panorama software,virtual tour software
Alternate Text
Joined: 2003-01-16
Send Msg:
Posts: 959
2005-11-02
#1

quality improvement for images

hi,

i tested something I've seen here a few times when it comes to image size improvement. I tried steping down from my stiched image size of eg. 4000x2000 in 3-4 steps. ie i have stiched image and run it through Noise ninja which does some sharpening and noise reduction. i save this bmp image as final step of my post stiching PS work.

i then reduced the image size to 3000, did 20 unsharp mask, resized again to 2000 and did 20% unsharp mask, reduced to my final image size of 1508x754px and did another 48% unsharp mask.

try this with a pano of ur own and also just step down once with the same pano and compare. I think u'll find the results... rewarding.

will post comparison later.


If I only had an hour to chop down a tree... I'd spend 45 mins sharpening the axe.
Alternate Text
Joined: 2003-01-04
Send Msg:
Posts: 751
2005-11-30
#2

does anybody have a comparision of

the one bang resizing vs the multiple step downs with unsharpen

one bang = goes from orginal to around 400kb at 72 dpi

multiple step downs = also ends at around 400kb at 72 pdi

i reckon creating an action will be the best to process the images once

youre happy with the end results.


Alternate Text
Joined: 2002-05-18
Send Msg:
Posts: 157
2005-12-03
#3
Here is the final solution from Ken Turkowski for all command-line geeks, and it works great:

Sizimg

Images can be resized with the use of the command-line tool sizimg. Tests have shown that the quality resulting from sizimg surpasses that of any other commercially available software.

sizimg is a UNIX-style command-line tool to be used on the Macintosh using the Terminal application, or in the Command Prompt window on Windows. As a command-line tool, it has no user interface, but it can be very powerful when incorporated into scripts. In particular, it can be used in shell scripts to batch process images.
Alternate Text
Joined: 2002-06-12
Send Msg:
Posts: 2239
2005-11-03
#4

ok I will try this

Dave


/s/
Dave
Forum Moderator for
EasyPano - Panoweaver
Pano2VR


Visit 360texas.com
Alternate Text
Joined: 2005-05-15
Send Msg:
Posts: 372
2005-11-04
#5

Yes this it the way to do it.

I hit the image first with a 50% sharpen at 4000x2000

Go to 3000 wide and sharpen at 15%

Then 2500 at 10-15%

It depends on the amount of tonal range in the image. Be careful. If the image has a lot of definition in tonal range it can make the image too contrasty.

But this works with all images and is the way to size down.

If you take stills at fine setting with a D70 the image is 3008x2000. If you wack the image down to 500 wide in one step the results arent great. Hitting it with big sharpen at this size will just make the image very contrasty.

General Lee.


Alternate Text
Joined: 2003-01-16
Send Msg:
Posts: 959
2005-11-06
#6

Hi there General Lee,

thanks for this tip by the way. I'd seen the post about this yonks ago and never really got round to try it until recently. It does actually seem to work rather well and I tend to get a better image as a result.

so once more big thanks... (I just could not recal was was the one with that tip)


If I only had an hour to chop down a tree... I'd spend 45 mins sharpening the axe.
Alternate Text
Joined: 2005-05-03
Send Msg:
Posts: 569
2006-01-31
#7

Hi All

 

I am sorry for continuing this thread, but I believe that the better I understand why and how certain procedures works, the better I will be a producing panoramas.

I have now tried resizing a couple of images in a couple of steps and unsharpen after each step. I must say that I am impressed that it actually improves the quality that much. My questions are:

1) is it so that the more steps you take when rezising the better?? would 5 steps from 4000x2000 to 2000x1000 be better then 3 steps??

2) @ gen lee. Why do you start at 50% unsharp?? and not e.g. 75%?? And why do you go down to 15% unsharp the next couple of steps?? I assume it is to keep the quality as good a possible, but honestly I can't see the difference in my images after just 1 step, that is why I ask. I just want to be sure that I am doing it the best way :o)

Best regards

morten Andersen 

A newbie trying to improve 


Best regards

Morten Andersen
- a newbie trying to improve
Alternate Text
Joined: 2005-06-16
Send Msg:
Posts: 24
2006-01-31
#8

one question: if i want to create a full screen qtvr file ( say 1024x512) what size should i  down size to ? My original file is around 4300 x 2200 ...i tried both 3000x1500 and 2000x1000 before ... For the first one, the output qtvr file size seem too big. For the second one, the pix seem blur (not enough pixel).

is there any rules to follow?

tks fatchai


Alternate Text
Forum Moderator
Joined: 2002-11-23
Send Msg:
Posts: 5438
2006-02-01
#9

For full screen it is recommended that you resize your image to no smaller than 4000x2000 you then compress as hard as possible without any real notice to the human eye. This typically is at around 70 in the quality setting (but can very depending on colour information) A fullscreen panorama should come in at around 2.2MB or smaller if done correctly. You certainly will not get under 800kb with any sort of quality.

Regards, Smooth


Alternate Text
Joined: 2005-06-16
Send Msg:
Posts: 24
2006-02-01
#10

thank you smooth for your answer... 2.2M seen quit big for download. but many times i can see full screen qtvr file from diff websites that their file was between 1.3M to1.6M. And the quality are quit good too. How can thy generate such small file with high quality?

tks 


Alternate Text
Forum Moderator
Joined: 2002-11-23
Send Msg:
Posts: 5438
2006-02-01
#11

It is all to do with compression. Most use "Sorenson" but there are many options to be considered. Photoshop is not the best option for setting compression. Check out www.jpg.com they do a program that is superior for making the smallest file possible. They once did (maybe still do?) a program called The JPG Wizard2

It also depends on on the amount of any one colour in the panorama. The more of one colour the smaller the end file will be.

Many more options as far as programs are out there to test!

Regards, Smooth