Pemampatan data citra berwarna menggunakan alihragam gelombang-singkat

SUKSMADANA, I Made Budi, Prof. Adhi Susanto, MSc.,PhD

2001 | Tesis | S2 Teknik Elektro

Sutu citru yung duput dioluh di komputer disebut citru digital. Citru digital duput disimpun lungsung pudu pita mugnetik. Ukurun media penyimpunun yung diperlukun unruk nienyimpun citru digital terguntung pudu besurnyu ukurun citru tersebut, semukin besur ukurun citru muka diperlukun ukurun mediu penyimpunun yung semukin besur pula. Seluin itu ukurun data citru yung besur ukun menyebubkan kelum butun duium pengirimun (trunsmisg citru tersebut, misulnyu j i b citru yung berukurun besur “di-down loud” pudu internet ukun memeriukun wuktu yung cukup punjung. Hal seperti ituluh yung meluhirkan pemikirun periunyu suutu usuhu untuk memumputkan dufu citru, sehinggu data tersebut duput disimpan dengun ukurun yung lebih kecil duripudu keuduun uslinyu. Ada 2 jenis s fut pemumputun a&, yaitu: pemumputun yang bers fut nir-rugi dun pemumputun yung berslfat ber-rugi. Untuk memumputkun dutu citru duput menggunukun pemumputun yung bers f i t ber-rugi, kurenu udunyu keherlebihun informusi yung terkundung pudu data citru tersebut. Pemumputan data citru yung bers fut ber-rugi nzemiliki husil pemulihun yung tiduk sumu persis dengun citru uslinyu, tetupi informusi yung terkandung didalumnyu tidak sampui berubuh, ha1 ini dilukukun dengun mengutur kuulitus citru husil pemulihun sesuui dengun yung diinginkun. Pemumptun yung berslfat ber-rugi memiliki keungguiun padu rusio pemumputun yung sungut besur, sehinggu ukurun media penyimpunun yung diperlukun kecil. Alihrugum Gelombung-singkut merupukun suluh sutu metode yung duput digunukun untuk memumpatkan data citra (khususnyu dutu citru berwurnu) yung bersfut ber-rugi. Husii pemumputun dutu citru berwurnu menggunukun ulihrugum geiombangsingkut yung dperoleh uduluh sebugui berikut: untuk pemumputun citru dengun tapis Duubhecies 2,.H uur, pudu tingkutun muksimum, sistem koordinut wurnu YIQ dun kualitus pemumputm I0 memiliki rasio pemumputun berkisur 70% - 90% sedungkun RMSE berkisur 4% - 15% wuktupemumputun dun rekonstruksi berkisur I - 5 detik. Duri husil pengumutun terhudup citru usli dun citru liusii rekonstruksi tumpuk tiduk duput dibedukun (citru rekonstruksi hampir mirip dengun citru uslinyu).

Acquired images, which are basically digital pictures or digital 2D data, should posses some proper form for storage, transmission, as well as digital processes. Taking into account that a picture is worth one thousand words, efforts have been done to minimize the average member of bits to represent the images without loosing their information essence. The basic idea of the practiced image data compression is based on facts that the original images posses a substantial degree of irrelevancies and redundancies. The method and techniques involved in the image data compression should not cause computational complexities so that the associated cost is higher then the saving targeted by the effort. The research carried out here utilize the advantage of wavelet-transforms, since most images are by nature non-stationary. Two fundamental frameworks were used, viz. the lossless and lossy compressions. The lossy compression was carried out under the constraint of some “lossless” subjective or perceptual critizion. For color images the result are: for compressing image with Daubhecies 2/Haar filter, on maximum level, YIQ color coordinate system and compression quality 10 that have compression rasio about 70% -go%, RMSE about 4% - 15%, compression and decompression time about 1 - 5 second. Of observe about original image and reconstruction image to seem not be differed (original image nearly be resemble with reconstruction image).

Kata Kunci : Pemampatan Data Citra, Komputer, wavelet, lossless, lossy, compression ratio, irrelevancy, redundancy, perceptual.