Abstract:
The method for coding live images in microscopy makes possible the recording of a first complete image ( 25   1 ) that depicts a portion of a microscopic preparation ( 14   a ). A first coded complete image ( 200 ) is generated therefrom and is stored in a buffer memory ( 27 ). The first coded complete image ( 25   1 ) can moreover be output, for example, on a monitor. When a second complete image ( 25   2 ) is recorded, only a part is processed and transmitted. That part corresponds to the offset of an X-Y stage ( 12 ). The coordinates of the portion of the second complete image ( 25   2 ), and further control data, are transferred to a control data decoder ( 26 ). A correspondingly assembled and coded complete image ( 210 ) is generated in an image assembler ( 32 ), the at least one coded partial image ( 220 ) and the preceding coded complete image located in the buffer memory ( 27 ) being used.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of the German patent application DE 100 26 392.5 filed May 27, 2000 which is incorporated by reference herein. 
   FIELD OF THE INVENTION 
   The invention concerns a method for coding live images in microscopy. In particular, the invention concerns a method in which the microscope images that are recorded are partially coded. Displacement of the X-Y stage induces an offset of a portion of the previously recorded image; it is sufficient if only the new image portion is coded and transmitted. 
   The invention furthermore concerns an arrangement for coding live images in microscopy. In particular, the invention concerns a system that improves, in terms of transmitted image quality, the transmission of microscope images from a microscope to a remote station. 
   BACKGROUND OF THE INVENTION 
   In existing video coding as presently practiced, algorithms are used inside the codec to recognize image changes, in order to find the image portions that are to be compressed. The calculation time needed to discover such image changes (a person&#39;s head has moved, etc.) is relatively long and, together with the transmission bandwidth, limits the number of moving images that can be processed per second. 
   U.S. Pat. No. 5,216,596 discloses a telepathology system. A workstation is set up at a remote location and receives images from a preparation (tissue) that is to be examined with a microscope. The microscope images are recorded with a conventional video camera, and displayed at the remote location on a conventional video monitor. A or coding of the image data is accomplished after imaging. The system presented here is tied to analog transmission links, and cannot achieve the necessary resolution in a conventional digital network. Coding is also ruled out because of the analog transmission. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to create a method with which an increase in video image rate and a reduction in compression outlay can be achieved in the context of the transmission of live microscope images over digital networks. The method is also intended to make it possible to enhance display quality, i.e. to prevent flicker effects due to continuous image transmission even when images are stationary. 
   According to the present invention, this is achieved by a method that comprises the following steps: 
   a) recording a first complete image that depicts a portion of a microscopic preparation; 
   b) generating a first coded complete image in a coding element; 
   c) storing the first coded complete image in a buffer memory; 
   d) outputting the first coded complete image; 
   e) recording a second complete image that is offset with respect to the preceding complete image in a plane defined by an X-Y stage; 
   f) transferring the coordinates of the portion of the second complete image, and further control data, to a control data decoder; 
   g) generating at least one coded partial image utilizing the data from the control data decoder; 
   h) generating an assembled and coded complete image in an image assembler, using the at least one coded partial image and the preceding coded complete image located in the buffer memory; 
   i) outputting a second assembled and coded complete image, the assembled and coded complete image also being stored in the buffer memory for that purpose; and 
   j) recording further images, steps f) through i) being repeated for each further image. 
   A further object of the invention is to create an arrangement which makes possible flicker-free image transmission of live microscope images at an increased image rate. 
   According to the present invention, this is achieved by an arrangement which comprises a coder to which complete images can be transferred, the coder comprising a coding unit that is connected to a buffer memory; a control data decoder being connected to the coding unit, to the buffer memory, and to an image assembler; and the image assembler receiving data from the buffer memory and transferring data to the buffer memory. 
   One advantage of the invention is an increase in the video image rate and a reduction in compression outlay in the transmission of live microscope images over digital networks. In addition, display quality is enhanced, i.e. flicker effects due to continuous image transmission even when images are stationary, or flickering due to continuous compression, are prevented. Compression of the image data is accomplished with several commercially common algorithms, in order to adhere to existing video compression standards. 
   A further advantage of the invention is that the coder/decoder algorithm according to the present invention takes into account the circumstance that the status data of an automatic microscope are utilized for video coding of moving images or live images from a microscope. In microscopic examinations, no unexpected movements occur within the image. The movements of the specimen or preparation are usually only displacements in the three spatial coordinates X, Y, and Z. Using this additional information, the coding time for the image that is to be transmitted can be considerably shortened, data volume is reduced, and a higher moving-image rate or better image quality (due to less-severe compression) is achieved. The algorithm used here utilizes additional input data; i.e. one control channel and two data channels with additional information are additionally used, as well as the image data, as input for the coder. The control channel contains information for controlling the partial coding of the input image. The data required for this (e.g. X-Y position, color values, etc.) are conveyed via the two additional data channels. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings schematically depict the subject matter of the invention, which is described below with reference to the Figures. In the drawings: 
       FIG. 1  schematically depicts a system in which the invention is applied; 
       FIG. 2  schematically depicts the recording of an image of a preparation, the position of the X-Y stage having been modified in the X position; 
       FIG. 3  schematically depicts the recording of an image of a preparation, the position of the X-Y stage having been modified in the Y position; 
       FIG. 4  schematically depicts the recording of an image of a preparation, the position of the X-Y stage having been modified in the X and Y positions; 
       FIG. 5  shows a schematic configuration of a coder; and 
       FIG. 6  shows a schematic configuration of a decoder. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   System  1  depicted in  FIG. 1  comprises a microscope  2  that is set up at a location where preparations (tissue sections) for examination are being produced. The location is usually a histology or pathology department of a hospital. A first computer  4  having a monitor  5  is associated with microscope  2 . A second computer  6 , also having a monitor  7 , is connected to first computer  4  via a conventional network  8 . The network is represented in  FIG. 1  by a connecting line having an interruption  8   a,  the better to illustrate that second computer  6  can in principle be installed at any desired distance from first computer  4 . 
   In the exemplary embodiment depicted here, microscope  2  is depicted as an automatic microscope. All the imaging parameters of microscope  2  can be set and modified, for example, from second computer  6 . In this case microscope  2  possesses corresponding motors for setting the parameters.  FIG. 1  depicts a motor  10  that makes possible displacement of an X-Y stage  12 . Motors for changing the imaging scale, moving X-Y stage  12  in the Z direction, and/or focusing are not depicted for reasons of clarity. The arrangement and use of these motors is, however, evident to one skilled in the art. First computer  4  usually serves to record the image data from microscope  2  and convert it into a corresponding data format for transfer via network  8 . A compression of the image data can also be performed by first computer  4 . In addition, microscope  2  is also equipped with position sensors (not depicted), which supply to first computer  4  signals which provide information about the X, Y, and Z position of X-Y stage  12 . It is also conceivable for X-Y stage  12 , or individual components of the microscope, to supply signals which allow a position determination. First computer  4  is also responsible for receiving data from second computer  6  in order to control microscope  2 , and for converting them into corresponding control signals. First and second computers  4  and  6  are used for communication via network  8 , “communication” being understood to mean data transfer in both directions. 
   A specimen slide  14 , with a preparation  14   a  on it, is placed on X-Y stage  12 . Depending on the selected magnification, an image window (not depicted) is imaged and is recorded by a camera  16 . Camera  16  can be configured, for example, as a conventional video camera or CCD camera. Camera  16  is connected via a connection  17  to first computer  4 . A further connection  18 , over which control signals are sent to the corresponding motors, exists between first computer  4  and microscope  2 . Control signals are conveyed via network  8  from second computer  6  to first computer  4 . Image data are similarly conveyed via network  8  from first computer  4  to second computer  6 . The two computers  4  and  6  can each be equipped with a WAN module  11  (ISDN, ASDL, ATM, satellite) that serves to establish a connection. An input unit  20  for user inputs is also connected to each computer  4  and  6 . Input unit  20  can be configured as a mouse, keyboard, or voice control unit. 
     FIGS. 2 through 4  illustrate the imaging of a portion of a tissue section  100 . A first image  102  is recorded by a video camera or CCD camera. The camera defines a first image frame  104  that is depicted in  FIGS. 2 through 4  with solid lines. X-Y stage  12  (see  FIG. 1 ) is displaced in the X direction, and this results in an offset image frame  106  that is depicted in  FIG. 2  with dashed lines. The difference between first image frame  104  and offset image frame  106  is a cross-hatched area  108 . 
   In  FIG. 3 , the X-Y stage is displaced in Y direction Y, and this results in an offset image frame  106  that in  FIG. 3  is again depicted with dashed lines. The difference between first image frame  104  and offset image frame  106  is again a cross-hatched area  108 . 
   In  FIG. 4 , the X-Y stage is displaced in X direction X and in Y direction Y, and this results in an offset image frame  106  that in  FIG. 4  is again depicted with dashed lines. The difference between first image frame  104  and offset image frame  106  is a cross-hatched area  108 . 
   The arrangement must furthermore make a comparison to determine whether the recorded image has experienced any change in the Z direction. It is then also necessary to detect any changes in the image content in which the new image encompasses a region that is completely outside the region of the preceding image. Suitable processing and identification methods are available for this purpose. 
   In order to improve the transmission of the recorded microscope images to a remote station and to increase the transmission speed, it is sufficient to transmit only the portion of the image that results from the offset by X-Y stage  12 . As is apparent from  FIGS. 2 through 4 , only cross-hatched area  108  of offset image frame  106  needs to be transmitted to yield a complete image at the receiving end. 
     FIG. 5  depicts a schematic configuration of a coder  21  for preparing for image transmission. At the beginning of the coding process, the type of image output must be defined. In this exemplary embodiment, coder  21  possesses three outputs. A coded complete image  200  that is completely coded is output at a first output  22   1 . A coded partial image  220  that is partially coded is output at a second output  22   2 . An assembled and coded complete image  210  that comprises several partial images  210   1  and  210   2  is output at third output  22   3 . Each of the partial images  210   1  and  210   2  is partially coded, and is correspondingly assembled into a coded complete image  210 . Coder  21  furthermore possesses four inputs. The image data of the input image (a first complete image  25   1 ) are transferred to coder  21  via a first input  24   1 . First complete image  25   1  can, for example, be recorded by way of a video camera or CCD camera (not depicted). 
   The first recorded complete image  25   1  is transferred to a coding element  26  and is always completely coded. The coded image is then stored in a buffer memory  27 . A complete image can be output at first output  22   1 . If, for example, X-Y stage  12  is displaced, a second complete image  25   2  is again recorded. In the example described here, the difference between the second recorded complete image  25   2  and the first recorded complete image  25   1  is a cross-hatched area  240 . The second recorded complete image  25   2  is again conveyed to coding element  26 . The procedure is the same for all further recorded images. 
   Coder  21  possesses a control data decoder  30  that has three inputs. A first input  26   1  is connected to a control channel  28  that supplies information for controlling partial coding of the input image. A first data channel  30   1  is connected to a second input  26   2 , and a second data channel  30   2  to a third input  26   3 . First and second data channels  30   1  and  30   2  supply, for example, information about the X-Y position of the X-Y stage, color values, or the like. Images that are recorded after the first recorded complete image  25   1  are partially or completely coded as a function of the information from control data decoder  30 . 
   Coder  21  also possesses an image assembler  32  which also receives information from control data decoder  30  in order to assemble the coded partial images  210   1  and  210   2  into a coded complete image  210 . Assembly of coded partial images  210   1  and  210   2  into a complete image  210  is necessary when, as depicted in  FIG. 5 , the difference between the first recorded complete image  25   1  and the subsequently recorded complete image  25   2  is, for example, cross-hatched area  240 . A datum is also sent from control data decoder  26  to buffer memory  27  so that the image information necessary for assembly of a complete image is sent to image assembler  32 . Once a complete image  210  has been generated from the coded partial images  210   1  and  210   2 , it can be output via third output  22   3 . In addition, the newly generated complete image  210  is stored in buffer memory  27  and thus constitutes a basis for possible assembly of a newly recorded input image. 
   In addition to the pure image data, a coded complete image  210  or partial image  220  additionally contains information about the type of coding (complete/partial) and, in the case of partially coded images, information about the location of the image in the overall image. 
     FIG. 6  shows a schematic configuration of a decoder  40 . As already mentioned above, the input images for decoder  40  are the coded complete image  200  or coded partial image  220  of  FIG. 5 . These images also contain, in addition to the pure image information, information about the type of coding (complete image  200 /partial image  220 ). In the case of the partially coded images, data concerning the position of the partial image in the overall image are additionally analyzed as input data. As already mentioned with reference to coding, the first image that is transmitted is a complete image  200 . 
   Decoder  40  possesses a control data decoder  42  that ascertains the corresponding position data and/or control data from complete image  200  or partial image  220  that is received. As already mentioned with regard to  FIG. 5 , the first image recorded is always a complete image  200 , which is output from coder  21  as coded image  200 . A corresponding procedure is used in decoder  40 . Control data decoder  42  receives the coded complete image  200  and forwards it to a decoder unit  44 . The coded complete image  200  is converted into a decoded complete image  45   1  and output. The decoded complete image  45   1  corresponds to the first recorded complete image  25   1  before coding. The first decoded complete image  45   1  is additionally stored in decoder buffer memory  46 . The procedure is the same for all further complete images: decode, buffer memory, output. 
   Coded partial images  220  are also transferred to control data decoder  42  and decoded, and then, as a function of the additional data (position in the overall image, etc.), combined in an image assembler  48  with the preceding image to form a decoded complete image  45   2 . This complete image  45   2  is stored in decoder buffer memory  46  as the new preceding image, and additionally output. Monitor  5 ,  7  respectively associated with first or second computer  4 ,  6  is usually used as the output medium. 
   The invention has been described with reference to one particular embodiment. It is self-evident, however, that changes and modifications can be made without thereby leaving the scope of protection of the claims recited hereinafter. 
   PARTS LIST 
   
       
         2  Microscope 
         4  First computer 
         5  Monitor 
         6  Second computer 
         7  Monitor 
         8  Network 
         10  Motor 
         11  WAN module 
         12  X-Y stage 
         14  Specimen slide 
         14   a  Preparation 
         16  Camera 
         17  Connection 
         18  Further connection 
         20  Input unit 
         21  Coder 
         22   1  First output 
         22   2  Second output 
         22   3  Third output 
         24   1  First input 
         25   1  First complete image 
         25   2  Second complete image 
         26  Coding element 
         26   1  First input 
         26   2  Second input 
         26   3  Third input 
         27  Buffer memory 
         28  Control channel 
         30  Control data decoder 
         30   1  First data channel 
         30   2  Second data channel 
         32  Image assembler 
         40  Decoder 
         42  Control data decoder 
         44  Decoder unit 
         45   1  First decoded complete image 
         45   2  Second decoded complete image 
         46  Decoder buffer memory 
         48  Image assembler 
         100  Tissue section 
         102  First image 
         104  First image frame 
         106  Offset image frame 
         108  Cross-hatched area 
         200  Complete image 
         210  Coded complete image 
         210   1  Partial image 
         210   2  Partial image 
         220  Coded partial image 
         240  Cross-hatched area