Re: filmscanners: Vuescan long pass mode
In a message dated 2/8/2001 9:33:58 PM EST, [EMAIL PROTECTED] writes: > Are you sure it works on other CCDs ? Yes, with varying degrees of success. > For example I used a pin and poked three different size holes in a very dark > Provia 400F slide. The 2 pixel hole showed no charge bleeding, the 10 > pixel hole showed medium charge bleeding and the 40 pixel hole showed a far > amount of bleeding. In all cases, the red seemed to bleed more than the > green which bled more than the blue. Also the bleed seems to be only in one > direction. Yes, other people have reported these same characteristics of the CCD in the Canon FS2710. I've been saying on this mailing list for more than a year that overexposing the CCD would have charge bleeding problems. This limits the usefulness of the long exposure feature on some scanners. It's a hardware limitation, and there's not a lot I can do to work around it. Regards, Ed Hamrick
Re: filmscanners: Vuescan long pass mode
Ed, is this why some of my 35mm. negative scans look a tad 'thin' when using VueScan and more 'gutsy' when using CanoScan? Chris. - Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, February 09, 2001 11:05 AM Subject: Re: filmscanners: Vuescan long pass mode > In a message dated 2/8/2001 9:33:58 PM EST, [EMAIL PROTECTED] writes: > > > Are you sure it works on other CCDs ? > > Yes, with varying degrees of success. > > > For example I used a pin and poked three different size holes in a very > dark > > Provia 400F slide. The 2 pixel hole showed no charge bleeding, the 10 > > pixel hole showed medium charge bleeding and the 40 pixel hole showed a far > > amount of bleeding. In all cases, the red seemed to bleed more than the > > green which bled more than the blue. Also the bleed seems to be only in > one > > direction. > > Yes, other people have reported these same characteristics of the > CCD in the Canon FS2710. > > I've been saying on this mailing list for more than a year that > overexposing the CCD would have charge bleeding problems. > This limits the usefulness of the long exposure feature on > some scanners. It's a hardware limitation, and there's not a > lot I can do to work around it. > > Regards, > Ed Hamrick
Re: filmscanners: Vuescan long pass mode
- Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, February 09, 2001 3:05 AM Subject: Re: filmscanners: Vuescan long pass mode > > I've been saying on this mailing list for more than a year that > overexposing the CCD would have charge bleeding problems. > This limits the usefulness of the long exposure feature on > some scanners. It's a hardware limitation, and there's not a > lot I can do to work around it. > I agree, although Vuescan long pass currently seems to make some very simple assumptions about the CCD charge bleeding characteristics. At the very least it would be nice not to have Vuescan include charge bled pixels in its output as it currently does. The examples I posted earlier provide enough information for a more sophisticated approach. Whether it's worth it or not I dunno. Clean filters, grain reduction filters or longpass algorithms are all great ideas but none of them work perfectly so I guess we have to accept their flaws given today's SOTA. I'd cast my one tiny insignificant vote for improved longpass algorithms rather than working on better clean filters though. Byron
Re: filmscanners: Vuescan long pass mode
In a message dated 2/9/2001 2:05:44 PM EST, [EMAIL PROTECTED] writes: > I agree, although Vuescan long pass currently seems to make some very simple > assumptions about the CCD charge bleeding characteristics. At the very > least it would be nice not to have Vuescan include charge bled pixels in its > output as it currently does. The examples I posted earlier provide enough > information for a more sophisticated approach. Can you describe this more sophisticated approach? Give a bit of pseudocode for this algorithm. Regards, Ed Hamrick
Re: filmscanners: Vuescan long pass mode
In a message dated 2/9/2001 2:05:44 PM EST, [EMAIL PROTECTED] writes: > I agree, although Vuescan long pass currently seems to make some very simple > assumptions about the CCD charge bleeding characteristics. At the very > least it would be nice not to have Vuescan include charge bled pixels in its > output as it currently does. The problem is that you haven't described an algorithm that differentiates between a charge bled pixel and an ordinary image pixel. > The examples I posted earlier provide enough > information for a more sophisticated approach. No, they don't provide any useful information for a more sophisticated approach. Regards, Ed Hamrick
Re: filmscanners: Vuescan long pass mode
- Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, February 09, 2001 11:08 AM Subject: Re: filmscanners: Vuescan long pass mode > > Can you describe this more sophisticated approach? Give a bit > of pseudocode for this algorithm. > > Regards, > Ed Hamrick "Psuedocode"? I'm just a photographer. Last I checked you were the developer so I was hoping you'd run with it. If it is too hard for you then strike up a relationship with your local university. They are always looking for interesting projects to work on. Cheers, Byron
Re: filmscanners: Vuescan long pass mode
- Original Message - From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, February 09, 2001 1:51 PM Subject: Re: filmscanners: Vuescan long pass mode > The problem is that you haven't described an algorithm Agreed, but one has to leave something for Vuescan's developers to do... > > The examples I posted earlier provide enough > > information for a more sophisticated approach. > > No, they don't provide any useful information for a more > sophisticated approach. > *shrug* Actually they do. That's why I selected them. But I'd rather be taking pictures than arguing so will leave it for the interested reader (assuming there are any !!) to pursue. Cheers, Byron
Re: filmscanners: Vuescan long pass mode
Hi Ed, How does the Minolta Dimage Dual Scan II (USB version) compare with the Canon FS2710 in terms of using overexposure scanning? Art [EMAIL PROTECTED] wrote: > In a message dated 2/8/2001 9:33:58 PM EST, [EMAIL PROTECTED] writes: > > >> Are you sure it works on other CCDs ? > > > Yes, with varying degrees of success. > > >> For example I used a pin and poked three different size holes in a very > > dark > >> Provia 400F slide. The 2 pixel hole showed no charge bleeding, the 10 >> pixel hole showed medium charge bleeding and the 40 pixel hole showed a far >> amount of bleeding. In all cases, the red seemed to bleed more than the >> green which bled more than the blue. Also the bleed seems to be only in > > one > >> direction. > > > Yes, other people have reported these same characteristics of the > CCD in the Canon FS2710. > > I've been saying on this mailing list for more than a year that > overexposing the CCD would have charge bleeding problems. > This limits the usefulness of the long exposure feature on > some scanners. It's a hardware limitation, and there's not a > lot I can do to work around it. > > Regards, > Ed Hamrick
Re: filmscanners: Vuescan long pass mode
charge bleeding is a characteristic of CCD sensors, once the electron wells get filled up you get these vertical smears as the charge "bleeds" into adjacent pixels..its a hardware problem, can only be solved by limiting the exposure. I suggest you do multipass with the Canon instead of a "long pass exposure" if you want to capture shadow detail in slides. "bjs" <[EMAIL PROTECTED]> wrote: >I agree, although Vuescan long pass currently seems to make some very simple >assumptions about the CCD charge bleeding characteristics. At the very >least it would be nice not to have Vuescan include charge bled pixels in its >output as it currently does. The examples I posted earlier provide enough >information for a more sophisticated approach. Whether it's worth it or not >I dunno. Herm Astropics http://home.att.net/~hermperez
Re: filmscanners: Vuescan long pass mode
>> > The examples I posted earlier provide enough >> > information for a more sophisticated approach. >> >> No, they don't provide any useful information for a more >> sophisticated approach. >> b> *shrug* Actually they do. That's why I selected them. But I'd rather be b> taking pictures than arguing so will leave it for the interested reader b> (assuming there are any !!) to pursue. Oh, it is very often when near-evident and natural looking theories, especially ones based on wrong issue workaround, just don't allow immediate successful formalization or just fail being applied to another situation. Also developer's point of view may be very different from the user's (for many reasons). It is a common pain we are to live with until we'll be writing our own VueScan's . Alex
Re: filmscanners: Vuescan long pass mode
>From: "bjs" <[EMAIL PROTECTED]> > > > No, they don't provide any useful information for a more > > sophisticated approach. > > > >*shrug* Actually they do. That's why I selected them. Whether Ed Hamrick can come up with a fix for this apparent hardware problem or not, it should be pointed out that just because an example of a problem is provided does not necessarily mean that a fix can be created based on that example. People have been dying in car crashes for many, many years. Examples can be found every single day and yet no foolproof solution has ever been found. Sometimes an example problem case just isn't enough. _ Get your FREE download of MSN Explorer at http://explorer.msn.com
Re: filmscanners: Vuescan long pass mode
> Also developer's point of view may be very > different from the user's (for many reasons). > It is a common pain we are to live with until > we'll be writing our own VueScan's . I noticed the , but I like to mention that Ed is doing a great job creating and maintaning VueScan the way he does! There is no doubt about that. Users can be critical about new features, but do not think that Ed do not like to improve his VueScan! It is the only software I know wich improves with new versions more than one time a week ;-) __ With kind regards, Henk de Jong E-mail: [EMAIL PROTECTED] Homepage Nepal - Trekking Around Annapurna - Photo Gallery: http://annapurna.wolweb.nl
Re: filmscanners: Vuescan long pass mode
- Original Message - From: "Herm" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, February 10, 2001 2:20 AM Subject: Re: filmscanners: Vuescan long pass mode > charge bleeding is a characteristic of CCD sensors, once the electron wells get > filled up you get these vertical smears as the charge "bleeds" into adjacent > pixels..its a hardware problem, can only be solved by limiting the exposure. I agree it is a hardware problem but smart programmers have been working around hardware problems for decades. I have a Pascal program that takes N files at arbitrary exposure levels and combines them into one "longpass" result. It accounts for charge bleeding and a number of other issues. The result has none of the gross errors that Vuescan currently shows and works far better. I'd give it to Ed but the algorithms are proprietary. People claiming the longpass results I'm seeing in Vuescan are the "best that can be done using software" simply don't know what they are talking about. Byron
Re: filmscanners: Vuescan long pass mode
Henk, my was in no way directed to Ed !! Certainly he is doing a great job and fully get the burden of the support as well as he moves VueScan forward (rapidly!). I am probably in the minority of this list because photography is my hobby: I am a software developer, not a professional photographer. So I believe I understand both sides quite well. My remarks in that message are just what probably every programmer would say to his/her users. Alex >> Also developer's point of view may be very >> different from the user's (for many reasons). >> It is a common pain we are to live with until >> we'll be writing our own VueScan's . HdJ> I noticed the , but I like to mention that Ed is doing a great job HdJ> creating and maintaning VueScan the way he does! There is no doubt about HdJ> that. HdJ> Users can be critical about new features, but do not think that Ed do not HdJ> like to improve his VueScan! HdJ> It is the only software I know wich improves with new versions more than one HdJ> time a week ;-) HdJ> __ HdJ> With kind regards, HdJ> Henk de Jong HdJ> E-mail: HdJ> [EMAIL PROTECTED] HdJ> Homepage Nepal - Trekking Around Annapurna - Photo Gallery: HdJ> http://annapurna.wolweb.nl -- Best regards, Alexandermailto:[EMAIL PROTECTED]
Re: filmscanners: Vuescan long pass mode
>From: "bjs" <[EMAIL PROTECTED]> > >People claiming the longpass results I'm seeing in Vuescan are the "best >that can be done using software" simply don't know what they are talking >about. I thought I had read all the messages on this thread and I don't recall any that have said that. Which ones were they? _ Get your FREE download of MSN Explorer at http://explorer.msn.com
Re: filmscanners: Vuescan long pass mode
bjs: Is it appropriate directly to give Ed the name and maker of the program so he can possibly get it on his own see what you are talking about? He seems quite well aware of ICE and GEM and has been able to adjust his program without violating any proprietary and copyright requirements in that case, yet be able to improve his own product. It is one thing to ask someone to look at a scan and then be asked to adjust his program to correct a possibly solvable problem. It is yet another to give him the background information that lets him know why you are saying what you are and let him figure out how to solve the problem you percieve to be in his program. Gordon bjs wrote: > -I have a Pascal program that takes N files at arbitrary exposure levels and > combines them into one "longpass" result. It accounts for charge bleeding > and a number of other issues. The result has none of the gross errors that > Vuescan currently shows and works far better. > > I'd give it to Ed but the algorithms are proprietary. > > Byron
Re: filmscanners: Vuescan long pass mode
this is multiscanning, its already available and implemented..leave Ed alone (g)...We have a problem communicating, we keep saying the same stuff over and over and over and over.. "bjs" <[EMAIL PROTECTED]> wrote: >I have a Pascal program that takes N files at arbitrary exposure levels and >combines them into one "longpass" result. It accounts for charge bleeding >and a number of other issues. The result has none of the gross errors that >Vuescan currently shows and works far better. Herm Astropics http://home.att.net/~hermperez
Re: filmscanners: Vuescan long pass mode
- Original Message - From: "Herm" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, February 11, 2001 3:27 AM Subject: Re: filmscanners: Vuescan long pass mode > this is multiscanning... There is a fundamental difference between combining multiple exposures (ie longpass) and simple averaging of multiple scans (ie multiscanning). Suggest trying the two options in Vuescan if you wish to learn the difference.
Re: filmscanners: Vuescan long pass mode
On Sat, 10 Feb 2001 12:16:15 -0800 bjs ([EMAIL PROTECTED]) wrote: > > I have a Pascal program that takes N files at arbitrary exposure levels and > combines them into one "longpass" result. It accounts for charge bleeding > and a number of other issues. The result has none of the gross errors that > Vuescan currently shows and works far better. > > I'd give it to Ed but the algorithms are proprietary. Who's the author? What is it called? It'd be interesting to know more. Regards Tony Sleep http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info & comparisons
RE: filmscanners: Vuescan long pass mode
> -Original Message- > From: bjs [SMTP:[EMAIL PROTECTED]] > Sent: Saturday, February 10, 2001 9:16 PM > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Vuescan long pass mode > > - Original Message - > From: "Herm" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, February 10, 2001 2:20 AM > Subject: Re: filmscanners: Vuescan long pass mode > > > > charge bleeding is a characteristic of CCD sensors, once the electron > wells get > > filled up you get these vertical smears as the charge "bleeds" into > adjacent > > pixels..its a hardware problem, can only be solved by limiting the > exposure. > > I agree it is a hardware problem but smart programmers have been working > around hardware problems for decades. > > I have a Pascal program that takes N files at arbitrary exposure levels > and > combines them into one "longpass" result. It accounts for charge bleeding > and a number of other issues. The result has none of the gross errors > that > Vuescan currently shows and works far better. [Oostrom, Jerry] Byron, "smart programmers" used in comparison to Ed, "gross errors", "far better", by the nuances in these words you sound as if you feel attacked, just like Ed and others in reply to you b.t.w. ;-) Perhaps, that is the common way we try to make others do what we want, by shooting them and let them dance to our bullets. In defence they shoot back with the same attitude. This list has a handful of people who sound like this in many of their mails and I am astounded that these people are generally past 40 years of age, i.e. supposedly grown ups. However, they are also generally the ones quickest to respond to requests for help, so that's a good reason for me to stay voluntarily on this list. Anyway, I'll give it a try, fortunately you all can lough at my silly attempt to help you and Ed only later, when I have shields up. I have no understanding of the idea behind the "long exposure" algorithm, though I did use it with my Scanwit, resulting in magenta tints in faces, especially lips, noses and cheeks. It sounds to me as if Ed's algorithm works like this: you do one or several normal exposure (multi-)scans and one long exposure scan and combine the results with some weighing factor (probably fixed or reciprocal to the luminance value of one or all color channels and also reciprocal to the exposure) for pixels in the long exposure scan that have not been exposed to the limit (e.g. 255 in 8 bit scan, only looking at one color channel). Perhaps the most simple approach would be to make this weighing factor in channel X or all channels 0 (zero) for any long pass exposure pixel adjacent to or in close neighbourhood of a long pass exposure pixel that was overexposed in channel X. The unfortunate result would be that you loose the shadow info in areas of high contrast, but the problem of bleeding should be smaller. In this case you don't make use of knowledge about which pixel is well exposed and which pixel contains change bleeding, so you don't need to know. Another, complex approach would be to apply scouring algorithm in the long exposure scan to the sections with pixels exposed to the limit (one/all channels). That is, if scouring algorithm can be applied that way. The pixels that were exposed to the limit would still have weighing factor 0, but the adjacent pixels could have their normal weighing factor, whatever that is. Time's up. I am sure some of you, programmer or not, or Ed, who is a smart programmer i.m.o., will come up with far more ingeneous approaches and accompany them even with pseudo code to combat the pixel bleeding problem. Some of you seem really knowledgeable about the physics of light and the engineerings behind CCDs and stuff, thus this poses little challenge to at least some of you. Perhaps inspiration or time available is the limiting factor for most. Jerry
RE: filmscanners: Vuescan long pass mode
Jerry Oostrom wrote: > Another, complex approach would be to apply scouring algorithm in the long > exposure scan to the sections with pixels exposed to the limit (one/all > channels). That is, if scouring algorithm can be applied that way. The > pixels that were exposed to the limit would still have weighing factor 0, > but the adjacent pixels could have their normal weighing factor, whatever > that is. I was thinking about this as well. I suspect that pixel bleeding may occur with some CCDs even before the highlight levels reach 255,255,255. (I did a scan of a hole in a piece of card with my Elite. The normal scan did lose some edge detail but a scan at the shortest scan duration showed card fibres at the edge of the hole.) So an option might be a combination of 3 scans, a short scan to retain highligh details & minimise/identify pixel bleeding, the normal scan for the majority of the pixel data and the long scan to minimise noise and maximise shadow detail. The short scan would have to act as a mask to determine which highlight detail is "real" and not bleeding, could provide detail for any of the highlight detail compromised by bleeding in the other 2 scans and, for midtones and shadows affected by bleeding, help determine which of the other scans provides the best data. Of course, I'm sure it's much more complicated than that and I wouldn't have a clue how it could all be coded! Certainly, my own experiments with masks in Photoshop have never managed to get rid of blooming/reduced contrast around highlights. Al Bond
