U.S. patent application number 16/565073 was filed with the patent office on 2020-04-09 for intrinsically safe video inspection system.
The applicant listed for this patent is Leonard Pool. Invention is credited to Leonard Pool.
Application Number | 20200112704 16/565073 |
Document ID | / |
Family ID | 43353977 |
Filed Date | 2020-04-09 |
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United States Patent
Application |
20200112704 |
Kind Code |
A1 |
Pool; Leonard |
April 9, 2020 |
Intrinsically Safe Video Inspection System
Abstract
An intrinsically safe video inspection system intended for use
in a Class I, Zone 0 area is capable of visually surveying
hazardous area locations; where the potential for fire or explosion
exists because of gases, dust, or easily ignitable fibers in the
atmosphere. The intrinsically safe camera of the present invention
has the distinct ability to be used all areas that require
increased safety and works in various hazardous environments,
allowing users the ability to remotely view and inspect various
mines, silos, and storage tanks. The inspection system includes a
low power, high 3.2 megapixel resolution camera with digital zoom
capability that allows for the close inspection and examination and
utilizes an LED fiber light pipe for illumination needs. The video
inspection system of the present invention provides for the
illumination in various cavity sizes, while reducing the risk of
unintended accidents.
Inventors: |
Pool; Leonard; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pool; Leonard |
San Diego |
CA |
US |
|
|
Family ID: |
43353977 |
Appl. No.: |
16/565073 |
Filed: |
September 9, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15862490 |
Jan 4, 2018 |
10412348 |
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16565073 |
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15018860 |
Feb 8, 2016 |
9866803 |
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15862490 |
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12803004 |
Jun 16, 2010 |
9258535 |
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15018860 |
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61268920 |
Jun 16, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 5/23241 20130101;
G06T 7/0004 20130101; H04N 7/183 20130101; H04N 2005/2255 20130101;
G02B 23/26 20130101; H04N 5/2256 20130101; H04N 7/22 20130101; G02B
23/2492 20130101 |
International
Class: |
H04N 7/22 20060101
H04N007/22; H04N 5/225 20060101 H04N005/225; H04N 7/18 20060101
H04N007/18; G06T 7/00 20060101 G06T007/00; H04N 5/232 20060101
H04N005/232; G02B 23/24 20060101 G02B023/24 |
Claims
1. An intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere comprising: a
camera chassis with a lens assembly defining a compartment for use
in a hazardous environment with a flammable and volatile
atmosphere; an intrinsically safe camera housed within the
compartment and configured to covert images from the lens assembly
to digital electronic signals and regulate the digital electronic
signals within a low voltage range of between 0 and 5 volts direct
current; and wherein the intrinsically safe camera is configured to
transmit the digital electronic signals to a host computer located
outside of the hazardous environment with a flammable and volatile
atmosphere.
2. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 1
further comprising a power source housed within the
compartment.
3. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 2
further comprising an antenna.
4. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 3,
wherein said camera chassis further comprises an antenna mold
housing the antenna.
5. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 4,
wherein said intrinsically safe camera further comprises: an
imaging device optically coupled to the lens assembly configured to
covert images to digital electronic signals; a controller in
communication with the imaging device; a memory in communication
with the controller; an input/output interface in communication
with the controller; and a fault protection safety circuit in
communication with the controller and configured to regulate the
digital electronic signals within the low voltage range of between
0 and 5 volts direct current.
6. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 1
further comprising an interconnecting cable connecting the
intrinsically safe video camera system located in the hazardous
environment with a flammable and volatile atmosphere to the host
computer located outside of the hazardous environment with a
flammable and volatile atmosphere.
7. An intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere comprising: a
camera chassis with a lens assembly defining a compartment for use
in a hazardous environment with a flammable and volatile
atmosphere; an intrinsically safe camera housed within the
compartment and configured to covert images from the lens assembly
to digital electronic signals and regulate the digital electronic
signals within a low voltage range of between 0 and 5 volts direct
current; an interconnecting cable for use in hazardous environments
with a flammable and volatile atmosphere in communication with the
intrinsically safe camera; and wherein the intrinsically safe
camera is configured to transmit the digital electronic signals to
a host computer located outside of the hazardous environment with a
flammable and volatile atmosphere though the interconnecting
cable.
8. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 7,
wherein said interconnecting cable extends through the camera
chassis.
9. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 8,
wherein the interconnecting cable comprises a first end in
communication with the intrinsically safe camera and a second end
configured to be removably attached to and in communication with
the host computer located outside of the hazardous environment with
a flammable and volatile atmosphere.
10. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 9,
further comprising an interconnecting cable conditioning module
located outside of the hazardous environment with a flammable and
volatile atmosphere connected to the interconnecting cable, the
interconnecting cable conditioning module is in line with the
interconnecting cable between the first end and the second end and
is configured to regulate the voltage and current received from the
host computer, thereby regulating the voltage and current in the
interconnecting cable between the cable conditioning module and the
first end of the interconnecting cable.
11. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 8,
further comprising an interconnecting cable conditioning module
located outside of the hazardous environment with a flammable and
volatile atmosphere comprising: a host computer interconnecting
cable attached to a cable conditioning module, wherein the host
computer interconnecting cable is configured to connect to the host
computer and the cable conditioning module is configured to connect
to the interconnecting cable; and wherein the interconnecting cable
conditioning module is configured to regulate the voltage and
current in the interconnecting cable between the cable conditioning
module and the intrinsically safe camera.
12. An intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere comprising: a
camera chassis with a lens assembly defining a compartment for use
in a hazardous environment with a flammable and volatile
atmosphere; an intrinsically safe camera housed within the
compartment and configured to covert images from the lens assembly
to digital electronic signals and regulate the digital electronic
signals within a low voltage range of between 0 and 5 volts direct
current; an interconnecting cable for use in hazardous environments
with a flammable and volatile atmosphere in communication with the
intrinsically safe camera; an interconnecting cable conditioning
module located outside of the hazardous environment with a
flammable and volatile atmosphere connected to the interconnecting
cable, wherein the interconnecting cable conditioning module is
configured to regulate voltage and current in the interconnecting
cable; and wherein the intrinsically safe camera is configured to
transmit the digital electronic signals to a host computer located
outside of the hazardous environment with a flammable and volatile
atmosphere though the interconnecting cable and interconnecting
cable conditioning module.
13. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 12,
wherein said interconnecting cable extends through the camera
chassis.
14. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 13,
wherein the interconnecting cable comprises a first end in
communication with the intrinsically safe camera and a second end
in communication with the host computer with the cable conditioning
module in line with the interconnecting cable between the first end
and the second end, thereby regulating the voltage and current in
the interconnecting cable between the cable conditioning module and
the intrinsically safe camera.
15. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 13,
wherein said interconnecting cable conditioning module comprises: a
host computer interconnecting cable attached to a cable
conditioning module, wherein the host computer interconnecting
cable is configured to connect to the host computer and the cable
conditioning module is configured to connect to the interconnecting
cable; and wherein the interconnecting cable conditioning module is
configured to regulate the voltage and current in the
interconnecting cable between the cable conditioning module and the
intrinsically safe camera.
16. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 12,
wherein said intrinsically safe camera comprises a power
source.
17. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 16,
wherein said intrinsically safe camera further comprises: an
imaging device optically coupled to the lens assembly configured to
covert images to digital electronic signals; a controller in
communication with the imaging device; a memory in communication
with the controller; an input/output interface in communication
with the controller; and a fault protection safety circuit in
communication with the controller configured to regulate the
digital electronic signals within the low voltage range of between
0 and 5 volts direct current and transmit the digital electronic
signals to the host computer.
18. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 17,
wherein said interconnecting cable conditioning module comprises at
least one Zener diode to limit over-voltage and at least one
resistor to limit over-current.
19. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 18,
wherein the fault protection safety circuit comprises redundant
Zener diodes across signal lines to eliminate over-voltage.
20. The intrinsically safe video camera system for use in hazardous
environments with a flammable and volatile atmosphere of claim 16,
wherein said intrinsically safe camera further comprises an
input/output interface in communication with the controller and
configured to convert digital signals to optical signals and an
optical interface transmitter in communication with the
input/output interface.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of, and claims the
benefit of priority to, U.S. Utility patent application Ser. No.
15/862,490 entitled "Intrinsically Safe Video Inspection System"
filed in Jan. 4, 2018, and currently co-pending, which is a
continuation of, and claims the benefit of priority to, U.S.
Utility patent application Ser. No. 15/018,860 entitled
"Intrinsically Safe Video Inspection System" filed in Feb. 8, 2016,
now issued as U.S. Pat. No. 9,866,803, which is a Divisional of,
and claims the benefit of priority to, U.S. Utility patent
application Ser. No. 12/803,004 entitled "Intrinsically Safe Video
Inspection System" filed in Jun. 16, 2010, now issued as U.S. Pat.
No. 9,258,535, which in turn claims the benefit of priority to U.S.
Provisional Patent Application Ser. No. 61/268,920 entitled
"Intrinsically Safe Video Inspection System" filed Jun. 16, 2009,
now expired.
FIELD OF THE INVENTION
[0002] The present invention relates generally to video cameras and
inspection systems which include video cameras. The present
invention is particularly, though not exclusively, related to video
inspection systems for use in hazardous environments and especially
those hazardous environments having a volatile vapors with a high
risk of fire or explosion.
BACKGROUND OF THE INVENTION
[0003] With the technological advances that have been made in
camera technology, including the development of miniature and solid
state digital cameras, it has been increasingly commonplace to
incorporate video cameras into ordinary diagnostic equipment. One
specific application of the modern cameras is in the field of
robotics, and remote inspection systems. For instance, cameras may
be incorporated into robotically controlled electronics
manufacturing systems for inspection of solder or weld joints, for
examining the proper placement of components in electronic
assembly, and other uses where visual feedback would be
advantageous.
[0004] Another practical application of modern camera technology
includes the inspection of hazardous environments. For instance, a
video inspection system can provide a more detailed inspection than
the naked eye, can be exposed to environments incompatible with
human life, and can often identify defects long before they become
apparent to less sophisticated inspection systems. These defects,
if left unnoticed, can result in significant safety hazards, and in
some environments, can lead to catastrophe. One such environment is
in the inspection of tanks used for the transport and storage of
hazardous materials, such as fuel tanks, oil tanks, or other
dangerous chemicals.
[0005] Hazardous environments that contain volatile gasses, vapors,
or liquids are typically classified by zones. Specifically, a Zone
2 environment has no risk of fire or explosion, Zone 1 has a higher
risk of fire or explosion, and Zone 0 has a high risk of fire or
explosion. Equipment is typically certified to operate in specific
zones. For instance, one device may be certified only for use in
Zone 2 environments, while another device may be certified for use
in Zone 1. Typically, devices certified for Zone 1 can also be used
in Zone 2 since Zone 2 has less stringent requirements for safety
than Zone 1.
[0006] In order to satisfy the requirements for Zone 1 and Zone 0,
certain electrical and mechanical design requirements must be met.
These design requirements are primarily focused on safety concerns,
and include the limitations to avoid excessive heat, fire, spark,
static, or other sources of ignition. Devices that are designed for
use within the Zone 0 environment are considered "intrinsically
safe."
[0007] Intrinsic safety is a protection model employed in
potentially explosive atmospheres and relies on the electrical
apparatus being designed so that it is unable to release sufficient
energy by either thermal or electrical means that can cause an
ignition of a flammable gas. A published discussion of this
protection technique can be found at www.iec.ch. Part of IEC 60079
specifies the construction and testing of intrinsically safe
apparatus intended for use in an explosive gas atmosphere and for
associated apparatus, which is intended for connection to
intrinsically safe circuits which enter such atmospheres. These are
locations where ignitable concentrations of flammable gases,
vapors, liquids, dust, or easily ignitable fibers are present
continuously, or are present for long periods of time.
[0008] Historically, video systems have been excluded from being
used in Zone 0 applications due to the potential for an explosion.
Typical video systems include sufficient voltage potentials and
power uses that can create excessive sparking, localized heat
sources, and in some cases, a circuit failure could result in a
fire developing within the video system itself causing a primary
explosion. This is particularly dangerous when considering the
highly volatile Zone 0 environments where a primary explosion would
necessarily result in a more catastrophic secondary explosion.
[0009] In order to inspect Zone 0 or Zone 1 environments, it is
estimated that millions of dollars spent each year are expended in
the opening, gas-freeing and inspection of vapor and gas storage
and transportation tanks. This estimate does not take into account
the substantial amount of time required to prepare permits, secure
the area, evacuate the tank, and send in a person wearing HAZMAT
equipment inside the tank with conventional recording and
inspection equipment. Many of these are unplanned and could have
been unnecessary.
[0010] In light of the above, it would be advantageous to provide a
video inspection system that offers a multifold increase in process
efficiency from reduction in time and cost in tank opening,
gas-freeing, and inspection. In addition, it would be advantageous
to provide a video inspection system that offers quantitative and
standardized inspection analysis and results which are not subject
to human judgment, error or variability. Cost savings associated
with such a video inspection system would include a substantial
reduction in labor costs that are typically associated with the
insertion of trained inspectors into these confined spaces and the
unnecessary ventilation and re-preservation of tanks.
SUMMARY OF THE INVENTION
[0011] The present invention includes an intrinsically safe video
inspection system intended for use in a Class I, Zone 0 area. The
system of the present invention is capable of visually surveying
hazardous area locations; where the potential for fire or explosion
exists because of gases, dust, or easily ignitable fibers in the
atmosphere. Examples of these areas include mines, fuel tanks, oil
and gas production plants, and pipelines.
[0012] Due to the extreme conditions and the potential of loss or
damage to persons and machines, these unique areas demand regular
assessment; such as verification of content, corrosion, failures in
the materials or construction and unwanted objects. Additionally,
these applications have restrictive conditions such as poor
lighting, access, and a greater potential for hazardous or
explosive gases and/or fluids.
[0013] The intrinsically safe camera of the present invention has
the distinct ability to be used all areas that require increased
safety. There are other commercially available inspection systems
yet none meet the conditions of certified "Intrinsically Safety is
Type".
[0014] The intrinsically safe camera system works in various
hazardous environments, allowing users the ability to remotely view
and inspect various mines, silos, and storage tanks. Because it is
a low power solution and high 3.2 megapixel resolution, it can be
used in other applications such as submersibles, surveillance, oil
rigs, etc. The digital zoom capability allows for the close
inspection and examination of specific areas with greater detail
and provides a lighter weight solution than using an optical zoom.
Utilizing an LED fiber light pipe for illumination needs, the video
inspection system of the present invention provides for the
illumination in various cavity sizes, while reducing the risk of
unintended accidents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The nature, objects, and advantages of the present invention
will become more apparent to those skilled in the art after
considering the following detailed description in connection with
the accompanying drawings, in which like reference numerals
designate like parts throughout, and wherein:
[0016] FIG. 1 is a system level block diagram of the intrinsically
safe camera system of the present invention showing a hazardous
environment having Zone 0, Zone 1, and Zone 2 ratings, being
inspected by the intrinsically safe camera in communication with a
local computer, and communicating with a remote base computer;
[0017] FIG. 2 is a block diagram of the intrinsically safe camera
of the present invention showing the protection circuitry and power
source in combination with a processor having input from a video
sensor, and in response to relevant clock signals, storing and
transmitting through a USB interface, the image or video data to
the host computer;
[0018] FIG. 3 is a diagrammatic representation of the intrinsically
safe camera system of the present invention showing the camera
assembly having a lens assembly adjacent an imaging device, and
capturing video from an image area, relaying that information to a
controller, memory, and input/output interface, and then
transmitting this information through fault protection safety
circuits to the host computer; and
[0019] FIG. 4 is a diagrammatic representation of an alternative
embodiment of the intrinsically safe camera system of the present
invention showing the camera assembly having a lens assembly
adjacent an imaging device, and capturing video from an image area,
relaying that information to a controller, memory, and input/output
interface, converting this information to an optical signal and
then transmitting this information optically through an optical
transmitter/receiver to the host computer.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0020] Referring initially to FIG. 1, a system level block diagram
of the intrinsically safe camera system of the present invention is
shown and generally designated 100. System 100 includes a host
computer 102 or other video display device, a hazardous environment
104, a cable conditioning module 106 and an interconnecting cable
108 extending to the intrinsically safe camera assembly 110 having
a video image area 112.
[0021] Hazardous environment 104 may, in some instances, include a
chamber or tank 120 having an internal space 124 designated as Zone
0. This represents an extremely hazardous environment. Adjacent
opening 122 of chamber 120 is a less hazardous area 126 designated
as Zone 1, and a least hazardous area 128 designated Zone 2.
[0022] As shown in this Figure, cable 108 extends from the host
computer or other video display device and cable conditioning
module 106, through opening 122 and into Zone 0, 124. As can be
appreciated, it is important that cable 108 be made to avoid any
short circuits, avoid creating any sparks or conducting any static
electricity whatsoever. Any one of these conditions could result in
a primary explosion within the Zone 0 environment.
[0023] In a preferred embodiment, cable 108 may be an electric
cable of twisted shielded pairs using a communication protocol
typical of the USB 2.0 standard, having low power, and fault
protection on each end of the cable. For instance, on the camera
assembly end of the cable 108, the system may be made intrinsically
safe by incorporating a limiting resistor on the USB line having a
resistance of 4.7 ohms at 5 volts DC. Also, parallel and redundant
Zener diodes may be used across signal and power lines to eliminate
any over-voltage conditions. Further, DC to DC converters may be
used to convert low voltage signals from cable 108 to higher
voltages for use in the camera assembly 110.
[0024] Additionally or alternatively, conditioning module 106 may
also include a limiting resistor of a value determined by the
length of the cable 108 and the acceptable voltage drop across the
cable. Parallel and redundant Zener diodes may also be used to
avoid over-voltage conditions. Conditioning module 106 may also
include a USB signal extender thereby allowing for longer cable 108
lengths, and may also step up transmitting power for longer cable
lengths.
[0025] The intrinsically safe camera of the present invention also
provides of the auto-cable detection using techniques known in the
art, including but not limiting to auto-voltage adjustment,
automatic gain control (AGC), and the like. This can be
accomplished within conditioning module 106, and can also provide
supervisory functions, such as over-voltage protection, over
current protection, signal level boosting and detection of USB
transmit and receive, video signal levels, and may have
user-observable signal indicators, such as LED lights to indicate
status of the signals. Also, module 106 may change signal types
from one communication standard to another depending on user or
system requirements.
[0026] In order to avoid the creation of sparks, static, and the
effects of wear and tear on the cable 108, it may be jacketed with
chemical and corrosion resistant materials, such as plastic
shielding having anti-static properties. Also, cable 108 may be
made from braided and shielded cabling with a greater than 95%
shielding to avoid stray radiation and the build-up of static
electricity. Steel tubing and corrugated armor may also be
implemented to create a durable and fault-free cable 108.
[0027] The intrinsically safe camera assembly 110 of the present
invention must be capable of use in the hazardous environment
having Zone 0, Zone 1, and Zone 2 ratings. In this application,
camera assembly 110 may be used to inspect the interior of chamber
120, and the video inspection data is then transmitted along cable
108 to the host computer 102.
[0028] In some cases, it will be advantageous for host computer 102
to communicate with a remote base computer 107, such as reporting
inspection data, or receiving inspection instructions. In such
circumstances, communication link 130, such as a wireless
communication link, provides a communication path between the host
computer and a base computer. This link can be accomplished using
any known communication protocol without departing from the present
invention, including but not limited to transmission over wired and
wireless channels, and the Internet.
[0029] Referring now to FIG. 2, a block diagram of the
intrinsically safe camera of the present invention is shown and
generally designated 200. Camera 200 includes a processor 202, such
as a field programmable gate array (FPGA). It is to be appreciated
that other processors known in the art may be used, including
microprocessors and microcontrollers. A memory 204 is provided for
storage of program data and to enable storage of video images and
files. Memory 204, in a preferred embodiment is a solid state
storage media, such as electrically erasable programmable read only
memory (EEPROM), battery backed random access memory (RAM), or
other media known in the art and suitable for use herein.
[0030] Memory 204 in a preferred embodiment is RAM. This RAM may be
partitioned into multiple memory blocks (shown by dashed line 205).
In a segmented configuration, memory 204 may be used to ping-pong
images. For instance, an image may be captured in bank 1 while
reading out an image from bank 2. When that image transfer is done,
an image can then be read out of bank 1 while a subsequent image is
stored in bank 2. In this fashion, the image capture and transmit
process can be expedited.
[0031] Clock signal generator 206 provides all clocking signals to
camera 200, and facilitates the transmission and capturing of image
data from video sensor 208. Video sensor 208 receives images from
lens 210 and converts this image data to digital data for use by
processor 202 and for storage and transmission. A video processor
209 may be included for compression and video enhancement of image
and video signals from video sensor 208.
[0032] A power source 212, such as a battery, receives electrical
charge from charging circuitry 214, and low drop out voltage
regulator circuit 216 maintains suitable voltage levels within
camera 200. Protection circuitry 218 provides the electrical
isolation and protection necessary to avoid electro static
discharge (ESD), electrical faults, and other conditions
unacceptable within a Zone 0 environment.
[0033] A communication interface 220 such as a USB interface and
microcontroller receives data from processor 202 or memory 204, and
transmits this data to the host computer (not shown this Figure).
This link is provided through I/O To/From Host Computer 222. In a
preferred embodiment, the communication link between camera
assembly 200 and host computer 102 is a standard USB communication
link.
[0034] Wireless communication between camera assembly 200 and host
computer 102 is also contemplated. This communication could include
Bluetooth, WiFi, ultra wide band (UWB) and mesh network
technologies. In such applications including wireless
communication, antennas could pose problems for spark creation. In
such applications, it would be advantageous to incorporate the
antenna into the chassis of camera 200. In this case, the antenna
would be molded into the chassis and would be made of insulated
plastics, which would prevent electrical shocks. Alternatively, the
antenna could be coated in spark-resistant coatings.
[0035] Referring now to FIG. 3, a diagrammatic representation of
the intrinsically safe camera system of the present invention is
shown and generally designated 300. Camera 300 includes camera
chassis 302 having a lens assembly 304 adjacent an imaging device
306. Imaging device 306, in a preferred embodiment, is a
high-resolution charge coupled device (CCD) image panel. Imaging
device 306 receives images from a video image area 112 through lens
assembly 304.
[0036] The imaging device 306 converts the images to a digital
electrical signal which is then communicated to controller 308,
memory 312 and input/output circuitry 310. Once image or video
signals are presented to input/output circuitry 310, it can then be
transmitted through fault protection safety circuit 316 to
electrical cable 320 for transmission to the host computer 102 (not
shown in this Figure).
[0037] It is also contemplated in the present invention that the
communication link over electrical cable 320 may be replaced by a
wireless communication signal, such as that transmitted from
antenna 322 back to the host computer 102. In this configuration,
the wireless video and image signals may be relayed from camera 300
to host computer 102 using a variety of communication protocols
known in the art.
[0038] Adjacent to assembly lens 304 is a plurality of light
sources 318, such as light emitting diodes (LEDs) that selectively
illuminate the video image area 112. This light source 318 may be
wavelength changing, intensity changing, or a combination of
wavelength and intensity changing in order to most accurately
illuminate areas for inspection.
[0039] FIG. 4 is a diagrammatic representation of an alternative
embodiment of the intrinsically safe camera system of the present
invention generally designated 400. Camera 400 includes a camera
chassis 402 having a lens assembly 404 adjacent an imaging device
406, and capturing video from video image area 112. This image data
is available to controller 408, memory 412, and electrical to
optical interface 410.
[0040] Electrical to optical interface 410 is an electrical to
optical conversion device, which receives electrical digital data
from memory 412, controller 408 and imaging device 406 and converts
it into an optical data stream for transmission through optical
interface transmit/receive 420 to optical fiber 422. In such an
application, cable conditioning module 106 converts the received
optical signals from camera 400 to electrical signals for
transmission to host computer 102, and converts electrical signals
from host computer 102 into optical signals for transmission to
camera 400. Converting this information between electrical and
optical signals can be accomplished through an
electrical-optical-electrical (EOE) interface.
[0041] Optical fiber 422 may include an optical high speed serial
bus interface (bi-directional communication link) between the
camera assembly 400 and the host computer 102. For instance,
bi-direction communication such as IEEE 1394 interface may be used.
This optical link will eliminate any transmission of electrical
signals between the camera assembly and the host computer. This is
particularly advantageous when considering the Zone 0 environmental
risks, and the problems inherent with spark and electromagnetic
radiation created by the transmission of electrical signals along a
conductive cable. In fact, when utilizing optical fibers for
communication, even a breach of the cable sheathing will not result
in a spark or fire hazard.
[0042] Battery 414 provides local power to camera 400 and may, in a
preferred embodiment, be removed from the camera chassis 402 for
charging. Alternatively, battery 414 may be charged within camera
400 through inductive or electrical plug-type charging means.
Alternatively, optical signals may be received from optical
interface 420 and a portion of the illumination may be split off
through fiber 428, such as a light pipe, to a photovoltaic (PV)
cell 430. PV cell 430 derives electrical power from any light
within fiber 428 thereby providing power for the camera, yet having
no electrical connections made through optical fiber 422.
[0043] Optical fiber 422 may also provide the lighting required for
camera 400. For instance, optical fiber 422 may include a light
pipe that 426, in addition to one or more digital data channels,
may also include a steady state light source. This source can be
received by optical interface 420 and fed into light pipe 426 for
transmission to light emitters 418 adjacent lens assembly 404. This
light source may be wavelength and intensity selectable to provide
a variety of lighting options for inspections. Specifically, the
wavelengths may vary, and may include visible, ultraviolet (UV) and
infrared (IR) light sources. Utilizing LED fiber light pipe
solution provides several benefits. The primary benefit is helping
yield a low power solution. The secondary benefit is providing
various light levels to illuminate various cavity sizes. Also,
using a fiber bundle provides a lighter weight camera system making
it easier to operate.
[0044] Alternative lighting solutions could include, in a preferred
embodiment, may include a local illumination, such as LED lighting
contained within chassis 402 or lens assembly 404. Alternatively,
light pipes, such as light pipe 426, may be used to channel light
from a remotely located xenon lamp. This would provide a high
intensity light for imaging purposes, however, eliminate the
high-power lamps in the camera assembly 400. Instead, these high
power lamps may be maintained outside the hazardous Zone 0.
Utilizing an LED fiber light pipe allows illumination in various
cavity sizes, while reducing the risk of unintended accidents.
[0045] In addition to the wavelength changing illumination and
focusing lens assembly 404, each camera 400 may be equipped with a
motion control device. Specifically, this motion control could
incorporate pneumatic and/or hydraulic motion device, and could
include pan, tilt and rotation motion, and linear drives. These
devices incorporating pneumatics and/or hydraulics would present no
risk for a Zone 0 environment as there would be no likelihood of
spark or explosion. Alternatively, electrical motion control
devices, such as brushless motors or micro electro mechanical
systems (MEMS) may be incorporated to provide motion control to
camera 400.
[0046] Referring back to FIG. 2 for reference, the video inspection
system of the present invention 100 is intrinsically safe, and
includes a camera 200 that meets intrinsically safe design
standards of IES 60079-11 of the year 2009. Using innovative design
techniques, a low power and high resolution intrinsically safe
camera has been created to incorporate key protection circuitry in
the areas of limiting current in case of a short circuit and over
voltage protection circuitry to minimize the potential of sparking.
With the potential for large data flows over the USB port, video
compression may be used to manage data information exchange between
the camera and the host computer or remote communication
device.
[0047] The camera of the present invention utilizes video
compression techniques for sending multiple images per second, and
also has the ability to send raw video at a lower image rate. The
communication protocol implemented in the present invention
contains extra I/O headers to allow for adding different features,
such as providing the ability of using a motorized zoom lens.
[0048] One principal feature of the design of the present invention
is low power operation. Specifically, components were selected
based on low power requirements, and capabilities to perform
various functions such as safety and performance. For instance, the
video sensor 208, such as a CCD imaging device, was selected on the
basis of low power and video resolution capabilities. The quarter
inch sensor has a video format of 2048.times.1536 pixels at 15
frames per second (fps) with good image quality, yet operates at
less than 300 mW. Utilizing the high resolution capabilities, alone
and in combination with mechanical 210 with mechanical zoom, allows
for implementing digital and manual zoom to see areas up close.
Digital zoom alone provides a lighter weight camera system with no
moving electrical components that may cause sparks or mechanical
zoom failure thereby increasing safety and improving
reliability.
[0049] Utilizing internal camera memory 204 allows the operation of
different video schemes. For instance, raw video may be delivered
at a reduced frame rate. In this configuration, the memory 204 may
be used as a dual buffer allowing video sensor data from video
sensor 208 to be written into one location in the memory 204 and
the data in another location being sent to the host computer or
remote communication devices via the USB interface micro-controller
220.
[0050] The processor 202, such as the FPGA, is the central hub
between the key components: video sensor 208, memory 204, and USB
micro-controller 220. It allows for data to flow seamlessly at
different clock and data rates generated by clock signals generator
206. A portion of the processor 202 is used to assist in
compressing the video images from sensor 208 on the fly. Also, the
processor 202 directs control information from the USB interface
micro-controller 220 to either video sensor 208 or memory 204.
[0051] The USB interface micro-controller 220 provides the ability
of communicating with other USB communications ports or hubs. For
example, the intrinsically safe camera of the present invention may
communicate to the host computer 102, such as a standardized Laptop
PC, via the USB port. Control and configuration information can be
sent from the host computer 102 to USB interface micro-controller
220 via I/O To/From host computer link 222. A principal benefit is
being able to transfer camera images from the camera 200 to the
host computer 102 at rates up to 480 Mbps. Another key feature of
using the USB port is being able to provide electrical power and
control the operation of the camera. For instance, the user of the
present invention has the option of sending commands to change from
manual to auto features such as exposure control, white balance,
and black level. Other user controls may include image size, image
quality, frame rate and amount of video compression.
[0052] Different clocks are required because of the distinct
requirements of the video sensor 208 and USB interface micro
controller 220 devices. The multiple clocks provided by clock
signals generator 206 allows the devices to operate at their own
internal clock rates and provide appropriate data and video
information that can be shared and distributed to other parts of
the camera system. The processor 202 also receives clock signals to
help properly align video image data as it comes in from the video
sensor 208 and is transmitted to host computer 102 through USB
interface micro-controller 220.
[0053] Low voltage drop out regulator circuitry 216 are included to
ensure that stable voltages are provided to the respective
components within camera 200. It provides stable output voltages
despite varying input voltages (2.5-5.5 VDC), and provides
protection against input reverse current, thermal, and
short-circuit.
[0054] Protection circuitry 218 may include a current limiting
resistor and 3 parallel Zener diodes. The current limiting resistor
ensure the camera current is limited if there is a short circuit.
The Zener diodes provide voltage protection if the voltage is
greater than 5V. Each of these safety features contributes to the
overall safety of the intrinsically safe camera of the present
invention.
[0055] A primary focus of the design of the present invention is to
provide an intrinsically safe camera system that will work in
explosive gas atmospheric environments. This allows users to
remotely view and inspect gaseous hazardous areas such as mines,
grain silos, oil refineries, petroleum storage tanks, fuel bays of
ships, trucks and cars, etc.
[0056] The intrinsically safe camera system is low power and can be
used in low power applications. It has been designed to operate at
less than 1 watt and provide 3.2 megapixel of resolution. Using a
low power motorized lens, it can be used in many environments, such
as submersibles, surveillance, oil rigs, etc. Images can be
captured and delivered in raw or various compression levels,
providing users different levels of image detail and image
rates.
[0057] In a typical operation of the intrinsically safe camera of
the present invention, the camera is attached to a host computer
102, which is outside the intrinsically safe Zone 0, through the
USB port. The host computer's USB port provides power and
communication to the camera. Upon powering up of the camera, the
camera will come up in the last known configuration and await
commands from the computer.
[0058] The user selects and runs the camera graphical user
interface (GUI) program on the computer. Once a communication link
occurs between the computer and camera, the operator can begin
downloading, storing and viewing images. Selecting various program
options will allow the camera to be configured for different modes
of operations. For example, using image control, the user can zoom
in and out to view specific details of an image area. Or, the
operator can change the image quality to show more or less detail
by changing image quality settings. It is anticipated that the user
will use the default mode for general purpose viewing and
recording.
[0059] The intrinsically safe camera of the present invention may
be equipped with post processing capabilities for the retrieved
video image data. Furthermore, it may utilize variable light
intensities and color and may be equipped with alarm features,
spectral defect detectors, and machine vision capabilities, which
all cooperate to assist a user in identifying defects.
[0060] The intrinsically safe camera may be enclosed in an
explosion proof chassis or housing. Strategically placed around the
housing will be the light source to provide uniform illumination in
dark areas. The chassis mount is designed to allow easy head
rotation both vertically and horizontally by the operator. Also
using extension sticks, the intrinsically safe camera of the
present invention can be lowered or raised to different heights for
maximal video viewing.
[0061] The intrinsically safe camera system of the present
invention will work in various hazardous environments, allowing
users the ability to remotely view and inspect various mines,
silos, and storage tanks. Because it is a low power solution with a
high power 3.2 megapixel resolution, it can be used in other
applications, such as submersibles, surveillance, oil rigs, etc.
The digital zoom capability allows looking at areas with greater
detail and provides a lighter weight solution than using a
mechanical zoom.
[0062] While there have been shown what are presently considered to
be preferred embodiments of the present invention, it will be
apparent to those skilled in the art that various changes and
modifications can be made herein without departing from the scope
and spirit of the invention.
* * * * *
References