Source: https://patents.justia.com/patent/8334898
Timestamp: 2019-06-18 02:49:21
Document Index: 177892190

Matched Legal Cases: ['§119', 'Application No. 61', '§119', 'Application No. 61', '§119', 'Application No. 61', '§119', 'Application No. 61', '§120', '§120', '§120', '§120']

US Patent for Method and system for configuring an imaging device for the reception of digital pulse recognition information Patent (Patent # 8,334,898 issued December 18, 2012) - Justia Patents Search
Justia Patents Special ApplicationsUS Patent for Method and system for configuring an imaging device for the reception of digital pulse recognition information Patent (Patent # 8,334,898)
Jun 19, 2012 - ByteLight, Inc.
In one aspect, the present disclosure related to a method for configuring one or more imaging sensors of an imaging device to capture digital images for digital pulse recognition demodulation. In some embodiments, the method includes initializing one or more imaging sensors of the imaging device, determining a subset of the one or more imaging sensors to configure, setting a configuration for each of the one or more imaging sensors of the subset by defining a region of interest as a metering area for each of the one or more imaging sensors of the subset and automatically adjusting a setting for each of the one or more imaging sensors of the subset, and adjusting input parameters of a demodulation function based on a device profile of the imaging device. In some embodiments, the adjusted setting is locked to prevent further adjustment of the adjusted setting.
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This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/639,428, filed Apr. 27, 2012 and entitled “Method For Measuring Modulation Frequency Of A Light Source,” the entire contents of which are incorporated herein by reference.
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/635,413, filed Apr. 19, 2012 and entitled “Digital Pulse Recognition Demodulation Techniques For Light Based Positioning,” the entire contents of which are incorporated herein by reference.
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/567,484, filed Dec. 6, 2011 and entitled “Systems And Methods For Light Based Location,” the entire contents of which are incorporated herein by reference.
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/511,589, filed Jul. 26, 2011 and entitled “System Using Optical Energy For Wireless Data Transfer,” the entire contents of which are incorporated herein by reference.
This application is a continuation-in-part of and claims benefit under 35 U.S.C. §120 to U.S. Utility application Ser. No. 13/446,520, entitled “Method And System For Tracking And Analyzing Data Obtained Using A Light Based Positioning System,” filed Apr. 13, 2012, which is a continuation of and claims benefit under 35 U.S.C. §120 to U.S. Utility application Ser. No. 13/445,019, entitled “Single Wavelength Light Source for Use in Light Based Positioning System,” filed Apr. 12, 2012; U.S. Utility application Ser. No. 13/435,448, entitled “A Method and System for Calibrating a Light Based Positioning System,” filed Mar. 30, 2012; U.S. Utility application Ser. No. 13/422,591, entitled “Self Identifying Modulated Light Source,” filed Mar. 16, 2012; U.S. Utility application Ser. No. 13/422,580, entitled “Light Positioning System Using Digital Pulse Recognition,” filed Mar. 16, 2012; U.S. Utility application Ser. No. 13/369,147, entitled “Content Delivery Based on a Light Positioning System,” filed Feb. 8, 2012; and U.S. Utility application Ser. No. 13/369,144, entitled “Independent Beacon Based Light Positioning System,” filed Feb. 8, 2012.
This application is also a continuation-in-part of and claims benefit under 35 U.S.C. §120 to U.S. Utility application Ser. No. 13/446,506, entitled “Method And System For Determining the Position Of A Device In A Light Based Positioning System Using Locally Stored Maps,” filed Apr. 13, 2012, which is a continuation of and claims benefit under 35 U.S.C. §120 to U.S. Utility application Ser. No. 13/445,019, entitled “Single Wavelength Light Source for Use in Light Based Positioning System,” filed Apr. 12, 2012; U.S. Utility application Ser. No. 13/435,448, entitled “A Method and System for Calibrating a Light Based Positioning System,” filed Mar. 30, 2012; U.S. Utility application Ser. No. 13/422,591, entitled “Self Identifying Modulated Light Source,” filed Mar. 16, 2012; U.S. Utility application Ser. No. 13/422,580, entitled “Light Positioning System Using Digital Pulse Recognition,” filed Mar. 16, 2012; U.S. Utility application Ser. No. 13/369,147, entitled “Content Delivery Based on a Light Positioning System,” filed Feb. 8, 2012; and U.S. Utility application Ser. No. 13/369,144, entitled “Independent Beacon Based Light Positioning System,” filed Feb. 8, 2012.
This application is also related to the following applications, filed concurrently herewith, the entire contents of which are incorporated herein by reference: U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Modifying A Beacon Light Source For Use In A Light Based Positioning System;” U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Modulating A Light Source In A Light Based Positioning System Using A DC Bias;” U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Device For Dimming A Beacon Light Source Used In A Light Based Positioning System;” U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Modulating A Beacon Light Source In A Light Based Positioning System;” U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Digital Pulse Recognition Demodulation;” U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Video Processing To Determine Digital Pulse Recognition Tones;” and U.S. patent application Ser. No. (TBA), filed on Jun. 19, 2012, entitled “Method And System For Demodulating A Digital Pulse Recognition Signal In A Light Based Positioning System Using A Fourier Transform.”
This disclosure relates generally to a system and method for configuring one or more imaging sensors of an imaging device to capture digital images for digital pulse recognition demodulation.
In one aspect, the present disclosure relates to a method for configuring one or more imaging sensors of an imaging device to capture digital images for digital pulse recognition demodulation. In some embodiments, the method includes initializing one or more imaging sensors of the imaging device, determining a subset of the one or more imaging sensors to configure, setting a configuration for each of the one or more imaging sensors of the subset by defining a region of interest as a metering area for each of the one or more imaging sensors of the subset and automatically adjusting a setting for each of the one or more imaging sensors of the subset, and adjusting input parameters of a demodulation function based on a device profile of the imaging device. In some embodiments, the adjusted setting is locked to prevent further adjustment of the adjusted setting. In some embodiments, the device profile is calculated by the imaging device. In some embodiments, the device profile is retrieved from a remote server. In some embodiments, the device profile includes at least rolling shutter speed of the one or more imaging sensors of the imaging device. In some embodiments, the demodulation function calculates a frequency content of an image captured by the one or more imaging sensors based on a detected stripe width. In some embodiments, a frequency corresponding to each stripe width is adjusted based on the rolling shutter speed of the one more imaging sensors from the device profile. In some embodiments, adjusting a setting for the imaging sensor includes adjusting one of exposure, focus, saturation, white balance, zoom, contrast, brightness, gain, sharpness, ISO, resolution, image quality, scene selection, and metering mode. In some embodiments, the defined region of interest is the brightest area of an image captured by a particular imaging sensor and automatically adjusting a setting for the particular imaging sensor includes lowering the exposure time for the particular imaging sensor. In some embodiments, the one or more imaging sensors of the imaging device includes at least a front-facing imaging sensor and a rear-facing imaging sensor. In some embodiments, initializing one or more imaging sensors of the imaging device includes setting at least one of frame rate, data format, encoding scheme, and color space for one of the one or more imaging sensors. In some embodiments, determining a subset of the one or more imaging sensors to configure is based on at least one of desired level of power consumption, desired level of demodulation accuracy, amount of time since each sensor was last modified, environmental conditions, and the battery state of the imaging device. In some embodiments, the subset of the one or more imaging sensors to configure is fewer than all of the one or more imaging sensors of the imaging device. In some embodiments, the subset of the one or more imaging sensors to configure is all of the one or more imaging sensors of the imaging device.
Another aspect of the present disclosure related to an image detection apparatus for capturing digital images for digital pulse recognition demodulation. In some embodiments, the image detection apparatus includes one or more imaging sensors and a processor in communication with the one or more imaging sensors configured to initialize one or more imaging sensors, determine a subset of the one or more imaging sensors to configure, set a configuration for each of the one or more imaging sensors of the subset by defining a region of interest as a metering area each of the one or more imaging sensors of the subset and automatically adjusting a setting for each of the one or more imaging sensors of the subset, and adjust input parameters of a demodulation function based on a device profile of the image detection apparatus. In some embodiments, the processor is configured to lock the adjusted setting to prevent further adjustment of the adjusted setting. In some embodiments, the processor is configured to calculate the device profile. In some embodiments, the processor is configured to retrieve the device profile from a remote server. In some embodiments, the device profile includes at least rolling shutter speed of the one or more imaging sensors of the image detection apparatus. In some embodiments, the processor is configured to calculate frequencies using the demodulation function based on a detected stripe width in images captured by the one or more imaging sensors. In some embodiments, a frequency corresponding to each stripe width is adjusted based on the rolling shutter speed of the one more imaging sensors from the device profile. In some embodiments, adjusting a setting for the imaging sensor includes adjusting one of exposure, focus, saturation, white balance, zoom, contrast, brightness, gain, sharpness, ISO, resolution, image quality, scene selection, and metering mode. In some embodiments, the defined region of interest is the brightest area of an image captured by a particular imaging sensor and automatically adjusting a setting for the particular imaging sensor includes lowering the exposure time for the particular imaging sensor. In some embodiments, the one or more imaging sensors includes at least a front-facing imaging sensor and a rear-facing imaging sensor. In some embodiments, the processor is configured to initialize one or more imaging sensors by setting at least one of frame rate, data format, encoding scheme, and color space for one of the one or more imaging sensors. In some embodiments, the processor is configured to determine a subset of the one or more imaging sensors to configure based on at least one of desired level of power consumption, desired level of demodulation accuracy, amount of time since each sensor was last modified, environmental conditions, and the battery state of the image detection apparatus. In some embodiments, the subset of the one or more imaging sensors to configure is fewer than all of the one or more imaging sensors of the image detection apparatus. In some embodiments, the subset of the one or more imaging sensors to configure is all of the one or more imaging sensors of the image detection apparatus.
In terms of the experience when using a light-based positioning system, the indoor location reception and calculation can happen with little to no user input. The process operates as a background service, and reads from the receiving module without actually writing them to the display screen of the mobile device. This is analogous to the way WiFi positioning operates, signals are read in a background service without requiring user interaction. The results of the received information can be displayed in a number of ways, depending on the desired application. In the case of an indoor navigation application, the user would see an identifying marker overlaid on a map of the indoor space they are moving around in. In the case of content delivery, the user might see a mobile media, images, text, videos, or recorded audio, about the objects they are standing in front of.
In scenarios where the mobile device 103 is in view of several light sources, it can receive multiple signals at once. FIG. 2 is a representation of a mobile device 103 receiving identification information 102a-102c from multiple LED light sources 101a-101c. Each light source is transmitting its own unique piece of information. In order to identify its position or receive location-based content, the mobile device 103 can then use the received information to access a database 802 containing information about the relative positions of the LED light sources 101a-101c and any additional content 903. When three or more sources of light are in view, relative indoor position can be determined in three dimensions. The position accuracy decreases with less than three sources of light, yet remains constant with three or more sources. With the relative positions of lights 101a-101c known, the mobile device 103 can use photogrammetry to calculate its position, relative to the light sources.
Enclosed area 602 is a spatial representation of an enclosed room containing four LED sources 101a-101d and two mobile devices 103a-103b, meaning that they can operate next to each other without interference. As a rule of thumb if the received image feed from the mobile device sees one or more distinct bright sources of light, it has the ability to differentiate and receive the unique information without interference. Because the light capture is based on line of sight, interference is mitigated. In this line of sight environment, interference can arise when the light capture mechanism of the mobile device is blocked from the line of sight view of the light source.
Network 601 represents a data network which can be accessed by mobile devices 103a-103b via their embedded network adapters 503. The network can consist of a wired or wireless local area network (LAN), with a method to access a larger wide area network (WAN), or a cellular data network (Edge, 3G, 4G, LTS, etc). The network connection provides the ability for the mobile devices 103a-103b to send and receive information from additional sources, whether locally or remotely.
FIGS. 18A-C represent several digitally modulated light sources 101a-c with varying duty cycles; a low duty cycle 1801, a medium duty cycle 1802, and a high duty cycle 1803. A duty cycle is a property of a digital signal that represents the proportion of time the signal spends in an active, or “on,” state as opposed to an inactive, or “off,” state. A light source with a low duty cycle 1801 is inactive for a high proportion of time. A light source with a medium duty cycle 1802 is inactive for about the same proportion of time that it is active. A light source with a high duty cycle 1803 is active for a high proportion of time. The duty cycle of a light source affects the luminosity of the light source. A light source having a higher duty cycle generally provides more luminosity than that same light source with a lower duty cycle because it is on for a higher proportion of time. Duty cycle is one aspect of a modulation scheme. Other aspects include pulse shape, frequency of pulses, and an offset level (e.g., a DC bias).
Because DPR modulated light sources 101 rely on frequency modulation, they are able to circumvent the limitations of traditional AM based approaches. Note that frequency modulation in this context does not refer to modifying the frequency of the carrier (which is the light signal), but instead to modifying the frequency of a periodic waveform driving the light source. One popular technique for dimming LED light sources 101 is with pulse width modulation (PWM), which controls the average power delivered to the light source by varying the duty cycle of a pulse. In a DPR modulation system utilizing PWM, a DPR modulator would control the frequency of the pulses, with the duty cycle determined by the dimming requirements on the light source 101. As used herein, a DPR modulated light source, having a DPR modulation frequency, refers to a light source having an output modulated in such a manner that a receiver using DPR demodulation techniques can demodulate the signal to extract data from the signal. In some embodiments, the data can include information in the form of an identifier which distinguishes a light source from other nearby DPR modulated light sources. In some embodiments, this identifier may be a periodic tone that the light source randomly selects to identify itself A periodic tone may be a signal that repeats with a given frequency. In other embodiments, a light source may receive such an identifier from an external source.
In order to solve for Toff in terms of duty cycle and modulation frequency, one can first start with the fundamental definition of what the duty cycle is: 1 minus the ratio of signal on time divided by the combination of signal on and off time. In the case of a modulated light source, D=1−Toff/(Ton+Toff). Next the modulation frequency (f) can be defined as the inverse of the sum of signal on and off times: f=1/(Ton+Toff). Substituting f into the previous equation for D yields D=1−f*Toff. The variable Toff, which was previously defined as a value less than twice Ts, can then be used to define the maximum duty cycle for any given modulation used in DPR demodulation. After rearranging and substituting Ts for Toff(Toff<0.5*Ts), D=1−f*(½)*(Ts). With this equation, we can now solve for the maximum duty cycle achievable given the modulation frequency of the transmitter, and the sampling time of the receiver.
When analyzing specific use cases, the duty cycles corresponding to a modulation frequency of 300 Hz and sampling frequencies for high quality image settings in some embodiments result in D=1−(300 Hz)*(½)*( 1/20 Khz)=99.25% and D=1−(300 Hz)*(½)( 1/36 kHz)=99.58%. The duty cycles corresponding to a modulation frequency of 300 Hz and typical sampling frequencies low quality sampling frequencies in other embodiments result in D=1−(300 Hz)*(½)*(¼ kHz)=96.25% and D=1−(300 Hz)*(½)*( 1/7 kHz)=97.86%. In yet other embodiments, a 2000 Hz modulation frequency and high quality sampling frequencies of 20 kHz and 36 kHz results in D=95.00% and 97.22% respectively, and for low quality sampling frequencies of 4 kHz and 7 kHz results in D=75% and 85.71% respectively.
While finding the maximum duty cycle supported by DPR demodulation is important for maintaining the brightest luminous output levels, it is also important to support the lowest duty cycle possible in order to support the dimmest luminous output levels. This is because the minimum duty cycle corresponds to the dimmest level that a modulated light source 101 can operate at while still supporting DPR demodulation from a receiving device. In order to account for this, we now consider the Ton portion of the signal rather than Toff. The limiting sampling factor now changes to require that Ts is greater than twice Ton (Ts>2Ton). Substituting this condition into the previous max duty cycle equation (replacing {1−D} with D), the resulting equation yields D=(½)*f*Ts.
In addition to modifying the overall duty cycle, there also exists the opportunity to tune the modulation scheme such that during the “off” portion 1805 of operation the light source 101 does not turn completely off As described in FIGS. 19A-C, modulation schemes 1901, 1902, and 1903 depict varying duty cycles where a DC bias 1904 has been added which correspond to the modulated light sources 101a-101c. Modulation schemes where the light source 101 does not turn all the way “off” are important when considering light source 101 brightness, efficiency, lifetime, and the signal to noise ratio (SNR) of the communications channel. The DC bias 1904 during modulation reduces the peak power required to drive the light source for a given brightness. A reduction in peak power will reduce the negative impact of overdriving the lighting source, which is known to cause efficiency losses known as “droop” for LEDs, in addition to decreasing light source 101 lifetimes.
As an example, consider that the average power delivered to the light source is defined as: PavD*Pon+(1−D)*Poff, where D is the duty cycle and Pon, Poff are the respective on/off powers. The impact on light source 101 brightness is that increasing the “off” power will increase the total power. This reduces the required peak power delivered to the lighting source, because the power transferred during the “off” period can make up the difference. In a system operating at a duty cycle of 50%, for a fixed brightness B, a 10% increase in the “off” period power translates to a 10% decrease in the “on” period power.
When approaching the above power equation from a constant voltage (V), average current (Iav), and on/off current (Ion/Ioff) standpoint (P=IV), Iav*V=D*Ion*V+(1−D)*Ioff*V. After removing the constant V, IavD*Ion+(1−D)Ioff. For example, in the case of a light source 101 requiring an average drive current (Iave) of 700 mA and off current of (Ioff) of 0 A undergoing modulation with a duty cycle (D) of 96.25%, the peak current (Ion) requirement is Ion=700 mA/0.9625=727 mA. If instead the current delivered during the “off” time is 100 mA the average current reduces to Iav=0.9625*700 mA+(1−0.9625)*100 mA=678 mA, a 6.7% decrease in overall required power given constant voltage. In other embodiments, a constant current may be applied with differing voltages to achieve a similar effect.
FIG. 24 contains the breakdown of Symbol Creator 2303, which holds possible symbols 2401a-2401d. These could include a saw tooth wave 2401a, sine wave 2401b, square wave 2401c, and square wave with a DC offset 2401d, or any other periodic symbol. Symbol creator then takes in a selected symbol 2402, and modifies it such that a desired brightness 2106 is achieved. In the case of a square wave symbol 2401c, dimmer signal 2003 would modify the duty cycle of the square wave. The resulting waveform is then sent to output signal 2005 for driving the light source.
After removing the background scene, Fourier Analysis can be used to recover the DPR tone based on signals received from modulated light source 103. Specifics of this method are further described in FIGS. 36-43. FIG. 36 contains a sample image 3601 of a surface illuminated by a light source undergoing DPR modulation. The image is being recorded from a mobile device using a rolling shutter CMOS camera. The stripes 3602 on the image are caused by the rolling shutter sampling function, which is modeled in by the sequence of Dirac Combs 2801 in FIG. 28.
1. A method for configuring one or more imaging sensors of an imaging device to capture digital images for digital pulse recognition demodulation, the method comprising:
initializing one or more imaging sensors of the imaging device;
determining a subset of the one or more imaging sensors to configure;
setting a configuration for each of the one or more imaging sensors of the subset by defining a region of interest as a metering area for each of the one or more imaging sensors of the subset and automatically adjusting a setting for each of the one or more imaging sensors of the subset; and
adjusting input parameters of a demodulation function based on a device profile of the imaging device, wherein the demodulation function calculates a frequency content of an image captured by the one or more imaging sensors based on a detected stripe width and the device profile comprises at least rolling shutter speed of the one or more imaging sensors of the imaging device.
2. The method of claim 1, wherein the adjusted setting is locked to prevent further adjustment of the adjusted setting.
3. The method of claim 1, wherein the device profile is calculated by the imaging device.
4. The method of claim 1, wherein the device profile is retrieved from a remote server.
5. The method of claim 1, wherein a frequency corresponding to each stripe width is adjusted based on the rolling shutter speed of the one more imaging sensors from the device profile.
6. The method of claim 1, wherein adjusting a setting for the imaging sensor comprises adjusting one of exposure, focus, saturation, white balance, zoom, contrast, brightness, gain, sharpness, ISO, resolution, image quality, scene selection, and metering mode.
7. The method of claim 1, wherein the defined region of interest comprises the brightest area of an image captured by a particular imaging sensor and automatically adjusting a setting for the particular imaging sensor comprises lowering the exposure time for the particular imaging sensor.
8. The method of claim 1, wherein the one or more imaging sensors of the imaging device comprises at least a front-facing imaging sensor and a rear-facing imaging sensor.
9. The method of claim 1, wherein initializing one or more imaging sensors of the imaging device comprises setting at least one of frame rate, data format, encoding scheme, and color space for one of the one or more imaging sensors.
10. The method of claim 1, wherein the determining a subset of the one or more imaging sensors to configure is based on at least one of desired level of power consumption, desired level of demodulation accuracy, amount of time since each sensor was last modified, environmental conditions, and the battery state of the imaging device.
11. The method of claim 1, wherein the subset of the one or more imaging sensors to configure is fewer than all of the one or more imaging sensors of the imaging device.
12. The method of claim 1, wherein the subset of the one or more imaging sensors to configure is all of the one or more imaging sensors of the imaging device.
13. An image detection apparatus for capturing digital images for digital pulse recognition demodulation comprising:
one or more imaging sensors; and
a processor in communication with the one or more imaging sensors configured to initialize one or more imaging sensors, determine a subset of the one or more imaging sensors to configure, set a configuration for each of the one or more imaging sensors of the subset by defining a region of interest as a metering area each of the one or more imaging sensors of the subset and automatically adjusting a setting for each of the one or more imaging sensors of the subset, and adjust input parameters of a demodulation function based on a device profile of the image detection apparatus, wherein the processor is configured to calculate frequencies using the demodulation function based on a detected stripe width in images captured by the one or more imaging sensors and the device profile comprises at least rolling shutter speed of the one or more imaging sensors of the image detection apparatus.
14. The image detection apparatus of claim 13, wherein the processor is configured to lock the adjusted setting to prevent further adjustment of the adjusted setting.
15. The image detection apparatus of claim 13, wherein the processor is configured to calculate the device profile.
16. The image detection apparatus of claim 13, wherein the processor is configured to retrieve the device profile from a remote server.
17. The image detection apparatus of claim 13, wherein a frequency corresponding to each stripe width is adjusted based on the rolling shutter speed of the one more imaging sensors from the device profile.
18. The image detection apparatus of claim 13, wherein adjusting a setting for the imaging sensor comprises adjusting one of exposure, focus, saturation, white balance, zoom, contrast, brightness, gain, sharpness, ISO, resolution, image quality, scene selection, and metering mode.
19. The image detection apparatus of claim 13, wherein the defined region of interest comprises the brightest area of an image captured by a particular imaging sensor and automatically adjusting a setting for the particular imaging sensor comprises lowering the exposure time for the particular imaging sensor.
20. The image detection apparatus of claim 13, wherein the one or more imaging sensors comprises at least a front-facing imaging sensor and a rear-facing imaging sensor.
21. The image detection apparatus of claim 13, wherein the processor is configured to initialize one or more imaging sensors by setting at least one of frame rate, data format, encoding scheme, and color space for one of the one or more imaging sensors.
22. The image detection apparatus of claim 13, wherein the processor is configured to determine a subset of the one or more imaging sensors to configure based on at least one of desired level of power consumption, desired level of demodulation accuracy, amount of time since each sensor was last modified, environmental conditions, and the battery state of the image detection apparatus.
23. The image detection apparatus of claim 13, wherein the subset of the one or more imaging sensors to configure is fewer than all of the one or more imaging sensors of the image detection apparatus.
24. The image detection apparatus of claim 13, wherein the subset of the one or more imaging sensors to configure is all of the one or more imaging sensors of the image detection apparatus.
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Assignee: ByteLight, Inc. (Boston, MA)
Inventors: Daniel Ryan (North Andover, MA), Peter Staats (Wenham, MA), Rob Sumner (Cambridge, MA)
Application Number: 13/526,656