Patent Description:
In general, light sources are operated to illuminate a target. However, it is relatively common for environmental abnormalities to affect the illumination of the target. These environmental abnormalities may include, but are not limited to, a blockage that occurs between the light source and the target or an incorrect positioning of the light source relative to the target.

For example, in a surgical environment, a surgical staff member might move between an area of a lighthead and an area of a surgical work surface, thereby blocking the area of the lighthead and inhibiting light emitted from the blocked area of the lighthead from reaching the corresponding area of the surgical work surface. In another example, a surgical staff member might move the surgical work surface to a different location that no longer corresponds to the positioning of one or more of areas of the lighthead.

Many systems have been developed to identify such abnormalities and automatically adjust the intensity or the location of the light emitted from a light source to maintain a desired luminance of an illuminated target. Such identification systems have been known to employ proximity sensors or coordinate referencing cameras. Closed loop luminance sensors, such as photodiodes or CCD cameras, have also been used to sense variances from optimal target luminance.

In such systems that incorporate a lighthead as the light source, the sensor input is communicated to a controller. The controller compensates for the sensed abnormalities by adjusting either the positioning of light modules in the lighthead to avoid the abnormalities or an intensity of light being emitted from the light modules to compensate for the abnormalities. In the latter case, when an abnormality is detected that blocks light emitted from a particular light module from reaching a target, the intensity of light emitted from the affected light module may be reduced while the intensity of light emitted from adjacent unaffected light modules may be increased to compensate for the abnormality. <CIT> discloses an operating room lighthead, said lighthead comprising a plurality of light sources for generating a light field on a site of surgical operation to be illuminated on a patient, and a controller for controlling the light sources. <CIT> discloses an apparatus comprising: a plurality of light emitting cells, wherein each of the light emitting cells comprises: a light source; and a focus-tunable lens associated with the light source, wherein each respective one of the light emitting cells is independently controllable relative to the one or more other light emitting cells.

The present invention provides an improved system and method of identifying abnormalities between a light source and an illumination target, such as light blockages and erroneous positioning, and compensating for those abnormalities. The present invention accomplishes this through the determination of the true distance between the light source and the illumination target and compensating for the abnormalities detected in the course of the true distance determination.

In accordance with the present invention, there is provided a system for identification of abnormalities related to illumination of a target and automatic compensation therefor. The system includes a lighthead and a controller. The lighthead is configured to illuminate the target. The lighthead includes a plurality of lighting modules configured to emit light therefrom. Each of the lighting modules includes a distance sensor configured to measure a distance from the lighting module to a surface toward which the lighting module is pointed. The controller is configured to identify one or more abnormalities of the measured distances, determine a true distance from the lighthead to the target based on the measured distances, predict an amount of illumination based on the true distance that would be supplied to the target without the identified abnormalities, and compensate for the identified abnormalities by respectively adjusting an amount of light emitted from the lighting modules to illuminate the target according to the predicted amount of illumination. The abnormalities of the measured distances respectively indicate that the surfaces toward which the lighting modules related to the abnormalities are pointed are not surfaces of the target. The true distance is a distance between a center of the lighthead and a surface to which the center of the lighthead is pointed, wherein the surface to which the center of the lighthead is pointed is the target. The determining of the true distance comprises respectively correcting the measured distances so that the corrected distances are centerline distances extending from a center of the lighthead to the surfaces toward which the lighting modules are pointed. The abnormalities are identified based on a comparison of all of the corrected distances, wherein one of the corrected distances is identified as an abnormality when a determination is made by the controller that, when compared with all of the corrected distances, the one of the corrected distances is not a distance to the target and light associated with the one of the corrected distances is not reading the target.

In accordance with another embodiment of the present invention, there is provided a method for identification of abnormalities related to illumination of a target and automatic compensation therefor. The method includes measuring a distance from each of a plurality of lighting modules of a lighthead to a surface toward which the lighting module is pointed. The method also includes identifying, via a controller, one or more abnormalities of the measured distances. The method further includes determining, via the controller, a true distance from the lighthead to the target based on the measured distances. The method additionally includes predicting, via the controller, an amount of illumination based on the true distance that would supplied to the target without the identified abnormalities. The method still further includes compensating, via the controller, for the identified abnormalities by respectively adjusting an amount of light emitted from the lighting modules to illuminate the target according to the predicted amount of illumination. The abnormalities of the measured distances respectively indicate that the surfaces toward which the lighting modules related to the abnormalities are pointed are not surfaces of the target. The true distance is a distance between a center of the lighthead and a surface to which the center of the lighthead is pointed, wherein the surface to which the center of the lighthead is pointed is the target. The determining of the true distance comprises respectively correcting the measured distances so that the corrected distances are centerline distances extending from a center of the lighthead to the surfaces toward which the lighting modules are pointed. The abnormalities are identified based on a comparison of all of the corrected distances, wherein one of the corrected distances is identified as an abnormality when a determination is made by the controller that, when compared with all of the corrected distances, the one of the corrected distances is not a distance to the target and light associated with the one of the corrected distances is not reading the target.

An advantage of the present invention is to provide automatic detection of an abnormality that comes between an illumination target and a lighting module of a lighthead pointed at the target.

Another advantage of the present invention is to provide such automatic detection without the need of photosensors and lighting filters to adjust for environmental conditions impacting the readings taken by the photosensors.

A further advantage of the present invention is to provide automatic detection of when a lighting module of the lighthead is not pointed toward the illumination target.

Still another advantage of the present invention is to determine a true distance of the lighthead to the illumination target and predict an amount of light required for illumination of the target based on the true distance.

These and other advantages will become apparent from the following description of illustrated embodiments taken together with the accompanying drawings and the appended claims.

The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:.

Referring now to the drawings wherein the showings are for the purposes of illustrating an embodiment of the invention only and not for the purposes of limiting same, <FIG> illustrate an example implementation of a lighting system in a surgical environment <NUM> in which a surgical table <NUM> is positioned.

The lighting system includes a lighthead <NUM> and a controller <NUM>. The lighthead <NUM> is configured to illuminate a target. In this example implementation, the illumination target is a work surface <NUM> of the surgical table <NUM> on which a surgical patient <NUM> is positioned to enable a surgical staff member <NUM> to perform a surgical operation thereon. The controller <NUM> may be a conventional microprocessor-based computer system that is in communication with various accessory devices of the lighting system, including the lighthead <NUM>. The controller <NUM> is equipped to receive and analyze data from the lighthead <NUM> and control operation of the lighthead <NUM> according to the analyzed data.

As is illustrated in <FIG>, the lighting system may also include a support assembly <NUM> depending on the configuration and the implementation of the lighting system. The support assembly <NUM> supports the lighthead <NUM> from a ceiling <NUM> of an area containing the surgical environment <NUM> and is adjustable to allow desired positioning of the lighthead <NUM> within the surgical environment <NUM>. The support assembly <NUM> may take the form of a conventional suspension system, which may include, but is not limited to, a plurality of suspension arms, hubs, mounts, and yokes.

As is illustrated in <FIG>, the lighthead <NUM> includes an outer ring <NUM>, a central hub <NUM>, a neck <NUM>, and a handle <NUM>. The outer ring <NUM> corresponds with a perimeter of the lighthead <NUM> and surrounds the central hub <NUM>. The neck <NUM> connects the outer ring <NUM> to the central hub <NUM>. The handle <NUM> is mounted on the central hub <NUM>. The handle <NUM> can be grasped by the surgical staff member <NUM> to manually adjust the positioning of the lighthead <NUM>. The handle <NUM> may also include control mechanisms by which the surgical staff member <NUM> can control the lighting provided by the lighthead <NUM>.

While the lighting system may be comprised of only the lighthead <NUM>, the controller <NUM>, and the support assembly <NUM>, embodiments described herein are not limited thereto. For example, the lighting system may be comprised of several lightheads and support assemblies respectively positioned throughout areas of the surgical environment <NUM>. Other lightheads and support assemblies may also be positioned on walls of the surgical environment <NUM> that are not illustrated herein.

In <FIG>, the controller <NUM> is illustrated as being mounted in a location within the surgical environment <NUM>. However, embodiments disclosed herein are not limited thereto. For example, the controller <NUM> may be positioned in or on the lighthead <NUM> or the support assembly <NUM>. Further, the controller <NUM> may be positioned outside of the surgical environment <NUM>. Moreover, there may be multiple controller interfaces spread throughout or outside the surgical environment <NUM> to allow remote operation of the controller <NUM>. In addition, the controller <NUM> itself may be inaccessible, thereby requiring remote interfaces to access the controller <NUM>.

The outer ring <NUM> and the central hub <NUM> have translucent portions enabling light to be emitted therethrough. Light is emitted from the outer ring <NUM> by a plurality of outer ring lighting modules <NUM> housed in the outer ring <NUM>. Light is emitted from the central hub <NUM> by a central hub lighting module <NUM> housed in the central hub <NUM>. In the illustrated embodiment, the outer ring <NUM> contains five outer ring lighting modules <NUM>, and the central hub <NUM> contains one central hub lighting module <NUM>.

Each of the lighting modules <NUM> and <NUM> contains a plurality of lamps <NUM> mounted therein. An example of a lamp <NUM> in accordance with the present invention is a light emitting diode. However, the lamps <NUM> are not limited to being light emitting diodes. The lamps <NUM> are best illustrated in <FIG>. In the embodiment illustrated herein, the outer ring lighting modules <NUM> are arranged end to end in the outer ring <NUM> such that the lamps <NUM> extend around a center circumference of the outer ring <NUM>. The lamps <NUM> contained in the lighting modules <NUM> and <NUM> are respectively oriented such that light emitted from the lamps <NUM> is transferred through the translucent portions of the outer ring <NUM> and the central hub <NUM>.

The outer ring lighting modules <NUM> and the central hub lighting module <NUM> are removably fixed to the outer ring <NUM> and the central hub <NUM>, respectively, using screws <NUM> or another fixing element that one having ordinary skill in the art would deem acceptable. As such, the outer ring lighting modules <NUM> and the central hub lighting module <NUM> can be removed to perform maintenance thereon. Such maintenance may include, but is not limited to, the replacement of lamps <NUM> or distance sensors <NUM> (described below) mounted within the outer ring lighting modules <NUM> and the central hub lighting module <NUM>.

While the lighthead <NUM> illustrated herein has the outer ring <NUM> and the central hub <NUM>, embodiments described herein are not limited to this functional design of the lighthead <NUM>. For example, a lighthead is contemplated in which only one outer ring lighting module <NUM> is included in the outer ring <NUM>. Alternatively, either the outer ring <NUM> or the central hub <NUM> may be omitted in the lighthead <NUM>. The outer ring <NUM> and the central hub <NUM> may be dimensioned in various shapes and sizes. As the embodiments described herein are not limited to the functional design of the lighthead <NUM> and the lighting modules <NUM> and <NUM>, the arrangement of the lamps <NUM> is limited only by the function design of the lighthead <NUM> and the lighting modules <NUM> and <NUM> in which the lamps <NUM> are mounted.

Each of the outer ring lighting modules <NUM> and the central hub lighting module <NUM> includes a distance sensor <NUM>. In the present embodiment, since there are six lighting modules <NUM> and <NUM> contained in the lighthead <NUM>, there are six distance sensors <NUM> contained in the lighthead <NUM> as well. However, embodiments disclosed herein are not limited thereto. For example, multiple distance sensors <NUM> can be respectively incorporated into each of the lighting modules <NUM> and <NUM>. Conceivably, sensors not directed to distance detection that sense other variables can be incorporated into the lighting modules <NUM> and <NUM> alongside the distance sensors <NUM> to complement the data obtained from the distance sensors <NUM>.

Each distance sensor <NUM> is configured to measure a single distance from the distance sensor <NUM> to a surface toward which the distance sensor <NUM> is pointed. Since the distance sensors <NUM> are respectively included in the lighting modules <NUM> and <NUM>, it can be said the single distances measured by the distance sensors <NUM> are respectively reflective of the distances between the lighting modules <NUM> and <NUM> and the corresponding surfaces being illuminated by the lighting modules <NUM> and <NUM>.

In an ideal situation, the single distances measured would be the distance from the distance sensors <NUM> to the work surface <NUM>. However, the surface toward which the distance sensor <NUM> is pointed may not be the work surface <NUM>. For example, after the lighthead <NUM> is positioned to optimally illuminate the work surface <NUM>, the surgical staff member <NUM> may come between the distance sensor <NUM> and the work surface <NUM>, thereby representing an abnormality. In such cases, the single distance measured would be the distance from the distance sensor <NUM> to the surgical staff member <NUM>. In another example, the work surface <NUM> may be moved such that one of the lighting modules <NUM> and <NUM> no longer is positioned to illuminate the work surface <NUM>. In such cases, the absence of the work surface <NUM> would be the abnormality, and the single distance measured would be the distance from the distance sensor <NUM> to the surface toward which the distance sensor <NUM> is newly pointed.

In any case, the single distances measured by the distance sensors <NUM> can be used to determine the true distance between the lighthead <NUM> and the work surface <NUM>. For example, if one or more of the lighting modules <NUM> is illuminating an abnormality, the single distances determined by the distance sensors <NUM> would reflect this to be the case. Then, from the single distances, the true distance from the lighthead <NUM> to the work surface <NUM> can be calculated. The respective intensities of the light being emitted from the lighting modules <NUM> and <NUM> can then be adjusted in consideration of the true distance and the one or more abnormality distances, thereby serving to compensate for the abnormalities.

The true distance between the lighthead <NUM> and work surface <NUM> is calculated from a center of the lighthead <NUM>. The true distance is, in fact, a representation of the distance between the center of the lighthead <NUM> and the surface toward which the center of the lighthead <NUM> is pointed. However, the true distance is determined in such a way that the surface toward which the center of the lighthead <NUM> is pointing is concluded to be the work surface <NUM>. An example of how this conclusion is reached is described more specifically herebelow with reference to <FIG>, which is a flow diagram illustrating an example method by which a true distance between the lighthead <NUM> and an illumination target, i.e., the work surface <NUM>, is determined.

After each of the distance sensors <NUM> has measured a single distance therefrom to a surface toward which the distance sensor <NUM>, i.e., the lighting modules <NUM> and <NUM>, is pointed, each of the distance sensors <NUM> reports (S100) the single measured distance and a state of the single measured distance to the controller <NUM>. The state of the single measured distance is related to the amount of time elapsed between the acquisition of the measurement data and the reporting of the measurement data to the controller <NUM>.

In this particular case, the state of the single measured distance is determined according to a predetermined time period. If the acquired measurement is reported to the controller <NUM> within the predetermined time period, the state of the single measured distance is indicated to the controller <NUM> as being current. However, if the acquired measurement is reported to the controller <NUM> after the predetermined time period has expired, the state of the single measured distance is indicated to the controller <NUM> as being stale. A stale measurement could be a result of an inability of the distance sensor <NUM> to determine the single measured distance by the time at which the distance sensor <NUM> is required to report the measurement to the controller <NUM>. A measurement that is stale may be a measurement that had previously been reported to the controller <NUM>.

After the controller <NUM> receives the respective single measured distances for the distance sensors <NUM>, the distances are corrected (S101) to centerline distances extending from the center of the lighthead <NUM> to the respective surfaces toward which the lighting modules <NUM> and <NUM> are pointed. Then, using the corrected distances, the controller <NUM> determines (S <NUM>) if one or more of the distance sensors <NUM> are subject to an out-of-range abnormality.

In this example, an out-of-range abnormality is an abnormality represented by a distance sensor <NUM> providing a corrected distance that, in comparison with all of the corrected distances, is either so short or so long that it could not be considered as a normal operating distance from the lighthead <NUM> to the work surface <NUM>. More specifically, the distance sensors <NUM> are not able to specifically identify the surface to which the distance is determined. The surface may be any surface located within the surgical environment <NUM>, including, but not limited to, the work surface <NUM>, the surgical patient, the surgical staff member <NUM>, other areas of the surgical table <NUM>, or even a floor on which the surgical table <NUM> is positioned. A determination of an existence of an out-of-range abnormality with respect to a corrected distance would lead one to believe, i.e. the controller <NUM>, that, when compared with all of the corrected distances, the instant corrected distance is not a distance to the work surface <NUM>, and the light associated with the instant corrected distance is not reaching the work surface <NUM>. In other words, the light being emitted from the lighting module <NUM> and <NUM> that includes the distance sensor <NUM> sensing the abnormality is not reaching the work surface <NUM>, i.e. the illumination target. As such, when a corrected distance from a distance sensor <NUM> results in a determination by the controller <NUM> of the specific distance sensor <NUM> as being subject to an out-of-range abnormality, the last known good, i.e., normal, corrected measurement obtained from the distance sensor <NUM> is substituted as a stale measurement in place of the distance related to the measurement associated with the out-of-range abnormality.

After the determination of any out-of-range abnormalities, a first central tendency of the corrected centerline distances is calculated (S103) by condensing the distances into a first single distance output. A stale reading state is also provided by condensing the stale readings into a single stale reading. The current or stale state of the single distance output is determined based on how many of the measured distances in were current or stale. In addition, the reliability of the single measured distances is also analyzed with statistical data regarding the effect of noise of the single measured distances. Noise is a function of distance. As such, the single measured distances will contain more noise at further distances and less noise at closer distances. Thus, the reliability of the measurements is a function of the noise.

After the first central tendency is calculated, a standard deviation is determined (S <NUM>) with respect to an expected discrepancy between the single measured distances and the condensed first single distance output. Through iteration, readings of the single measured distances that are considered abnormal are discarded (S <NUM>). The single measured distances are then averaged, thereby leading to the determination (S <NUM>) of whether the expected discrepancy related to the standard deviation is acceptable. If single measured distances outside of the expected discrepancy are discarded or the averaged value falls outside the standard deviation, the first central tendency is recalculated (S103), another standard deviation is determined (S104), and additional abnormal distances are discarded (S105).

This process repeats until it is determined (S <NUM>) that no additional single measured distances are discarded in an iteration in S <NUM> or the expected discrepancy is within acceptable limits. After such a determination, the converted distances are weighted (S <NUM>) toward a center of the lighthead <NUM>. In the instant example, the distance sensor <NUM> of the central hub lighting module <NUM> is more likely to be aimed at the work surface <NUM> than the distance sensors <NUM> of the outer ring lighting modules <NUM>. Further, the distance sensor <NUM> of the central hub lighting module <NUM> is less likely to experience out-of-range abnormalities than the distance sensors <NUM> of the outer ring lighting modules <NUM>. As such, the converted distance of the distance sensor <NUM> of the central hub lighting module <NUM> is weighted more heavily than the converted distances of the distance sensors <NUM> of the outer ring lighting modules <NUM>, as the distance sensor <NUM> of the central hub lighting module <NUM> is closer to the center of the lighthead <NUM>. An additional weighting is also applied to reduce the weight of stale measured distances as compared with current measured distances.

A second central tendency (S <NUM>) is then calculated by condensing the measured distances are condensed into a single distance output, even if it is stale. If the single distance output is not updated, the last known plausible (or default) single distance output is used (S <NUM>). Low pass filtering is then applied to remove noise and provide a more stable value for the single distance output. A final single centerline distance - the true distance - from the lighthead <NUM> to the work surface <NUM> is then calculated (S110).

The intensity or amount of light emitted from the lighting modules <NUM> and <NUM>, i.e., the lamps <NUM> of the lighting modules <NUM> and <NUM>, is then adjusted to compensate for the detected out-of-range abnormalities to ensure that a predetermined amount of light is illuminating the work surface <NUM>. The light being emitted from the lighting modules <NUM> and <NUM> is selectable according to whether the respective lighting modules <NUM> and <NUM> are subject to abnormalities.

For example, if an abnormality is identified through the readings reported by a distance sensor <NUM> in one of the outer ring lighting modules <NUM>, the controller <NUM> will use the distance readings reported to predict the amount of illumination that the abnormality affected outer ring lighting module <NUM> is providing to the work surface <NUM> in view of the abnormality. The controller <NUM> will then use the true distance to predict the amount of illumination that should be provided to the work surface <NUM> if all of the lighting modules <NUM> and <NUM> are unaffected by abnormalities.

Claim 1:
A system for identification of abnormalities (<NUM>) related to illumination of a target (<NUM>) and automatic compensation therefor, the system comprising:
a lighthead (<NUM>) configured to illuminate the target (<NUM>), the lighthead (<NUM>) comprising a plurality of lighting modules (<NUM>, <NUM>) configured to emit light therefrom, each of the lighting modules (<NUM>, <NUM>) comprising a distance sensor (<NUM>) configured to measure a distance from the lighting module (<NUM>, <NUM>) to a surface toward which the lighting module (<NUM>, <NUM>) is pointed; and
a controller (<NUM>) configured to identify one or more abnormalities (<NUM>) of the measured distances, determine a true distance from the lighthead (<NUM>) to the target (<NUM>) based on the measured distances, predict an amount of illumination based on the true distance that would be supplied to the target (<NUM>) without the identified abnormalities (<NUM>), and compensate for the identified abnormalities (<NUM>) by respectively adjusting an amount of light emitted from the lighting modules (<NUM>, <NUM>) to illuminate the target (<NUM>) according to the predicted amount of illumination,
wherein the abnormalities (<NUM>) of the measured distances respectively indicate that the surfaces toward which the lighting modules (<NUM>, <NUM>) related to the abnormalities (<NUM>) are pointed are not surfaces of the target (<NUM>);
wherein the true distance is a distance between a center of the lighthead (<NUM>) and a surface to which the center of the lighthead (<NUM>) is pointed, and
wherein the surface to which the center of the lighthead (<NUM>) is pointed is the target (<NUM>);
wherein the determining of the true distance comprises respectively correcting the measured distances so that the corrected distances are centerline distances extending from a center of the lighthead (<NUM>) to the surfaces toward which the lighting modules (<NUM>, <NUM>) are pointed;
wherein the abnormalities (<NUM>) are identified based on a comparison of all of the corrected distances, and
wherein one of the corrected distances is identified as an abnormality when a determination is made by the controller (<NUM>) that, when compared with all of the corrected distances, the one of the corrected distances is not a distance to the target (<NUM>) and light associated with the one of the corrected distances is not reaching the target (<NUM>).