A review of head-mounted display devices, etc.CRTsMost camcorder viewfinders can be removed (e.g. from a broken camcorder,or from a surplus supply)and easily adapted to mount over one eye.It's preferable to mount above the eye, rather than to the side, due toweight balance and, more importantly, the desire to minimize moment ofinertia. The sense (whether a clockwise pattern appears clockwise orcounterclockwise) of the display can be reversed by reversing the terminalson the deflection (yoke) coil. It is usually preferable to reversethe horizontal terminals rather than the vertical terminals owing to thefact that timing would otherwise get reversed quite severely (making itdifficult to switch back and forth if you later decide to use a spinningfilter wheel for color). Note, however, that the horizontal circuitoperates at higher frequencies and higher voltages are often involved thanin the vertical circuits. Thus insulate carefully, and keep leads asshort as they were originally.Good strong safetyglasses or other solid polycarbonate glasses(something that passes the .22 calibre bullet test) are a good idea,to keep all the sharp optics (and pieces of broken glass if the tubeimplodes) out of your eye.If properly configured, the viewfinder can be made detachable,so it can be snapped in place when in use, and popped off forstowing in a pocket when not in use. In this way, it will notblock your field of view while walking around (particularly importantfor dusting, or other work in low light).Shields for the high voltage are also a good idea (see the copper meshI have on WearComp6).The copper mesh shield is grounded and also forms part of the groundplane for the antenna.Most cheap camcorder CRTs cannot display sharp text in an 80 column display.WearComp2based on a 6502 processor, hadvideo output with 40 characters per line of text, and only uppercasetext. This worked quite well worn on my back with a CRT over oneeye, but not with an 80 column card, as the text became too small,resulting in considerable eyestrain. Some better CRTs (like the viewfindersfrom high-end cameras rather than camcorders)can display 80 column text quite well. My 1980 CRT-based system still displays80 rows of text quite nicely.Unfortunately, computers generally no longer output video like theApple ][ and Amiga computers used to do. Now you need to buya VGA to NTSC converter. I bought an AI Tech VGA to NTSC converterfor $249;it runs on 9 volts, and draws 1/2 amp.More recently there are smaller VGA to NTSC converters, and the power consumption can be reduced considerably.See the WearComp6 howto (wearhow) guide).If you only need it to work inside X (e.g. don't mind not seeing BIOSand textmode), you can connect directly to TV. This is quiteeasy to do. There used to be a good summary of it on the WWW, athttp://www.sput.dsl.nl/~rob/, but this link doesn't work anymore,(Rob's page on how to connect directly to TV sets, and otheruseful info) neither does the mirror site,http://www.signature.nl/~rob/, but the essentialportions of this info (e.g. specifics of the TV connection) isavailable here, http://wearcam.org/wearhow/tv-x.htmlOf course images display well on CRTs;although the screen is not in color, the tonal range is quite good.In fact, the tonal range of an old CRT taken from the curb on garbagecollection day is much nicer than many expensive LCD displays.Ed GritzYou can get a really high quality CRT from ED Gritz, Tel. 619 434 4676;Fax: 619 434 7875. This is a business he operates out of his house,distributing high-quality Miyota CRTs.The one that I've been using is the one with the 6kv anode (black and white),$750, and it works very well, especially for making critical tone-scaledecisions in image acquisition adjustments, placement of lighting, etc.;the extra voltage gives it much betterperformance than a camcorder viewfinder.Consider also a waist-mounted TVAn alternative to HMDs is a belly-mounted TV set, less than $50new, and works well with appropriate fonts (e.g. XF86Config file or thelike).To see how to mount, seea picture of author wearing a waist mounted TV,second from leftmost image. TV was attached to a heavy belt.In the early days, a power inverter was needed, but morerecently 12 volt TVs have become readily available.See below for some alternative small VGA sets, or consideralso the newer LCD TV sets, such as the $99 Sharp TFT LCD fromhttp://www.eio.com/colorlcd.htm.The Sharp TFT LCDis an amazingly small size TV for its 6 inch diag. display size.It's approx. 6in wide, 4.5in high, 7/8in thich compared to a commerciallyavailable 6in TV set which is (for example my SONY 6in TV) 7in wide, 6in high,and 1.5in thick.The small size of the Sharp TFT LCD makes it great for WearComp, shareddisplay, etc., or worn around neck so others can see the output.It requires backlight power supply (inverter) obtainable from Jameco(800) 831-4242, part number 142252.Product No. FPWR1.Watch this site for future additions on new applications of thissmall size Sharp TFT LCD.M1, Liquid Image Corporation A nice sleek, slender, and readily available HMD is the M1 madein Canada, by liquidimage. The unit takes NTSC or VGA, and automaticallyselects between NTSC and VGA depending on which is connected.Power consumption is reasonable, although it's CPLD-based (e.g. a littlemore power consumption than an ASIC-based system).It's 240 down by 320 across pixels: not full VGA resolution,but good enough for 40x15 size text window to clearly read text(and slightly higher amounts of text if you don't mind someeyestrain).Liquid Image Corp has been very helpful in terms of providing information,and in terms of custom work on small numbers of these units.Liquid Image Corporation(204) 988-3003(204) 988-3000(204) 988-3050 Faxliquid@liquidimage.cahttp://www.liquidimage.ca/skyex/albatech The skyex/albatech "personal monitor",Personal Color Monitor US$ 1490,is a high quality wearable video display. An ingenious beamsplitterdesign routes the image from a single display medium into both eyes,so that it can be used for many hours with minimal eyestrain.Although one eye output is slightly brigher than the other (due to thedesigns needed to make it so ultra compact) one very quickly adapts tothis difference, and what is perceived is a very clear television picture.Despite the small size of the unit, it has many adjustments so that itcan be adjusted for comfortable viewing without too many of thecompromises that lead to eyestrain in fixed (non-adjustable) units.Although there is no means to input separate images to each eye,the device is outstanding in applications where there is a single(mono, as in non-stereo, not to be confused with monochromewhich the unit is definitely not) video signal.Color rendition is really good.Text is not as sharp as on a CRT or other high resolution device, but thecolor fidelity is such that pictures of natural scenes look quite good.Because of its light weight,the apparatus is also very comfortable to wear for many hours.It is built into eyeglasses rather than a helmet type design, and this makesit more natural to wear, and also more acceptable to those who don't wantto "mess up their hair".See a mirrored copy of their main www page.Colorado :20361 W. Thunder RdColorado Springs, Colorado 80908USATel : (719) 495-3254Fax : (719) 495-8508E-Mail : klugex@pcisys.net Florida :1408 Sw 13th CourtPompano Beach, Florida 33069USATel : (954) 941-8066Fax : (954) 941-3426E-Mail : albatech@skyex.com http://www.skyex.com/albatech/Timeline They have one small size CRT (1 inch) and also some smallish monitors(5 inch) which are a bit large for a wearable, but small enough tohaul along to review previously recorded video, etc.If anyone buys one of the 5in displays, please let me know how wellit works...How well do TTL or CGA work on std VGA?1.0in CRT: resolution 250*300, 6kV; complete composite viewfinder.(this from miyota... buy and sell closeouts, only 70 units got; now down to 50)THE 1 INCH CRT IS NOW SOLD OUT!!! :-(5" Amber or B&W $25.005" Color Monitor $39.00 or 2 for $69.00 Flat faceplate 320 x 200 dot resolution CGA & Hercules Compatible 12VDC Operation 15.75 KHz Horizontal Frequency 60 Hz Vertical Sync. Frequency Open Frame Construction Standard Interface Connector Degaussing Coil Included Mfr. Samtron http://www.digisys.net/timeline/blowout.html#monitorPrivate EyeUsing a row of red LEDs and a vibrating mirror, the Private Eyeproduces a razor-sharp binary display. The Private Eye isn't much good forimage display but text is amazingly clear.I find the color (red) to bother me, but many peopleare not bothered by this and find theprivate eye quite comfortable to view for extended time periods.Despite its shortcomings, it has the tightest point spread functionof any of the displays I've tried, and the best contrast as well.The private eye is also very robust (e.g. can withstand a great dealof physical shock) and can easily be made waterproof for all-weather use.The following info is now obsolete (Private Eye no longer in mass production)Phoenix group, phone=516-349-1919; fax=516-349-1926$1500 for 280down, 720across, with driver boardapprox. $4000 768down, 1280across (not available yet)will make higher-resolution displays on request.cybermaxx really blurry image, couldn't even easily read really big fonts. poor quality for image display. very uncomfortable, even for short time period.VR4Here are my "magic glasses" (the hardwareon which "VisualFilter" runs)implemented with a VR4 display (to which I've attached cameras andcommunications antenna). The VR4 is a high-quality RS-170 color video display,made by Virtual Research, virtualres@aol.com.http://www.virtualresearch.com/products.htmlHaving worn it for extended periods of time, over a 2 week period,I found it to be quite comfortable. The display quality is quitehigh, close to that of a good television monitor (e.g. almost asgood as a color CRT). Adjustment knobs for head size make it very easy tohave someone else quickly try it on.Two separate inputs are provided, one for each eye, and there isa stereo/mono switch which makes it easy to quickly test a singlevideo input, feeding it to both eyes. There is a buffered monitor outputon the left channel to plug into an external TV set or the like.The input can be either component (YC) or RGB RS-170 video.The supply voltage is 16 volts. The VR4 comes with a lightweight,high-efficiency switching power supply for operation from 120 volts AC.I found it to work quite well from one of my wearable AC outlets,though it is also quite easy to build a DC to DC converter from 12 voltsto 16 volts so that it can be run from a standard 12 volt battery.The VR4 is probably one of the best choices for color RS-170 video display,but is not quite sharp enough for display of small fonts on a computerscreen.VR5To be available September 1995:Model: VR5Display: Dual 1" CRTs with color shuttersFOV: 53x at 100% overlap; 72x at 50% overlapResolution: SVGA or betterInput: Field Sequential (RS-170)Weight: Under 2 lbs.IPD: Adjustable 52mm - 74mmEye relief: Adjustable, users may wear glassesAvailable: September '95Price Point: Under $20,000Virtual Research Systems, Inc. V6 US$ 7.900, V8 US$ 13.5002326 Walsh AvenueSanta Clara, California 95051Tel: (408) 748-8712Fax: (408) 748-8714E-mail: info@virtualresearch.com KopinIf you are willing to give up color, and stereo,the Kopin display is very goodfor crisp clear display of small fonts.It does quite well with combined text and greyscale imagedisplay.The Kopin display is used in the ``Personal Assistant'', madeby CPSI: However, using the Personal Assistant for an extended period of time, I find that the green display is a little annoying --after taking the Personal Assistant off, I can read3-D comics without 3-D glasses.This is because my display eye sees everything with a magenta cast(after having been stimulated by green),while the other eye sees normally (which even looks a little greenby comparison).Possible work-around: change backlighting to white, although thelcd only works with monochromatic sources (need an lcd that workswith broadband sources).I also found the Personal Assistant displayslides down my face, and I have to keep pushing it backup every couple of minutes, unless I set the tension high (but thatcauses it to be uncomfortable due to the pressure on my head).Work-around: additional supports around the top of the head to prevent itfrom sliding down.Result with both these work-arounds: a very comfortable display withgood clear crisp text and greyscale image display capability.Virtual VisionPerhaps the nicest-looking, or at least the most natural-looking glasses are those made by ``Virtual Vision''.These are wrap-around sunglasses (resembling ski-goggles) with built-incolor television, introduced April 1993.I find these ``cool shades'' are comfortable to wear for many hours at a time,and provide a convenient display for video: There are even miniature earphones that can be stowed on the sides whennot in use.While the image is not razor sharp (so they're not too good fordisplaying text), the small size, comfortable design, and``normal'' appearance makes themquite useful for image display. They are neither intended, nor marketedfor virtual reality, but, rather, are meant for image display (e.g. for use as a cameraviewfinder).They are available in either the left-eyed version or the right-eyedversion (you need to specify at time of purchase because they cannoteasily be reversed.The operating voltage is 6, and they come with battery and charger.The company wisely used a standard battery type (exactly like thoseused on a Sony HandyCam) rather than introducing yet another battery type.Thus if you already own a Sony HandyCam, your battery managementwill be simplified.My time wearing the Virtual Vision totals hundreds of hours, and theyhave been very reliable. The only small flaw is the connector fromthe eyewear to the control box, which you may want to strain-reliefby attaching a small metal support with hot-melt glue and wrappingto the plug with gaffer's tape. Otherwise,the wires may weaken over a year or two of heavy use,and break off inside the plug.Of course, new cables are available (changing the cable is quiteeasy with a phillips screwdriver to open up the eyewear),but a simple strain-relief willeliminate the need to keep spare cables around.There are 3 different visors available, dark, medium, and light.Virtual vision refers to their product as an ``augmented reality''system, because you see through the glasses and augment the realworld with what appears to be a very large television set quite faraway. The focus is adjustable so that eyestrain can be minimized,and I've found that there is sufficient range of adjustmentthat people who have relatively strong prescription glassescan see Virtual Vision without their glasses.Virtual Vision also comes with a tuner module which may be removed whennot in use. The tuner facilitates reception of standard broadcasttelevision, or use with a downconverter to receive amateur television (ATV).Its external antenna jack makes it easy to plug in an ATV downconverter.Alternatively, if you're notsqueamish regarding the sight of bare components,you might wantopen it up and modify it to receive ATV directly.Using Virtual Vision with ATVis a nice way to stay in touch with apartner -- seeing eye to eye.The sound quality of the Virtual Vision is excellent; it has two verysmall earphones that can be disconnected if desired, or they can alsobe stowed out of the way (in small holdersmoulded into the eyewear) but remain connected when not in usewhen rapid deployment capability is desired.The sound comes in the standard audio subcarrier of the received signalin RF mode (just like a normal TV set).There is an antenna jack in the tuner.When you plug video into theexternal video input jack, the video automatically switches from RFto baseband. Likewise with the sound. You can switch the sound and videoindependently from baseband to RF. For example, you can plugin an external baseband video input (e.g. camera) and listen to theRF (e.g. broadcast television) sound at the same time by havingnothing plugged into the audio jacks.Virtual Vision, Inc.7659 178th Place N.E.Redmond, Washington, 98052tel: 206 882 7878fax: 206 882 7373(I also observe that 1800 619 4680 can get there)Cost is under $1000 (e.g. list is around $900; should beable to get it for around $700).Virtual Vision sold the rights to the Virtual Vision Sport Glasses to the following company:http://www.vetco-inc.comVETCO Electronics 13029 Northup Way 7866 Southwest Nimbus Ave Bellevue, WA 98005 Beaverton, OR 97008 Phone (425) 869-7025 Phone (503) 574-2299 Fax (425) 881-5064 FAX (503) 469-0520 E-Mail: vetco@vetco-inc.com E-Mail: vetc0@gte.netSee also,http://www.virtualvision.com/Virtual vision has evolved into Virtual Image Dislays Incand Seattle Sight Systems. The new systemdescribed inhttp://www.seattlesight.com/sss.htmlis quite innovative.Seattle Sight Systems, Inc. , starts at US$ 3500http://www.seattlesight.com/gpseries.html14150 N.E. 20th Street., #313; Bellevue, WA 98007Telephone: (425) 643-1966; Fax: (425) 643-9976General inquiries may be directed to: ssightsys@aol.comSee also, a picture of Virtual Vision's new VCAP.PT-01 The PT-01 is comfortable as-is (e.g. I didn't find I needed to modify itor add any extra padding to wear it for long periods of time).The PT-01 is very similar to the Virtual Vision (it even has the same styleof connector, so if you already have a Virtual Vision, you can plug thePT-01 directly into the Virtual Vision belt pack, which means that youcan use the PT-01 as a tuner with the Virtual Vision belt pack).The PT-01 has the same high-quality color rendition as the Virtual Visiondisplay. Basically the PT-01 is a high-quality NTSC monitor, withsufficient quality of color rendition to facilitate its use inadjusting the color balance of cameras, etc. The spatial resolutionis not quite high enough to read 24 rows of 80 column text.The PT-01 delivers the identical NTSC input to both eyes, so that eyestrainis reduced during long viewing periods, and the PT-01 also fills a greaterangle than the Virtual Vision, but you can't see through the PT-01,so it may be less or more preferable than aVirtual Vision depending on your application and preferences.Basically I use the Virtual Vision when Iwant to monitor a signal while walkingaround (e.g. for testing video transmitters by walking around andlooking at the signal quality), but the PT-01 when I want to concentratemore on the video signal and less on the surroundings.This finding appears consistent with the manufacturers' intent, because thePT-01 requires a wall-socket (e.g. comes with a 7.5 volt wall adapterbut no battery) while the Virtual Vision is battery powered.Of course it is a simple matter of obtaining a 7.5 volt battery or running thePT-01 from the VirtualVision belt pack to liberate it from being tetheredto the AC. However, care should be used -- perhaps it is just as wellit is tethered because of the obvious danger of walking aroundwith your eyes covered up (unless you're using it for a`reality mediator' as I often do).The PT-01 swings up out of the way,and you can still see the screen when it is pulled out and swung upout of the way.The sound quality of the PT-01 is superb, and it has standard RCA inputs forstereo sound (3 RCA jacks, 1 for video, 2 for sound). There is also aBNC connector for video input which often comes in handy. Having bothBNC and RCA inputs for the video was a wise design decision, and therugged metal construction of the belt pack is consistent with thehigh quality that is typical of equipment that has BNC connectors on it,as opposed to the lower quality "consumer grade" equipment that typicallyonly has RCA connectors.If you're serious about video in the field, you probably want to get botha Virtual Vision and a PT-01 so you can adapt to any situation you mightencounter.Both of these units together can be packed into a carrying casethat is smaller than most color monitors, and definitely much less weightto haul around.Look at a diagram of how this displayis used.PT-01 email: Optix1@aol.comhttp://www.optics1.com/HMD.htm01 Products, Inc.3050 Hillcrest DriveSuite 100Westlake Village, CA800-538-3008805.446.1453 FAX:1+ 805.373.8966A division of Optics 1, Incorporated3050 Hillcrest Drive, Suite 100Westlake Village, CA 91362Phone: 805/446-1453 (800-538-3008)Fax: 805/373-8966e-mail: hmd@optics1.com Virtual I/O i.glassesNTSC version approx. $500; VGA version approx. $700:the difference between the two is that the VGA version comes with aVGA to NTSC converter. However, the VGA to NTSC converter does no betterthan, say, the $139 AI-Tech converter, so it makes sense to buy theNTSC version and just use another scan converter. Text is readable in40 characters per row, but it is still different to tell differencebetween certain characters such as 8 and 0, and some run together such as``m''; just a blur across. The display is quite comfortable to wear,and forms the basis of a good starting point to then build around(e.g. using better display technology into the i.glasses frame).1370 Willow Road Suite 101; Menlo Park, CA 94025-1515PHONE: 1-800-339-5287 650-323-8407; FAX: 650-323-1742E-Mail: info@i-glasses.com; http://www.i-glasses.com (was http://www.vio.com)Olympus Eye-TrekRecently, there was a review of theOlympus Eye-Trek: http://wearables.about.com/library/weekly/aa031201a.htmSome other more recent productsAn up-to-date listing of many modernhead mounted displaysappears in http://wearables.about.com/cs/displays/index.htmreturn to personal imaging, WearComp... other head mounted display pages/resources: A newer and more up-to-date list of head-mounted-displays: http://wearables.about.com/cs/displays/index.htm Olympus Eye-Trek: http://wearables.about.com/library/weekly/aa031201a.htm other resources... from emo@ai (with stereo color lcd interleaved pixels...)http://www.imaginative.com/VResources/http://www.imaginative.com/VResources/vr_hardw/vr_hardw.htmlhttp://www.cms.dmu.ac.uk/~cph/VRbib.htmlhttp://vr-atlantis.com/vr_systems_guide/vr_systems_list2.htmlContact info:Prof. Steve MannUniversity of TorontoDepartment of Electrical Engineering10 King's College Road, Room 2001Toronto, Ontario,Canada,M5S 3G4416.946-3387mann@eecg.toronto.eduhttp://www.eecg.toronto.edu/~mannRelated info:http://genesis.eecg.toronto.edu/wearpubs.html |
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