lokokkee

I have just upgraded to ADSL broadband, but the modem would not work if I connect a lightning surge protector, so I have to leave it out and it is a rather expensive piece of equipment compared to the old 56K dialups that kept getting hit by lightning surges. I live in the tropics, so thunderstorms are pretty normal. Any suggestions as to how to overcome this?

Another question: Which is better in terms of picture quality, scanning a photo at high resolution and then saving it in JPEG format, or scan at a lower resolution and save it uncompressed in bitmap format? I have tried using 300 dpi scanning, which results in a image of around 3-4 meg before conversion. But the JPEG image after compression is only around 250k, so lots of details would have been lost. But visually, the image is no worse than a bitmap one scanned at half the resolution (150 dpi), taking up 1 meg. I am thinking of sending a photo album over the net, so a compromise between resolution and file size is required. Advice please.
Thanks.

Dream Weaver

Loko - it can be done. I have my system running through a surge protection unit.

The key is to run a telephone extension cable from your socket, and into your surge protector. You then plug the ADSL micro filter into the surge protector as though it was the normal socket. Works a treat and means everything is protected.

Re the images, scan at 300 then reduce the jpeg image. 250k sounds way too big for my liking. Try reducing the quality to 65 ish. It all depends what it is really. bmp can be a bit harsh

DW

boomer

Dunno about the lightening, but as for the pictures..

Scan at high-res and store as JPEG!

Bitmap stores every single pixel, so a typical outdoor shot would contain "blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, blue-sky pixel, ..." repeated 50 thousand times, whereas the JPEG would simply say "blue-sky pixel times fifty thousand" and be much smaller.

You only start to lose significant information in JPEG when you repeatedly edit a picture.

mb

lokokkee

DW, thanks. The modem is not connected to a micro-filter, even though one was supplied and I used it to connect to my phone instead, as the line was quite noisy after ASDL was installed. What's the micro-filter for anyway? I just plugged the modem into the phone outlet of the surge protector and couldn't get a connection, so maybe should try with the filter on. I asked the protector supplier and they were talking about a DSL protector or something digital, (the technical person was out, so no definite answer yet).

Re the photo format thing. I need to do some editing, e.g. exposure adjustments. Should this be done at the bitmap stage before conversion, or at the JPEG stage? Also, for archiving purpose, where file size is not critical but fidelity is, e.g. using a CD-R, which format would be best? What format is used for commercial Cd-photo finishers? Thanks.

suba

what type of surge block you are using? some cheapo "pasar malam" type? when i was in KL, i cant seems to find any proper surge block that will protect the equipment from lightning strike. i know belkin sell some surge block that will protect from lighning but dunno if they are available in KL.


always scan at the highest/best resolution so your source (the digital format) will be at the best quality. save it as TIFF if you dont wanna loose any compression quality.

p/s do you drive a scooby in KL? there's one always (or used to) parked outside HSBC in Bukit Bintang Road opposite Lot10.

lokokkee

Suba, I am using a Cal-Lab unit, which is locally made, but claims to be 99.99% effective with a money back guarantee. While I have to replace the unit a number of times on a part-exchange basis, there has been no damage to the rest of the equipment (touch wood) so far.

I do drive a Scoob, but not the one parked where u mentioned. That stretch is a no-parking zone, and I am not rich nor famous enough to afford or avoid parking tickets. There is a Porsche, however, that is parked in front of the pizza parlour, owned by the boss of the place, who apparently needs to keep an eye on his toy all the time or flaunt it. Don't know how he takes care of the cops though.

You are now confusing me some more with this TIFF format thingy. Got to do some research into the pros and cons of the various formats now.

suba

well, from what i know from digital camera, TIFF format is the "raw" digital picture without any compression. JPEG and GIF are compressed digital pictures therefore losing details.

hey, i dont see much scooby in KL, only saw 1 or 2 new age impreza. a lot more evo and lots of "evo lookalike" wira!

lokokkee

Suba, so TIFF is without compression, equivalent to bitmap then. You are right about the rarity of Scoobs in KL. With a minimum of 170% import duties, only diehards will buy them and I was told there are only about 40 "classic" 220 p.s. official imports, not sure about STI and WRX grey imports though. So if one is to pay such duties, won't blame them for going for the 280 p.s. Evo's rather than the watered down Turbos. I bot the Scoob cos there is supposedly after sales support from the official agent, unlike the Evo, but not much help there as they are only a catalog shop. Go see what u want and they'll order from Japan. Takes one month for even the most mundane part like oil seals.

Dream Weaver

Loko - the filter filters out high and low frequency coming in through your phone line. High for the ADSL and low for the normal phoneline.

You defo need to add this into your system.

lokokkee

DW, I am running the modem at the moment without the micro-filter, so it appears to be not mandatory. I'll jiggle the thing with the filter on when I have the time to see any results. Thanks.

suba

there's no way your broadband can work without the micro-filter (aka splitter)! just imagine your fone line was carrying 1 traffic (voice fone) before broadband. now with broadband, the same fone line is carrying 2 traffic (voice AND broadband). by the way, is your micro-filter split into 2 connection???

so with the micro-filer, it will split the 2 traffic at the end of the termination, eg, to a voice fone and broadband modem.

i dunno if ADSL is affected by "noise" on the line but i know that telecommunication in malaysia is not the best and "noise" on fone lines are so common. no wonder analogue modem keep dropping lines.

as for connecting it into the surge block, from the wall, connect it up to the surge block, and on the surge block, connect the micro-filter, then to voice fone and broadband modem.

lokokkee

Suba, I think the confusion is over the micro-filter. The one I have is not a splitter design, there is only 1 connection in and one connection out. As I said, the installing technician brought one along, but didn't see fit to connect it and the modem has been working so far, albeit at a slower than advertised speed and dropping the connection now and then. I have complained and the reply was that the copper wires were very old and not in prime condition. They then pulled a new wire from the junction box to the house and that seems to improve matters a bit. I used a splitter jack from the wall socket to connect my phone, which is routed through the surge block. I'll try the filter with the modem, and then connect the phone from the phone-out jack of the modem and see if it works. Thanks.
BTW, Suba, how long were u in KL to know such terms like 'pasar malam' and places like Bukit Bintang?

chiark

Just another bit of advice on image format...

JPEG is lossy, and discards information that *it* thinks you will not notice. Continual editing and saving in jpeg will lose information and degrade quality.

I recommend that you store using some non-lossy format (tif has been mentioned, gif won't do as that's limited to 256 colours ) until you do your processing, then save as jpeg.

Note that you can set the "quality" factor on JPEG too, which controls how much info it throws away.

Saying all this, JPEG is a damn clever file format and the change in generations (ie saving, resaving) is very slight.

For the web, I guess you'll make a thumbnail for the album and link this to the bigger picture?

lokokkee

Another thread here directed me to the ADSL guide web page and got more info there. Apparently, the microfilter is only required for the phone to filter out interference from the ADSL modem if they share the same line (I have a fax and two extension phones attached, so that's where all the noise came from, lol), so the latter will still work if the filter is not connected. The surge protector manufacturer has called back and suggested I get their DSL model instead (more expense?) Since the ADSL modem is supplied by the ISP, i.e. not privately owned, should I bother or just let it be. The downside is that if they take their own sweet time to replace, I'll be without service in the meantime if struck.

Chiark, thanks for the suggestion. If the ultimate format is JPEG for use on a 800x600 screen resolution, what is the most practical scanning resolution to use in the first place in terms of scanning time, e.g. at 300 dpi for a postcard size foto, there are already more pixels than the screen can display? Is it then redundant to scan at a higher resolution than the final screen resolution?

carl

Originally posted by boomer:Actually what you describe is Run Length Encoding (RLE). JPEG uses the discrete cosine transform. Basically it takes a 'block' and tries to fit a curve to describe the change in colours between the top left and the bottom right hand corner. Then it stores the equations rather than the pixels. Works well with smooth graduations, but not on hard edges (which is why you get spurious JPEG encoding artefacts on hard edges, e.g. text).

chiark

A standard display is assumed to have a resolution of 72 dpi (dots per inch) so you could take it from there...

Does that answer? Not quite sure I understand the question, because I can be a bit slow at times

lokokkee

Chiark, that's what I mean. If it is for screen display only, then the weakest link is the screen resolution and there is nothing to be gained (if I am right) in higher scanning resolution. On the other hand, if it is for print output where printer resolution can exceed 700 dpi, then one will need a higher scanning resolution to match.