Abstract:
A device and a process are provided for uniformly lighting an operating area for performing the lighting of an operating area ( 2 ) of a bed ( 30 ) by means of a lighting unit ( 3 ) such that a selected lighting field ( 13 ) is lighted uniformly. The image signals of a camera ( 7 ) are sent to an image processing unit ( 17 ), in which the image signals are analyzed and the individual lighting elements ( 6 ) are switched via the control unit ( 18 ). A lighting situation is acquired in the process for initializing and operating this lighting system and a lighting field ( 13 ) of interest is selected. The image signals are analyzed during the operation and sent to the control unit ( 18 ) in order to switch the lighting elements ( 6 ) such that uniform lighting is obtained in the first lighting field ( 13 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2008 019 191.4 filed Apr. 17, 2008, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a device comprising a lighting fixture for an operating room with a lighting unit, in which a plurality of lighting elements with at least one light source are arranged, a camera for imaging, with an image processing system, with a control unit for actuating the lighting elements, with a display unit and with an operating unit. Furthermore, the present invention pertains to a process for lighting preselected lighting fields of an operating area. 
       BACKGROUND OF THE INVENTION 
       [0003]    A combination of imaging system, image processing system and operating area is known from DE 20 2005 021111 U1. 
         [0004]    EP 1785665 A1 describes an operating area with an actuating means of groups of lighting means, wherein the lighting means can be controlled in terms of luminosity in a plurality of zones separately from one another. 
         [0005]    EP 1433998 B1 describes a lighting fixture for an operating room with a control unit, imaging and processing system, in which it is possible to determine shadow zones above an operating area by imaging and by an analysis unit. After determination of the shadow zone, the light distribution is changed by means of the control unit in order to reduce the shadow effect. 
         [0006]    The drawback of this arrangement of cameras and lighting fixtures for the operating room is that it is necessary to divide the lighted operating area into checkerboard-like partial areas and that a certain, defined and known group of a number of lighting means is permanently assigned to each of these partial areas. 
       SUMMARY OF THE INVENTION 
       [0007]    An object of the present invention is therefore to provide a device with an operating area and a process for operating same in such a way that uniform lighting of the operating area is guaranteed. 
         [0008]    The device according to the present invention comprises a lighting fixture for a lighting means of an operating room. The lighting means comprises a plurality of individual lighting elements. In a preferred form, these are LED lighting elements. The device comprises, furthermore, at least one camera, which is aligned stationarily in relation to the operating area; at least one central lighting unit or a group of centrally positioned lighting means; an image processing system; a display unit; an operating unit, and a control unit for controlling the plurality of lighting elements. The camera is arranged in a fixed relationship to an operating area belonging to it, which is located in the area covered by the camera. The lighting unit is equipped with a plurality of lighting elements such that the operating area can be lighted in a plurality of lighting zones. 
         [0009]    The process for operating a lighting system for uniformly lighting a lighting field begins with the switching on of the plurality of lighting elements sequentially one after another and with the acquisition of an image by at least one first camera, an image being acquired for every single switch-on event, recorded and stored in a first data field. The data image acquired by the at least first camera is subsequently analyzed in a continuous sequence and compared with the first data field. The actuation parameters of a first parameter field are thereupon adjusted and the control unit continuously controls the individual lighting elements of the lighting unit according to the first parameter field. 
         [0010]    A sequence of eleven steps specifically illustrates the process according to the present invention for operating a lighting system for uniformly lighting a lighting field. The process takes the following course:
   a) All lighting elements of the lighting unit are switched on simultaneously by the control unit in a first step;   b) an image of the operating area is acquired by at least one first camera and displayed on the display unit in a second step;   c) at least one first lighting field of interest with a corresponding defined brightness distribution is set by means of the operating unit in a third step;   d) all lighting elements of the lighting unit are switched off by the control unit in a fourth step and each one of the plurality of lighting elements is switched on one after another in a sequence and an image is acquired, recorded and stored in a first data field for every single switch-on event of every single lighting element by at least one first camera;   e) the first data field is analyzed in a fifth step to determine whether the at least first camera was hidden during the imaging;   f) the first data field is analyzed in a sixth step and the parameters for actuating the plurality of lighting elements are determined and stored in a first parameter field;   g) the individual lighting elements are switched by means of the control unit in a seventh step and a control view of the lighting is outputted on the display unit;   h) the actuation of the plurality of lighting elements is confirmed by means of the operating unit in an eighth step, the initialization is terminated and operation is started;   i) a polling is carried out in a ninth step to execute the first mode of operation for uniform lighting, and the first mode of operation is continued;   j) the data image acquired by the at least first camera is analyzed in a tenth step in a continuous sequence and compared with the first data field, and the actuating parameters of the first parameter field are adjusted; and   k) the actuation of the individual lighting elements of the lighting unit is performed in an eleventh step according to the first parameter field and the first mode of operation is continued without interruption with return to the ninth step.   
 
         [0022]    In a special embodiment of the process, a polling is provided in the ninth step to terminate the first mode of operation with simultaneous lighting, as well as a polling is provided for switching over into at least a second mode of operation, wherein the second mode of operation may be designed as a mode with maximum luminosity of all lighting elements, as a mode based on an average brightness distribution of all lighting elements according to the first parameter field, or as a mode of manually preset luminosity of all lighting elements. 
         [0023]    In another preferred embodiment of the process, a first lighting field of interest and at least one second lighting field are set by means of the operating unit in the third step. 
         [0024]    In an expanded embodiment of the process, a return to the first step and hence a restart of initialization can take place following the fifth step, if the at least first camera is hidden, as a result of the analysis of the data in the first data field, and the user is informed of the reason for the return in the form of a message. The process according to the present invention comprises an arrangement of at least one lighting unit for lighting an operating area, wherein each lighting unit comprises a plurality of lighting elements, and comprises an image recording of the lighting situation by means of at least one stationarily arranged first camera. The lighting situation is displayed for the user on a display unit. The user defines by means of an operating unit the lighting fields in the operating area in which uniform lighting must be guaranteed. The geometric shape of the lighting fields may be as desired, the extension of the lighting field being smaller than the operating area. 
         [0025]    Exemplary shapes of the lighting field are circles, ellipses, square, trapezoidal and rectangular tetragonal shapes, honeycomb shapes with five, six or seven corners. Sequential switching on of all lighting elements is performed in the next step by the actuating unit, and an image is recorded by the camera for each switch-on event of every single lighting element. 
         [0026]    The images recorded by the camera are stored in a first data set. The percentage of an image segment of the operating area and of the defined lighting field for which an individual lighting element is responsible is calculated in the next step. A two-dimensional data field of lighting values of the operating area with the subset of a data field, which describes the defined lighting field, is obtained from this. 
         [0027]    After this initialization, the control unit actuates individual lighting elements, so that uniform lighting of the lighting field defined by the user is guaranteed. 
         [0028]    The camera detects the lighting situation of the operating area and of the defined lighting field. The image signals are sent to the image processing unit, which analyzes the lighting for uniformity. The uniformity of lighting can be determined by a comparison with a preset limit value. Mathematical methods make it additionally possible to determine the conditions of the luminosities in relation to one another, to a preset limit value or to a mean value of the luminosities. Thus, the deviation of the brightness distribution of a group of measured values in relation to the stored or preselected desired values or even the brightness distribution of the measured values within the group of measured values in relation to one another is determined by the analysis by means of the least-squares method. 
         [0029]    The use of the least-squares method represents a known image analysis method here; other image analysis methods, such as an analysis of the frequency components in the form of a distribution analysis (histogram analysis) with preceding frequency transformation (FFT), the targeted analysis of certain dot marks in a first lighting field represent alternative and additionally applicable methods for image analysis. The inclusion of past image data for a trend analysis of the change in brightness and also of a brightness shift from one group of image segments to another group of image segments makes it possible in a special embodiment to recognize both a temporary shadowing of individual areas of the first lighting field and dynamic shadow processes caused by motion. The results of the analysis are stored in a first parameter field, and the luminosity of individual lighting elements is controlled in the control circuit with the control unit such that the lowest possible relative deviation of the brightness distribution of the lighting detected with the camera remains within the lighting field in relation to stored or preselected desired values of the brightness distribution or also within one group of image segments in the lighting field. 
         [0030]    In a preferred embodiment, means for pulsed switchover are provided and the lighting elements are designed such that switchover of the lighting elements can take place at a switchover frequency above the flicker fusion frequency of 80 Hz so rapidly that the switchover processes cannot be perceived by the human eye as disturbing processes in the brightness of the emitted light. Suitable lighting elements for rapid switchover are light-emitting diodes. 
         [0031]    At least two cameras, whose acquisition areas overlap and which are arranged in a fixed relationship to the operating area, are present in a preferred embodiment. 
         [0032]    The control unit is designed in an alternative variant to control a number of at least two lighting units on the basis of the image analysis. The first and/or second camera is part of a central lighting unit in another preferred embodiment. 
         [0033]    The lighting unit connected to the camera is arranged in a special embodiment stationarily on the ceiling of the operating room directly centrally above the operating area, whereas other additional lighting units are arranged movably and pivotably about the central lighting unit, and these additional lighting units are also included in the lighting control. 
         [0034]    A special variant of the process is designed such that a special mode of operation is provided, in which low priority can be set for uniform lighting of the lighting field in favor of higher intensity of lighting of the operating area. 
         [0035]    An exemplary embodiment of the present invention will be explained in more detail below on the basis of the drawings. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    In the drawings: 
           [0037]      FIG. 1  is a schematic view showing an arrangement comprising an operating area, a lighting unit, a display unit, an operating unit and a control unit as well as a first camera; 
           [0038]      FIG. 2  is a view showing the division of the imaging of the operating area into image segments and a first acquisition area of a first camera; 
           [0039]      FIG. 3  is a view showing the division of the operating area in connection with a defined lighting field; 
           [0040]      FIG. 4  is a schematic view showing an arrangement comprising an operating area, a lighting unit, a display unit, an operating unit and a control unit as well as two cameras with two overlapping acquisition areas; 
           [0041]      FIG. 5  is a view showing the division of the image of the operating area into image segments and a first acquisition area and a second acquisition area of two cameras; 
           [0042]      FIG. 6  is a view showing the division of the operating area in connection with two defined lighting fields; 
           [0043]      FIG. 7  is a view showing the division of the image of the operating area into image segments together with the lighting zones of individual lighting elements; and 
           [0044]      FIG. 8  is a view showing a flow chart for initializing and activating a mode of operation for uniform lighting. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]    Referring to the drawings in particular,  FIG. 1  shows a first lighting unit  3  according to the present invention as it is used, for example, in operating rooms of hospitals, comprising a lighting fixture housing  1 , with a plurality of lighting elements  6 . The lighting fixture housing  1  is fastened via a suspension  9  to a ceiling, not shown, of the operating room. Also shown is a first camera  7  with a first acquisition area  10 . This first acquisition area  10  is designed such that it is suitable for covering the operating area  2  of a bed  30 . The first lighting unit  3  is connected via a first control line  22  to a first control unit  18 . 
         [0046]    The data acquired by the camera  7  as a field of image segments  26  are sent via a first signal and switching line  20  to an image processing unit  17 . The image processing unit  17  is connected to an operating unit  16  by means of a second control line  23  and to a display unit  19  by means of a third control line  24  as well as to the control unit  18  by means of a fourth control line  25 . 
         [0047]    The control line  18  is designed to individually control the luminosity of the individual lighting elements  6 . 
         [0048]      FIG. 2  shows an image of the operating area  2  with image segments  26  of a first acquisition area  10  of the first camera  7 , which said image segments are acquired by the first camera  7 . The image segments  26  are indexed in one orientation by means of variable i ranging from 1 to n, and in an orientation at right angles thereto by means of variable j ranging from 1 to m in a first data field  57  (see  FIG. 8 ). The image segments determined by the indices of the first data field  57  determine a horizontal and vertical resolution of a camera image, the product of the horizontal and vertical resolutions being usually expressed as resolution in pixels in the description of the technical features of a digitally recording camera. 
         [0049]      FIG. 3  shows an image of the operating area  2  with the image segments  26  and with a first acquisition area  10  of the first camera  7 . A first lighting field  13  is represented in the image of the operating area  2  with the corresponding subset of a first group of image segments  26 , which is described in position and size in the operating area  2  with a first set of coordinates  27  by means of the field indices i=60 to 200 and j=30 to 80. 
         [0050]    Besides the components from  FIG. 1 ,  FIG. 4  shows a second camera  8  with a second acquisition area  11 . The second camera  8  is connected to the image processing unit  17  by means of a second signal and switching line  21 . Components that are identical to those in  FIG. 1  are designated by the same reference numbers. 
         [0051]      FIG. 5  shows an image of the operating area  2  with the indexed image segments  26  and with a second acquisition area  11  of the second camera  8 , as well as with an alternative third acquisition area  12  of the first camera  7 . 
         [0052]      FIG. 6  shows an image of the operating area  2  with the image segments  26  and with a second acquisition area  11  of the second camera  8  as well as with an alternative third acquisition area  12  of the first camera  7 . A second lighting field  14  with the corresponding subset of a second group of image segments  26 , which lighting field is described in terms of its position and size in the operating area  2  with a second set of coordinates  28  by means of the field indices i=60 to 140 and j=30 to 80. A third lighting field  15  is described with a third set of coordinates  29  by means of the field indices i=200 to 250 and j=40 to 70. 
         [0053]      FIG. 7  shows an image of the operating area  2  according to  FIG. 2  with the image segments  26  and with an exemplary number of 10 lighting zones  31 ,  32 ,  33 ,  34 ,  35 ,  36 ,  37 ,  38 ,  39 ,  40  shown. The lighting zones arise from a number of 10 switched-on lighting elements  6  of the first lighting unit  3  in the lighting fixture housing  1 . 
         [0054]    The process of uniformly lighting a lighting field is shown in  FIG. 8  as a flow chart and begins after the start  50  in a first step  51  with the simultaneous switching on of all lighting elements  6  in a first lighting unit  3  by the control unit  18 , the lighting elements  6  of the first lighting unit  3  emitting the light into the lighting zones  31 ,  32 ,  33 ,  34 ,  35 ,  36 ,  37 ,  38 ,  39 ,  40 . An image of the operating area  2  is acquired by the first camera in a second step  52  and displayed on the display  19  as a first lighting view  53 . In a third step  54 , the user sets the first lighting field  13  of interest with a corresponding, defined brightness distribution in a first operation  55  by means of the operating unit  16 . All lighting elements  6  are at first switched off in a fourth step  56  and each one of the plurality of lighting elements  6  is switched on one after another in an initialization routine, and an image is acquired, recorded and stored in a first data field  57  by the first camera  7  for every single switch-on event  58  of an individual lighting element  6 . The first data field  57  is analyzed in a fifth step  59  by means of the image processing unit  17  to determine whether the first camera  7  was hidden during the image processing. If the first camera  7  was hidden, the process returns to the beginning of initialization in the first step  51  and the user is informed of the unsuccessful initialization via the display unit  19 . The first data field  57  is analyzed in a sixth step  61  by means of the image processing unit  17  and the actuation parameters for actuating the plurality of lighting elements  6  for achieving uniform lighting in the first lighting field  13  are determined and stored in a first parameter field  60 . The individual lighting elements  6  are switched by means of the control unit  18  in a seventh step  64  corresponding to the determined actuation parameters of the first parameter field  60 , and the switched lighting zones  31 ,  32 ,  33 ,  34 ,  35 ,  36 ,  37 ,  38 ,  39 ,  40  bring about uniform lighting in the first lighting field  13 . Furthermore, a control view  62  of the lighting is outputted on the display unit  19  in this seventh step  64 . Initialization is concluded and brought to the end  65  in an eighth step  67  with a second operation  63  as a confirmation of the shown control view  62  of the lighting by the user. 
         [0055]    The process for uniform lighting is then continued with the start  66 . The user is polled in a ninth step  69  to determine whether he would like to activate the first mode of operation  71  for uniformly lighting the first lighting field  13  or whether he would like to activate a second mode of operation  72  for lighting. If the user selects the first mode of operation for uniformly lighting  71  the first lighting field  13  in a third operation  68  by means of the operating unit  16 , the image data  74  currently being acquired by the first camera  7  are analyzed in a continuous sequence in the tenth step  70  and compared with the first data field  57 , and the actuation parameters of the first parameter field  60  are adjusted. The individual lighting elements  6  of the first lighting unit  3  are actuated in an eleventh step  75  corresponding to the determined actuation parameters of the first parameter field  60 . The process is returned after the eleventh step  75  to the ninth step  69  and remains in a repeating permanent loop, which can be brought to an end  73  by the user by jumping into the ninth step  69 . In the third operation  69 , the user has, alternatively to the first mode of operation  71 , the choice of switching off the first mode of operation  71  and to switch over into a second mode of operation  72  for lighting the first operating area  2 . The second mode of operation  72  may be a mode with maximum luminosity of all lighting elements  6  or a mode based on an average brightness distribution of all lighting elements  6  according to the first parameter field  60  or a mode in which the luminosities of all lighting elements are preset manually. 
         [0056]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
       List of Reference Numbers  
       [0000]    
       
           1  Lighting fixture housing 
           2  Operating area 
           3  First lighting unit 
           4  Second lighting unit 
           5  Third lighting unit 
           6  Lighting elements 
           7  First camera 
           8  Second camera 
           9  Suspension 
           10  First acquisition area 
           11  Second acquisition area 
           12  Third acquisition area 
           13  First lighting field 
           14  Second lighting field 
           15  Third lighting field 
           16  Operating unit 
           17  Image processing unit 
           18  Control unit 
           19  Display unit 
           20  First signal and switching line 
           21  Second signal and switching line 
           22  First control unit 
           23  Second control line 
           24  Third control line 
           25  Fourth control line 
           26  Image segments 
           27  First set of coordinates 
           28  Second set of coordinates 
           29  Third set of coordinates 
           30  Bed 
           31 - 40  Lighting zones 
           50  Start  1   
           51  First step 
           52  Second step 
           53  First lighting view 
           54  Third step 
           55  First operation 
           56  Fourth step 
           57  First data field 
           58  Switch-on event 
           59  Fifth step 
           60  First parameter field 
           61  Sixth step 
           62  Control view 
           63  Second operation 
           64  Seventh step 
           65  Stop  1   
           66  Start  2   
           67  Eighth step 
           68  Third operation 
           69  Ninth step 
           70  Tenth step 
           71  First mode of operation 
           72  Second mode of operation 
           73  Stop  2   
           74  Image data 
           75  Eleventh step