Medical observation apparatus with a movable beam deflector and method for operating the same

Abstract

Medical observation apparatus (1) and method for observing an object or patient (67) in an operation area (21). Solutions of the art (3, 5) do not allow displaying further information, are expensive, bulky and non-intuitive. The inventive apparatus (1) overcomes these problems by comprising: an image acquisition assembly (41) with a camera subassembly (43) comprising at least one viewing camera (9) with a field of view (85) and an optical camera axis (75) for acquiring interoperative image data (83); a deflector subassembly (47) for deflecting the optical camera axis (75) into an optical viewing axis (77) directed towards the operation area (21), the deflector subassembly (47) comprising at least one optical beam deflector (71) and being arranged between the viewing camera (9) and the operation area (21), wherein the viewing camera (9) and the at least one optical beam deflector (71) are movable with respect to one another; and an image display assembly (37) comprising at least one monitor arrangement (35) for displaying the interoperative image data (83), the monitor arrangement (35) being visible at least from a user's observation position (29).

Claims

1. A medical observation apparatus (1) for observing an object in an operation area (21) from a user's observation position (29) during surgery, comprising: an image acquisition assembly (41) including a camera subassembly (43) comprising at least one viewing camera (9) for acquiring interoperative image data (83), the viewing camera (9) having a field of view (85) and an optical camera axis (81); and a deflector subassembly (47) for deflecting the optical camera axis (81) into an optical viewing axis (77) directed towards the operation area (21), the deflector subassembly (47) comprising at least one optical beam deflector (71) and being arranged between the viewing camera (9) and the operation area (21), wherein the viewing camera (9) and the at least one optical beam deflector (71) are movable with respect to one another; and an image display assembly (37) including at least one monitor arrangement (35) for displaying the interoperative image data (83), the monitor arrangement (35) being visible at least from the user's observation position (29); wherein the image display assembly (37) further includes at least one observation beam deflector (31) located between the user's observation position (29) and the monitor arrangement (35), wherein the observation beam deflector (31) is for redirecting an optical observation axis (17) from the user's observation position (29) towards the monitor arrangement (35), wherein the deflector subassembly (47) comprises a rotational support assembly (125) for supporting at least one of the viewing camera (9) and the at least one optical beam deflector (71) of the deflector subassembly (47), the rotational support assembly (125) being rotatable around a rotational axis (111), wherein the deflector subassembly (47) comprises a movable range-setting support assembly (127) for supporting at least one of the viewing camera (9) and the at least one optical beam deflector (71) of the deflector subassembly (47) and for positioning the at least one optical beam deflector (71) at a variable distance (143) from the viewing camera (9), wherein the rotational axis (111) coincides with the optical camera axis (81) of the viewing camera (9), and wherein the range-setting support assembly (127) is a radial range-setting support assembly (137) which is rotatable around a support system axis (139), wherein a rotation (147) of the radial range-setting support system is synchronized with a rotation of the rotational support assembly (125).

2. The medical observation apparatus (1) according to claim 1, wherein the observation beam deflector (31) and the monitor arrangement (35) are movable with respect to one another.

3. The medical observation apparatus (1) according to claim 1, wherein the deflector subassembly (47) comprises a pair of optical beam deflectors (71) between the viewing camera (9) and the operation area (21), wherein at least one of the optical beam deflectors (71) of the pair is movable with respect to the other optical beam deflector (71) of the pair with regard to at least one of tilt (145) and distance (147).

4. The medical observation apparatus (1) according to claim 1, wherein the viewing camera (9) is rotatable around the optical camera axis (81).

5. The medical observation apparatus (1) according to claim 4, wherein the range-setting support assembly (127) is supported by the rotational support assembly (125).

6. The medical observation apparatus (1) according to claim 1, wherein the camera deflector subassembly (47) comprises at least one operational mode (Mm) in which the optical viewing axis (77) coincides with the optical observation axis (17).

7. The medical observation apparatus (1) according to claim 1, further comprising an eye-tracker arrangement (91), the eye-tracker arrangement (91) comprising an eye-tracker camera (93) having a field of view (85) directed to the user's observation position (29) and for providing eye-tracking data (101) representative of the direction of the optical observation axis (17), and a motion controller (97) for controlling the position of at least one of the viewing camera (9), the at least one optical beam deflector (71) of the image acquisition assembly (41), the monitor arrangement (35) and the at least one observation beam deflector (31) of the image display assembly (37) depending on the eye-tracking data (101).

8. The medical observation apparatus (1) according to claim 7, wherein the image display assembly (37) comprises a further beam deflector device (95) which is located between the eye-tracking camera (93) and the observation beam deflector (31) for deflecting an optical axis (99) of the eye-tracking camera (93) towards the observation beam deflector (31).

9. The medical observation apparatus (1) according to claim 1, wherein the viewing camera (9) and the at least one optical beam deflector (71) are positioned with respect to each other based on 3D camera data (130) provided by a 3D camera system (128).

Description

BRIEF DESCRIPTION OF THE DRAWING VIEWS

(1) The figures show:

(2) FIGS. 1A and 1B: prior art solutions of medical observation apparatuses and the first embodiment of the inventive medical observation apparatus;

(3) FIGS. 2A and 2B: a magnified view of the working principle of the prior art solution applying a robot arm-based system compared with the inventive image acquisition assembly of the inventive medical observation apparatus;

(4) FIGS. 2C and 2D: further possible setups for the inventive image acquisition assembly;

(5) FIG. 3: a second embodiment of the inventive medical observation apparatus;

(6) FIG. 4: another embodiment of the inventive medical observation apparatus and a particular operation mode of the same;

(7) FIGS. 5A and 5B: schematic working principle of different operation modes of the inventive medical observation apparatus;

(8) FIGS. 6A and 6B: different embodiments of an inventive rotational support assembly and the range-setting support assembly.

DETAILED DESCRIPTION OF THE INVENTION

(9) FIG. 1A shows medical observation apparatuses 1 of the art. These may be embodied as a surgical microscope 3, which may be equipped with an eyepiece 7.

(10) Another embodiment of the medical observation apparatus 1 of the art is a robotic arm-based system 5 which comprises a viewing camera 9 which is positioned by means of a robotic arm 11. The robotic arm 11 shown in FIG. 1A is merely exemplary, i.e. a robot arm having a different number of axes may be applied.

(11) A surgeon 13 (or observer, or user) either looks through the eyepiece 7 or onto a display 15. Each of the prior art solutions comprises an optical observation axis 17 which is defined by the surgeon 13. Each system furthermore comprises an optical viewing axis 19 which is directed towards an operation area 21. It is to be noted that each axis 17, 19 is centered within a bundle of rays 23.

(12) FIG. 1A shows that, in the case of the surgical microscope 3, the disadvantage arises that the virtual image 25 as seen by the surgeon 13 only shows the operation area 21, and the optical observation axis 17 is oriented at an observation deviation angle 27 to the optical viewing axis 19. In case of the robotic arm-based system 5 the observation deviation angle 27 may be much larger than in the case of a surgical microscope 3. This may be one reason why operating such a robotic arm-based system 5 is considered less intuitive and requires special training. Furthermore, the robotic arm 11 requires a large space in the operation room to accommodate it, as well as the infrastructure necessary for its operation.

(13) FIG. 1B shows a medical observation apparatus 1 according to the invention. The surgeon 13 is located at the user's observation position 29, which is, in particular, determined by the position of his or her eyes 29a. The surgeon 13 looks at an observation beam deflector device 31 which is embodied as a mirror 33 in the embodiment shown.

(14) The observation beam deflector 31 redirects the optical observation axis 17 from the user's observation position 29 towards a monitor arrangement 35. The monitor arrangement 35 may be embodied as a display 15 and dependent on the orientation of the observation beam deflector 31. The monitor arrangement 35 is located at a different position than the virtual image 25 as seen by the surgeon 13.

(15) The at least one observation beam deflector 31 (different embodiments may comprise more than one observation beam deflector 31), the optical observation axis 17 as well as the monitor arrangement 35 and possible further optical elements (not shown) form an image display assembly 37 acting as the interface 39 to the medical observation apparatus 1 for the surgeon 13, user or observer.

(16) The inventive medical observation apparatus 1 further comprises an image acquisition assembly 41 with a camera subassembly 43, which in an easy embodimentas shown in FIG. 1Bmerely comprises the viewing camera 9, and with a deflector subassembly 47 which will be described in more detail with reference to FIG. 2B.

(17) FIG. 2A shows a magnified view of the working principle of the prior art solution applying a robot-based system 5 compared to the inventive image acquisition assembly 41 of the inventive medical observation apparatus 1 (FIG. 2B).

(18) In the prior art solution, the viewing camera 9 is attached to the robotic arm 11 and may be freely translated and rotated in the three-dimensional space. It is therefore possible to move the viewing camera 9 on trajectories 49 which may be located on a sphere 51.

(19) Furthermore, the viewing camera 9 may be tilted, which is indicated by tilt trajectories 50, which are marked using dashed lines. The tilt trajectories 50 therefore indicate a possible tilt 145. A tilt 145 of the viewing camera 9 allows the user 13 to change at least one, preferably two incident angles 61, 63 at which the optical viewing axis 19 is oriented to an operation plane 65. The incident angles 61, 63 are indicated separately. It is be noted that the operation plane 65 is fixed in space with respect to a patient 67 and preferably comprises the center 53 of the sphere 51, i.e. the viewing camera 9 and its optical system (not shown) is adjusted, i.e. focused to the operation plane 65. The schematic drawing shows a first projection 69a and a second projection 69b of the exemplary optical viewing axis 19, wherein a first incident angle 61 and a second incident angle 63 are obtained. The prior art system allows almost any arbitrary combination of incident angles 61, 63.

(20) The center 53 of said sphere 51 is located in the operation area 21, wherein the operation area 21 is a deep surgical cavity 55 which is kept open by a tube 57. The tube 57 comprises 3D markers 59, via which the viewing camera 9 may be positioned with respect to the operation area 21.

(21) It can be seen that, in the prior art shown in FIG. 2A, the whole viewing camera 9 is moved by the robotic arm 11, wherein a weight limit may apply which may render impossible the application of certain heavy cameras 9, sensitive cameras 9 as well as cameras requiring delicate infrastructure e.g. for cooling and the like.

(22) FIG. 2B shows the inventive image acquisition assembly 41 comprising the viewing camera 9 and the deflector subassembly 47 previously mentioned. The deflector subassembly 47 comprises two optical beam deflectors 71, which, along an optical path 73 from the viewing camera 9 to the patient 67, may be referred to as a first optical beam deflector 71a and a second optical beam deflector 71b.

(23) The first optical beam deflector 71a and/or the second optical beam deflector 71b may be embodied as a mirror 33, wherein said mirrors 33 are arranged anti-parallel to each other. The viewing camera 9 comprises an optical camera axis 75 which indicates the direction towards which the viewing camera 9 is directed.

(24) The first optical beam deflector 71a is oriented towards the optical camera axis 75 at an angle of approximately 45, such that a deflected axis 75a is oriented essentially perpendicular to the optical camera axis 75.

(25) In the embodiment shown in FIG. 2B, the second optical beam deflector 71b is movable along a trajectory 49, which is, however, linear in the embodiment shown. Additionally, the second optical beam deflector 71b is tiltable, as indicated by the tilt trajectories 50 which are plotted with a dashed line.

(26) The optical path 73 between the second optical beam deflector 71b and the patient 67 is referred to as the optical viewing axis 77, which is a directed towards the operation area 21.

(27) Contrary to the prior art solutions, the viewing camera 9 remains at a fixed position, wherein the movement (translation and/or tilt) of the second optical beam deflector 71b is applied to linearly translate and/or angularly direct the optical viewing axis 77.

(28) In another embodiment of the inventive image acquisition assembly 41 of the medical observation apparatus 1, also the first optical beam deflector 71a may be movable and/or tiltable.

(29) The position at which the optical path 73 hits the second optical beam deflector 71b may be referred to as origin 79. In this regard, the term origin is to be understood as one predetermined point through which the optical viewing axis 77 passes. It is not to be understood as the point from which electromagnetic radiation (light reflected, scattered or emitted from the patient 67) is generated and starts its propagation.

(30) In the embodiment of FIG. 2B, the second optical beam deflector 71b is only movable along one trajectory 49. In different embodiments, a movement along a trajectory 49 perpendicular to the one shown in the figure may be possible. Such an embodiment, however, requires a readjustment of the angle of the first optical beam deflector 71a in order to maintain the optical path 73 on the second optical beam deflector 71b. Furthermore, different embodiments may comprise a tiltable first optical beam deflector 71a.

(31) Additionally, the viewing camera 9 may be rotatable around an optical camera axis 81.

(32) In the configuration shown in FIG. 2B, the viewing camera 9 acquires interoperative image data 83 from the camera's field of view 85, which is shown in the figure as a distance but which may be represented by a two-dimensional plane extending into the drawing plane.

(33) For the sake of clarity, a rectangle 87 indicates a view onto the patient 67 along the optical viewing axis 77. The rectangle 87 shows the tube 57 as well as the two 3D markers 59, in between which the field of view 85 of the viewing camera 9 is located. The field of view is indicated by shading and does not encompass the upper portion 57a of the tube 57. The latter may, however, be the case in different embodiments. The interoperative image data 83 corresponds to a representation of a light distribution in the operation area 21 covered by the field of view 85.

(34) When a surgeon is positioned as indicated in FIG. 1B, the portion shown in the rectangle 87 is to be rotated by 90 in the clockwise direction. By rotating the viewing camera 9 around the optical camera axis 81, the field of view 85 and thus also the interoperative image data 83 may also be rotated. This allows for intuitive observation from a position other than that shown in FIG. 1B.

(35) In FIGS. 2C and 2D, different configurations of the inventive image acquisition assembly 41 are shown. In particular the position of the viewing camera 9 may determine an initial orientation of the first optical beam deflector 71a and the second optical beam deflector 71b. Additionally, a third optical beam deflector (not shown) may also be incorporated in order to allow the application of a viewing camera 9 which is located at a position different to that shown and which may not be relocated because of its weight and/or its mechanical stability requirements.

(36) In FIG. 3, a further embodiment of the inventive medical observation apparatus 1 is shown. The image display assembly 37 corresponds to the one shown in FIG. 1B, wherein an additional gimbal mount 89 is shown which forms part of the observation beam deflector 31. The gimbal mount 89 allows for variation of the redirecting of the user's optical observation axis 17 towards the monitor arrangement 35.

(37) The image display assembly 37 additionally comprises an eye-tracker arrangement 91, which comprises an eye-tracker camera 93, a further beam deflector device 95 which is located between the eye-tracking camera 93 and the observation beam deflector 31, and a motion controller 97.

(38) The eye-tracking camera 93 also has a field of view 85 which is directed to the user's, i.e. the surgeon's 13 observation position 29, in particular the eyes 29a of the surgeon 13. The eye-tracker camera 93 also has an optical camera axis which will be referred to as the 3D tracker axis 99. The 3D tracker axis 99 is deflected by the further beam deflector device 95 and the observation beam deflector 31 such that the eyes 29a of the surgeon 13 are detected, wherein a changed viewing direction of the surgeon 13 is detectable by the eye-tracker arrangement 91.

(39) Thus, the eye-tracker camera 93 provides eye-tracking data 101 which is indicated in the drawing by a single rectangular impulse 103 and which is representative of the direction of the optical observation axis 17. The eye-tracking data 101 may be provided to the motion controller 97.

(40) The motion controller 97 may comprise a data line 105 for providing the eye-tracking data 101 to a deflection controller 107. The motion controller 97 thus controls the position of at least one of the viewing camera 9, the at least one optical beam deflector 71 of the image acquisition assembly 41, the monitor arrangement 35 and the at least one observation beam deflector 31 of the image display assembly 37.

(41) For the sake of clarity, control data lines, drive systems as motors, power supply lines and the like, which are applied to control said above listed elements, are not shown in the figure.

(42) In the embodiment of the medical observation apparatus 1 shown in FIG. 3, also the first optical beam deflector 71a is tiltable, wherein a tilt axis 109 intersects with the optical camera axis 75. The tilt axis 109 is preferably positioned in the reflective surface of the first optical beam deflector 71a.

(43) Additionally, the first optical beam deflector 71a and the second optical beam deflector 71b may be collectively rotated around a rotational axis 111 which coincides with the optical camera axis 75. This collective rotation is indicated by a rotational support trajectory 50b. A rotation 147 occurs around the rotational axis 111.

(44) By means of this collective rotation, the optical viewing axis 77, which is directed towards the operation area 21, in particular the deep surgical cavity 55, may be rotated such that a cone or a truncated cone of possible orientations of the optical viewing axis 77 is obtained. A second possible position 113 resulting from this rotation is indicated in the figure for the second optical beam deflector 71b and the optical viewing axis 77.

(45) The figure also shows a virtual location 115 of the monitor arrangement 35. This virtual location 115 overlaps with the operation area 21 and thus allows for intuitive handling by the surgeon 13. The virtual location 115 indicates the position at which the surgeon 13 apparently perceives the monitor arrangement 35.

(46) FIG. 4 shows one particular operation mode M of the inventive medical observation apparatus 1, namely a merged operation mode M.sub.m, which will be described in the following.

(47) It is to be noted that FIG. 4 shows an embodiment of the medical observation apparatus 1 which differs from the previously shown embodiments in that the viewing camera 9 directly views the operation area 21. However, the merged operation mode M.sub.m may also be set by any of the previously shown embodiments of the medical observation apparatus 1, as is indicated by a viewing camera 9 and two optical beam deflectors 71 of the deflector subassembly 47.

(48) The merged operation mode M.sub.m is particularly advantageous as in this operation mode M, the optical viewing axis 77 of the image acquisition assembly 41 (or 41 if the optical beam deflectors 71 and viewing camera 9 are applied) coincides with the optical observation axis 17 of the user, e.g. the surgeon 13. Consequently, the virtual location 115 of the display 15 of the monitor arrangement 35 may coincide with the position of the virtual image 25 as seen by the surgeon 13. In other words, the surgeon 13 is provided with interoperative image data 83 shown on the display 15 which may exactly match the surgeon's 13 view if no observation beam deflector 31 or image acquisition assembly 41, 41 would be present, at least in terms of an observation angle at which the operation area 21 is observed.

(49) Although surgeons 13 are trained to transpose the movements of surgical instruments, e.g. scalpels etc., during an operation, particularly if an endoscope is applied, said merged operation mode M.sub.m mimics the most intuitive way of performing surgery (in which the surgeon 13 apparently directly views the operation area 21).

(50) In another embodiment of the inventive medical observation apparatus 1, a monitor arrangement 35 is provided which is tiltable around a monitor rotation axis 117 and/or movable along a trajectory 49. In FIGS. 5A and 5B, such a schematic working principle of the inventive medical observation apparatus 1 is shown.

(51) As can be seen in FIG. 5A, the viewing camera 9 has an optical viewing axis 77 which is oriented perpendicular to the operation area 21. The interoperative image data 83 recorded by the viewing camera 9 is shown on the display 15. As the display 15 is oriented at a tilt angle 119 different than 90, the virtual image 25 as seen by the surgeon 13 lies in the plane of the operation area 21. The surgeon 13 therefore perceives an image projection 121, which is indicated in the figure by a dashed line. Such a projection 121 slightly distorts the distances and angles of the operation area.

(52) By rotating the display 15 in a counterclockwise direction as shown in FIG. 5B, the virtual image 25 as seen by the surgeon 13 is tilted with respect to the operation area 21, such that no distortion occurs due to the projection 121 (not shown in FIG. 5B as no projection is present). Distances and angles are correctly displayed and seen by the surgeon 13. However, the surgeon 13 may overestimate or underestimate the actual position of the patient 67 if viewing the outlying areas 123 of the virtual image 25.

(53) FIGS. 6A and 6B show different embodiments of an inventive rotational support assembly 125 and a range-setting support assembly 127. The viewing direction of the lower panel of both figures is from the operation area 21 along the optical viewing axis 77 towards the at least one optical beam deflector 71. The upper panel of both figures shows a side view of the inventive rotational support assemblies 125.

(54) The rotational support assemblies 125 furthermore comprise a 3D camera system 128 which comprises 3D cameras 129. The 3D cameras 129 are already shown in FIG. 3. The 3D camera system 128 provides 3D camera data 130 which is merely indicated but not further described. The 3D camera system 128 may furthermore comprise a 3D controller (not shown) which calculates a 3D position of elements located in the operation area 21 and provides 3D camera data 130 for controlling and/or repositioning the viewing camera 9 and/or the at least one optical beam deflector 71.

(55) In the embodiment of the rotational support assembly 125 shown in FIG. 6A, the first optical beam deflector 71a and the second optical beam deflector 71b are attached via posts 131 to a rotation base 133 may perform a rotation 147 around the rotational axis 111. As explained above, it is advantageous if the rotational axis 111 corresponds to the optical camera axis 75. A rotation 147 of the rotational support assembly 125 therefore does not change the relative position between the first optical beam deflector 71a and the second optical beam deflector 71b. The viewing camera 9 may also be rotated together with both optical beam deflectors 71.

(56) This embodiment furthermore comprises the range-setting support assembly 127 which comprises a guiding slot 135 along which the post 131 supporting the second optical beam deflector 71b may be moved following the linear trajectory 49.

(57) FIG. 6B shows a further embodiment of the inventive rotational support assembly 125, wherein the range-setting support assembly 127 is embodied as a radial range-setting support system 137. In this embodiment, the first optical beam deflector 71a is supported by the rotation base 133 and rotatable around the rotational axis 111. Also in this embodiment, the viewing camera 9 may be rotatable around the same axis 111. The radial range-setting support system 137 of this embodiment does not perform a linear movement but a rotation 147 around a support system axis 139 which is essentially parallelly offset from the rotational axis 111.

(58) The second optical beam deflector 71b is supported by a post 131 and attached to a support system base 141 of the radial range-setting support system 137.

(59) The rotational support assembly 125 and the radial range-setting support system 137 may be rotated either independently of each other or in a synchronized manner.

(60) In particular, a combination of the rotation 147 of the rotational support assembly 125 and the (off-center) rotation 147 of the radial range-setting support system 137 may change a distance 143 between the first optical beam deflector 71a and the second optical beam deflector 71b.

(61) In order to maintain the optical path 73 on the first optical beam deflector 71a and on the second optical beam deflector 71b, the optical beam deflectors 71 may also be rotatable.

REFERENCE NUMERALS

(62) 1 medical observation apparatus

(63) 3 surgical microscope

(64) 5 robotic arm-based system

(65) 7 eyepiece

(66) 9, 9 viewing camera

(67) 11 robotic arm

(68) 13 surgeon

(69) 15 display

(70) 17 optical observation axis

(71) 19 optical viewing axis

(72) 21 operation area

(73) 23 bundle of rays

(74) 25 virtual image

(75) 27 observation deviation angle

(76) 29 user's observation position

(77) 29a eye

(78) 31 observation beam deflector

(79) 33 mirror

(80) 35 monitor arrangement

(81) 37 image display assembly

(82) 39 interface

(83) 41 image acquisition assembly

(84) 43 camera subassembly

(85) 47, 47 deflector subassembly

(86) 49 trajectory

(87) 50 tilt trajectory

(88) 50a further tilt trajectory

(89) 50b rotational support trajectory

(90) 51 sphere

(91) 53 center

(92) 55 deep surgical cavity

(93) 57 tube

(94) 57a upper portion

(95) 59 3D marker

(96) 61 incident angle

(97) 63 incident angle

(98) 65 operation plane

(99) 67 patient

(100) 69a first projection

(101) 69b second projection

(102) 71, 71 optical beam deflector

(103) 71a first optical beam deflector

(104) 71b second optical beam deflector

(105) 73 optical path

(106) 75 optical camera axis

(107) 75a deflected axis

(108) 77 optical viewing axis

(109) 79 origin

(110) 81 optical camera axis

(111) 83 interoperative image data

(112) 85 field of view

(113) 87 rectangle

(114) 89 gimbal mount

(115) 91 eye-tracker arrangement

(116) 93 eye-tracker camera

(117) 95 further beam deflector device

(118) 97 motion controller

(119) 99 3D tracker axis

(120) 101 eye-tracking data

(121) 103 rectangular impulse

(122) 105 data line

(123) 107 deflection controller

(124) 109 tilt axis

(125) 111 rotational axis

(126) 113 second position

(127) 115 virtual location

(128) 117 monitor rotation axis

(129) 119 tilt angle

(130) 121 image projection

(131) 123 outlying area

(132) 125 rotational support assembly

(133) 127 range-setting support assembly

(134) 128 3D camera system

(135) 129 3D camera

(136) 130 3D camera data

(137) 131 post

(138) 133 rotational base

(139) 135 guiding slot

(140) 137 radial range-setting support system

(141) 139 support system axis

(142) 141 support system base

(143) 143 distance

(144) 145 tilt

(145) 147 rotation

(146) Mm merged operation mode

(147) M operation mode