Abstract:
There is disclosed a microscopic image pickup apparatus to be attached to a microscope device to which a plurality of specular methods are applicable, the apparatus being configured to set conversion coefficients for use in conversion of a color image into a monochromatic image so as to adapt the coefficients to a selected specular method. In the present invention, since the conversion coefficients suitable for the selected specular method are set, monochromatic conversion coefficients suitable for the specular method can easily be set without performing any special image processing. As a result, it is possible to obtain the monochromatic image adapted to the specular method and having an excellent gray-scale characteristic.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2006-021629, filed on Jan. 31, 2006, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a microscopic image pickup apparatus which outputs a monochromatic image derived from a color image observed with a microscope. More particularly, it relates to a microscopic image pickup apparatus constituted so that an output monochromatic image has a broad gray-scale characteristic. 
         [0004]    2. Description of the Related Art 
         [0005]    Performing microscopic observations and electronically storing observation images have been widely conducted. There are various microscopic observation methods (specular methods), and the suitable method is selected in accordance with an observation purpose. Among these specular methods, in a fluorescence observation method, an observation sample is dyed using a fluorescence reagent, and a fluorescence color emission state of the sample when irradiated with exciting light is observed. The fluorescence basically causes a monochromatic light emitting phenomenon. Therefore, it is sufficient to record a monochromatic image instead of recording any color image, and this is also advantageous in respect of a capacity of an image file. 
         [0006]    As the fluorescence reagent for use in the fluorescence observation, FITC, Rodamine, DAPI and the like are known. The FITC emits the fluorescence in which a green component is dominant, Rodamine emits the fluorescence in which red and green components are dominant, and DAPI emits the fluorescence in which a blue component is dominant, respectively. 
         [0007]    When an RGB color image signal defined by color component signals of red (R), green (G) and blue (B) is converted into a monochromatic image (gray scale) signal, the signal is in general converted into a monochromatic image signal (luminance signal) Y by the following equation: 
         [0000]        Y=k   R   *R+k   G   *G+k   B   *B    (Equation 1), 
         [0000]    wherein as conversion coefficients k R , k G  and k B , 0.3, 0.59 and 0.11 are in general employed, respectively. This set of conversion coefficients is suitable for a general image without any deviation in the RGB components, but in a case where monochromatic light is emitted as in the above fluorescently observed image, an only specific color component contributes to the luminance signal. Therefore, when the conversion coefficient set is applied, only about 10% of the maximum gray scale of the luminance signal can be utilized in a case where a B component is dominant as an extreme case. 
         [0008]    To solve the problem, one example of technologies to adjust the conversion coefficients k R , k G  and k B  in accordance with a luminance distribution of the color image is described in Japanese Patent Application Laid-Open No. 2000-105820. In this method, a luminance histogram of the color image is prepared during preprocessing of conversion of a color image into a monochromatic image, and the conversion coefficients are determined based on this histogram. 
         [0009]    Moreover, a technology is described in Japanese Patent Application Publication No. 7-96005 in which to record an endoscopically observed image, specific color components of RGB are selected, and an image is converted into a monochromatic image, and displayed in a plurality of monitor devices so that the visibility of the resulting monochromatic image is improved. 
         [0010]    However, in the inventions described in the above documents, it is required to produce and analyze a histogram, or to use a plurality of monitor devices. Therefore, these inventions require special image processing in addition to calculation processing of Equation 1. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    A microscopic image pickup apparatus of the present invention is a microscopic image pickup apparatus to be attached to a microscope device to which a plurality of specular methods are applicable, the apparatus being configured to set conversion coefficients for use in conversion from a color image into a monochromatic image so as to adapt the coefficients to the selected specular method. 
         [0012]    The setting of the conversion coefficients includes: a case where an operator arbitrarily sets the conversion coefficients; a case where the conversion coefficients are selected from alternatives or recommended values prepared on the side of the microscopic image pickup apparatus; and a case where the conversion coefficients are automatically set on the side of the microscopic image pickup apparatus. In any case, since the conversion coefficients suitable for the selected specular method are set in the microscopic image pickup apparatus of the present invention, the monochromatic conversion coefficients suitable for the specular method can easily be set without performing any special image processing. As a result, it is possible to obtain a monochromatic image having an excellent gray-scale characteristic adapted to the selected specular method. 
         [0013]    One example of a configuration of the microscopic image pickup apparatus in the present invention will be described hereinafter. The apparatus comprises: an image sensor which outputs a microscopically observed image as a color image; a coefficient setting section which sets color image/monochromatic image conversion coefficients adapted to a selected specular method; and an image converting section which converts the color image into a monochromatic image by use of the set color image/monochromatic image conversion coefficients. 
         [0014]    Moreover, the present invention can be understood as a method of activating a monochromatic image by use of a microscopic image pickup apparatus to be attached to a microscope device to which a plurality of specular methods are applicable. Furthermore, the present invention can be understood as an information recording medium to record a program which allows the above method to be executed. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0015]    These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
           [0016]      FIG. 1  is a block diagram of a microscopic image pickup apparatus in a first embodiment; 
           [0017]      FIG. 2  is a flow chart showing a photographing operation in the first embodiment; 
           [0018]      FIG. 3  shows one example of a conversion coefficient selection GUI in the first embodiment; 
           [0019]      FIG. 4  shows one example of a conversion coefficient selection GUI in a modification; 
           [0020]      FIG. 5  is a block diagram of a microscopic image pickup apparatus in a second embodiment; 
           [0021]      FIG. 6  is a flow chart showing a photographing operation in the second embodiment; 
           [0022]      FIG. 7  shows one example of a conversion coefficient selection GUI in the second embodiment; 
           [0023]      FIG. 8  shows one example of a conversion coefficient selection GUI in a modification; 
           [0024]      FIG. 9  shows one example of a conversion coefficient selection GUI in another modification; 
           [0025]      FIG. 10  is a block diagram of a microscopic image pickup apparatus in a third embodiment; 
           [0026]      FIG. 11  is a flow chart showing a photographing operation in the third embodiment; and 
           [0027]      FIG. 12  is a flow chart showing a best conversion coefficient extracting operation. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Preferred embodiments of the invention are described below with reference to the accompanying drawings. 
       First Embodiment 
       [0029]    A configuration of a first embodiment will be described.  FIG. 1  is a block diagram showing the first embodiment of the present invention. A microscope  1  has a configuration suitable for performing fluorescence observation that is one type of specular methods. Exciting light b emitted from a lamp  6  reaches a sample  3  on a stage  2  through a fluorescence cube  4 . The fluorescence observation sample  3  is dyed with a fluorescence reagent, and emits fluorescence a. The fluorescence cube  4  includes an optical filter having a function of selecting a specific wavelength of the exciting light b and removing the component of the exciting light from the fluorescence a. In a cube turret (not shown) to which a plurality of fluorescence cubes  4  can be attached, one of the plurality of fluorescence cubes  4  can be selected manually or by an electromotive actuator, and an operator can select the fluorescence cube  4  having the optical filter provided with an appropriate characteristic in accordance with the specular method. 
         [0030]    The fluorescence a emitted from the sample  3  is guided to an image sensor (image pickup means)  7 , and converted into an image signal. A preprocessing section  8  is a front-end section which processes the image signal from the image sensor  7 . Here, noise component removal and signal level adjustment are performed, and the preprocessing section outputs the image signal according to the type of a color filter of the image sensor. An A/D converter  9  converts this image signal into a color digital image signal. An timing generator (TG)  10  is a driving pulse generator for driving the image sensor  7 , the preprocessing section  8  and the A/D converter  9  at predetermined timings. 
         [0031]    A memory control section  13  writes the color digital image signal output from the A/D converter  9  into a memory  12 , and outputs the color digital image signal read from the memory  12  to an RGB synchronization processing section  14  at another timing. 
         [0032]    The RGB synchronization processing section  14  performs a parallelization by separating the color digital signal into RGB color components and forming a RGB image signals  20 . When the image sensor  7  is a color image sensor having the Bayer arrangement, the RGB synchronization processing section  14  performs the parallelization by separating, into the RGB color components, a Bayer encode image signal output from the image sensor  7  in accordance with a color encode scheme (Bayer arrangement) to obtain the RGB image signals  20 . 
         [0033]    A monochromatic converting section  15  converts the RGB image signals  20  output from the RGB synchronization processing section  14  into a monochromatic image signal in accordance with monochromatic conversion coefficients (color image/monochromatic image conversion coefficients) designated by a system control section  11 . In this sense, the monochromatic converting section  15  can be referred to as an image converting section (image converting means) which converts the color image into the monochromatic image. A data transfer section  16  transfers the monochromatic image signal output from the monochromatic converting section  15  into a calculator (computer device)  17 . The system control section  11  controls operations of the TG  10 , the memory control section  13 , the RGB synchronization processing section  14 , the monochromatic converting section  15  and the data transfer section  16  via a bus line. 
         [0034]    The computer  17  reads out a processing program  18  to successively execute designated commands. This processing program is stored in a storage medium  18   a  readable by the computer device. This storage medium may be of either a fixed type or a detachably attached type. 
         [0035]    The computer  17  reads out the monochromatic image signal output from the data transfer section  16  in accordance with the processing program  18 , and displays the signal in an image monitor  19 . Moreover, the processing program  18  is also provided with a screen user interface (GUI) for an operator to arbitrarily set monochromatic conversion coefficients  21 , and also notifies the system control section  11  of the monochromatic conversion coefficients  21  set by the operator. In this sense, the computer  17  may be referred to as a coefficient setting section (coefficient setting means) which sets the color image/monochromatic image conversion coefficients. 
         [0036]    Subsequently, there will be described a function of the first embodiment provided with such a configuration. 
         [0037]      FIG. 2  is a flow chart showing an outline of an operation procedure of an operator in the first embodiment. First, the operator sets the monochromatic conversion coefficients  21  by the GUI (S 001 ). One example of a GUI screen at this time is shown in  FIG. 3 . This GUI screen is displayed in the image monitor  19  at a time when the computer  17  executes the processing program  18 . 
         [0038]    The operator checks a check box  100  to validate a monochromatic conversion coefficient setting function in this GUI screen. At this time, designation can be performed by arbitrarily combining a check box  101  to set a conversion coefficient k R  for a red component R to be off (0.0) or on (1.0), a check box  102  to set a conversion coefficient k G  for a green component G to be off or on, and a check box  103  to set a conversion coefficient k B  for a blue component B to be off or on. The figure shows an example in which the check boxes  100 ,  101  and  102  are turned on, and the check box  103  is off. In this example, a digitalized selection is performed to set the monochromatic conversion coefficient to 0 or 1. 
         [0039]    As to this check box setting, for example, in a case where a fluorescence image is observed using fluorescence reagent Rodamine, the R component and the G component are dominant in the fluorescence emitted color as described above. Therefore, when the check boxes  100 ,  101  and  102  are turned on, and the check box  103  is turned off (state of  FIG. 3 ), the monochromatic image having a preferable gray-scale characteristic can be obtained. 
         [0040]    The computer  17  inputs the monochromatic conversion coefficients  21  set in the GUI into the system control section  11  via the data transfer section  16 . The system control section  11  inputs the set monochromatic conversion coefficients into the monochromatic converting section  15 . 
         [0041]    Returning to  FIG. 2 , the operator operates the computer  17  to which the processing program  18  is applied to instruct the system control section  11  to capture a static picture (S 002 ). The system control section  11  controls the TG  10 , the memory control section  13 , the RGB synchronization processing section  14 , the monochromatic converting section  15  and the data transfer section  16 , and converts the captured RGB image of the fluorescence a into the monochromatic image to transfer the image to the computer  17 . At this time, the monochromatic converting section  15  converts the RGB image into the monochromatic image by use of the monochromatic conversion coefficients  21  set in the step S 001 . 
         [0042]    As described above, according to the first embodiment, since the monochromatic conversion coefficients can easily be set with the GUI, it is possible to easily obtain the monochromatic image having excellent gray-scale characteristic optimized with respect to the monochromatic image such as in the fluorescence observation. 
         [0043]    It is to be noted that in the first embodiment, there has been described the configuration of the GUI check box selection system of  FIG. 3 , but the present invention is not limited to this configuration. As a modification, there may be employed a system in which the monochromatic conversion coefficients are set in a quasi analog manner by use of slide bars similarly by the GUI, instead of the check boxes. An example in which the slide bars are used is shown in  FIG. 4 . 
         [0044]    According to this modification, the monochromatic conversion coefficients can remarkably finely be set. Therefore, for example, values recommended by a fluorescence reagent maker can be applied as they are. 
       Second Embodiment 
       [0045]    Next, a second embodiment will be described. In the present embodiment, a configuration in which a fluorescence cube operation is set with a GUI is added to the configuration of the first embodiment.  FIG. 5  is a block diagram showing the configuration of the second embodiment. A program  18  sets monochromatic conversion coefficients  21  using the GUI in conjunction with a set fluorescence observation method. In a modification of the second embodiment, a fluorescence cube operation command  22  is set using the GUI. Since another configuration is similar to that of the first embodiment, redundant descriptions are omitted. 
         [0046]    A function of the second embodiment will be described. 
         [0047]      FIG. 6  is a flow chart showing an image pickup procedure of fluorescence observation in the second embodiment. An operator designates the fluorescence observation method using the GUI (S 011 ). One example of GUI screen display displayed in a monitor  19  at this time is shown in  FIG. 7 . The operator designates the fluorescence observation method by use of a combination box  121  capable of designating various types of fluorescence observation method (i.e., fluorescence reagent), and checks a check box to “set the monochromatic conversion coefficients  21  to recommended values”. According to this setting, a computer  17  notifies a system control section  11  of the monochromatic conversion coefficients  21  via a data transfer section  16 . The monochromatic conversion coefficients  21  are conversion coefficients adapted to each fluorescence observation method. When, for example, DAPI is selected as the fluorescence reagent, 0.0, 0.3 and 0.7 are set as k R , k G  and k B , respectively. When Rodamine is selected, 0.7, 0.3 and 0.0 are similarly set, respectively. 
         [0048]    Returning to  FIG. 6 , capturing of a static picture is instructed in order to obtain a monochromatic image converted by use of the monochromatic conversion coefficients  21  set in the step S 011  (S 012 ). 
         [0049]    As described above, according to the second embodiment, since the monochromatic conversion coefficients optimum for various types of fluorescence observation methods are automatically set using the GUI, a monochromatic image having an excellent gray-scale characteristic can easily be obtained. 
         [0050]    It is to be noted that in the second embodiment, there has been described a configuration in which the monochromatic conversion coefficients suitable for the fluorescence observation method (specifically, a fluorescence reagent) set by the GUI are automatically set as shown in  FIG. 7 , but the present invention is not limited to this configuration. As a modification, the monochromatic conversion coefficients may automatically be set in accordance with, for example, a fluorescence cube selected by the operator. In this case, a turret provided with various types of fluorescence cubes can be driven by an electromotive actuator. One example of a GUI displayed in the monitor  19  is shown in  FIG. 8 . 
         [0051]    This modification will be described along the procedure of  FIG. 6 . The operator selects a filter of the fluorescence cube using the GUI (S 011 ′). In a fluorescence cube selection GUI  130 , the operator can select filters such as WU, WB and WG. In addition, it is possible to automatically set monochromatic conversion coefficients optimum for the filter selected by the fluorescence cube selection GUI  130 . Here, the filter WU selects a B component as exciting light, and transmits all of RGB components in fluorescence to guide the components into an image sensor  7 . In a case where the filter WU is selected in the fluorescence cube selection GUI  130 , the monochromatic conversion coefficients  21  for producing a monochromatic image from all of the RGB components are set. 
         [0052]    Subsequently, the operator operates the computer  17  to which the processing program  18  has been applied to instruct the system control section  11  to capture the static picture (S 012 ′). The system control section  11  controls a TG  10 , a memory control section  13 , an RGB synchronization processing section  14 , a monochromatic converting section  15  and the data transfer section  16 , and converts a captured RGB image of fluorescence a into the monochromatic image to transfer the image to the computer  17 . At this time, the monochromatic converting section  15  converts the RGB image into the monochromatic image by use of the monochromatic conversion coefficients  21  set in the step S 011 . 
         [0053]    According to this modification, since the monochromatic conversion coefficients adapted to the selected fluorescence cube are automatically set, the monochromatic image having an excellent gray-scale characteristic can easily be obtained. 
         [0054]    Furthermore, in the above modification, the monochromatic conversion coefficients suitable for the filter selected in the fluorescence cube are automatically set. In a further modification, as shown in  FIG. 9 , a GUI  141  to select a filter wheel is disposed, and monochromatic conversion coefficients adapted to a selected filter may be set. 
       Third Embodiment 
       [0055]    Next, a third embodiment will be described.  FIG. 10  is a block diagram showing a configuration of a third embodiment. In the present embodiment, a monochromatic conversion coefficient candidate producing section  23  which produces a plurality of monochromatic conversion coefficients, and a best conversion coefficient storage section  24  are disposed in a system control section  11 , and further a contrast evaluating section  25  is disposed which evaluates a contrast value of an output of the monochromatic converting section  15 . 
         [0056]    A function of the third embodiment will be described. 
         [0057]      FIG. 11  is a flow chart showing an image pickup procedure of fluorescence observation in the third embodiment. When an operator instructs photographing start, first an RGB image photographing step is started, and the photographed RGB image is stored in a memory  12  in the same manner as in the embodiments described above (S 031 ). 
         [0058]    Subsequently, the monochromatic conversion coefficient candidate producing section  23  in the system control section  11  produces N monochromatic conversion coefficient candidates. One example of the conversion coefficient candidate produced at this time is as follows: 
         [0000]        k   R =0.1 *m  ( m =0, 1, 2, . . . 10)   (Equation 2); 
         [0000]        k   G =0.1 *n  ( n =0, 1, 2, . . . 10)   (Equation 3); 
         [0000]      and 
         [0000]        k   B =1 −k   R   −k   G  ( k   B &gt;=0.0)   (Equation 4). 
         [0059]    When k R , k G  and k B  are defined by Equations 2 to 4, respectively, N=55 sets of conversion coefficient candidates are produced in accordance with a combination of m and n (S 032 ). It is to be noted that the conversion coefficient candidates may be included as a table in a part of a processing program  18  beforehand. 
         [0060]    Next, the system control section  11  operates in accordance with a flow chart shown in  FIG. 12  in order to extract such monochromatic conversion coefficients as to give the best contrast evaluation value. First, the system control section  11  performs initialization to set the number N of the conversion coefficient candidates to  55 , set a counter I of the monochromatic conversion coefficients to 0, set a coefficient value BEST to be stored in the best conversion coefficient storage section to 0, and set an evaluation value BEST_VALUE of the best conversion coefficient storage section to 0 (S 041 ). 
         [0061]    The system control section  11  reads out an I-th monochromatic conversion coefficient to transfer it to a monochromatic converting section  15 , and reads out an RGB image signal stored in the memory  12  to similarly transfer it to the monochromatic converting section  15  (S 042 ). 
         [0062]    The monochromatic converting section  15  produces a monochromatic image by use of the monochromatic conversion coefficients set in S 042 , and transfers the image to the contrast evaluating section  25  (S 043 ). 
         [0063]    The contrast evaluating section  25  calculates a contrast value EVAL of the monochromatic image acquired in S 043  (S 044 ). It is defined that the larger this contrast value EVAL is, the higher the contrast becomes. 
         [0064]    The system control section  11  acquires the contrast value EVAL from the contrast evaluating section  25  to compare the value with the best evaluation value. Here, the comparison is performed by the following procedure. 
         [0065]    When BEST_VALUE&lt;EVAL, the following is set: 
         [0066]    BEST=I; and 
         [0067]    BESTVALUE=EVAL (S 045 ). 
         [0068]    The system control section  11  increments the counter I in order to evaluate the next conversion coefficient candidate (S 046 ). When I=N, S 048  is executed as described later. At another time, the flow returns to S 042  (S 047 ). All of 55 monochromatic conversion coefficient candidates are evaluated by this loop processing and the best conversion coefficient is set to BEST. 
         [0069]    The system control section  11  reads out an RGB image from the memory  12 , and inputs the best conversion coefficient into the monochromatic converting section  15  (S 048 ). The monochromatic converting section  15  converts the RGB image into the monochromatic image by use of the best conversion coefficient set in S 048  (S 049 ). 
         [0070]    As described above, according to the present embodiment, a plurality of monochromatic conversion coefficients are prepared, all the monochromatic conversion coefficients are successively applied to the photographed RGB image, and the best conversion coefficient is determined to produce a monochromatic image having the highest contrast evaluation value. Therefore, it is possible to obtain the monochromatic image having an excellent gray-scale characteristic. 
         [0071]    While there has been shown and described what are considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention not be limited to the exact forms described and illustrated, but constructed to cover all modifications that may fall within the scope of the appended claims.