The present invention relates to an apparatus and system for evaluating the surface and sub-surface properties of a surface and, in particular, to an apparatus and system for irradiating the surface with adjustable polarized light and viewing the optical reflectance through a polarizing viewer.
Light reflected from skin has two components: regular reflectance, or “glare” arising from the surface, and light backscattered from within the tissue. The regular reflectance contains the visual cues related to surface texture, whereas the backscattered component contains the cues related to pigmentation, erythema, infiltrates, vessels and other intracutaneous structures. Unlike the backscattered component, regular reflectance preserves the plane of polarization of polarized incident light. Thus, viewing skin through a linear polarizer, under linearly polarized illumination, separates the two components of tissue reflectance. When the planes of polarization are parallel, images with enhanced surface detail are obtained. When the planes are orthogonal, wrinkles and surface detail disappear, and an enhanced view of vasculature, pigmented lesions, and other subsurface details is obtained.
The prior art discloses various devices and methods that accomplish surface irradiation and reflection detection. However, none of the prior art devices or methods provide a means or method of illuminating a surface and then view either surface or subsurface reflectance at the discretion of the user. The prior art also requires elaborate and often fixed setups to perform any type of surface analysis. These setups usually require the surface of interest to be moved past a positioned optical array. There is little teaching of portable units that would enable the imaging to be done in remote locations or manipulate the illuminator source with respect to the object being viewed. Finally, most prior art systems are costly and, therefore, are not practical for those with limited resources.
For example, U.S. Pat. No. 2,120,365, issued to Kriebel, discloses the use of polarizing lenses in eyeglasses for orthogonally polarizing light being viewed. The light originates from a source located on the side of an object or material of interest opposite to the viewer, which allows for examining the photo-elastic effects of the light bending around the object.
U.S. Pat. No. 2,947,212 to Woods shows detection of surface conditions of sheet metal by irradiating a surface with polarized light and using a polarizer in the optical path of the detector. This allows for only the viewing the intensity of the polarized light while eliminating all extraneous light rays. Similarly, U.S. Pat. No. 3,904,293 to Gee uses linearly polarized light to irradiate a surface and then detection of the reflected light. Prior to the reflected light being detected, it must first pass through a polarizing beam splitter, which separates the light into its principal polarized (incident) and orthogonally polarized (depolarized) wave components. These two distinct waves are then detected by different detectors, and changes in the surface texture will cause corresponding changes in the detected signal characteristics to be compared.
U.S. Pat. No. 5,053,704, issued to Fitzpatrick, discloses the imaging of a surface to detect cracks, flaws, voids, and the like. To accomplish this detection, a magneto-optical substrate including a conductive sheet is laid over the target material. A current is passed through the conductive sheet to provide a biased magnetic field. Polarized light is then directed through the substrate into the target material and the reflected light is viewed through a separate linear polarizer. The biased magnetic field induces a rotation of the plane of polarization of the incident projected light such that viewing the reflection through a linear polarizer will render flaws visible.
U.S. Pat. No. 5,198,875, issued to Bazin et al., also teaches irradiation of a surface with polarized light. Bazin et al sets up two detectors, one at an angle of reflectance equal to the angle of incident while another detector is located perpendicularly to the surface. The reflected polarized light is passed through polarization separation cubes and eventually four detectors detect the reflected light. These detectors are connected through an electronic processing means, which evaluates the various signals for brightness comparison.
U.S. Pat. No. 5,442,489 to Yamamoto et al relates to a magnifying apparatus. A polarized light irradiates an object and the reflected light is transmitted through a polarizing means and is in turn imaged by an imaging device. This arrangement magnifies and images practical areas of interest.
The article, “Polarized Light Examination and Photography of the Skin” by Rox Anderson, MD, which appeared in the Archives of Dermatology, July 1991, volume 127, pages 1000-1005, describes the above mentioned failings in the art to provide adequate viewing of surface and subsurface epidermis. In response to these failings, the authors of the article developed the polarized material inspection apparatus that is described in U.S. Pat. No. 5,742,392, which is incorporated herein by reference. This apparatus, although providing distinct advantages over prior art systems, has certain attributes that have been seen as drawbacks in some circumstances.
First, the use of a head-mounted apparatus, often connected by wires to a power supply, has been found to restrict the movement of physicians utilizing the apparatus. Second, the mounting of a hot lamp in close proximity to the user's head can cause the user to overheat and perspire. Third, head mounting of the unit creates the risk of a user temporarily blinding others within the operating room by inadvertently pointing the light source at the eyes of that person. Finally, the weight of the head-mounted apparatus can, during periods of extended wear, cause neck strain and general discomfort to the user.
In addition, as the Anderson apparatus includes the light source and first polarizer, others viewing the image at different positions around the object will see a different image when they utilize polarizers set to the same level of polarization as those of the apparatus worn by the user. This inability to coordinate the images viewed is due to the difference in the optical path of the polarized light caused by the different angular arrangement of the other viewers from the light source. Accordingly, the Anderson apparatus has not heretofore been adapted for use with remotely mounted cameras, which have utility in the growing field of telesurgerey, nor for teaching or collaborative procedures where it is important for all present to view the same image. Similarly, as there has heretofore been no way for a camera to view the same image as is seen by a user, there has also been no way to record and save what the user sees for future use during litigation, case review or for teaching purposes.
Therefore, there is a need for a device for irradiating a surface with polarized light in association with a polarized viewer that provides separation between surface and subsurface reflection, that allows the light source and viewer to be integrally or remotely connected, that allows either the surface or subsurface reflectance to be viewed alternatively and at the discretion of the user or a third party viewer, that does not restrict the movement of the user or cause the user to perspire, that eliminates the risk of a user temporarily blinding another person by inadvertently pointing the light source at the other person's eyes. Further, there is a need for a system for irradiating a surface with polarized light in association with a polarized viewer that provides separation between surface and subsurface reflection, that allows cameras and other viewers within a room to see the same image as is seen by the user of the device and allows the image viewed by the user to be stored for later viewing.
The present invention is a polarized material inspection apparatus for viewing a material with a polarized light, and a polarized material inspection system utilizing the same.
In its most basic form, the polarized material inspection apparatus includes a light source having a first optical path, a first polarizing filter disposed within the first optical path of the light source, a frame, a second polarizing filter disposed within the frame, and a support attached to the frame for positioning the frame.
In the preferred polarized material inspection apparatus, the second polarizer is rotatably attached to the frame such that a rotational position of the second polarizer is adjustable to a desired level of polarization relative to the first polarizer. The preferred embodiment also includes an imaging means, such as a camera or charge coupled device, which is disposed proximate to the second polarizing filter such that the second polarizing filter and imaging means lie within a second optical path.
Some embodiments of the present invention include a polarization level selection means for selecting a desired level of polarization. In its simplest form, the polarization level selection means is a lever, mechanically coupled to either the first or second polarizing filter, which, when moved, rotates the polarizing filter. Those of ordinary skill in the art would also recognize that the polarization level selection means could alternatively be in the form of a knob, dial, or the like, mechanically coupled to polarizing filter which, when rotated, causes the polarizing filter to rotate relative to the other polarizing filter.
Other embodiments include a control means that allows the polarization level selection means to be physically displaced from the second polarizing filter. In this arrangement, the polarization level selection means generates an output, preferably in the form of a digital electrical signal, which in turn is received by the control means, which is preferably a servomotor that sets the rotational position of the second polarizing filter in response the signal received from the selection means. Although the preferred output from the selection means is a digital electrical signal, those of ordinary skill in the art would also recognize that this signal could alternatively be in the form of an analog electrical signal, a radio wave, a fiber optic signal, an infrared light signal, an acoustical signal, or a pneumatic signal. Similarly, although the preferred control means is a servomotor, those of ordinary skill in the art would also recognize that a solenoid, motor, synchronous motor, stepping motor, pneumatic cylinder, pneumatic bellows, or the like, could be substituted for the preferred servomotor to achieve similar results.
In still other embodiments, a position sensing means monitors the position of the light source relative to the second polarizing filter and communicates with the control means to adjust the position of the second polarizing filter. The preferred position sensing means includes a radio signal transceiver co-located with the light source, a radio wave transponder co-located with the second polarizing filter, and a microprocessor, which calculates the position of the second polarizing filter relative to the light source based on direction finding and range finding between the transceiver and the transponder. The transceiver transmits the above-calculated positional information to the control means, which in turn adjusts the level of polarization based upon the selected polarization level and the position of the light source relative to the second polarizing filter. The selected level of polarization is thereby continuously maintained as the position of the light source relative to the second polarizing filter is changed. Although the preferred position sensing means is based on a radio wave transceiver, transponder and microprocessor system, those of ordinary skill in the art would also recognize the position sensing could alternatively be based on a GPS (global positioning satellite) system, an optical transceiver-transponder system, an acoustical transceiver-transponder system, or any other art recognized means of transmitting orientation.
In some embodiments of the invention, a polarization level sensing means is added to the apparatus to determine the level of polarization of the second polarizer. This polarization level sensing means is useful in embodiments of the system that allow multiple users to see an image with the same level of polarization as a designated user, such as a physician performing a procedure, a physician viewing the procedure via a remote network connection, or the like.
In an alternative embodiment, the apparatus is constructed to function as an electronic mirror. In these embodiments, an imaging means, such as a camera or charge coupled device, is again disposed proximate to the second polarizing filter such that the second polarizing filter and imaging means lie within a second optical path. The imaging means then sends the image to a display screen. The display screen may take many forms, and may or may not be attached to the frame. Preferred embodiments of the electronic mirror include image storage means for storing a desired image and image manipulation means for manipulating the image.
Therefore, it is an aspect of the invention to provide a device and system for irradiating a surface with polarized light in association with a polarized viewer that provides separation between surface and subsurface reflection.
It is another aspect of the invention to provide a device and system for irradiating a surface in which the light source and viewer may be integrally or remotely connected.
It is another aspect of the invention to provide a device and system for irradiating a surface that allows either the surface or subsurface reflectance to be viewed alternatively and at the discretion of the user.
It is another aspect of the invention to provide a device and system for irradiating a surface that does not restrict the movement of the user.
It is another aspect of the invention to provide a device and system for irradiating a surface that does not cause the user to perspire.
It is another aspect of the invention to provide a device and system for irradiating a surface with polarized light and to provide an independent self supported device for viewing, through a second polarizing filter, a portion of this polarized light that is reflected off of the surface.
It is another aspect of the invention to provide a device and system for irradiating a surface that eliminates the risk of a user temporarily blinding another person by inadvertently pointing the light source at the other person's eyes.
It is another aspect of the invention to provide a device and system for capturing, transmitting and/or storing the same image that is viewed by a user.
It is another aspect of the invention to provide a device and system in which a user may face a display screen, be irradiated with polarized light, and view a reproduced image of his or her own face with a desired level of polarization, magnification, or the like.
These aspects of the invention are not meant to be exclusive and other features, aspects, and advantages of the present invention will be readily apparent to those of ordinary skill in the art when read in conjunction with the following description, appended claims and accompanying drawings.
Referring first to
As shown in
In operation, the device 10 will be positioned relative to an object to be viewed, the light source 12 will be energized and the light will be polarized by the first polarizing filter 14 and will pass on to illuminate the object. The light will then be reflected off of the object and will pass through the second polarizing filter 18 for viewing by the user. Depending upon the details to be viewed, the first polarizing filter 14 may be rotated into a parallel relationship to the second polarizing filter 18, or may be rotated into an orthogonal relationship to the second polarizing filter 18.
Referring now to
Referring now to
As shown in
In operation, a user will position the device 10 in the desired position relative to the surface to be viewed and position their eye 34 above the magnifying lens 30 to view the surface. The first polarizing filter 14 may then be rotated such that the planes of polarization of the first polarizing filter 14 and the second polarizing filter 18 are in parallel relation to one another and to be rotated again such that the planes of polarization are in orthogonal relation.
Referring now to
In
Referring now to
Although
In other embodiments, the imaging means 112 is used in concert with the image storage means 114 without any image transmission means 116. In such embodiments, the combination of the imaging means 112 and the image storage means 114 may be an image storing camera, such as a film based camera, a photographic plate based camera, a video tape based camera or an electronic camera which stores images directly on storage media such as a memory chip, memory card, CD ROM, magnetic disc or tape, or other art recognized storage media. Such embodiments are useful as a means for documenting a procedure for later retrieval during subsequent visits, litigation, or for other art recognized purposes.
In still other embodiments, the image storage means 114 is eliminated. In such embodiments, the image transmission means 116 receives the output of the imaging means 112 and transmits the image to a remote location, either by cable or by a “wireless” system, such as transmission of radio waves, television broadcast or infrared (IR) transmission. In this context, the imaging means 112 is a camera of either a charge coupled device (CCD) or television type camera, which allows the image to be viewed in “real time” at a remote location. As noted above, such a system is useful in the growing field of telesurgery, which allows experienced surgeons in remote locations to provide their expertise to performing physicians in real time during the course of a medical procedure.
Referring now to
Referring now to
Although a control system using a servomotor and a ring and pinion gear system has be disclosed, those of ordinary skill in the art would also recognize that other components, such as chains and sprockets, belts and pulleys, linear actuators coupled with flexible cables, friction drive, or the like could be substituted for the preferred servomotor and a ring and pinion gear components to achieve similar results. It is also recognized that there need not be mechanical contact between the control means actuator, e.g., the servomotor, and the second polarizing filter 18, and that a non-contact control means, such as a system using magnetic coupling to rotate the second polarizing filter, may be utilized to achieve similar results. Similarly, one of ordinary skill in the art would also recognize that other position sensing means, such as optical encoding, hall effect sensing, rotary potentiometers, or the like, could be substituted for the disclosed means in order to achieve similar results.
Referring now to
In the embodiment of
In operation some of the light emitted by the annular light source 166 is reflected off of the patient 102 and returns trough the second polarizing filter 18. In this embodiment, a polarization level sensing means (not shown), such as those described with reference to
An imaging means 112 for viewing an image, an image storage means 114 for storing the image viewed by the imaging means 112, and an image transmission means 116 for transmitting the stored image are attached fixedly to frame 16 in the manner described in
The user 174 is shown wearing polarizing glasses 175 having a glass frame 176, a first transceiver 177, a first antenna 178, a spatial position sensor 179 and polarizing lenses 180 and 181. The first transceiver 177 transmits and receives through a second antenna 178. Polarizing lenses 180 and 181 are rotatably attached to the glass frame 176. The angular position of polarizing lens 180 is set by a control means (not shown), which functions in the same manner as the control means described with reference to
In operation the user 174 sets the desired level of polarization via polarization level selection means 132. The output signal of the polarization level sensing means 150 is emitted via a first antenna 168 and received by second transceiver 171 via third antenna 170. The first transceiver 177 transmits positional information from spatial position sensor 179 via antenna 178 to second transceiver 171 via third antenna 170. The central processing unit 172 then (based on spatial positional information from the spatial position sensor 179 and polarization level from polarization level sensing means 150) calculates the angular position of polarizing lenses 180 and 181 required to provide user 174 with the same level of polarization as exists between annular polarizing filter 164 and second polarizing filter 18. The calculated angular position is then transmitted via the second transceiver 171 and third antenna 170 to the first transceiver 177 via first antenna 178. The first transceiver 177 then provides this calculated angular position to a control means (not shown) which functions in the same manner as the control means described in
Referring now to
In operation the user (not shown) positions patient 102 (on table 104) in the desired position, relative to the imaging means 112 and light source 12. The user then adjusts support 222 as required to aim imaging means 112 at precise region on the patient for which viewing is desired. The user then selects the desired level of polarization via a polarization level selection means (not shown). Although a polarization level selection means is not shown, it is understood that it could be a device such as polarization level selection means 132 as described with respect to
Although the combination the imaging means 112, image storage means 114, image transmission means 116, stanchions 212, 214, 216 and 218, second polarizing filter 18 and frame 220, are shown and describes as attached, via support 222, to a fixed structure 124, such as a ceiling of a room, it would be understood by one skilled in the art that other fixed structures such as the wall or floor or a room could be substituted.
Referring now to
The viewer can, if desired, store the resulting displayed image via the image storage means 214. The preferred image storage means is a compact disk writer and compact disk, one of ordinary skill in the art would however recognize that other storage devices and media could be substituted such as a floppy disk drive and floppy disk, magnetic tape drive and magnetic tape, printer and paper, “RAM”, and the like.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions would be readily apparent to those of ordinary skill in the art. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
This application is a Continuation-in-Part of co-pending U.S. patent application Ser. No. 09/543,650, filed Apr. 5, 2000, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/129,645, filed Apr. 16, 1999.
Number | Date | Country | |
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60129645 | Apr 1999 | US |
Number | Date | Country | |
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Parent | 09543650 | Apr 2000 | US |
Child | 10747515 | Dec 2003 | US |