting the subject image onto the image sensor;
2. The electronic imaging apparatus according to claim 1, wherein a contour emphasis frequency by the contour emphasizing unit can be varied according to a type of the lens system. Gain adjusting means for adjusting a signal level of an image output from the image sensor to a predetermined gain;
2. The electronic imaging apparatus according to claim 1, wherein a contour emphasis frequency by the contour emphasizing unit can be varied in accordance with a gain value of the gain adjusting unit. An electron for a microscope having an aperture stop for adjusting the numerical aperture of illumination light and an objective lens, connected to a microscope having at least one port for outputting an image from the objective lens, and capturing an image output from the port In a typical imaging device,
Contour emphasizing means capable of varying the contour emphasis strength for performing contour signal processing on the image output from the port and captured;
An electronic imaging apparatus for a microscope, wherein the contour emphasis intensity by the contour emphasis means is varied in accordance with a change in the state of the aperture stop. A microscope having an aperture stop for adjusting the numerical aperture of illumination light and an objective lens, connected to a microscope having at least one port for outputting an image from the objective lens, and taking an image output from the port In an electronic imaging device,
An image sensor for capturing a subject image;
Displacement means for periodically displacing the image sensor and outputting an image signal of the subject image from the image sensor for each displacement position;
Image processing means for rearranging the image signals of the image sensor for each displacement position by the displacement means and combining the images;
A contour emphasizing unit capable of varying a contour emphasizing frequency for performing contour signal processing on an image rearranged by the image processing unit in accordance with a state change of the aperture stop ,
The electronic imaging apparatus for a microscope , wherein the contour emphasizing unit sets the contour emphasizing frequency so as to emphasize a frequency range up to a resolution limit point determined according to a shape of an opening of the image sensor .

Images