Softdrink cans

kyodai · Post by **kyodai** » Sun Jul 17, 2011 2:25 pm

I have changed my setup a bit and the laser is now on the same level as the object. Here are some softdrinks...

What i noticed is that the depth and sharpness cam e out great but there is kinda geometry distortion from some angles. Just wanted to be sure this is normal... What is remarkable that the sprite and cherry coke can got nearly realistic colors from most angles, making it nearly look like a color hologram. The red coke (To the right) can however came out like "yellow" , not sure why.

And of course a video.

http://www.youtube.com/watch?v=0507LRieRlk

kaveh1000 · Post by **kaveh1000** » Sun Jul 17, 2011 3:47 pm

Good job.

I would say that because there are so many depth cues in a hologram, and it captures texture, reflection, etc, your brain fills in the gaps and you think the colors are there too. Hard to judge without seeing it.

The fringes show I think that the objects moved during exposure. The fringes in the middle can are curved, showing that it is not due to translation of objects but distortion. I think if you leave these overnight and not touch them your next hologram will not have fringes (at least not due to object motion), and you might get a brighter hologram too.

kyodai · Post by **kyodai** » Sun Jul 17, 2011 6:04 pm

Thanks a lot for your comment and helpful analysis! Ah, so thats how movement looks? Definitely good to know.

How can you get rid of distortion? Is that different from movement (The round fringes)?

kaveh1000 · Post by **kaveh1000** » Mon Jul 18, 2011 3:00 am

Distortion is when the object moves in a non-linear way, i.e. its shape changes, during recording. This could be because you were holding it tight before putting it down, or it came out of a fridge say and started expanding at room temperature. The simplest solution is to leave the objects alone and leave them to settle.

But there is a whole field of non-destructive testing call holographic interferometry, whereby you deliberately have a long exposure to see where movements are occurring in the object. It literally gives you contours of movements.

And if you know how to "read" the fringes, you can work out where the movement was. Whether the object moved forward or sideways or whether it rotated. The "localization" of the fringes gives you a lot of clues. So you move your head around a bit and see how fringes move. Do they seem to be localized on the object, or at infinty, say? I have forgotten, but by a bit of practice you can use that info to work out exactly what the movement was.

favalora · Post by **favalora** » Mon Jul 18, 2011 9:13 am

Kaveh - Is the question possibly about the topic of magnification being a function of depth?
g

kaveh1000 · Post by **kaveh1000** » Mon Jul 18, 2011 11:19 am

I don't think there is any magnification there. I think they are miniature soda cans, right? I was just addressing the movement of objects.

By the way is there a notification option here to mail when there is a reply on a topic I am discussing? Couldn't find it under control panel.

kyodai · Post by **kyodai** » Mon Jul 18, 2011 11:48 am

Yes these are miniature cans with the plate simply leaning against them. The "leaning" technique does not seem to be that great i think.

You can click on "subscribe" on the button of the topic and get an email, even by those not from you, so you can follow topics that interest you. YOu can also subscribe to a complete subforum like the gallery. I don't think there is an option to only subscribe to threads of your own, so if you want that you might need to click subscribe manually on threads were you feel involved or interested in.

kaveh1000 · Post by **kaveh1000** » Mon Jul 18, 2011 12:57 pm

OK. Leaning probably not good idea. You are letting the objects rest overnight, then leaning the plate against them. I would say better not touch them at all during exposure. Just put a solid metal support on one side and lean the plate against that.

Tony · Post by **Tony** » Fri Jul 22, 2011 8:29 am

Judging from the vertical lines I would say that the plate moved rather than the cans.
Good job though.
Was this DCG? If so can you give some detail on how it was shot and processed?
Good Luck

holomaker · Post by **holomaker** » Fri Jul 22, 2011 8:53 am

Yes good job indeed ! Improved results ,means progress! Im not sure about these bands, are the cans solid filled models or hollow (fill with sand if empty)? These bands are the same as last shot... how long laser was warmed up?,it some how is starting to look like mode banding to me , how long did you allow everyting to settle after placing film plate? how ling was the exposuer time?....................are you using batteries to run it ?