JP2008301505A - Electronic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic imaging apparatus which has small variations of color reproduction and sensation of edge enhancement, even if the γ characteristics are changed, and also has a small decrease in S/N accompanying edge emphasization. <P>SOLUTION: An electronic imaging apparatus has a solid-state imaging device, a variable grayscale characteristics correcting means (50) of correcting an image signal, obtained by the solid-state imaging device to one kind of grayscale characteristics selected from among a plurality of kinds of grayscale characteristics, and an outline emphasizing means (201) for varying outline emphasization levels (82, 83) of an outline signal to be added to an image signal, according to the grayscale characteristics (81) selected during imaging operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic camera that records captured images as digital data.

  In recent years, a subject image optically photographed by a photographing optical system such as a photographing lens is photoelectrically converted by an image pickup means such as an image pickup device, and an image signal as an electric signal obtained by photoelectric conversion is electronically recorded. Electronic imaging devices such as electronic cameras (hereinafter referred to as electronic cameras) are widely used.

  As a result, in order to record the observation image with a microscope, a method of photographing the observation image with a camera using a silver salt film has been used, but recently, with the improvement in performance of the electronic camera, the observation image can be recorded with the electronic camera. Therefore, many image capturing methods are used.

  In this electronic camera, a solid-state imaging device such as a CCD is generally used as an imaging means. Further, as a display device for reproducing and displaying an image photographed and recorded by an electronic camera, a display device using a cathode ray tube such as a CRT or a liquid crystal display device (LCD) is generally used.

  The inclination of the photoelectric conversion characteristic indicating the relationship between the incident light amount (input) incident on the CCD of the electronic camera and the output signal, that is, the γ (gamma) characteristic, which is a gradation characteristic, is generally constant over a wide range. Is desirable. However, since the electro-optical conversion characteristic (γ characteristic) of the above-described display device has a non-linear characteristic, in order to satisfactorily reproduce and display an image taken with an electronic camera using this display device, It is necessary to perform γ correction processing on the image output signal so that the intensity of the incident light of the camera is proportional to the light emission intensity of the display device.

As this γ correction processing technique, there is disclosed a technique characterized in that a gamma γ characteristic according to the type of output destination of image data is used (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-113006

However, when the γ characteristic changes, the color reproduction and the edge enhancement feeling change accordingly, and there is a problem that the S / N due to edge enhancement decreases.

  The present invention has been made to solve such problems, and electronic imaging with little change in color reproduction and edge enhancement even when the γ characteristic is changed, and little reduction in S / N due to edge enhancement. An object is to provide an apparatus.

  The electronic imaging apparatus according to the first aspect of the present invention for solving the above-described problems is selected from a plurality of types of gradation characteristics for a solid-state imaging device and an image signal obtained by the solid-state imaging device. Variable gradation characteristic correction means for correcting to one gradation characteristic, and contour enhancement means for changing the contour enhancement degree of the contour signal added to the image signal according to the gradation characteristic selected during the photographing operation.

  According to this configuration, since the edge enhancement level is switched based on the gradation characteristics, it is possible to ensure optimum edge enhancement regardless of the gradation characteristics, and to improve the captured image signal. An electronic imaging device that can be reproduced and displayed on a display device as an image can be provided.

  An electronic imaging apparatus according to another aspect of the present invention improves the S / N ratio of the contour signal in the electronic imaging apparatus according to the above-described invention according to the gradation characteristics selected during the photographing operation. Variable coring processing means for changing the coring level by switching the coring processing.

  According to this configuration, since the coring level is switched based on the gradation characteristics, an optimum S / N can be ensured regardless of the gradation characteristics, and the captured image signal is improved. It is possible to provide an electronic imaging device that can be reproduced and displayed on a display device as a simple image.

  According to the electronic imaging device of the present invention, even if the γ characteristic is changed, there is little change in color reproduction and edge emphasis, and there is little S / N reduction due to edge emphasis.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a microscope system according to an embodiment of the present invention. In FIG. 1, an objective lens 27 facing the sample 3 on the stage 26 is disposed in the microscope body 1. On the observation optical axis via the objective lens 27, an eyepiece lens unit 6 is disposed via the trinocular tube unit 5, and an electronic camera 36 is disposed via the imaging lens unit 100. Yes.

  FIG. 2 is a diagram showing a detailed configuration of the microscope system. FIG. 2 shows a configuration in which various spectroscopic methods such as transmitted bright field observation, dark field observation, phase difference observation, differential interference observation, and fluorescence observation can be appropriately selected.

  The microscope system shown in FIG. 2 includes a transmission illumination optical system 11 and an epi-illumination optical system 12 as an illumination system. The transmitted illumination optical system 11 includes a transmitted illumination light source 13. A collector lens 14 that collects the transmitted illumination light on an optical path of the transmitted illumination light emitted from the transmitted illumination light source 13, and a transmitted filter unit. 15, a transmission field stop 16, a transmission shutter 161, a bending mirror 17, a transmission aperture stop 18, a condenser optical element unit 19, and a top lens unit 20 are disposed. The epi-illumination optical system 12 includes an epi-illumination light source 21, and the epi-illumination filter unit 22, the epi-illumination shutter 23, and the epi-illumination field stop are arranged on the optical path of the epi-illumination light emitted from the epi-illumination light source 21. 24 and an epi-illumination aperture stop 25 are arranged.

  On the observation optical path S where the optical axes of the transmitted illumination optical system 11 and the epi-illumination optical system 12 overlap each other, a plurality of sample stages 26 and objective lenses 27 on which a specimen to be observed is placed are mounted. Is selected by rotation and positioned on the observation optical path S, an objective lens side optical element unit 29, for example, a dichroic mirror on the observation optical path S according to various spectroscopic methods such as transmitted bright field observation or fluorescence observation. And a beam splitter 31 for branching the observation optical path S into an observation optical path S ′ and an observation optical path S ″. The beam splitter 31 is disposed in the trinocular tube unit 5. Yes.

  An eyepiece 6 a is disposed on the observation optical path S ′ bent forward by the beam splitter 31. Further, on the observation optical path S ″ transmitted through the beam splitter 31, an image forming lens unit 100 including an intermediate variable magnification optical system (zoom lens barrel) 33, an autofocus (AF) unit 371 and a photographic eyepiece unit 35, and An electronic camera 36 is disposed.

  The intermediate variable magnification optical system (zoom lens barrel) 33 incorporates a variable magnification zoom lens 33 a for changing the magnification of an image picked up by the electronic camera 36. If intermediate zooming is not required, the intermediate zooming optical system (zoom lens barrel) 33 can be removed. An image sensor 42 is disposed in the electronic camera 36. The light image from the objective lens 27 is imaged on the imaging surface of the image sensor 42 by the photographic eyepiece lens 35 a in the photographic eyepiece unit 35.

  A beam splitter 34 is disposed in the autofocus (AF) unit 371, and an AF light receiving element 34a is disposed on the optical path branched from the observation optical path S ″. The autofocus unit 371 includes: The focus detection is performed based on the output signal from the light receiving element 34a. When the AF function is unnecessary, the unit can be removed.

  A transmission filter unit 15 in the transmission illumination optical system 11, a transmission field stop 16, a transmission shutter 161, a transmission aperture stop 18, a condenser optical element unit 19, and a top lens unit 20; an incident light filter unit 22 in the incident illumination optical system 12; The epi-illumination shutter 23, the epi-illumination field stop 24, the epi-illumination aperture stop 25, the revolver 28, the objective lens side optical element unit 29, the cube unit 30, the beam splitter 31, and the intermediate variable magnification optical system (zoom lens barrel) 33 are driven. It is driven by each motor (not shown) by each drive signal from the circuit unit 37.

  On the other hand, the revolver 28 is provided with an objective lens detector 38 that detects the type of the objective lens 27 positioned on the observation optical path S, and the objective lens side optical element unit 29 has a retardation adjustment that detects a retardation adjustment operation. An operation detection unit 39 is arranged, and the photographic eyepiece lens unit 35 is arranged with a photographic eyepiece lens detection unit 40 for detecting the type of the photographic eyepiece.

  The microscope control unit 41 controls the operation of the entire microscope. The transmission illumination light source 13, the epi-illumination light source 21, the drive circuit unit 37, the objective lens detection unit 38, the retardation adjustment operation detection unit 39, and the photographic eyepiece detection The unit 40 and the electronic camera 36 are connected.

  The microscope control unit 41 performs dimming of the transmitted illumination light source 13 and the epi-illumination light source 21 according to the operation of the operation unit (not shown) by the spectrographer, and issues a control instruction to the drive circuit unit 37. Further, the microscope control unit 41 starts a control state for the transmission illumination light source 13 and the epi-illumination light source 21 and a control state for the drive circuit unit 37, an objective lens detection unit 38, a retardation adjustment operation detection unit 39, and a photographic eyepiece lens detection unit. The detection information from 40 is output to the electronic camera 36, and the imaging conditions of the electronic camera 36 are automatically set.

  FIG. 3 is a block diagram showing a configuration of an electronic camera used in the microscope system. In FIG. 3, a portion surrounded by a one-dot chain line indicates a configuration of the electronic camera 36 in which imaging conditions are set by the microscope control unit 41.

  In FIG. 3, an image pickup device 42 picks up a color image and is disposed on the observation optical path S ″ together with the above-described microscope eyepiece unit 35. A solid-state image pickup device such as a CCD (hereinafter simply referred to as a CCD). ) 42 captures and photoelectrically converts an observation image of the specimen magnified by a microscope.

  The electronic camera 36 has a CDS circuit (correlated double sampling circuit) 43 that extracts an image signal component from the output signal of the CCD 42 and an output signal level of the CDS circuit 43 to adjust the gain level to a predetermined gain value. An amplifier (AMP) 44 that is a gain control means including an AGC circuit, an A / D converter 45 that converts an analog signal output from the AMP 44 into a digital signal, and an output from the A / D converter 45 A first frame memory 46 that stores a digital signal, a color separation circuit 47 that separates the image signal into each of the three primary colors of the RL signal, the GL signal, and the BL signal, and a WB 48 that adjusts the white balance (WB) of the image signal. A color correction circuit 49 that performs color correction to improve color reproducibility, and a gamma color signal (Γ) Color signal γ correction circuit 50 that performs correction, and R, G, and B color signals are converted into a luminance signal YL and two color difference signals (R−Y signal and B−Y signal) to change the hue and color. A color difference matrix circuit 51 that adjusts the saturation degree, a γ correction circuit 62 that performs γ correction of the image signal, and only a luminance signal (Y signal) is extracted from the image signal that has been γ corrected by the γ correction circuit 62 and generated. A Y signal generation unit 63, a high-pass filter (HPF) unit 64 for extracting a contour signal (hereinafter referred to as an edge signal) by removing a low frequency component from the Y signal, and a noise component of the edge signal generated by the HPF 64 And a coring unit 65 for performing a coring process for improving the S / N ratio, and an integrator for multiplying the Y signal subjected to the coring process by the coring unit 65 by a predetermined coefficient, Edge An edge emphasis circuit 66 that performs tone processing, and an edge-enhanced Y signal output from the edge emphasis circuit 66 are added to the luminance signal YL for color difference signals output from the color difference matrix circuit 51 to obtain a luminance signal. An adder 52 that outputs YH, a liquid crystal display (LCD) 59 that is a display means including a signal processing circuit that processes the image signal into a displayable form, and a built-in camera memory such as a memory that temporarily stores the image signal A DRAM 56 as a means, a compression / decompression circuit 57 that performs compression processing and decompression processing of an image signal, a recording medium 58 such as a memory card that stores the image signal, and an AF operation at the time of shooting and an exposure operation are started. Trigger switch that can generate a trigger signal, trigger signal for re-taking shading correction, objective lens rotation operation switch, An operation unit 61 composed of a plurality of switches such as opening and closing the mouth aperture is constituted by a sync signal timing generator for generating (TG) 53 and a signal generator (SG) 54 such as the driving pulse of the CCD 42.

  The constituent members are electrically connected to a CPU 60 that is a control means, and the entire electronic imaging apparatus of the present embodiment is comprehensively controlled by the CPU 60. The CCD 42 has an electronic shutter function (means) so that the exposure time can be controlled.

  FIG. 4 is a block diagram of a main part extracted from a part of the internal configuration of the electronic camera, and shows in detail a color correction circuit 49 and the like for performing color correction processing in the electronic camera. is there.

  As shown in FIG. 4, the CPU 60 includes a light source recognition unit 70 for recognizing the illumination environment condition at the time of shooting, that is, the type of the light source, from the image signal obtained by the CCD 42, and the recognition result of the light source recognition unit 70. In addition, variable matrix color correction means 71, which is variable color correction means for switching the color correction coefficient matrix supplied to the color correction circuit 49, is provided.

  Further, as shown in FIG. 5, γ curve selecting means 72 for selecting three kinds of γ curves, three kinds of matrix correction coefficients 73 according to the three kinds of γ curves, γ curve selecting means 72 and matrix correction coefficients 73. The operation unit 61 for performing the selection operation, and the multiplication unit 74 that multiplies the variable matrix color correction unit 71 and the matrix correction coefficient 73.

  A first embodiment of the electronic camera configured as described above will be described below.

  As shown in FIG. 4, the digital image signal output from the A / D converter 45 is stored in the frame memory 46 and read out as described above, and then input to the color separation circuit 47. The signals are separated into r, g, and b color signals, then input to the WB 48 and input to the color correction circuit 49.

  On the other hand, the output signal (digital image signal) of the A / D converter 45 is supplied to the light source recognition means 70 in the CPU 60, and the light source recognition means 70 identifies the light source type at the time of photographing. For example, the type of light source (sunlight, fluorescent lamp, light bulb, etc.) is identified based on the luminance information of the subject.

  The variable matrix color correction unit 71 is based on the result of light source recognition by the light source recognition unit 70, and a plurality of color correction coefficient matrices set in advance corresponding to a plurality of light source types (four types of light sources in this embodiment). The color correction coefficient matrix corresponding to the type of the light source at the time of photographing the image signal is selected and output, and the selected color correction coefficient matrix is supplied to the color correction circuit 49.

In the color correction circuit 49, predetermined color correction processing is performed for each color signal of the input signal from the WB 48, that is, the R, G, and B signals. Examples of the color correction processing performed here include so-called masking processing. This masking process is a process of multiplying the color correction coefficient matrices from the variable matrix color correcting means 71, and the process is shown by the equation (1).

  The calculation represented by this equation is executed by an accumulator and an adder, and the resulting color corrected color signals (R1, G1, B1 signals) are output to the color signal γ correction circuit 50. Then, the color signal γ correction circuit 50 performs color signal γ correction on the color signal and outputs the color signal to the color difference matrix circuit 51 as each color signal of the R2, G2, and B2 signals.

  Since faithful color reproducibility may not be obtained depending on the type of light source, the light source recognition unit 70 recognizes the type of illumination light source at the time of shooting, and the color correction coefficient from the variable matrix color correction unit 71 based on the recognition result. Perform color correction using a matrix. As a result, it can be expected that optimum color reproducibility is ensured regardless of the illumination conditions of the subject at the time of shooting.

  However, in the case of a system having three types of γ correction curves as in the present embodiment, the color reproducibility changes by changing the γ correction curves.

  When the matrix correction coefficient 73 is fixed in the case of the γ curve Low, Normal, and Hi as shown in FIG. 5, the color reproduction is as shown in FIG. FIG. 6 is a color reproduction vector diagram when a color bar chart including R, G, B, Ye, Mg, and G is imaged. The R, G, and B signals of the video signal are represented as a color space, the vertical axis is represented as RY, and the horizontal axis is represented as BY. The distance from the center point (0, 0) is expressed as saturation, and the rotation direction is expressed as hue.

  For example, paying attention to Ye in FIG. 6, among the three types of γ curves, the saturation of the γ curve Low is small. When attention is paid to R, the saturation of Nowmal is large. Therefore, it can be seen that color reproduction differs in an image corrected using these three types of γ curves.

  In order to compensate for the above drawbacks, the present embodiment includes a plurality of types (three types) of matrix correction coefficients 73 corresponding to the γ correction curve. FIG. 7 shows these matrix correction coefficients 73 as a table.

  FIG. 8 is a color reproduction vector diagram after processing with the matrix correction coefficient 73. It can be seen that even if the γ curve changes, the color reproduction hardly changes.

  Thus, by switching the matrix correction coefficient 73 corresponding to the three types of γ curve selection means 72, it is possible to output a similar color reproduction image.

  Further, by supplying a coefficient obtained by multiplying the matrix correction coefficient 73 and the coefficient of the variable matrix color correction means 71 by the multiplication means 74 to the color correction circuit 49, the type of illumination light source at the time of shooting and the type of γ correction curve are selected. Since the masking process using the color correction coefficient matrix is performed, more accurate color reproducibility can be obtained, and thus a better image can be reproduced and displayed on a display device or the like.

  FIG. 9 shows a flowchart when the above method is installed in an electronic camera.

  The electronic camera is imaged when the power is turned on. Then, the still image capture trigger switch on the operation unit 61 is pressed, and the still image is stored in the memory. Therefore, the light source recognition means 70 recognizes the light source and switches the variable matrix color correction means 71. Further, it is checked whether or not the object recognition means 75 is mounted. If it is mounted, the γ curve selection means 72 value is selected from the result. If not, the γ curve selection means 72 value selected by the operation switch is selected. To be decided.

  A matrix correction coefficient 73 corresponding to the value of the γ curve selecting means 72 is determined, transferred to the signal processing unit 49 through the multiplying means 74, subjected to image processing, recorded on the card, and imaging starts again.

  The object recognition type γ correction for selecting the γ curve selection means 72 value from the object recognition means 75 will be described with reference to FIGS.

  In FIG. 10, the image data input to the object recognizing means 75 is subjected to a gradation frequency distribution of the image data as shown in (1) of FIG. Here, “A” and “B” described on the horizontal axis of FIG. 11 represent the minimum value and the maximum value of a level range that gives a frequency equal to or higher than a certain threshold level t.

  The gradation frequency distribution of the image data processed by the image distribution detection circuit 102 is sent to the γ correction curve setting circuit 103, and the γ correction curve setting circuit 103 selects a γ correction curve to be selected based on the gradation frequency distribution. Identify.

  The γ correction curve setting circuit 103 determines the γ curve by judging the contrast of the image data from the range c from the minimum value A to the maximum value B in FIG. For example, as shown in FIG. 11 (1), when the range c is wide, a low-contrast γ curve Low is selected. As shown in FIG. 11 (2), when the range c is narrow, a high-contrast γ curve. Hi is selected. As a result, the γ curve can be made appropriate regardless of the contrast of the image data.

  FIG. 12 is a diagram illustrating a modification of the first embodiment.

  This modification is characterized in that twelve variable matrix color correction means 71 incorporating a γ matrix correction coefficient 73 are provided. According to this configuration, it is possible to shorten the color correction processing time by the color correction coefficient matrix.

  Next, a second embodiment of the present invention will be described.

  FIG. 13 shows an internal configuration of the electronic camera according to the second embodiment of the present invention, and is a block diagram showing the main part of the main part relating to the color correction processing. Note that the present embodiment has substantially the same configuration as that of the first embodiment described above, and only the configuration of a color correction circuit that performs color correction processing is slightly different. Therefore, illustration of the entire configuration of the electronic camera is omitted, and FIG. 3 is referred to. FIG. 13 is a diagram corresponding to FIG. 4 in the first embodiment described above. Therefore, the same reference numerals are given to the same configurations, the description thereof is omitted, and only different members will be described below.

  In the apparatus of FIG. 13, the RGB signals of the input color video signal are input to the 6-color separation circuit 49a. The six-color separation circuit 49a will be described by taking an extraction circuit for separating the R signal as an example. The minimum value detection circuit 49b selects a signal having a lower level of the RG signal and the RB signal based on the original signal, Further, the negative component of the selected signal is removed by the clip circuit 49c and output as the R 'signal.

  Accordingly, the six-color separation circuit 49a expresses a color video signal in which the ratio of R, G, and B signals is 0.4: 0.5: 0.1 as shown in FIG. (2) Equivalent to separating as follows.

0.4R + 0.5G + 0.1B
= 0.1 (R + G + B) +0.3 (R + G) + 0.1G (2)
Here, (R + G + B) represents white, (R + G) represents Ye ′,
G represents G ′.

  Therefore, it is determined that the color of the video signal represented by Expression (2) is a mixture of Ye ′ and G ′ at a ratio of 0.3: 0.1.

  Then, the color correction primary color signals R ′, G ′, B ′ whose signal levels are in the ratio of 0.0: 0.1: 0.0, respectively, and the signal levels are 0.3: 0.3, respectively. : Complementary color signals Ye ′, Cy ′, Ma ′ for color correction having a ratio of 0.0 are output.

Similarly, for a color video signal in which the ratio of R, G, B signals is 0.4: 0.3: 0.3,
0.4R + 0.3G + 0.3B = 0.3 (R + G + B) + 0.1R
Thus, only the output level of the color correction primary color signal R ′ is 0.1, and the other color correction signals are output with a level of 0.

  The color correction primary color signals R ′, G ′, B ′ and the color correction complementary color signals Ye ′, Cy ′, Ma ′ thus output from the six-color separation circuit 49a are respectively supplied to the multiplication circuit. After being supplied and multiplied by a correction coefficient output from the CPU 60, each of the RGB signals is added and subtracted by an adder / subtracter circuit and output as an RGB signal subjected to a predetermined correction. Become.

  Here, for example, the meaning of adding a value obtained by multiplying the Ye ′ signal by the coefficient K10 to the R signal and subtracting the value from the G signal will be described with reference to the color reproduction vector diagram of FIG. Means moving the position of the Ye color in the rotational direction and changing the hue of the Ye color by a factor of K10.

  In addition, multiplying the Ye ′ signal by the coefficient K7 and adding the value to the R signal and the G signal in FIG. 6 moves the position of the Ye color in the opposite direction from the center in FIG. This means changing the color saturation.

    Similarly, the values obtained by multiplying the respective signals of the color correction primary color signals R ′, G ′, B ′ and the color correction complementary color signals Cy ′, Ma ′ by the coefficients K1 to K12 are added to or subtracted from the R signal and the G signal. By doing so, it is possible to adjust the hue and saturation of each color of R, G, B, Cy, and Ma. As a result, according to the apparatus shown in FIG. 13, the hue and saturation of each color of R, G, B, Cy, Ma, and Ye can be adjusted independently.

  Even when the color correction method according to the second embodiment (hereinafter referred to as “chroma correction”) is used, the color correction method according to the first embodiment (hereinafter referred to as “matrix correction”). Similarly, the color reproduction changes due to the γ curve.

  Therefore, as shown in FIG. 13, chroma correction coefficients 73a corresponding to the three types of γ curve selection means 72 are prepared. By switching the chroma correction coefficient 73a by the three types of γ curve selection means 72, it is possible to output a similar color reproduction image.

  Furthermore, by recognizing the type of illumination light source at the time of photographing and preparing a chroma correction coefficient 73a based on the recognition result of the light source recognition means 70, constant color reproduction is realized regardless of the illumination light source and the γ curve. It becomes possible.

  Since the flowchart of the correction operation according to the second embodiment is the same as that of FIG. 9 shown in the first embodiment, detailed description thereof is omitted.

  Next, a third embodiment of the present invention will be described.

  FIG. 15 is a diagram showing in detail the edge signal processing unit 201 of FIG. 3 and the CPU 60 that controls it. In FIG. 15, since only the γ correction of the main signal (color signal) component is changed, the edge component added to the main signal component is constant.

  FIG. 16 is a diagram illustrating the reason why the output signal changes by switching the γ curve. For input signals having the same amplitude, the amplitude of the output signal is large when the γHi curve is used, and the amplitude of the output signal is small when the γLow curve is used.

  FIG. 17 is a diagram schematically showing an output signal when edge correction is performed according to the γ curve. (1) and (2) in FIG. 17 show the correction results when the gamma correction of the third embodiment shown in FIG. 15 is performed.

  When an appropriate edge component is added using the γHi curve, there is no problem with the output signal as shown in (1) of FIG. 17, but when this edge component is added using the γLow curve, ( As shown in 2), the image is unnatural because the image is excessively edge-enhanced (has a lot of high-frequency components). From this, it can be seen that it is better to change the edge enhancement degree according to the characteristic of the γ curve.

  Here, FIG. 18 shows input / output characteristics of coring processing performed by the coring unit 65 in a general electronic camera.

  As shown in FIG. 18A, in the normal coring process, a dead band K is provided for the output corresponding to the input of the edge signal extracted from the Y signal of the image signal by the HPF unit 64. The noise component of the output is suppressed.

  In such a coring process, the S / N ratio is improved as the noise level to be suppressed is increased by increasing the dead band K, that is, as the coring level is increased, as shown in FIG. If the coring level is set low, the S / N ratio tends to deteriorate.

  Further, when the edge enhancement degree is also variable according to the γ curve, the S / N ratio also changes as shown in FIG. Therefore, in order to maintain the S / N ratio of the image signal at a predetermined constant level, control may be performed so that the coring level is changed according to the γ curve of the image signal. Therefore, in the third embodiment, the coring coefficient 82 and the edge enhancement coefficient 83 are switched according to the γ curve to variably control the coring processing level applied by the coring unit 65. .

  In the CPU 60 of FIG. 15, there is shown a configuration diagram in which the changeover switch of the edge enhancement coefficient 83 is changed correspondingly when γ is changed.

  FIG. 19 is a flowchart when the above method is mounted on an electronic camera.

  The electronic camera is imaged when the power is turned on. Then, the still image capture trigger switch on the operation unit 61 is pressed, and the still image is stored in the memory. Next, it is checked whether or not the object recognition means 75 such as histogram detection is mounted. If it is mounted, the γ value is selected from the result, and if not, the γ value selected by the operation switch is selected and determined. Is done.

  The edge enhancement coefficient and the coring coefficient corresponding to the γ value are determined, transferred to the signal processing unit, subjected to image processing, recorded on the card, and imaging is started again.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 20 is a block diagram when the γ correction 62 for edges is not provided. The fourth embodiment is characterized in that edge enhancement is applied after adding edge components. In this case, unlike the third embodiment, as shown in FIGS. 17 (3) and 17 (4), when γ correction is set to Hi, an image with excessive edge enhancement at the same time as contrast may be formed. is there.

  In the CPU 60 of FIG. 20, there is shown a configuration in which the changeover switch of the edge enhancement coefficient 83 operates corresponding to the change of γ.

  Since the flowchart when this method is mounted on an electronic camera is the same as that shown in FIG. 19 in the third embodiment, detailed description thereof is omitted.

  Next, a fifth embodiment of the present invention will be described.

  When recording an observation image with a microscope, it is generally used to shoot with an electronic camera by switching the magnification of the objective lens. In general, increasing the magnification of the objective lens decreases the NA (numerical aperture), There is a problem that the resolution and contrast of the image projected there are lowered, and it is difficult to confirm the image sufficiently depending on the specimen. On the other hand, when the magnification of the objective lens is lowered, there is a problem that the peripheral portion of the image becomes dark due to a decrease in the peripheral light amount of the optical image.

  Therefore, in this embodiment, when the magnification of the objective lens is lowered, a low-contrast γ curve (Low) is selected, and when the magnification of the objective lens is increased, a high-contrast γ curve (Hi) is selected. .

  FIG. 21 shows a flowchart when the above method is installed in a microscope system.

  When the system power is turned on, the sample is set, and the electronic camera is turned on, an image is taken. Then, a still image capturing trigger switch provided in the operation unit is pressed, and the still image is stored in the memory. Next, it is checked whether or not there is switching of the objective lens. If there is switching, the γ value matched with the objective lens is selected and transferred to the signal processing unit, and if not, the γ value is left as it is. Finally, image processing is performed, the image is recorded on the card, and imaging is started again.

  According to this embodiment, it is possible to provide an electronic camera that can cope with a sense of contrast and a decrease in the amount of peripheral light.

  Next, a sixth embodiment of the present invention will be described.

  In this embodiment, the γ curve is automatically determined according to the objective lens, and the color matrix coefficient is determined according to the curve.

  FIG. 22 shows a flowchart when the above method is installed in a microscope system.

  When the system power is turned on, the sample is set, and the electronic camera is turned on, an image is taken. Then, the still image capture trigger switch on the operation unit is pressed, and the still image is stored in the memory. Next, it is checked whether or not there is an objective lens switching. If there is a switching, a γ value that matches the objective lens is selected, and a matrix coefficient corresponding to the γ value is determined and transferred to the signal processing unit. Otherwise, the γ value is left as it is. Finally, image processing is performed, the image is recorded on the card, and imaging is started again.

  Next, a seventh embodiment of the present invention will be described.

  In the seventh embodiment, the γ curve is automatically determined according to the objective lens, and the edge enhancement coefficient and the coring coefficient are determined according to the curve.

  FIG. 23 is a flowchart when the above method is installed in a microscope system.

  When the system power is turned on, the sample is set, and the electronic camera is turned on, an image is taken. Then, the still image capture trigger switch on the operation unit is pressed, and the still image is stored in the memory. Next, it is checked whether or not there is switching of the objective lens. If there is switching, a γ value that matches the objective lens is selected, an edge enhancement coefficient and a coring coefficient corresponding to the γ value are determined, and the signal processing unit Otherwise, the γ value is left as it is. Finally, image processing is performed, the image is recorded on the card, and imaging is started again.

  In the present invention, based on the electronic camera according to each of the embodiments described above, a microscope system using the electronic camera can be configured as follows.

(1) In a microscope system that uses an electronic imaging device equipped with a solid-state imaging device to capture an observation image with a microscope,
Conversion means for switching between at least the objective lens on the microscope side and the optical system related to the projection magnification of the photographic eyepiece;
Variable gradation characteristic correcting means for correcting, to an image signal obtained by the solid-state imaging device, one gradation characteristic selected in conjunction with the switching operation of the conversion means among a plurality of types of gradation characteristics; A microscope system comprising:

(2) In the microscope system described above,
Variable color correction means for switching the color correction processing according to the gradation characteristics selected during the photographing operation is further provided.

(3) In the microscope system described above,
The image processing apparatus further includes contour emphasizing means for changing the contour emphasis degree of the contour signal added to the image signal in accordance with the gradation characteristic selected during the photographing operation.

  The microscope system according to each embodiment configured as described above has the following effects.

  According to the configuration of (1), even when the bright signal level changes due to replacement of the objective lens, the photographing is performed by switching to the optimum gradation characteristics according to the change of the bright signal. It is possible to provide a microscope system using an electronic image pickup device that can reproduce and display the image signal as a better image on the display device.

  According to the configuration of (2), the gradation characteristics at the time of shooting are switched by exchanging the objective lens, and the color correction processing is switched based on the gradation characteristics. It is possible to provide a microscope system using an electronic imaging device that can ensure gradation and optimum color reproducibility and can reproduce and display a captured image signal as a better image on a display device.

  According to the configuration of (3), the gradation characteristics at the time of photographing are switched by exchanging the objective lens, and the contour enhancement degree is switched based on the gradation characteristics. Thus, it is possible to provide a microscope system using an electronic imaging apparatus that can ensure optimum contour enhancement and can reproduce and display a captured image signal as a better image on a display apparatus.

  The present invention can be configured as follows based on the electronic camera of each of the embodiments described above.

(A) An electronic imaging apparatus according to a first aspect of the present invention for solving the above-described problems is obtained from a plurality of types of gradation characteristics with respect to a solid-state imaging device and an image signal obtained by the solid-state imaging device. Variable gradation characteristic correcting means for correcting to one selected gradation characteristic, and variable color correcting means for switching color correction processing in accordance with the gradation characteristic selected during the photographing operation.

  According to this configuration, since the color correction processing is switched based on the gradation characteristics, the optimum color reproducibility can be ensured regardless of the gradation characteristics, and the captured image signal is improved. It is possible to provide an electronic imaging device that can be reproduced and displayed on a display device as a simple image.

(B) An electronic imaging apparatus according to another aspect of the present invention is a solid-state imaging device and one gradation characteristic selected from a plurality of types of gradation characteristics for an image signal obtained by the solid-state imaging element. Selected at the time of the photographing operation and the light source recognition means for recognizing the type of the illumination light source of the subject, based on the image signal obtained by the solid-state image sensor Variable color correction means for switching the color correction processing according to the gradation characteristics.

  According to this configuration, the type of the illumination light source at the time of shooting is recognized by the light source recognition means, the color correction process is performed based on the recognition result, and the color correction process is switched based on the gradation characteristics. Therefore, the optimum color reproducibility can be ensured regardless of the illumination conditions and gradation characteristics of the subject at the time of shooting, and the shot image signal can be reproduced and displayed on the display device as a better image. An electronic imaging device can be provided.

(C) An electronic imaging apparatus according to another aspect of the present invention includes a solid-state imaging device, luminance distribution recognition means for recognizing the luminance distribution of a subject based on an image signal obtained by the solid-state imaging device, and solid-state imaging. Variable gradation characteristic correcting means for correcting the image signal obtained by the element to one gradation characteristic selected based on the recognition result of the inner luminance distribution recognition means of a plurality of types of gradation characteristics, and the selected Variable color correction means for switching color correction processing according to the gradation characteristics.

  According to this configuration, the gradation characteristic at the time of shooting is switched by the luminance distribution recognition means, and the color correction processing is switched based on this gradation characteristic. It is possible to provide an electronic imaging device that can ensure optimum color reproducibility and can reproduce and display a captured image signal as a better image on a display device.

(D) An electronic imaging apparatus according to another aspect of the present invention is a solid-state imaging device and one gradation characteristic selected from a plurality of types of gradation characteristics for an image signal obtained by the solid-state imaging element. Variable gradation characteristic correcting means for correcting the contour signal, and contour emphasizing means for changing the contour enhancement degree of the contour signal added to the image signal in accordance with the gradation characteristic selected during the photographing operation.

  According to this configuration, since the edge enhancement level is switched based on the gradation characteristics, it is possible to ensure optimum edge enhancement regardless of the gradation characteristics, and to improve the captured image signal. An electronic imaging device that can be reproduced and displayed on a display device as an image can be provided.

(E) An electronic imaging apparatus according to another aspect of the present invention includes a solid-state imaging device, contour enhancement means for adding a contour signal to an image signal obtained by the solid-state imaging device, and an image signal obtained by the solid-state imaging device. On the other hand, the variable gradation characteristic correcting means for correcting one gradation characteristic selected from a plurality of types of gradation characteristics, and the S / N ratio of the contour signal according to the gradation characteristic selected during the photographing operation Variable coring processing means for changing the coring level by switching the coring processing to improve the coring.

  According to this configuration, since the coring level is switched based on the gradation characteristics, an optimum S / N can be ensured regardless of the gradation characteristics, and the captured image signal is improved. It is possible to provide an electronic imaging device that can be reproduced and displayed on a display device as a simple image.

(F) Further, the microscope system according to the first aspect of the present invention provides an image signal obtained by a conversion unit that switches an optical system related to a projection magnification of at least an objective lens and a photographic eyepiece on the microscope side, and an image signal obtained by a solid-state imaging device. On the other hand, it has variable gradation characteristic correcting means for correcting one gradation characteristic selected in conjunction with the switching operation of the conversion means among a plurality of kinds of gradation characteristics. Even if the signal level of the light changes due to replacement, the captured image signal is displayed as a better image by switching to the optimum gradation characteristics in accordance with the change of the light signal. It is possible to provide a microscope system using an electronic imaging apparatus that can reproduce and display the image.

The figure which shows the structure of the microscope system which concerns on embodiment of this invention. The figure which shows the detailed structure of a microscope system. The block diagram which shows the structure of the electronic camera used for a microscope system. The principal part block block diagram which extracted and showed some internal structures of the electronic camera. The figure which shows three types of (gamma) curve. The color reproduction vector figure when a color bar chart is imaged. The figure which shows a matrix correction coefficient as a table | surface. The color reproduction vector figure when processing by a matrix correction coefficient. The flowchart which shows operation | movement of the electronic camera of 1st Embodiment. The figure which shows the structure of an object recognition means. The figure which shows gradation frequency distribution. The figure which shows the modification of 1st Embodiment. The block block diagram which shows the principal part of an electronic camera. The figure which shows ratio of each signal of R, G, B of a color video signal. The figure which showed the edge signal processing part and CPU which controls it in detail. The figure which shows the reason that an output signal changes with (gamma) curves. The figure which shows typically the output signal at the time of performing edge correction | amendment according to (gamma) curve. The figure which shows the input / output characteristic of coring processing. The flowchart which shows operation | movement of the electronic camera of other embodiment. The figure which showed the edge signal processing part and CPU which controls it in detail. The flowchart which shows operation | movement of the electronic camera of other embodiment. The flowchart which shows operation | movement of the microscope system of other embodiment. The flowchart which shows operation | movement of the microscope system of other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Microscope main body, 3 ... Sample, 27 ... Objective lens, 36 ... Electronic camera, 37 ... Drive circuit part, 38 ... Objective lens detection part, 39 ... Retardation adjustment operation detection part, 40 ... Photography eyepiece lens detection part, 41 ... Microscope control unit, 42... CCD (solid-state imaging device), 49... Color correction circuit, 49 a... 6 color separation circuit, 49 b... Minimum value detection circuit, 49 c. 61: Operation unit, 62: γ correction circuit, 65: Coring unit, 66: Edge enhancement circuit unit, 70: Light source recognition unit, 71: Variable matrix color correction unit, 72: γ curve selection unit, 73: Matrix correction Coefficient 75: Object recognition means 82: Coring coefficient 83: Edge enhancement coefficient

Claims (2)

A solid-state image sensor;
Variable gradation characteristic correcting means for correcting the image signal obtained by the solid-state imaging device to one gradation characteristic selected from a plurality of types of gradation characteristics;
An electronic image pickup apparatus comprising: an edge enhancement unit that changes an edge enhancement degree of an edge signal added to the image signal in accordance with a gradation characteristic selected during a photographing operation. The apparatus further comprises variable coring processing means for changing the coring level by switching coring processing for improving the S / N ratio of the contour signal according to the gradation characteristics selected during the photographing operation. The electronic imaging device according to claim 1.

Images