Method and device for controlling an operating light

Abstract

Method for controlling an operating light (10) illuminating an operating field, comprising the following steps in the order mentioned: a) location-selective determination of the luminance distribution in a measuring field (13) which is larger than a maximum luminous field size (14) of the operating light (10), b) adjusting the size of the light field of the operating light (10) to the size of the operating field (15) taking into account the luminance distribution, and c) Adjusting a light intensity of the operating light taking into account the luminance of the surroundings of the operating field located within the measuring field (13), characterized in that in step c) a characteristic field is used to adjust the light intensity, in which light intensities are stored as a function of the size of the operating field (15) and the brightness of the surroundings of the operating field.

Description

[0001] The present invention relates to a method and a device for controlling an operating light illuminating an operating field.

[0002] When illuminating a surgical field, setting the correct brightness is of great importance. For this purpose, it is known from the prior art to measure the distance between the surgical light and the surgical field and to keep the illuminance constant depending on the distance. It is also known to perform a luminance measurement and adjust the brightness of the surgical light accordingly. Keeping the illuminated field size constant by focusing depending on a measured distance is also known from the prior art. DE 10 2009 037 316 A1 describes a method for operating a surgical light, wherein an image and a control signal are generated which controls at least the direction, the intensity, the spectral properties of the light or the size or shape of the illuminated area.EP 2 215 987 A1 discloses an operating light which is movable by means of a pivoting arm and whose position can be detected by a position detection device.

[0003] When using conventional surgical lights, an incorrectly adjusted light field size can result in excessive illumination of the area surrounding the actual surgical field, which is covered by drapes or other coverings. This creates a bright environment to which the surgeon adapts, causing the actual surgical field to appear even darker. Furthermore, excessive luminance differences in the surgeon's field of vision can lead to negative physiological and psychological effects, which can impair visual comfort and visual performance.

[0004] It is the object of the present invention to provide a method and a device for controlling an operating light illuminating an operating field, with which an optimized adjustment of the light intensity can be carried out regardless of the distance of the operating light from the operating field.

[0005] This problem is solved by the features of the independent patent claims.

[0006] The present invention is defined by the appended claims. The following technical disclosure may extend beyond the scope of the claims in certain respects. Elements of the disclosure that do not fall within the scope of the claims are provided for information.

[0007] The method according to the invention comprises the following steps in the order stated: First, a location-selective determination of the luminance distribution is carried out in a measurement field that is larger than a maximum light field size of the operating light. The maximum light field size of the operating light can be changed, for example, by focusing or by controlling individual lamps within the operating light, i.e., the maximum light field size of the operating light is known. Accordingly, a measurement field that is larger than the maximum light field size can be selected, and within this measurement field, the luminance distribution can be determined location-selectively, i.e., with spatial resolution.

[0008] The determined luminance distribution allows the actual size of the surgical field to be deduced, so that in a second step, the size of the surgical light's illuminated field can be adjusted to the size of the surgical field determined in the first step, taking the luminance distribution into account. Thus, in the second step, the illuminated field size can be enlarged or reduced so that the generated illuminated field is adapted to the size of the surgical field, i.e., essentially corresponds to the size of the surgical field.

[0009] In a third step, the light intensity of the operating light is then adjusted, taking into account the luminance of the area surrounding the operating field within the measurement field. The light intensity of the operating light can be adjusted to optimize the luminance ratio between the operating field and the area surrounding the operating field. For example, if the area surrounding the operating field is very poorly reflective, the light intensity of the operating light can be set higher. If the area surrounding the operating field is highly reflective, the light intensity can be set lower to avoid glare. The light intensity of the operating light is therefore adjusted, taking into account the luminance of the area surrounding the operating field within the measurement field.The invention is characterized in that a characteristic field is used to adjust the light intensity, in which light intensities are stored as a function of the size of the operating field (15) and the brightness of the surroundings of the operating field.

[0010] Advantageous embodiments of the invention are described in the description, the drawings and the subclaims.

[0011] According to a first advantageous embodiment, a luminance object corresponding to the surgical field can be determined from the determined luminance distribution. By measuring the luminance selectively and using known methods, such as the gradient method, a luminance object can be defined whose outer contour corresponds to the outer contour of the surgical field. The luminance object thus determined can then be used to adjust the size of the surgical light's luminous field.

[0012] Setting a desired light intensity adapted to the surroundings of the surgical field can be achieved in various ways. In each case, the light intensity is adjusted so that it is optimized for the surgeon depending on the brightness of the surroundings of the surgical field. According to the present invention, a characteristic field is used to set the adjusted light intensity. In this field, light intensities are stored depending on the size of the surgical field and the brightness of the surroundings of the surgical field. Since the brightness in the surroundings of the surgical field and also the size of the light field are known, an optimized brightness value, which has been determined empirically, for example, can be read from the characteristic field.

[0013] In addition, to adjust the light intensity, a ratio between the luminance in the surgical field and the luminance in the area surrounding the surgical field can be specified. This specified ratio can vary, in particular, with the size of the light field. For example, it can be specified that the luminance within the surgical field is always a certain percentage higher than the luminance in the area surrounding the surgical field. It can also be specified, for example, that the luminance is lower for a smaller surgical field and higher for a larger surgical field, or that the luminance is higher for a smaller surgical field and lower for a larger surgical field.

[0014] According to a further advantageous embodiment, a luminous field size that describes the luminous object can be calculated from a determined luminance object. In other words, the geometric center of the luminance object and its outer contour can be determined, and from these data, a luminous field size can be achieved that completely describes the previously determined luminance object, i.e., the surgical site.

[0015] According to a further advantageous embodiment, the location-selective determination of the luminance distribution can be carried out as a point-based luminance measurement using several individual sensors. Alternatively, the luminance distribution can be determined using a calibrated camera, such as a grayscale camera, which is possible in a cost-effective manner. Finally, the use of a luminance camera is also possible.

[0016] According to a further advantageous embodiment, at least one reflective mark can be used to better identify the edge of the surgical field. Such a reflective mark can, for example, be inserted only temporarily and manually before the actual operation. According to a further advantageous embodiment, a surgical field cover can be used whose edge is provided with a reflective mark that reflects in the non-visible range (for example, in the infrared range or the near UV range) or in the visible range. Such a surgical field cover, as is commonly used, has an opening with a circumferential edge, so that the circumferential edge can be provided with one continuous or several individual reflective marks, which facilitates the automated detection of the size or contour of the surgical field.

[0017] The size of the illuminated field can generally be adjusted to the size of the surgical field so that the size of the illuminated field is equal to the extent of the surgical field. However, according to another embodiment, the size of the illuminated field can also be set slightly larger than the size of the surgical field, so that the illuminated field always covers the outer contour of the surgical field.

[0018] According to a further aspect of the present invention, this relates to a device for carrying out a method of the type described above, wherein the device comprises a sensor system for the location-selective determination of the luminance distribution in a measuring field. Furthermore, a device for adjusting the light field size of a surgical light is provided and a device for adjusting the light intensity of the surgical light is designed such that the light intensity can be adapted to the environment of a surgical field within the measuring field. Preferably, this device is integrated into a handle for a surgical light so that existing surgical lights can be retrofitted with the device. Alternatively, the device can be integrated into a light body of the surgical light or into the handle and light body.

[0019] The present invention will now be described purely by way of example using an advantageous embodiment and with reference to the accompanying drawings. Fig. 1 a perspective view of an operating field illuminated by an operating light; Fig. 2 and Fig. 3 the adaptation of the light field size to the surgical field; and Fig. 4 a control scheme for adjusting the light field size and controlling the luminance within the operating field.

[0020] Fig. 1 shows a perspective view of a surgical light 10, shown only schematically, in whose central handle 12 measuring devices and electronics for measuring device control, information processing, and the generation of control signals for the light, as well as for monitoring controlled variables, are provided. The integration of both the measuring devices (sensors in the form of a camera or light sensors) and the information processing in the form of hardware and software in the handle enables customer-oriented retrofitting of the functions according to the invention. The unit integrated into the handle 12 merely transmits control signals to the light body, similar to a light control unit, in order to change the light intensity and the light field size of the surgical light.

[0021] How Fig. 1, the operating light 10 illuminates an operating field 15 with a preselected light field size 14, which is shown in dashed lines and is larger than the actual operating field 15, so that the surroundings of the operating field 15 are also illuminated in a ring strip.

[0022] A sensor system provided within the handle 12, preferably a luminance camera, serves to detect brightness differences at different positions in the surgeon's working area and the detected brightness differences can be correlated to the position of the light or at least to the optical axis of the light, so that the luminance distribution can be determined in a location-selective manner in a measuring field 13 that is larger than the maximum light field size 14 of the operating light.

[0023] According to the method according to the invention, the luminous field size of the operating light is then first adapted to the size of the operating field 15, taking into account the determined luminance distribution.

[0024] Fig. Figure 2 illustrates the adjustment of the light field size when the initial light field is too large. This involves first recording the luminance in the camera image field, with the light 10 directed towards the surgical field ( Fig. 2, reference symbol A). The area boundaries or the luminance objects in the image field can then be calculated, so that the average luminances in the detected areas L1 (surgical field), L2 (illuminated area), and L3 (surroundings) can be calculated. Based on the data thus determined, the illuminated field size, i.e., the spatial extent of the area with luminance L2, can then be reduced so that the illuminated area essentially corresponds to the surgical field.

[0025] The illuminance can then be varied ( Fig. 2, reference symbol B), that the luminance L1* in the operating field assumes a value optimized for the visual task and the existing ambient luminance L3*, whereby the ambient luminance L3* can also change within a certain range compared to L3 before the size adjustment by adjusting the size of the luminous field.

[0026] The Fig. The luminance values shown in Figure 2 are purely exemplary. It is also possible that the luminance L1* is greater than the luminance L3*.

[0027] Fig. Figure 3 illustrates a situation in which the initial luminous field L1 is smaller than the surgical field L2. Here, too, the luminous field size is changed so that it essentially corresponds to the surgical field, and the luminance is subsequently adjusted to a value L1* that is optimized relative to the ambient luminance L3*. In all cases, the method according to the invention is carried out without a distance measurement.

[0028] The above procedure, which can be designed as a control or as a regulation, is explained again below with reference to Fig. 4 explains: The method begins with step 100 and then carries out a luminance measurement in step 102. In step 104, the determined luminance image is evaluated and one or more luminance objects are determined from the luminance distribution. In the following step 106, a query is made as to whether the illuminated field 14 of the surgical light 10 is larger than the surgical field 15 determined by the determined luminance distribution. If this is the case, the illuminated field is reduced in size in the following step 108, and the process returns to step 102. If this is not the case, a query is made as to whether the illuminated field is smaller than the surgical field 15. If this is the case, the illuminated field is enlarged in step 112, and the process returns to step 102.If this is not the case, the illuminated field has the size of the operating field and the light intensity of the operating light can then be optimized taking into account the surroundings of the operating field. To this end, a query is made in step 114 as to whether the luminance L1* of the currently existing illuminated field has an optimized luminance ratio to the luminance of the surroundings L3*. If this is the case, the method can be terminated in step 120. If this is not the case, the light intensity of the operating light is changed in step 116 by changing its power values, i.e. by regulating the intensity. The luminance is then measured again in step 118 and the process returns to step 114.

[0029] It is understood that instead of step 120, one can also return to step 102 or step 114 to achieve continuous control. It is also obvious that the invention described above can be applied not only to operating room lights, but equally to any other lights, such as examination lights and the like.

[0030] To activate the method described above, a dedicated switching element can be provided on a control unit of the surgical light. Furthermore, it is possible to manually deactivate the automatic intensity adjustment at any time. Furthermore, the brightness of the light 20 and / or the size of the light field can be reduced if, for example, the luminance measurement determines that the light is not oriented toward the surgical field but rather toward the room. This prevents dazzling of medical personnel.

Claims

[1] Method for controlling an operating light (10) illuminating an operating field, comprising the following steps in the order mentioned: a) location-selective determination of the luminance distribution in a measuring field (13) which is larger than a maximum luminous field size (14) of the operating light (10), b) adjusting the size of the light field of the operating light (10) to the size of the operating field (15) taking into account the luminance distribution, and c) Adjusting the light intensity of the operating light taking into account the luminance of the surroundings of the operating field within the measuring field (13) characterized by that in step c) a characteristic field is used to adjust the light intensity, in which light intensities are stored as a function of the size of the operating field (15) and the brightness of the surroundings of the operating field. [2] Method according to claim 1, characterized bythat a luminance object corresponding to the operating field (15) is determined from the luminance distribution. [3] Method according to claim 1 or 2, characterized by that in step c) for adjusting the light intensity, a ratio between the luminance in the operating field and the luminance in the surroundings of the operating field is specified, which ratio varies in particular with the size of the light field. [4] Method according to claim 2, characterized by that a particularly circular luminous field size is calculated from the luminance object, which inscribes the luminance object. [5] Method according to at least one of the preceding claims, characterized by that the location-selective determination of the luminance distribution is carried out as a point-based luminance measurement using several individual sensors. [6] Method according to at least one of the preceding claims 1-4, characterized bythat the luminance distribution is determined using a calibrated grayscale camera. [7] Method according to at least one of the preceding claims, characterized by that at least one reflective mark is used to better identify the edge of the surgical field. [8] Method according to claim 7, characterized by that in order to better identify the edge of the surgical field, an operating field cover is used, the edge of which is provided with a reflective mark that reflects in the invisible or visible area. [9] Method according to at least one of the preceding claims, characterized by that in step b) the light field size is set slightly larger than the size of the surgical field. [10] Device for carrying out a method according to at least one of the preceding claims, comprising a sensor system for the location-selective determination of the luminance distribution in a measuring field, a device for adjusting the light field size of an operating light, and a device for adjusting the light intensity of the operating light in such a way that the luminance of the surroundings of the operating field within the measuring field (13) is taken into account, wherein the device is accommodated in particular within a handle for an operating light.

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