二戰盟軍頭盔上的圖案

A lot of Insignia can be found in an US GI Helmet (Marine does not put Insignia on their helmet as often)

It take some time to decode it, some insignia are still be using today.

Basically, all 4 sides of an US Army Helmet can be painted and used to identified either rank, unit, or formation

Insignia in the front of an helmet are usually rank
Insignia on the side of an helmet are usually unit
Insignia on the back of an helmet are either unit/status of a soldier

我睇過有套戲叫《雷霆救兵》，有D盟軍頭盔上有D特別圖案，有：

1.「口」


圖片參考：http://upload.wikimedia.org/wikipedia/en/a/ac/Saving_Private_Ryan_poster.jpg


If you mean the insignia above, that is the rank of a Captain in the Army. Only Officer wear their Insignia in front of the helmet commonly, there are some NCO will put their rank up as well, not too common tho.

Rank that are below captain are painted on the helmet, while rank above Major are studded on.

2.十字架

There are 2 insignia involve a cross on a helmet the first one is a combat medic. The second one is a chaplain of the army.

If your cross is red in white background and painted all over the helmet like this:


圖片參考：http://www.diggerhistory.info/images/uniforms3/us-medic1.jpg



If the cross you see is a silver cross that studded in front of a helmet like the rank. Then it mean that soldier is a Chaplain.

3.個頭盔凹凸不平

I have no idea what you mean on this, can you specify it?

4.有個心心

A heart shaped insignia painted on the side of a helmet denote that soldier was serving in 2d Brigade, 101st Airborne Division. Usually refer to the soldier fromthe famous 502d PIR (The five-o-duece) noted the photo


圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Eisenhower_d-day.jpg/748px-Eisenhower_d-day.jpg


Each of the different Brigade within 101st Airborne Div have their own insignia, usually comprise of the pattern from a deck of playing card (Poker Card)

Where as ;

1st Brigade uses ♣ (Club)
2nd Brigade uses ♥ (Heart)
3rd Brigade uses
圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/e/e7/Torii.svg/10px-Torii.svg.png
(Torii)
4th Brigade uses ♠ (Spade)
Heavy Weapon Brigade uses ♦ (Diamond)

Bear in mind, only 101st Airborn uses unit insignia in WW2 helmet as a common practices, even the sister airborne unit does not uses any Unit insignia in their helmet.

Most armor brigade uses insignia in their helmet too.

小弟在此只為 steven 兄作些少補充：
1) D-day 當日尚有海軍人員參與，除駕駛登陸艇的之外，特別是想提提在灘頭負責分配登陸 zoneing 和疏導灘頭交通的第二、第六及第七 Navel Beach Battalion, 佢哋嘅標記係在頭盔正面有一個彩虹咁嘅「半圓拱」。
2) 至於陸軍方面 steven 兄忙中有漏答少咗您嘅係：頭盔後面，一般多數都無嘢，但亦有啲有一條約一吋粗嘅線。係用嚟比自己友就算從後面或遠處都知道邊度揾阿 sir。直線嘅意思係：Officer；橫線嘅意思係：NCO。

我估“個頭盔凹凸不平”是頭盔包了偽裝網，但無安裝樹枝，所以看起來像凹凸不平。

嗰個應該唔係“口”字，應該係類似羅馬數字二既“II”，你係唔係見湯漢斯個頭盔有呢個標誌﹖呢個係美軍上尉既標誌，全軍適用，即係無論海軍、空軍及陸軍上尉都係呢個標誌。

個十字頭盔係唔係紅色﹖其實好明顯係救護兵，套戲開頭有個軍醫，我估你講既係佢。唔明咩叫“有個心心”，如果你見個個係紅心，我懷疑係某一個連既代號。有啲美軍團及營鐘意將犀下既連用啤牌既紅心、階磚、葵扇及梅花來代表，我估個紅心係呢個意思。至於“個頭盔凹凸不平”就更加唔明你講乜，頭盔一定拱形唔會凹，我懷疑你見既唔係頭盔，而係軟既貝雷帽(Beret)，呢種帽完全係一頂廢既軟帽，帶來純粹為左靚仔啲同埋唔好凍親個頭，美軍裝備一流唔會cheap到要士兵戴貝雷帽，而係人人一頂鋼盔，只有英軍呢啲裝備缺乏既軍隊先會比貝雷帽士兵戴。講下提外話，美國陸軍係越戰有一啲精銳既前線偵察部隊叫Green Beret，呢班人係真正戴綠帽也，而且佢地仲鬼咁自豪。