Quote:Analog Video Technology (Part 4)Display Technology - section 1Before the deep dive, let's discuss some fundamentals:a) Consumer electronics is typically very competitive. The initial phase of the product has to win a major market share/brand&model recogniztion (hopefully high quality and low price tag), then reduce the cost and sell it in a large volume. This is the reason why "do your homework" and tracking the product's current state (hopefully by not-tinted end-users' opinions) is very important. For hungry manufacturers/distributors, it's understandable what they have to do ...I strongly suggest we do not quote those glossy' numbers/features unless these are proven facts.(Too busy picking up my jaw on the floor... )b) There are "brand-only" products, i.e., company sold the "name" to others. c) Even the device came from a known brand, model X does not necessarily have a good correlation with model Y, checking with the specifics is important. In few cases, even with the same model number, different versions/generations may give surprises.d) CRT displays, by trade, always have to deduct 1" from its stated diagonal size. LCD displays usually do not. e) From the tradition 4:3 display format (thinking its is 12-wide : 9-height is more helpful for calculation) evolving into 16:9 HDTV (or called "wide") format, there are few interesting points:- Wide screen has 4 extra unit width-wise, two units on the left and two on the right (16 in Wide vs. 12 in std)- since diagonal is still the measurement method for display size, one may find 8.5" Wide LCD is about the same as 7" standard LCD display, if you display the NTSC (4:3) format as is, i.e., not let the monitor stretch automatically in horizontal direction to fill the entire screen (unless you really like fat face )example 2, a 22" wide would show the same area as 18" std display, if not horizontally stretchedexample 3, a 7" wide would show the same area as 5.6" std display, if not horizontally stretched[Hint: you might want to check the recent pricing premium over just "only inches" bigger (but really it's just wider) monitor ]f) Experienced users and manufacturers know: monitor's adjustment knobs disappeared long ago for reliability/maintenance/cost reasons. Usability does not always track well with reliability. Now back to our normal program ...=========================================================6.1 Immersion, Resolution, and Viewing DistanceThe commonly asked question is what size monitor is the right size. There are two different ways to answer it:- what type of viewing distance works the best for you (this probably is the primary constraint)(close inspecting or sit back and relax)- It turns out that optimizing the best angular resolution (i.e., see the picture sharp and clear) with the spatial resolution of the intended "system" need provide will give a range (min. and max.) of acceptable viewing distance. Too close, will see the scan lines and actual pixels. Too far away, picture looks fuzzy. Looking close but not shorter than the minimum distance will have wider FoV, giving the sense of more immersion. This is one reason certain organization's recommendation on viewing distance tend to be on the short end, since they are known for "better (immersion) experience".Please note I did not say it's just the monitor resolution which counts, but the overall "system". For example, if a high quality 500 TVL monitor is used to display a video signal which only has a 280 TVL resolution, then use the 280 TVL number, since close-inspection of the monitor will not be able to show anything greater than 280 TVL, but will only let you down since the fuzziness of the 280 TVL video are now seen as "watercolor-like" very clearly. I.e., 500 TVL monitor will not be able to invent a beautiful picture in which it does not have in the first place.The following is the commonly used viewing distance guideline, based on monitor size.(NTSC resolution) 480i system 5:1 up to 10:1 (5 to 10 times the monitor height)(HDTV-like resolution) 1080p system 2:1 up to 4:1 (2 to 4 times). Note two times distance is awfully close, presuming the video it's displaying came from a high-quality HD source. If a regular noisy broadcast SD (standard defiition) program or a VHS tape is played and displayed on that HDTV arrangement with close-distance viewing, one will definitely regret setting the distance too short .One might also notice that computer monitor (especially for XGA resolution or higher) viewing distance is quite short, if viewing text (like reading this forum post). But it is possible to view a movie (especially on a low quality YouTube movie) from quite a distance away.In general, 30 degrees FoV is the maximum recommended value, e.g., large screen/home theater HDTV.While for NTSC (SDTV), 15 degrees FoV is normal. If you note in the potpourri section on eye's FoV is about 120 degrees, you'll notice the surrounding beyond the TV set will be a distraction. I.e., not much an immersion experience.Let's say NTSC-color has 330 TVL and has 15 degrees FoV. If a 4" LCD monitor (3.6" width and 2.4" height) is used to display a 330 TVL quality video, the viewing distance should be about 12".We can say for 470 TVL higher-quality NTSC 4:3 aspect ratio video on the same monitor will be about 8.5".Also note for the same 330 TVL but 8" LCD display, the viewing distance doubled. But you may notice the light output has to brighter and can cause greater light distraction (or L.P.).Please note a lot of these are subjective.(To be continued) In later sections:- Some key LCD monitor attributes (response time, contrast, illumination, viewing angle, etc.) and how to tell- example of LCD display devices- resolution of the monitors and how to measure them===========================================================================Potpourri:About Human Eye: Spatial Resolution: in well lighted situation, it's about 8000*8000 (sharper in central region)FoV is about 120 degreesDynamic range in a dark adapted environment: 20 stops (Wow!! Amazing )===========================================================================Attached picture(test resolution display on a $20 5" CRT B&W TVnote the last region is washed out) signal source: a professional test signal generatorpatterns: 0.5MHz (3 white+3 black strips), 1, 2, 3, 3.58, and 4MHz. Detailed explanation will follow soon.Clear Skies!ccs_hello
MC is using a 768*494 (better than standard-resolution) CCD as its imaging sensor. Assuming it's a color version and S-video cable is used, in best case 470 TVL can be achieved. I suggest someone with that camera and a very good CRT monitor to use the measurement method (print out the resolution chart ...) I described then check the resolution achievable.
500 TVL type of display is very nice. Usually studio monitors used in a SDTV boardcast station would be 600 (or even 800) TVL models. These are heavy and power hungry.
But if the camera and the transmission system combined together does not deliver such type of resolution, e.g., just 400 TVL (Horizontal), then many 400 TVL monitors will suffice.
BTW, mine is a SONY PVM-xxyzQ chromacity-correct/8MHz >600 TVL/super-fine pitch (0.25mm) Trinitron model (list $1,200, fleabay: 1/30 to 1/6th the list price, used.) It is very heavy (18 Kg approx.) and consumes a lot of energy (100W approx).
Older sketches in Members Galleries (rolandlinda3)
Equipment: Binoculars & Telescopes & plain old eyes
Special equipment: sometimes astrovideo in place of eyepieces
Thanks again for helping me understand a little more about matching a camera to a monitor. If I understand correctly...(and that's a BIG if)... A person only needs a monitor that is capable of handling the output of the camera being used. Using the best cables for the application (S-Video) will reduce noise and help get the best image possible on the monitor. Using an up converter will not magically produce a high definition image if the camera only puts out 768*494 resolution.
I know this is over simplifying the subject, and is probably not 100% correct, but this is what I've come to understand on the subject of matching a camera to a monitor for the best live view.
The night sky is the canvas....
My optics are the brush....
The Milky Way is the masterpiece
reductio ad absurdum of epistomology is solipsism....
Quote:Bill,Mine is KWorld 1440 TV Box. For the test, I fed signal into its composite input but not noticed C-signal leakage into the Y-channel.I have not yet noticed difference on composite vs. S-video. Probably I am not "exercising" it hard enough .But I would not say that specific box is THE determining factor. I think the computer monitor resolution is the key factor. Its resolution is much, much better than a traditional LCD video monitor . This leaves a lot of headroom for the 'converter" box.I have a hunch that the new winner is already here and it's cheap. In the 2007 BF sale a month ago, there was a 19" Wide LCD HDTV on sale for $199 in C.C. (normal price $230-$270.) That device has an ATSC digital tuner, a NTSC tuner, composite/S-video/component/HDMI inputs, and computer VGA input. That is all-in-one contained within one LCD display. But I ran out the $ ... Well, price will drop on these LCD monitors anyway.Clear Skies!ccs_hello