光學(xué)編碼器的優(yōu)點(diǎn)

　　手機(jī)相機(jī)上的光學(xué)變焦功能避免了數(shù)碼變焦造成的質(zhì)量下降，但目前的實(shí)現(xiàn)往往是噪音大、體積大、耗電大。Avago的aedr-8400編碼器采用了一種獨(dú)特的方法，解決了這些問(wèn)題。

　　介紹

　　廣泛的商業(yè)應(yīng)用使用帶有變焦機(jī)構(gòu)的照相機(jī)。也許最普遍的應(yīng)用是相機(jī)電話。相機(jī)變焦的關(guān)鍵設(shè)計(jì)標(biāo)準(zhǔn)包括低功耗，當(dāng)然還有空間限制。本文介紹了一種光學(xué)編碼器技術(shù)，它為相機(jī)變焦設(shè)計(jì)提供了一種新的方法來(lái)應(yīng)對(duì)這些挑戰(zhàn)。

　　光學(xué)和數(shù)字變焦

　　相機(jī)手機(jī)可能有光學(xué)變焦、數(shù)碼變焦，或者兩者都有。光學(xué)變焦改變相機(jī)鏡頭的有效焦距，使得原始圖像被放大，并可由CCD或cmos圖像傳感器捕獲。隨著放大倍數(shù)的增大，光被分散到整個(gè)圖像傳感器上，并且所有的像素都可以使用。光學(xué)變焦可以被解釋為一個(gè)真正的變焦，這將提高拍攝圖像的質(zhì)量。

　　Digital zoom， on the other hand， is a bit different. In this case， a software algorithm is applied rather than a hardware movement （i.e.， changes in lens positioning） to magnify the image. Such magnification involves only a certain portion of the captured image. This is known as the interpolation technique. Using such a technique， or algorithm， requires information to be added in order to enlarge the corresponding image portion. It may seem that the captured image is being magnified. However， only a certain portion of the real image information is being utilized and the rest of the image is coming from the interpolation outputs.

　　One thing worth mentioning is that the higher the digital zoom， the smaller the portion of real information that is taken. Therefore， many of the originally captured pieces of information on the image sensor will be discarded and more interpolated image data will be incorporated in the resultant image.