WO1996005502A1

WO1996005502A1 - Video imaging inspection system

Info

Publication number: WO1996005502A1
Application number: PCT/EP1995/003160
Authority: WO
Inventors: Israel Fraier; Shaul Israeli
Original assignee: MERON GABRIEL DAVID
Current assignee: MERON GABRIEL DAVID
Priority date: 1994-08-09
Filing date: 1995-08-09
Publication date: 1996-02-22
Anticipated expiration: 1997-02-09
Also published as: AU3343795A; IL110596A0

Abstract

A video imaging inspection system comprising an integral solid-state essentially maintenance-free video imaging device containing means for uniform multiwavelength illumination by one or more single or multiwavelength LEDs, an imaging array sensor, a lens system for acquiring an image of an object, portable image reader unit (PIR) containing a power source, signal conditioning and processing electronics and means for creating a color or false color multi-spectral video image of the object, and means for evaluating it. The system can contain a black and white or color image sensor which is a solid state imaging sensor array. There is also provided a method for the production and evaluating of an image of an object located in a compartment or facility with difficult accessibility, which comprises illuminating the object by a uniform multiwavelength beam, sensing the image by an imaging array sensor, and by a lens system, the illumination being by at least one or more single or multiwavelength LEDs, which can be activated at will and which are connected to a portable image reader unit (PIR) comprising of a power source and signal conditioning and processing electronics and means for creating a color or false color multi-spectral video image of the object, and for evaluating it, thus obtaining the desired image of the object, and evaluating such image. Also fluorescent emissions from suitable objects can be imaged.

Description

DESCRIPTION VIDEO IMAGING INSPECTION SYSTEM Field of the invention

The invention related to a method of operation and a Viαeo related Imaging Inspection system comprising a plurality of very long life, maintenance free, low cost color or multispectral Video Imaging and illumination Devices, hereafter VID, to be permanently installed in hard to reach compartments of planes, vehicles, ships, and various facilities, which can be activated at will by a Portable Image Reader connection hereafter PIR, for visual , periodical maintenance inspection by video, which can be pre - , post or in process inspection , of hard to reach compartments without dismounting or opening these compartments.

State of Prior Art

The visual or Video Imaging inspection in hard to reach compartments in planes, vehicles, ships and various facilities is very important for preventive maintenance of these platforms and facilities and for their safe and reliable performance.

Usually these inspections are performed by opening or dismounting such compartments or with the help of boroscopes and fiber scopes. In both cases these are complicated, time consuming and costly operations. The cost of these inspections become even higher if one wants to use Video Imaging with multiviewer capabilities and documentation purposes.

The video Imaging has to be in color, in order not to loose the color information from the inspected object.

Additional spectral information ,for example IR, to color relative response can not be obtained with common systems and except for very special, very costly inspection tasks it is usually not recovered. Color Video imaging requires a high temperature 3200° - 5000° C light sources which are power consuming, limited in their life span and suffer from deterioration in their color spectral characteristics, with operation time.

Background of the Invention

For various applications there exists a need for a miniature Video Imaging device that will be capable to provide an image from inaccessible places in bodies of airplanes, ships, submarines, motor gears, cable canals, air and liquid pipes, radioactive chambers, and other hard to reach compartments in moving platforms and various facilities.

Such images have to be in color or be multispectral due to the additional information that color can provide, for example wiring integrity control, corrosion control, etc.

Usually all these images are required for maintenance periodical inspection or for safety checks before or after use , for example preflight inspections or after a shutdown of a chemical or nuclear process etc. Therefore such a VID can be of an unpowered dormant type which is activated by connecting to it some Portable

Image reader comprising power supply means and all the other necessary electronics which are necessary to obtain a video image on a monitor.

An essential feature is that such a VID has to be maintenance free: regarding the difficult places in which one would like to install (bury) such a sensor . Any service needed, for example the replacement of a burnt out light bulb, will cut down considerably the usefulness of this VID concept.

All white light sources for color imaging are built with a glass envelope increasing their physical size and making them vulnerable to shock and vibration.

Another critical feature would be the price of such a VID: taking in consideration the vast number of possible VID sites for example in an airplane alone, to be provided with such an inside imaging capabilities, one needs a very low-cost VID to be cost effective. Summary of the Invention

The present invention relates to a method of operation and a related virtual Imaging system comprising a plurality of very long life, maintenance free, low cost color or multispectral Video Imaging and Illumination Devices, hereafter VID, to be permanently installed in hard to reach compartments of vehicles or facilities, which can be activated at will by connection of a Portable Image Reader, hereafter PIR, for visual by video, periodical maintenance inspection and pre-, post or in-process inspection of hard to reach compartments, without dismounting or opening such compartments.

The imaging array can be a color sensor and white light illumination can be produced by uniformly combining and intensity balancing red, blue and green LED lights from corresponding single wavelength LEDs or multicolor LEDs. The system can comprise means for shutting down all visible LEDs for a frame period or any other chosen period in order to facilitate the imaging sensor to record chemiluminescence or radio luminescence or phosphorescence or any other light emission induced effect in the observed object. A flash-type UV-excitation light source can be coupled to the illumination light beam combiner for induced fluorescence purposes. Preferably the Portable Image Reader comprises a power supply and electronics required to create a color or false color multispectral video image by analog and digital signal processing of the signals from the video imaging devices (VID's) imaging sensor and by synchronized switching and intensity control of the VID's LED illumination light sources, and optionally equipped with data acquisition, storage, computing and transmission means.

The invention further relates to a method for acquiring color image of an object located within a hard to reach interior of a compartment or facility, which comprises activating at will a stand-by integral solid state video imaging device as defined above, obtaining the image of the desired object and evaluating same. More particularly the invention relates to a video imaging inspection system comprising an integral solid-state maintenance-free video imaging device comprising means for providing a uniform multiwavelength illumination of at least one or more single or multiwavelength LED, an imaging array sensor, and a lens system for acquiring an image of an object, which system can be activated at will by connection to a portable image reader unit (PIR) containing a power source and signal conditioning and processing means for creating a color or false color multi-spectral video image of the object, and for evaluating it. It advantageously contains a black and white or color image sensor which is a solid state imaging array sensor of the CCD, MOS, CID and Photo-diode type, with or without on-chip memory, where the imaging device comprises video signal processing electronics or a dedicated single chip monolithic video camera. According to one embodiment the imaging array sensor is a black and white sensor adapted to produce a color image or false color image by electronically memorizing and combining three sequential images, each of them illuminated by one of the corresponding RED, GREEN and BLUE LEDs, or for producing a false color multispectral image by electronically memorizing three or more sequential images, each of these being illuminated by a specific LED wavelength from UV to near IR and by electronically combining three of the images to be displayed on a color RGB monitor as a false color multispectral image.

It relates to a method for acquiring and evaluating an image of an object located at a location with difficult accessibility, which comprises illuminating such object by a multi-wavelength illumination beam, obtaining an image of the object via a lens system, an imaging array sensor, an integrated solid-state video imaging device, an image reader comprising signal conditioning and processing means and means for creating a color or false-color multi-spectral video image of the object, and evaluating the image of the object. The imaging array sensor can be a black and white sensor and a color image can be produced by electronically memorizing and combining three sequential images, each of them illuminated by one of the corresponding red, green and blue LEDs. The imaging array sensor can be a black and white sensor, where a false color multi-spectral image is produced by electronically memorizing three or more sequential images, each of these being illuminated by a specific LED wavelength, and by electronically combining three of the images to be displayed on a color RGB monitor as a false color multi-spectral image.

The method of operation of the novel system is based on a separation between the unpowered all solid state and maintenance free miniature video imaging and illumination device, the VID, and a Portable Image Reader which supplies all the power requirement of the VID and also all the electronic signals to the sensor and

LEDs and signal processing necessary for creating a color or multispectral image of the region of interest in the specific compartment and its display on a video or computer monitor.

The VID units are inexpensive constitute a very long life, maintenance free, color imaging and illumination device. The VID units can be permanently installed in large numbers and one needs only one PIR unit per inspection staff resulting in a very cost effective and fast inspection process.

The VID unit comprises, a CCD or CCD like MOS, CID, Pin Photodiode area imaging sensor, with or without on board peripheral electronics, coupled to multiwavelength illumination means built of one or more Light Emitting Diodes or switchable Laser

Diodes of a single or multiwavelength type and beam combining means for creating a uniform color illumination of the object and electrical connection means to connect it to the external world.

The PIR unit comprises power supply means for the VID and its own electronic, signal conditioning, signal processing and control electronics for creating a color or multispectral video image, connection means for fast connection of the PIR to the

VID and optionally a video display for visualization of the acquired image.

A color image in the system of the present invention can be produced by electronically memorizing and combining three sequential images, each of them illuminated with one of the corresponding RED, GREEN and BLUE LED lights. A false color multispectral image in the system of the present invention is produced by electronically memorizing three sequential images each of them, illuminated with a different wavelength band for example chosen from 900 nanometer Near IR, 800 nm

Near IR, Red, Yellow, Green, Blue etc...

According to the present invention one can emphasize the response in a particular wavelength by increasing the illumination intensity or duration of the particular LEDs,

The sensor in the VID can be operated at normal video standards or in a long integration mode for induced luminescence image capture in spectral inspection tasks using fluorescent or chemiluminescent activators.

In a particular embodiment of the invention, one can use a color CCD sensor and illuminate it with white light produced by uniform combining and intensity balancing of

Red, Blue and Green LED lights form corresponding single wavelength LEDs or multicolor LEDs.

The invention is exemplified by way of illumination only and the examples are not to be construed in a limited manner.

Fig. 1

Fig. 1 is a schematic block diagram of one unit consisting of the Video Imaging and illumination Device and of the Portable Image Reader 13,14,15 .

The VID in this particular example is built with a through-wall connector for installation, for example in Toxic chemical processing chambers.

In Fig. 1 the object to be inspected 12, is illuminated by the light of LEDs. 6, combined in the fiber optic light combiner 5, through the light window 4. The object image is collected through the image window 1 and focused by the lens 2 on the imaging sensor 3.

The signal pulses and power to the LEDs 6 and from the Imaging sensor 3 are fed through the wiring 8 to the connector 7. The components 1 ,2,3,4,5,6,7,8 are enclosed in a water-proof body 9 for mounting it through the chamber wall 11.

The VID is powered through the PIR fast connector 13. The VID signals are transferred to the signal conditioning unit 14 via the fast connector and displayed on monitor 15.

Description of an embodiment of the novel system

Fig. 2 is an operational block diagram of a PIR system as described in FIG. 1 The power and pulses to the sensor, and the output signal from it are connected through the connector 35 and cable 37 to the signal conditioning unit. The pulses from the driver 21, timing 22 and controller 26 together with the adequate power signals from the power supply 4 are fed to the sensor unit for driving the LEDs and Video Image (Fig. 1 ).

The output signal from the sensor unit is fed to the video processor 23. The video signal produced by 23 is digitized by analog-to-digital circuit 27 and memorized in the memories 28 under controller and operator control panels management. The output from the memories 28 are converted to an analog signal by the digital to analog circuits 29 and fed to buffer-circuits 30. The buffered signals are encoded by the video encoder circuit 31 to a composite video signal 32 and a Y.C. video signal 33.

The composite video signal 32 or YC video signal 33 are supplied to a portable VTR with CCD color display 36 for recording and observation.

All circuits in the signal conditioner unit are powered by the power supply 24 which is fed by the battery pack 25. The same battery 25 supplies also the VTR 36. An operational system as described in Fig.1 and Fig. 2: The image is focused via a lens 2 on the Video Imager (CCD Sony ICX058), the pulses to imager are supplied by driver (Sony CXD 1250) and timing (Sony CXD 1261). The imager signal output is processed by video processor (Sony CXA 1310). The video signal is digitized by A/D circuits (BT 218) memorized in memories (TMS4C1050). The digital signal's from memories are converted into analog video signals by D/A circuits (BT 121) and via buffers (MC 14577) are encoded in standard composite video signal or Y.C. video signal by encoder (MC 1377) and fed to VCR (Sony JV-S50I )input to be recorded and observed on the built in CCD color.

Claims

1. A video imaging inspection system comprising an integral solid-state maintenance-free video imaging device comprising means for providing a uniform multiwavelength illumination of at least one or more single or multiwavelength LED, an imaging array sensor, and a lens system for acquiring an image of an object, which system can be activated at will by connection to a portable image reader unit (PIR) comprising of a power source and signal conditioning and processing means for creating a color or false color multi-spectral video image of the object, and for evaluating it.

2. A system according to claim 1 , containing a black and white or color image sensor which is a solid state imaging array sensor of the CCD, MOS, CID and Photo- diode type, with or without on-chip memory, where the imaging device comprises the imaging array sensor or a dedicated single chip monolithic video camera.

3. A system according to claim 1 , where the imaging array sensor is a black and white sensor adapted to produce a color image or false color image by electronically memorizing and combining three sequential images, each of them illuminated by one of the corresponding RED, GREEN and BLUE LEDs, or for producing a false color multispectral image by electronically memorizing three or more sequential images, each of these being illuminated by a specific LED wavelength from UV to near IR and by electronically combining three of the images to be displayed on a color RGB monitor as a false color multispectral image.

4. A system according to claim 1 , where the imaging array is a color sensor and white light illumination is produced by uniformly combining and intensity balancing of red, blue and green LED lights from corresponding single wavelength LEDs or multicolor LEDs.

5. A system according to claim 1 , comprising means for shutting down all visible LEDs for a frame period or any other chosen period in order to facilitate the imaging sensor to record chemiluminescence or radio luminescence or phosphorescence or other light emission induced effect in the object or site under observation.

6. A system according to claim 1 , where an I.R. LED or UV-excitation light source is implemented into video imaging device for induced fluorescence purposes.

7. A system according to claim 1 , where the Portable Image Reader comprises a power supply and electronics required to create a color or false color multispectral video image by analog and digital signal processing of the signals from the video imaging devices (VID's) imaging sensor and by synchronized switching and intensity control of the VID's LED illumination light sources, and optionally equipped with data acquisition, storage, computing and transmission means.

8. A method for acquiring color image of an object located within a hard to reach interior of a compartment or facility, which comprises activating at will a stand-by integral solid state video imaging device defined in claim 1 , obtaining the image of the desired object and evaluating same.

9. A method for acquiring and evaluating an image of an object located at a location with difficult accessibility, which comprises illuminating such object by a multi¬ wavelength illumination beam, obtaining an image of the object via a lens system an imaging array sensor and an integrated solid-state video imaging device and image reader comprising signal conditioning and processing means and means for creating a color or false-color multi-spectral video image of the object, and evaluating the image of the object.

10. A method according to claim 8, where the imaging array sensor is a black and white sensor where a true or false multispectral color image is produced by electronically memorizing and combining three or other number of sequential images which are illuminated by a specific LED wavelengths from U.V. to near I.R.

11. A method according to claim 10 where the imaginary array sensor is a color CCD, and a true color image is produced by using the red green and blue LEDs at the same time.