Wavelet kusandutsa: kudziŵa ntchito chitsanzo

Kubwera kwa makamera yotchipa digito kwatanthauza kuti mbali yaikulu ya anthu a dzikoli, kaya akhale a msinkhu ndi kugonana, amamuonera chizolowezi kugwila wake khwerero liri ndi kuika mafano awo poyera mu Intaneti chikhalidwe. Komanso ngati kale Archive banja chithunzi anaikidwa mu Album yemweyo, lero tichipeza mazana a zithunzi. Kuti atsogolere yosungirako ndi kufala kudutsa Intaneti amafuna fano digito wa kuchepetsa thupi. Kuti zimenezi zitheke, amagwiritsa ntchito kuti zochokera ma aligorivimu zosiyanasiyana, kuphatikizapo wavelet asinthe. Kodi izo, muzimuuza nkhani yathu.

ndi fano digito Kodi

zambiri zooneka kompyuta akuyimiridwa mu mawonekedwe a manambala. Mawu osavuta, chithunzi anatengedwa ndi chipangizo digito, tebulo lomwe maselo omwe alowa mfundo aliyense mapikiselo ake mtundu. Pamene izo zifika kwa monochrome image, ndiye iwo m'malo mwa makhalidwe luminance kuchokera imeneyi [0, 1], kumene 0 amagwiritsidwa ntchito ponena wakuda ndi 1 - woyera. mitundu ina amapatsidwa manambala fractional, koma iwo zovuta ntchito, kotero osiyanasiyana ndi anawonjezera ndi mtengo osankhidwa imeneyi pakati pa 0 ndi 255. N'chifukwa chiyani tikutero? Ndi yosavuta! Zosangalatsa mu chifaniziro bayinare kwa kabisidwe ndi luminance aliyense mapikiselo amafuna ndendende mamvekedwe wina. N'zoonekeratu kuti kwambiri yokumbukira chofunika kusunga ngakhale fano yaing'ono. Mwachitsanzo, chithunzi kukula kwa 256 × 256 pixels amatenga 8 Kbytes.

mawu ochepa A za njira chithunzi psinjika

Ndithudi aliyense waona khalidwe osauka zithunzi pamene pali chinyengo mu mawonekedwe a rectangles wa mtundu womwewo, amene ayitanidwa zakale. Yak chifukwa cha otchedwa lossy psinjika. Maphunzirowa, angathe kuchepetsa kulemera kwa fano Komabe, izo zivute zitani zimakhudza khalidwe lake.

Pakuti lossy psinjika ma aligorivimu monga:

• JPEG. Ichi ndi kutali imodzi mwa ma aligorivimu otchuka. Bukuli lili pa ntchito cosine apawokha asinthe. Mu chilungamo tisaiwale kuti pali zimene mungachite kuti JPEG zochita lossless psinjika. Zikuphatikizapo Lossless JPEG ndi JPEG-LS.
• JPEG 2000. aligorivimu The ntchito pa nsanja m'manja, ndi zochokera ntchito ya wavelet apawokha asinthe.
• fractal psinjika. Nthawi zina timatha inu kupeza zithunzi zabwino kwambiri ngakhale ndi psinjika amphamvu. Komabe, chifukwa mavuto ndi patenting njira apitiriza kukhala zosowa.

Lossless psinjika ma aligorivimu anachita ndi:

• RLE (ntchito ngati njira yaikulu mu TIFF mtundu, BMP, TGA).
• LZW (ntchito gif mtundu).
• LZ-Huffman (ntchito PNG mtundu).

Foriya kusandutsa

Pamaso kutembenukira kwa wavelet, ndi bwino kufufuza ntchito ofanana pofotokoza koefishienti cha kufutukuka mfundo koyamba m'zigawo pulayimale, mwachitsanzo. E. amgwirizano Phokoso ndi mafurikwense osiyana. Mu mawu ena, Foriya kusandutsa - chida wapadera polumikiza apawokha ndi mosalekeza wazolengedwa.

Izo zikuwoneka ngati izi:

The inversion chilinganizo kwalembedwa motere:

ndi wavelet Kodi

Kumbuyo dzina ili Amabisa ntchito masamu, amene amalola kudziwa zigawo zosiyana pafupipafupi deta mayeso. Zithunzi ake ndi undulation amene matalikidwe amachepetsa 0 kuchokera anayambira. Mu chidwi ambiri ali koefishienti wavelet anatsimikiza yofunika chizindikiro.

spectrograms Wavelet ndi osiyana ochiritsira Foriya makulidwe, kuyambira mbali zosiyanasiyana kugwirizana chizindikiro sipekitiramu ndi chigawo awo mwakanthawi.

Wavelet kusinthika

Njira imeneyi chizindikiro kutembenuka mtima (ntchito) amalola kuti kumasulira kwa nthawi mu nthawi pafupipafupi chifaniziro.

Kuti wavelet kusintha zikanakhala zotheka, chifukwa ntchito lolingana wavelet zinthu zotsatirazi ayenera kukwaniritsa:

• Ngati ena ψ ntchito (T) -Fourier kusandutsa ali mawonekedwe

chikhalidwe chimenecho azikhutitsidwa:

Kuwonjezera:

• Wavelet ayenera mphamvu amalire;
• zikhale integrable mosalekeza ndi akundithandiza yaying'ono;
• wavelet ayenera isanafalikire onse pafupipafupi ndipo nthawi (danga).

mitundu

A wavelet mosalekeza kusandutsa ntchito zizindikiro ziwalo. Chachilendo ndi analogue ake apawokha. Pajatu angagwiritsidwe ntchito processing mudziwe makompyuta. Komabe, vuto akauka kuti chilinganizo kwa fiberboard apawokha sungagulire ndi yosavuta yoyenera discretization mitunduyi DNP.

Njira yothetsera vutoli anamupeza Daubechies, amene anali kusankha njira kumanga mndandanda wa wavelets orthogonal, omwe ndi chimafotokozera nambala amalire wa koefishienti. Patapita ma aligorivimu kudya zinalengedwa, monga aligorivimu Malla. Mu ntchito zake kuwola ndinso kapena zobwezeretsa kuti chofunika kuchita ntchito CN, kumene N - chitsanzo m'litali, ndi - chiwerengero cha koefishienti.

Vayvlet Haar

Kuti compress fano, m'pofunika kupeza nthawi zonse zina mwa deta yake, ndipo ngakhale bwino ngati izo zidzakhala yaitali maunyolo ziro. Apa ndi pamene zingakhale zothandiza wavelet ndi kusandutsa aligorivimu. Komabe, tiyenera kupitiriza tikambirane njira ntchito mu dongosolo.

Choyamba m'pofunika kukumbukira kuti zithunzi kuwala kwa pixels pafupi nthawi yodziwika ndi zochepa. Ngakhale pali zithunzi pa malo enieni ndi lakuthwa, kusiyanitsa kusiyana kuwala, iwo amakhala mbali yaing'ono ya fano. Mwachitsanzo, kutenga pa kudziwika mayeso Lenna grayscale fano. Ngati timatenga bokosi la luminance wa pixels kwake, ndiye gawo la mzere woyamba adzaoneka monga ndondomeko ya manambala 154, 155, 156, 157, 157, 157, 158, 156.

mungagwiritse ntchito otchedwa ankadziwana njira kuti ziro kwa izo. Kuti tichite zimenezi, kusunga okha nambala yoyamba, ndi ena azimwa kusiyana aliyense amene kale chizindikiro "+" kapena "-".

Chifukwa ndi ndondomeko 154,1,1,1,0,0,1, -2.

A sangathe wa kabisidwe ankadziwana zake sanali m'deralo. M'mawu ena, sikutheka kuti azimwa kagawo wa zinayendera ndi kupeza chomwe kuwala ndi ndiyotengera, decoded, ngati si onse a makhalidwe pamaso pake.

Kugonjetsa sangathe lino, chiwerengero lagawidwa awiriawiri ndipo aliyense ndi theka Uwerenge (v. A) ndi theka kusiyana (v. D), m. F. Pakuti (154,155) (156,157) (157,157) (158,156) ndi (154.5, 0,5) (156.5,0.5) (157,0.0), (157, -1.0). Pankhaniyi, nthawi zonse zimatheka kupeza phindu la manambala awiri awiri a.

Nthawi zambiri, wavelet apawokha kusandutsa a mbendera S, tili:

Njira imeneyi motere kuchokera apawokha nkhani ya wavelet mosalekeza asinthe, Haar ndipo ankagwiritsa ntchito zosiyanasiyana zokhudza processing ndi psinjika.

psinjika

Monga tanenera kale, mmodzi wa ntchito wavelet kusandutsa aligorivimu ndi JPEG 2000 psinjika njira ntchito Haar zochokera kumasulira vekitala wa pixels awiri mu X ndi Y vekitala (X + Y) / 2 (X - Y) / 2. Ndi okwanira awonjezere vekitala koyamba masanjidwewo pansipa.

Ngati mfundo zambiri, kutenga masanjidwewo kwambiri, yomwe imakonzedwa pa opendekera masanjidwewo H. Choncho, vekitala koyamba payekhapayekha m'litali kukonzedwa awiriawiri.

Zosefera

Chifukwa "theka-ndalama" - ndi pafupifupi luminance mfundo za pixels awiriawiri. Kuti ndi phindu pamene anatembenukira kwa fano ampatseko buku, yafupika nthawi 2. Mu ichi theka-ndalama pakuchitika kuwala, T. E. "osasankhidwa" bursts mwachisawawa mfundo zawo ndiponso kuchita zinthu ngati Zosefera pafupipafupi.

Tsopano tiyeni kuchita ndi anthu amene amasonyeza kusiyana. Iwo "olekanitsidwa" interpixel "bursts", kuchotsa mbali zonse, mwachitsanzo. E. "osasankhidwa" makhalidwe pa mafurikwense otsika.

Ngakhale kuchokera pamwamba Haar wavelet kusintha kwa "dummies" n'zoonekeratu kuti peyala ya Zosefera kuti kugawanitsa mbendera m'zigawo ziwiri: pafupipafupi mkulu ndi otsika pafupipafupi. chabe kachiwiri pogwirizanitsa zinthu izi kupeza chizindikiro pachiyambi.

Mwachitsanzo

Tiyerekeze tikufuna compress chithunzi (mayeso chithunzi Lenna). Taganizirani chitsanzo cha wavelet ndi kusintha masanjidwewo wa mapikiselo brightnesses. Mkulu-pafupipafupi zikuluzikulu za chithunzichi ndi udindo kusonyeza mwatsatanetsatane chabwino ndipo limafotokoza phokoso. Koma otsika-pafupipafupi, muli nkhani za mawonekedwe a nkhope ndi gradients yosalala kuwala.

Features zithunzi za maganizo a anthu oterowo kuti yamasika Mbali yofunika kwambiri. Izi zikutanthauza kuti pamene wothinikizidwa gawo lina la deta mkulu-pafupipafupi akhoza kuchotsedwa. The kwambiri chifukwa ali zochepa mtengo ndipo ndiyotengera chogwiritsira kwambiri.

Kuonjezera digiri ya psinjika ingagwiritsidwe kangapo Haar kusintha kwa deta ndi otsika-pafupipafupi.

Ntchito magulu awiri azithunzi omwe tikunena

Monga tanenera kale, fano digito mu kompyuta ali mu mawonekedwe a bokosi la intensities mfundo za pixels ake. Motero, tiyenera kukhala ndi chidwi mu ziwiri ooneka enieni Haar wavelet asinthe. Kugwiritsa m'pofunika chabe kuchita kutembenuka ake ooneka enieni aliyense mzere ndi pagawo lililonse makamaka kwa masanjidwewo wa intensities wa pixels pa chithunzichi.

Makhalidwe pafupi ziro, akhoza kuchotsedwa popanda kuwononga kwambiri ndi chifaniziro decoded. ndondomeko Ichi chikudziwika ngati quantization. Ndipo panthawi imeneyi ya nkhani atayika. Mwa njira, chiwerengero cha zinthu nullable angasinthe, potero kusintha mlingo wa psinjika.

masitepe awa onse kungachititse kuti masanjidwewo analandira muli yambiri 0. Kuyenera olembedwa mzere ndi mzere file lemba ndi compress archiver iliyonse.

decoding

The osiyanitsidwa kusinthika mu chifanizo pa aligorivimu zotsatirazi:

• Iwo unpacks ndi Archive;
• likukhudza osiyanitsidwa Haar kusandutsa;
• Chithunzi decoded ali n'kukhala masanjidwewo a.

Ubwino poyerekeza JPEG

было сказано, что он основан на ДКП. Tikaonetsetsa aligorivimu olowa Zithunzi Akatswiri Gulu anauzidwa kuti zachokera DCT. kutembenuka kwa ikuchitika midadada (8 × 8 pixels). Chifukwa, ngati psinjika kwambiri fano yafupika amakhala appreciable chipika dongosolo. Pa psinjika ntchito wavelets vuto palibe. Komabe, phokoso angaoneke mtundu wina omwe ali nawo mawonekedwe nambwibwi kuzungulira konsekonse. Akukhulupirira kuti zakale ofanana pafupifupi osaonekera kuposa "mabwalo" amene analenga ntchito JPEG aligorivimu.

Tsopano inu mukudziwa zomwe wavelets kodi iwo ali ndi othandiza ntchito iwo anapezeka m'munda wa processing ndi compressing digito zithunzi.