How to straighten curved objects in PShop while preserving the dimesnional ratios?

Hi guys, I have some PhotoShop experience but I have never faced this kind of a problem, so I don't know how to solve it.
I have this photo of a Japanese short sword (Wakizashi)

As you can see, the sword is curved. I want to make it look straight without messing up its dimensions, i.e. I want to straighten it in PhotoShop as like it was made of clay. I hope you get what I mean.
I have the image of the sword on a separate layer, the background is a different layer.

So, what tool(s) should I use for the job? (I tried with the Warp but it screws up and distorts everything)

Thanks for your help!

Some of the things in Edit > Transform would be a good place to start. Experiment with skew and the other options there to see what works for you.

I did that - the Transform function does more damage than useful work.
It warps and it distorts the whole thing fixing one thing and ruining another at the same time.

Hmmm... I guess that there is no way to do what I want.

Not sure what you mean about the clay, but you could maybe try the Forward Warp tool in the Liquify dialog (Filter > Liquify) Try using the maximum size brush and gently pulling down in the centre of the sword.

Thanks Wano, it worked.

i was gonna suggest rotating the graphic 90 degress and trying the Shear filter, but if the other technique worked, cool :-)

The Shear works too, thanks KillerWolf.
Both methods compromise the image's proportions but they are still better than nothing and deffinitely superior to the highly destructive Warp tool.

Some guy on another forum adviced me this:

TRY APPLYING the ARCH effect at the top left hand side of the page ---menu----

I was unable to locate such tool. Arch effect? Is it from an older PS version? I am using CS2.

You're welcome, Svetovid. Glad you got a result. I think the guy on the other forum may be referring to the Custom Warps in the Warp Options Bar in CS2. At the top left of the Options Bar when you choose Warp, there's a drop-down menu that allows you to choose from a selection of pre-set warps such as Arch, Bulge, Fish-eye among others. They are useful, but can degrade your image if you're not careful, as you've discovered. I think you get more degradation if you warp, click the tick to accept, then decide to warp again. So it's better if you can get away with a small amount of warp and do it all in one go!

Aaaah, thanks, I tried this Arch preset now and it worked quite OK too.