Patent Description:
More recently, an increasing number of optical sensors and cameras are being used to research the underwater environment. These sensors and cameras require windows that stay substantially clear and free from biofouling for long periods of time without mechanical cleaning. Painting or coating the surface is not an option for this application because of the need for light passage through the windows.

The recent development of ultra violet (UV) light emitting diodes (UV LEDs), such as those comprising aluminum nitride, have made available the option to use generated UV light to kill microbes on and near surfaces to be protected against biofouling. There are commercial apparatuses on the market that irradiate underwater surfaces with UV light, such as those described in Http://www. amloceanographic. com/CTD-Sound-Velocity-Environmental-Instrumentation-Home/Biofouling. Another example of the use of UV light to prevent biofouling is described in <CIT> and related <CIT>. Notably, most of the UV light sources used with these apparatuses are situated outside of their housings, such that the light source is positioned in front of the window such that water is within the space between the light source and the window. As such, the light sources may at least partly obstruct the view. Moreover, parts of the window may also be in the shade of mounting brackets used in these apparatuses, and biofouling may still occur in these shadowed areas. In addition, the UV intensity may be attenuated by travelling through the water. Finally, it is often challenging to deliver power to such apparatuses in offshore underwater environments, and conventional apparatuses are not generally designed to reduce power consumption. As such, one of the advantages of the present invention is to reduce biofouling through the effective delivery of UV light using minimal electrical power. Document <CIT> provides another example of prior art method and system for reducing biofouling in a marine environment and discloses a method for reducing biofouling in a marine environment in accordance with the preamble of claim <NUM> and an apparatus suitable for reducing biofouling in a marine environment in accordance with the preamble of claim <NUM>.

An example of a method for reducing biofouling in a marine environment according to the disclosure includes disposing an optical device in the marine environment, wherein the optical device is directed at an object in the marine environment, obtaining an image of the object with the optical device, determining a quality of the image, determining a high power value and a high power duration based on the quality of the image, determining a low power value and a low power duration based on the quality of the image, and activate at least one ultraviolet light source for a plurality of cycles based on the high power value, the high power duration, the low power value and the low power duration, wherein the at least one ultraviolet light source is disposed proximate to the optical device and directed at the object.

Many technical papers distinguish between UV power at the wavelength of the LED and the electrical power required to generate this UV power. In general, an electrical-to-UV-C conversion efficiency of <NUM>% is attained with current LED technologies. In an effort to reduce ambiguity, power specifications used herein are labeled with electrical or UV units.

Implementations of such a method may include one or more of the following features. At least one ultraviolet light source may be characterized by emission wavelength of between <NUM> nanometers and <NUM> nanometers. The flash duration may be between <NUM> seconds and <NUM> seconds. The flash power value may be between <NUM> milliwatt (UV) and <NUM> milliwatts (UV). The rest power value may be less than <NUM> milliwatt. The rest duration may be between <NUM> second and <NUM>,<NUM> seconds. The flash power value may be approximately <NUM> milliwatts (UV), the flash duration may be approximately <NUM> seconds, the rest power value may be less than <NUM> milliwatts, and the rest duration may be approximately <NUM> seconds. Determining the quality of the image may be based on a sharpness value associated with a contrast boundary in the image. The flash power value, the flash duration, the rest power value and the rest duration may be provided to a server. The flash power value, the flash duration, the rest power value and the rest duration may be received from a server.

An example of an apparatus for reducing biofouling in a marine environment according to the disclosure includes a housing including a cavity and an ultraviolet transparent window disposed over the cavity, an optical device disposed in the cavity and directed towards the ultraviolet transparent window, one or more ultraviolet light emitting diodes disposed in the cavity and directed toward the ultraviolet transparent window, and a controller operably coupled to the one or more ultraviolet light emitting diodes and configured to provide at least one lamp power function to the one or more ultraviolet light emitting diodes, obtain an image of an object in the marine environment, determine a quality of the image, and activate at least one ultraviolet light emitting diode for a plurality of cycles based on a high power value, a high power duration, a low power value and a low power duration. A lamp power function is the representation of the electrical power applied to the UV LED over time.

Implementations of such an apparatus may include one or more of the following features. The ultraviolet transparent window may be constructed at least in part with at least one material selected from a group consisting of sapphire, silicon carbide (SiC), diamond, zinc sulfide (ZnS), zinc selenide (ZnSe), Barium fluoride (BaF2), aluminum dioxide (Al203), quartz (SiO2), and magnesium fluoride (MgF2). At least one of the one or more ultraviolet light emitting diodes may be characterized by emission wavelengths between <NUM> nanometer and <NUM> nanometers. A power source may be operably coupled to the one or more ultraviolet light emitting diodes. The controller may be configured to receive the at least one lamp power function from a remote server. The controller may include at least one data structure configured to store the at least one lamp power function. The flash duration may be between <NUM> seconds and <NUM> seconds and the flash power value may be between <NUM> milliwatt (UV) and <NUM> milliwatts (UV). The rest power value may be less than <NUM> milliwatts and the rest duration may be between <NUM> second and <NUM>,<NUM> seconds. The flash power value may be approximately <NUM> milliwatts (UV), the flash duration is approximately <NUM> seconds, the rest power value may be less than <NUM> milliwatts (UV), and the rest duration is approximately <NUM> seconds.

An example of an apparatus according to the disclosure includes a housing means including a cavity configured to enclose one or more optical device means and one or more ultraviolet light emitting means, an ultraviolet transparent window means disposed on the housing means over the cavity, such that the one or more optical device means and the one or more ultraviolet light emitting means are directed towards the ultraviolet transparent window means, and a controller means operably coupled to the one or more ultraviolet light emitting means and configured to provide at least one lamp power function to the one or more ultraviolet light emitting means, such that the at least one lamp power function is based on at least a flash power value, a flash duration, a rest power value and a rest duration.

Items and/or techniques described herein may provide one or more of the following capabilities, as well as other capabilities not mentioned. An optical sensing device may be placed behind a window in a marine environment. The window may be a transparent or semi-transparent component through which light is passed. An ultraviolet (UV) light source may be directed at the.

The UV light may impede the growth of marine algae on the window. A programmable controller may be operably coupled to the UV light source and configured to cyclically activate the UV light source using two or more periods at varying power levels. A cycle may include a short high-power UV light flash, followed by a relatively longer period of relatively low power UV light or no UV light. The cyclical operation may reduce the power consumed by the controller. The reduced power consumption may extend the operational service life of the optical sensing device. Other capabilities may be provided and not every implementation according to the disclosure must provide any, let alone all, of the capabilities discussed. Further, it may be possible for an effect noted above to be achieved by means other than that noted, and a noted item/technique may not necessarily yield the noted effect. Claims <NUM> and <NUM> respectively define a method and an apparatus in accordance with the invention.

Techniques are discussed herein for extending the service life of optical sensors in a marine environment. For example, an optical sensor may be disposed in an apparatus that includes a window used for underwater applications. The container and window may be operable under a pressure of up to <NUM>,<NUM> of water. A method to keep the window substantially clear and free from biofouling includes using two or more periods of UV radiation with varying power. The sequence of these periods as defined by duration and UV power comprises a cycle. In certain embodiments, a cycle repeats itself indefinitely. In a non-limiting example, one cycle may comprise a short, high power UV light (i.e., a flash), followed by a relatively longer period of relatively lower power UV light or no UV light. As used herein, "window" refers to any transparent or semi- transparent component through which light is passed.

The optical sensor and window apparatus may be utilized in underwater environments, such as underwater optical sensors, underwater cameras and underwater lights. They may also be used to expose deep sea environments to UV light, where such light would otherwise never be found. In addition to being used for biocidal applications, the window apparatus may be suitable for other related applications, such as curing materials extruded into the deep-water environment and forming structures needed outside of a vessel. Specifically, in certain embodiments, the apparatus may use less than 20mW electrical power (continuous), preferably less than 10mW (electrical, continuous) and even more preferably less than 5mW (electrical, continuous). As used herein, continuous power refers to the energy consumed during all periods of one entire cycle divided by the duration of that entire cycle. These techniques are examples only, and not exhaustive.

Referring to <FIG>, an example apparatus <NUM> to prevent biofouling is shown. In an example, the apparatus includes a housing <NUM>, a UV transparent window <NUM>, a device cavity <NUM>, one or more UV light emitting diodes (LEDs) <NUM>, an optical device <NUM>, and a controller <NUM>. The housing <NUM> may be a cylindrical housing that is open on one end. Other shapes and configurations may also be used. In general, the housing <NUM> may be constructed from suitable materials to withstand an underwater environment and corresponding mechanical forces to which it will be subjected. The housing <NUM> includes the device cavity <NUM> configured to accommodate one or more optical devices <NUM>. The cavity <NUM> may optionally be filled with dry air, substantially pure nitrogen, argon and/or other inert gas. The opening on the housing <NUM> is fitted with a leak-tight window <NUM> comprising one or more UV-transparent materials. The housing <NUM> includes an internal arrangement of one or more UV LEDs <NUM> configured to project light onto the window <NUM>. In an example, the UV LEDs <NUM> are characterized by emission wavelengths of between <NUM> - <NUM>, preferably around <NUM>. In certain embodiments, individual UV LEDs <NUM> may be configured to emit the same or different wavelengths in the same apparatus. The UV LEDs <NUM> are operably coupled to a power source (not shown in <FIG>) and the controller <NUM>. Power source may be an internal source (e.g., a battery) or an external source (e.g., via a water-tight connector in the housing <NUM>). Inductive charging (e.g., wireless) techniques may also be used to charge the internal battery.

The housing <NUM> further encloses one or more optical devices <NUM> and equipment as necessary for its application, such as a camera, an optical sensor, a lamp or simply the UV LEDs <NUM> only. The spatial arrangement of the UV LEDs <NUM> can be used to control the UV intensity distribution in the water-facing surface of the window. The intensity distribution can be designed depending on the intended use. For example, the UV intensity distribution is uniform across the window in some embodiments, while in other embodiments, the UV intensity is highest in the center of the window, while in still other embodiments, the UV intensity is highest around the window annulus.

The UV LEDs <NUM> are configured to irradiate the UV transparent window <NUM> from the inside of the housing <NUM>. That is, the UV LEDs <NUM> are orientated in the same general direction as the optical device <NUM> (e.g., both are directed toward an object). Additionally, in contrast to apparatuses of the prior art that project UV light from the outside of associated housings through water with attenuates UV light, the internal UV LED configurations of the present invention offer many advantages such as a reduction in energy consumption because UV light does not travel through water. The internal UV LEDs do not require external structures to support a light source, which may protrude from the outside surface of the housing and thus increase drag on an underwater apparatus. Further, the window <NUM> may be made flush with the surface of the housing <NUM> and the UV LEDs <NUM> can be installed inside the same watertight device cavity <NUM> that protects the optical devices <NUM> (e.g., cameras and other components within the apparatus), thus reducing complexity.

Referring to <FIG>, with further reference to <FIG>, an example lamp duty cycle graph <NUM> is shown. The graph <NUM> includes a lamp power axis <NUM>, a time axis <NUM> and a lamp power function <NUM>. The UV LEDs <NUM> is/are driven by controller <NUM> that is configured to apply a timed sequence of power to the UV LEDs <NUM>. The timed sequence may be a lamp power function <NUM> that includes a number of periods of varying power and duration, i.e., a complete cycle. In certain embodiments, the sequence is a period of relatively higher power 206a followed by a period of relatively lower power 206b, as schematically depicted in <FIG>. The duration of the higher power period (e.g., duty period, flash) may be in a range from <NUM> seconds to <NUM>,<NUM> seconds. As an example, and not a limitation, the power applied during the duty period may be between <NUM>. 01x and <NUM>. 0x of the maximum rated continuous output of the UV LEDs <NUM>, and the duration of the lower power period ("rest period") may range from <NUM> second to <NUM>,<NUM> seconds. The cycle profile - or the sequence of periods - may be tailored for specific marine biofouling environments. In an example, the power applied during the rest cycle is between <NUM>. 001x and <NUM>. 0x of the maximum rated continuous output of the LED. Commercially available UV LEDs (e.g., Klaran LED by Crystal-IS) may be rated at a maximum power of approximately 4W (electrical, continuous). In an example, the controller <NUM> may be configured to provide a power function to each of the UV LEDs <NUM> individually, as a group, or combinations therein. The controller <NUM> may be configured to supply different lamp power functions to different UV LEDs <NUM> or different groups of UV LEDs <NUM>.

Some effects of the interaction of the UV light with water are known to be biocidal (e.g. formation of ozone and hydrogen peroxide). The UV LEDs <NUM> generate(s) a high intensity of UV light energy at the window <NUM> surface in contact with seawater, thus producing a high concentration of biocidal chemical agents on and near the window surface.

In an embodiment, the UV transparent window <NUM> may be comprised of specialty window materials, which work together with the UV light to lower the UV dosage required for biofouling reduction or elimination. Such embodiments make use of windows that are substantially optically clear but have outer surfaces that are modified to contain atoms or compounds of metals such as silver, copper, tin and/or lead. The UV LEDs <NUM> activates biocidal effects in these metals, which do not leach into surrounding water. Thus, there is no environmental damage and no deterioration of the effect over time. In other embodiments, the water-facing surface of the window may be mechanically modified to provide additional anti-biofouling properties; such as, for example, being engraved with a micro pattern of a periodicity of <NUM> to <NUM>,<NUM>.

The controller <NUM> may include one or more processors and associated memory devices configured to provide a voltage signal to the UV LEDs <NUM>. For example, the controller <NUM> may include a micro control unit (MCU) like an Attiny-<NUM> by Microchip and suitable electronic components to control different temporal patterns and UV power settings to establish multiple irradiation modes for one or more UV LEDs <NUM>. Example modes include continuous and pulsed UV irradiation. Under both such modes, the UV power can be selected. For example, flash intensity and duration values may be determined based on the marine environment. Similarly, rest intensity and duration values may be determined. The intensity and duration values may vary cycle to cycle and need not be constant (i.e., sinusoidal, sawtooth or other signal profiles may be used for the flash and rest periods). This allows adjustment for improved anti-biofouling results and energy economy. For example, pulsed irradiation with very high intensity pulses for short periods to use the lowest possible electrical power or as a special case where duty power and rest power are equal (e.g., continuous irradiation at intensity levels that prevent biofouling but still minimize the electrical power that is consumed). The controller <NUM> may be internal to the housing or external and coupled to the UV LEDs <NUM> via a waterproof coupler (not shown in <FIG>).

The controller <NUM> may be configured to provide control for both the power and timing of all UV LEDs <NUM> individually or collectively. The apparatus may comprise several UV LEDs <NUM> of different wavelengths. The controller <NUM> may be configured to provide each individual UV LED <NUM> with its own individual control signal to enable a temporal light pattern.

In an example, the materials used to make the housing <NUM> may be electrically conductive, in which case the housing <NUM> can be used as an electrode for the UV LEDs <NUM>. Example materials for the housing <NUM> include, but are not limited to, stainless-steel, copper, biocidally treated PVC, ABS and PE, ceramics such as SiN, A1203, BN, porcelain, glass and fiberglass. These materials may be treated to minimize biofouling, such as by coating or integration of anti-biofouling materials. For example, a stainless-steel housing could be copper clad. Polymer materials may be infused with nanoparticles that are known to prevent biofouling. Other antifouling techniques may also be used on the exterior surface of the housing <NUM>.

Referring to <FIG>, transmittance graphs of example UV transparent windows is shown. The UV transparent window <NUM> may be constructed from materials such as, for example, sapphire, silicon carbide (SiC), diamond, zinc sulfide (ZnS), zinc selenide (ZnSe), Barium fluoride (BaF2), aluminum dioxide (Al2O3), quartz (SiO2), magnesium fluoride (MgF2), and other UV transparent materials. In an example, the UV transparent window <NUM> may be a composite of different materials such as the result of chemical or plasma vapor deposition process. The transmission properties of some of these materials are graphically illustrated in <FIG>. A first graph <NUM> illustrates the transmittance versus wavelength for Barium Fluoride. A second graph <NUM> illustrates the transmittance versus wavelength for Silicon Dioxide. A third graph <NUM> illustrates the transmittance versus wavelength for Magnesium Fluoride. A fourth graph <NUM> illustrates the transmittance versus wavelength for Sapphire. A combination of these materials and/or multiple windows may be required for requisite mechanical strength for deep sea applications. Generally, the embodiments of the UV transparent window <NUM> are characterized by mechanical strengths suitable for water pressures from <NUM> to <NUM> MPa (<NUM> - <NUM>,<NUM> water column). Thick windows from water soluble material like MgF2 with high UV transparency and adequate mechanical strength may be combined with a thin sapphire or quartz protective window. In an example, a hydrophobic coating (e.g., Al2O3) may be applied to the exterior of the UV transparent window <NUM> to help reduce biofouling. In an example, the exterior coating on the UV transparent window <NUM> may be the result of an atomic layer deposition process to produce an atomically smooth surface in an effort to reduce biofouling on the exterior surface.

Referring to <FIG>, with further reference to <FIG> and <FIG>, example results of chlorophyll buildup and prevention are shown. A first test results graph <NUM> includes a fluorescence axis <NUM>, a light wavelength axis <NUM>, a first control curve <NUM>, and a results curve <NUM>. The fluorescence axis <NUM> is expressed in arbitrary units to show the fluorescence emission intensity of chlorophyll buildup on a control window in an underwater marine environment. In an example, the apparatus <NUM> may be used as a fouling resistant fluorometer. That is, the optical sensor <NUM> may be configured to measure the fluorescence of seawater and the control curve <NUM> and the results curve <NUM> represent measure of fluorescence at the indicated wavelengths. The control curve <NUM> shows the results of a window placed in a marine environment that was not irradiated by a UV source. The control curve <NUM> indicates the formation of chlorophyll (e.g., the appearance of the chlorophyll emission) on the control window material. The formation of chlorophyll is an early indicator for the onset of biofouling, because biofouling communities include algae and cyanobacteria that produce chlorophyll. In comparison, the results curve <NUM> illustrates the results of illuminating an identical window in the same marine environment as the control window with the UV LEDs <NUM>. The results curve <NUM> indicates the absence of chlorophyll formation on the window that was irradiated with 40mW (285UV) (400mA) for <NUM>. 1sec - the flash intensity and duration 206a - followed by darkness (or 10e-12mW for the low intensity cycle) for <NUM>. 9sec - the rest intensity and duration 206b. Summation of the energies used during the periods and division by the sum of durations of the periods provides the equivalent of <NUM> microwatt - of 285UV continuous or - considering an electrical to UV conversion efficiency of <NUM>% of state-of-the-art UV LEDs - 20mW electrical continuous.

Referring to <FIG>, with further reference to <FIG> and <FIG>, example results of chlorophyll buildup and prevention are shown. A second test results graph <NUM> includes the fluorescence axis <NUM>, the light wavelength axis <NUM>, a second control curve <NUM>, a <NUM>-microwatt results curve <NUM>, and a <NUM>-microwatt results curve <NUM>. The control curve <NUM> shows the results of a window placed in a marine environment that was not irradiated by a UV source. The control curve <NUM> indicates the formation of chlorophyllon the control window material. (by the appearance of the chlorophyll emissionspectrum) The <NUM>-microwatt results curve <NUM> and the <NUM>-microwatt results curve <NUM> illustrates the results of illuminating an identical window in the same marine environment as the control window with the UV LEDs <NUM>. The <NUM>-microwatt continuous (averaged) results curve <NUM> indicates a relatively less amount of chlorophyll formation on a window that was irradiated with 1mW (285UV) (10mA current) for <NUM>. 1sec (e.g., the flash intensity and duration 206a), followed by darkness (or 10e-12mW for the low intensity cycle) for <NUM>. 9sec (e.g., the rest intensity and duration 206b). The <NUM>-microwatt continuous (averaged) results curve <NUM> indicates no amount of chlorophyll formation on a window that was irradiated with approximatley <NUM> mW (285UV) (<NUM> mA current) for <NUM>. 1sec followed by darkness of <NUM> sec, or <NUM>µW integrated UVC. The <NUM>-microwatt results curve <NUM> illustrates that a virtual elimination of biofouling may be achieved with much less power as required by other light-based biofouling solutions and as expected by those skilled in the art. The flash and rest intensity and duration values are examples only as other values may be used based on the marine environment and operational application of the apparatus <NUM>.

Referring to <FIG>, with further reference to <FIG>, a method <NUM> of determining a lamp duty cycle includes the stage shown. The method <NUM> is, however, an example only and not limiting. The method <NUM> may be altered, e.g., by having stages added, removed, rearranged, combined, performed concurrently, and/or having single stages split into multiple stages. For example, stages <NUM> and <NUM> for determining the flash and rest intensity and duration values may be combined into a single stage. Still other alterations to the method <NUM> as shown and described are possible.

At stage <NUM>, the method includes disposing an optical device in a marine environment, such that the optical device is directed at an object in the marine environment. The optical device <NUM> may be located within the device cavity <NUM> in the housing <NUM> and behind the UV transparent window <NUM>. In an example, the optical device <NUM> may be capable of movement within the cavity <NUM> thus optical device <NUM> may be directed along a different axis than the housing <NUM>. The housing <NUM> may include multiple UV transparent windows <NUM> at different orientations (e.g., on different planes) and the optical device <NUM> may be configured to align with each of the different orientation to obtain an image through the windows. The object in the marine environment may be a visual test pattern, quick response code, bar code, or other object with known dimensions or visual features. In an example, the object may be a reflector or a constant light source. In some installations, the object may be part of the environment such as a coral formation, or a man-made object such as an anchor chain or cable. In general, the object is used as a reference to compare image quality over a period of time.

At stage <NUM>, the method includes obtaining an image of the object with the optical device. The optical device <NUM> may be a camera or other sensor configured to obtain and store an electronic representation of the object. The representation of the object may be stored in a memory within the optical device <NUM>, the controller <NUM>, or other device within or external to the housing <NUM>. In an example, the image may persist in a computerized file formats such as raw formats (e.g., camera image file format (CIFF), digital negative (DNG), etc.), raster formats (e.g., joint photographic experts group (JPEG), tagged image file format (TIFF), graphics interchange format (GIF), bitmap (BMP), portable network graphics (PNG), etc.), stereo formats (e.g., portable network graphics (PNS), multi picture object (MPO), etc.), or other electronic formats that are suitable for use in objective image quality algorithms.

At stage <NUM>, the method includes determining a quality of the image. The controller <NUM>, or other computer system, may be configured to execute one or more objective methods to determine a quality of the image obtained at stage <NUM>. For example, full-reference and reduced-reference methods may be used based on a previously obtained or stored image of the object. No-reference methods may also be used to determine the quality of image without reference to a prior image. The quality of the image may be based on a sharpness value associated with contrast boundaries in an image. Example of image sharpness quality measures include cumulative probability detection (CPBD) and just noticeable blur (JNB). The image quality measure may be based on a frequency domain image blur measure. Other objective image quality algorithms may be used to determine a quality of the image of the object. The quality of the image may be compared to a previously determined threshold value to determine whether or not the image quality is operationally acceptable. That is, a low-quality image may be an indication of a potential increase in biofouling on the exterior surface of the UV transparent window <NUM>. The image quality may be used to modify the control signal provided to the UV LEDs <NUM>.

At stage <NUM>, the method includes determining a flash intensity value and a flash duration based on the quality of the image. The controller <NUM>, or other computer system, may be configured to modify the power signal provided to the UV LEDs <NUM>. In an example, a look-up table or other data structure may include one or more tables to correlate one or more image quality values with flash intensity and duration values (e.g., the period of relatively higher power 206a). For example, in response to a low-quality image obtained at stage <NUM>, the controller <NUM> may increase the intensity value of the flash (e.g., provide a high-power flash), increase the duration of flash (e.g., a longer active time), or a combination of both. In an example, the flash intensity value may be between <NUM> mW and 100mW, and the flash duration may be between <NUM> seconds and <NUM> seconds.

At stage <NUM>, the method includes determining a rest intensity value and a rest duration based on the quality of the image. The controller <NUM>, or other computer system, may be configured to modify the power signal provided to the UV LEDs <NUM>. In an example, a look-up table or other data structure may include one or more tables to correlate one or more image quality values with rest intensity and duration values (e.g., the period of relatively lower power 206b). For example, in response to a low-quality image obtained at stage <NUM>, the controller <NUM> may increase the intensity value of the rest power (e.g., provide a lower rest lamp intensity), decrease the duration of rest period (e.g., increase the rate of flashes), or a combination of both. In an example, a look-up table or other function may be used to determine a combination of flash intensity, flash duration, rest intensity and rest duration (e.g., the lamp power function <NUM>) based on the image quality. The lamp power function <NUM> need not be limited to impulse signals (e.g., flashes) as other power profiles may be used (e.g., stepped functions, saw-tooth, quick pulses, etc.). The lamp power function <NUM> may be based on more than one image quality calculation. For example, multiple image quality calculations may be used to determine a rate of image quality degradation, and the lamp power function <NUM> may be based on the rate of image quality degradation. The objective of changing the lamp power function <NUM>, including the flash and rest periods, is to retard the rate of biofouling and/or possibly reduce the amount of accumulated biofouling.

At stage <NUM>, the method includes activating at least one ultraviolet light source for a plurality of cycles based on the flash intensity value, the flash duration, the rest intensity value, and the rest duration, wherein the ultraviolet light source is disposed proximate to the optical device and directed at the window. The controller <NUM> is configured to provide one or more lamp power functions <NUM> to one or more of the UV LEDs <NUM> disposed within the cavity <NUM>. The UV LEDs <NUM> are directed toward the UV transparent window <NUM> and thus in the direction of the object. The proximity of the UV LEDs <NUM> to the optical device <NUM> and the UV transparent window <NUM> enables a reduction of lamp power to achieve a reduction in biofouling as compared to externally mounted lamps because the emitted UV energy is not absorbed by intervening seawater. The number of cycles may be based on an expected results time period. For example, the UV LEDs <NUM> may be activated based on the determined flash intensity value, the flash duration, the rest intensity value, and the rest duration for a period of minutes, hours, days, weeks. After a plurality of cycles, the method includes obtaining another image at stage <NUM> and iterating through the method <NUM> again. In an example, the optical device <NUM> may be configured to enter a dark mode (e.g., not active) or a shutter down mode (e.g., closing the optical path) when the UV LEDs <NUM> are activated.

In an example, the apparatus <NUM> may be included in a network including a plurality of similar apparatuses. The network may include optical devices in a relatively small operational area (e.g., harbor, offshore oil rig) or a larger network (e.g., ocean region). Each of the apparatuses <NUM> may be configured to send and receive lamp power functions <NUM> to one or more network servers/data storage devices. In an example, the controller <NUM> may include a communication module configured to send and receive wired or wireless communication packets (e.g., ethernet, WiFi, BLUETOOTH, near-field communication technologies, infra-red, UV, and visible light communication, etc.). In such a networked environment, the lamp power functions <NUM> may be crowdsourced such that particularly effective lamp power functions <NUM> determined on one apparatus may be stored on one or more networked servers and then propagated to other devices on the network. An effective lamp power function <NUM> may be evaluated based on a steady or slowly decreasing image quality. The effectiveness of a particular lamp power function <NUM> may be evaluated based on the geographic location of the reporting apparatus (i.e., some lamp power functions may be more effective in certain areas). The design of the apparatus <NUM> enables the transfer of power lamp functions across a network of similar system because the UV LED <NUM> is located within the cavity <NUM> for each apparatus <NUM> in the network. That is, the present design reduces the possibility of non-linear effects caused by the seawater located between a window and UV source as may occur in the prior art.

For example, due to the nature of software and computers, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination of any of these.

Also, as used herein, "or" as used in a list of items prefaced by "at least one of" or prefaced by "one or more of" indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C," or a list of "one or more of A, B, or C," or "A, B, or C, or a combination thereof' means A or B or C or AB or AC or BC or ABC (i.e., A and B and C), or combinations with more than one feature (e.g., AA, AAB, ABBC, etc.).

As used herein, unless otherwise stated, a statement that a function or operation is "based on" an item or condition means that the function or operation is based on the stated item or condition and may be based on one or more items and/or conditions in addition to the stated item or condition.

Further, an indication that information is sent or transmitted, or a statement of sending or transmitting information, "to" an entity does not require completion of the communication. Such indications or statements include situations where the information is conveyed from a sending entity but does not reach an intended recipient of the information. The intended recipient, even if not actually receiving the information, may still be referred to as a receiving entity, e.g., a receiving execution environment. Further, an entity that is configured to send or transmit information "to" an intended recipient is not required to be configured to complete the delivery of the information to the intended recipient. For example, the entity may provide the information, with an indication of the intended recipient, to another entity that is capable of forwarding the information along with an indication of the intended recipient.

Substantial variations may be made in accordance with specific requirements.

The terms "machine-readable medium" and "computer-readable medium," as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. Using a computer system, various computer-readable media might be involved in providing instructions/code to processor(s) for execution and/or might be used to store and/or carry such instructions/code (e.g., as signals). In many implementations, a computer-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media and volatile media. Non-volatile media include, for example, optical and/or magnetic disks. Volatile media include, without limitation, dynamic memory.

Common forms of physical and/or tangible computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, any other physical medium with patterns of holes, a RAM, a PROM, EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code.

Various forms of computer-readable media may be involved in carrying one or more sequences of one or more instructions to one or more processors for execution. Merely by way of example, the instructions may initially be carried on a magnetic disk and/or optical disc of a remote computer. A remote computer might load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and/or executed by a computer system. The apparatus <NUM> may be operably coupled to one or more processors via a wired and/or wireless connections.

For instance, in alternative configurations, the methods may be performed in an order different from that described, and that various steps may be added, omitted, or combined.

Also, configurations may be described as a process which is depicted as a flow diagram or block diagram. Although each may describe the operations as a sequential process, some operations may be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional stages or functions not included in the figure. Furthermore, examples of the methods may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the tasks may be stored in a non-transitory computer-readable medium such as a storage medium. Processors may perform one or more of the described tasks.

Components, functional or otherwise, shown in the figures and/or discussed herein as being connected, coupled (e.g., communicatively coupled), or communicating with each other are operably coupled. That is, they may be directly or indirectly, wired and/or wirelessly, connected to enable signal transmission between them.

"About" and/or "approximately" as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, encompasses variations of ±<NUM>% or ±<NUM>%, ±<NUM>%, or +<NUM>% from the specified value, as appropriate in the context of the systems, devices, circuits, methods, and other implementations described herein. "Substantially" as used herein when referring to a measurable value such as an amount, a temporal duration, a physical attribute (such as frequency), and the like, also encompasses variations of ±<NUM>% or ±<NUM>%, ±<NUM>%, or +<NUM>% from the specified value, as appropriate in the context of the systems, devices, circuits, methods, and other implementations described herein.

A statement that a value exceeds (or is more than or above) a first threshold value is equivalent to a statement that the value meets or exceeds a second threshold value that is slightly greater than the first threshold value, e.g., the second threshold value being one value higher than the first threshold value in the resolution of a computing system. A statement that a value is less than (or is within or below) a first threshold value is equivalent to a statement that the value is less than or equal to a second threshold value that is slightly lower than the first threshold value, e.g., the second threshold value being one value lower than the first threshold value in the resolution of a computing system.

Claim 1:
A method for reducing biofouling in a marine environment, comprising:
disposing an optical device (<NUM>) in the marine environment, wherein the optical device is directed at an object in the marine environment;
obtaining an image of the object with the optical device;
determining a quality of the image;
characterized in that the method further comprises:
determining a high power value and a high power duration based on the quality of the image;
determining a low power value and a low power duration based on the quality of the image; and
activate at least one ultraviolet light source (<NUM>) for a plurality of cycles based on the high power value, the high power duration, the low power value and the low power duration, wherein the at least one ultraviolet light source is disposed proximate to the optical device and directed at the object.