Self adjusting operation lamp system

[0001] This application claims priority of U.S. Provisional Application No. 60/688,669 filed on Jun. 8, 2005, which is incorporated herein by reference in its entirety.

[0002] The invention relates to operation lamps and, more particularly, to a combined operation lamp image detecting system and a method for operating such a system.

[0003] Operation lamps provide illumination of a medical workspace and, as will be appreciated, generally are oriented so as to minimize the formation of shadows in the medical workspace. EP 1 340 470 B1 discloses a conventional illumination system that includes an operation lamp attached to a moveable mount, and at least one camera arranged in a fixed, known and/or detectable positional relationship relative to the operation lamp.

[0004] In some situations, maintaining a shadow-free environment of the medical workspace may be difficult using conventional operation lamps, particularly if the surgeon comes between the lamps and the patient. In such cases, the operation lamp is manually adjusted and/or rearranged so as to achieve an optimal illumination of the medical workspace.

[0005] A combined operation lamp and image detecting system includes a moveable mount having movement devices that can be controlled on the basis of image signals detected by a camera. In other words, the image content captured by camera (i.e., the camera image) may be linked to the positioning of the operation lamp, such that the position of the lamp can be adjusted so as to achieve a shadow-free and/or optimal illumination of the medical workspace (also referred to as the operation field). If it can be inferred from the image content that the illumination is no longer optimal (e.g., if instruments that should be present in the operation field disappear from the camera image), the operation lamp's position can be automatically and autonomously readjusted until the instruments and, therefore the operation field, are again within the field of view of the camera (and thus illuminated by the operation lamp). This is possible because the camera and operation lamp are directed onto substantially the same field of view.

[0006] Data transfer devices can be provided for transferring data between the movement devices and the camera. The system also can include a control/regulating unit integrated into data transfer, in particular a medical navigation system, wherein the navigation system advantageously forms or includes the control/regulating unit for controlling/regulating the movement devices. In principle, however, a separate control/regulating unit also can be provided without a navigation system or in addition to the navigation system. The data transfer devices, for example, can be data transfer cables or wireless data transfer devices that include transmitters and receivers.

[0007] The camera can be arranged centrally in the operation lamp housing. Further, the camera can be provided with a housing that also serves as a shaft for a sterile holding grip of the operation lamp.

[0008] The system can include a light source for emitting light in a delimited spectral range, in particular an infrared light source. This light source can be controllable together with the camera or can directly control the camera. Preferably, the camera is operative to detect light in the aforesaid spectral range, and is provided with a filter that is permeable to light in said range.

[0009] The system also can include a number of cameras that may be used together, individually and/or alternately. It is also possible to assign the system an instrument or set of instruments that are clearly identifiable by the navigation system, in particular known to and/or stored in the navigation system on the basis of a characteristic reference array. Instruments also can be identified by way of contour recognition (external contour of instruments), for example. Advantageously, using such instruments that are “known to the system”, it is possible to track corresponding reference arrays using the camera and also to determine if the reference arrays have left the camera's field of view and, therefore, also has left the field of optimal illumination. If it is determined that the reference arrays are not within the field of view, then the light source can be automatically repositioned so as to change the illumination.

[0010] A method for operating a combined operation lamp image detecting system includes controlling/regulating the moveable mount by means of controllable movement devices on the basis of signals from the camera. The signals can be used to move the operation lamp image detecting system to a desired position. Here again, the possibility exists of providing a separate control/regulating unit or one integrated into a navigation system, and of incorporating the control/regulating unit into data transfer. In accordance with one embodiment, a light source for light in a delimited spectral range, in particular an infrared light source, also can be controllable and/or controlled together with the camera, wherein the camera can be designed for detecting light in this spectral range. Preferably, the camera is provided with a filter that is permeable to light in said range, and wherein the operation lamp is aligned with the aid of the light reflections.

[0011] The operation lamp image detecting system can comprise only a single camera or a number of cameras, wherein at least one camera, which can be used individually or in combination with the other cameras, captures image data that can be evaluated to establish whether the field of view of one of the cameras is restricted. If a camera's field of view is found to be restricted, another camera or a number of other cameras whose field of view is not restricted can be used. The light sources then can be controlled individually by or using the individual cameras, and can be arranged on individual mounts (e.g., holding arms). When a number of cameras are used, it is possible to compare and/or match image signals and to determine mismatches and, based on this information, take appropriate correction measures.

[0012] In accordance with another embodiment, the camera can be used to track instruments, wherein an instrument or set of instruments that are clearly identifiable by the navigation system (e.g., known to or stored in the navigation system on the basis of a characteristic reference array) is/are positionally detected. Another way of evaluating the image signal is to change the focus or illumination field of the operation lamp on the basis of the image signals captured by the camera.

[0013] The invention also includes a combined operation lamp image detecting system comprising an operation lamp attached to a mount, and a camera that is arranged in a fixed, known and/or detectable positional relationship relative to the operation lamp. The camera may be the only camera in the system and may be operable to detect positions in three-dimensional space. In this environment, all of the system features outlined above can be realized. The invention also includes a method for operating the combined operation lamp image detecting system.

[0016] FIG. 1 shows an operation lamp 2 attached to a ceiling attachment 8 via a moveable mount 1. The moveable mount 1 includes a number of arms that are jointed together, wherein the lamp 2 is jointed to the last arm. In the joints, movement devices are provided (e.g., actuators such as rotational servo-motors or the like) and are indicated by a single reference sign 4. With the aid of the rotational servo-motors or servos 4 in the joints, the lamp 2 can be moved on the arms to any desired position. The operation lamp 2 can have movement devices in one or more axes and/or may be adjusted only at the last gimbal-mounted member.

[0017] It should be noted that the movement devices do not necessarily have to be rotational servo-motors. Any known movement devices can be used, including elongation devices such as, for example, telescoping systems.

[0018] The lamp 2 comprises illumination means 13 for illuminating the operation field. The illumination means 13 centrally supports a camera 3 that is operable to detect optical image signals, and infrared LEDs 10 are arranged on the camera 3. The lamp Illumination also can be used as the navigation light. FIG. 1 also schematically shows a surgical instrument 11 in front of the camera, said instrument 11 supporting a reference array 12 comprising three infrared light reflectors. Alternatively, active elements (e.g., LEDs), which may be referred to as active emitter reference arrays, can be used in place of or in conjunction with the reflectors.

[0019] FIG. 1 shows two possible systems for transferring data between a control/regulating unit 5 and the other system parts (rotational servos 4, camera 3). These two data transfer systems need not co-exist; they can be used individually and independently of each other. The control/regulating unit 5 is essentially an integrated circuit or a computer for signal processing, and may be a medical navigation system and/or a medical tracking system, as is for example described in DE 19 639 615 A1, the contents of which is hereby incorporated by reference in its entirety. The unit 5 also can be a data processing part of said navigation system.

[0020] One form of data transfer as shown is based on a cable connection 9 which electrically and/or optically connects the unit 5 to the servo-motors 4, the camera 3 and the LED array 10. The second form of data transfer relates to cable-free or wireless data transfer, wherein a transmitter/receiver 6 is arranged on the control/regulating unit 5. This transmitter/receiver 6 communicates with other transmitters/receivers 7A, 7B, 7C (on the servo-motors 4) and 7D (for the camera 3 and the infrared LEDs 10).

[0021] The transmitters/receivers 6 and 7 (7A to 7D) serve to transfer data between the unit 5 and the other systems. In particular, movement commands may be output from the unit 5 to the servos 4, and on/off commands may be output to the camera 3 and the LED array 10. Additionally, the servos 4 can convey positional feedback to the unit 5, and the camera 3 can transfer images to the unit 5 for processing.

[0022] When in use, the system can be used, for example, for the shadow-free illumination of an area (operation field). The camera can provide two-dimensional or three-dimensional images that in combination with the unit 5, for example, may be used to control and/or regulate the position of the lamp 2 and/or to track the surgical instrument 11. This utilizes the fact that a particular instrument 11 having a clearly identifiable reference array 12 or contour (which is known to the navigation system 5) is situated in the operation field during the operation. If light is intermittently or continually emitted by the infrared LEDs 10, this light is then reflected by the marker array 12, and the camera 3 can detect this reflection. On the basis of this detected data, it is then possible to determine whether the operation lamp 2 is situated at the optimal location and/or is optimally adjusted, since the corresponding image data are transferred to the control/regulating unit 5 (navigation system) where they are evaluated. If it is determined that the lamp 2 is no longer in an optimal position, the unit 5 can issue readjustment commands to the servo-motors 4 which then move the lamp 2 such that the instrument is once again in an optimal position. As a result, the lamp 2 is optimally illuminating the operation field without shadows.

[0023] In a simple regulation scheme, for example, it may be determined that the marker array 12 is or has been removed from the camera's field of view (e.g., repeatedly and/or in a particular direction over a predetermined period of time) or the marker array is always concealed in one direction. This direction could be determined by evaluating the camera image within the unit 5 and, based on the evaluation, calculating a desired counter movement of the lamp 2. The lamp 2 then can be repositioned by controlling the servo-motors 4. As a result of the movement, the camera again has an optimal line of sight, which also means that the operation field is optimally illuminated.

[0024] The camera can simultaneously be used to identify and/or track instruments (i.e., positionally locate and track), such as the schematically shown instrument 11, on the basis of the marker array 12. This is possible with a single camera if the instruments are clearly identifiable and their shape and/or characteristic marker arrays are stored in a memory of the navigation system 5. A number of cameras can also be used, which in addition to the tracking and lamp positioning functions can also fulfil redundant functions, in order to eliminate obstructions to the view or differences in the image content.

[0025] Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.