{"id":10716,"date":"2023-08-25T00:00:00","date_gmt":"2023-08-25T00:00:00","guid":{"rendered":"https:\/\/tech-lib.eu\/tech\/jak-ditherovat-obrazek-a-comprehensive-guide\/"},"modified":"2023-08-25T00:00:00","modified_gmt":"2023-08-25T00:00:00","slug":"jak-ditherovat-obrazek-a-comprehensive-guide","status":"publish","type":"post","link":"https:\/\/tech-lib.eu\/tech\/jak-ditherovat-obrazek-a-comprehensive-guide\/","title":{"rendered":"Jak ditherovat obr\u00e1zek. A Comprehensive Guide"},"content":{"rendered":"
P\u0159edstavte se: Ve zpracov\u00e1n\u00ed obrazu je dithering metoda pro sn\u00ed\u017een\u00ed po\u010dtu barev v obr\u00e1zku p\u0159i zachov\u00e1n\u00ed vzhledu barevn\u00e9 hloubky. V p\u0159\u00edpad\u011b, \u017ee je barevn\u00fd prostor omezen, jako nap\u0159\u00edklad p\u0159i p\u0159evodu obr\u00e1zku na ni\u017e\u0161\u00ed bitovou hloubku nebo p\u0159i zobrazov\u00e1n\u00ed obr\u00e1zk\u016f na za\u0159\u00edzen\u00edch s omezenou barevnou paletou, je obzvl\u00e1\u0161t\u011b u\u017eite\u010dn\u00e1. C\u00edlem t\u00e9to str\u00e1nky je p\u0159edstavit d\u016fkladn\u00fd n\u00e1vod, jak dithering obr\u00e1zku prov\u00e1d\u011bt, v\u010detn\u011b prozkoum\u00e1n\u00ed n\u011bkolika technik ditheringu, vysv\u011btlen\u00ed, jak jej prov\u00e1d\u011bt ve Photoshopu, diskuse o ditheringu v PNG a rady, kdy jej prov\u00e1d\u011bt. Jak\u00e9 jsou r\u016fzn\u00e9 typy ditheringu obr\u00e1zk\u016f? <\/p>\n
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P\u0159id\u00e1n\u00edm \u0161umu nebo vzor\u016f do obr\u00e1zku simuluj\u00ed techniky ditheringu obr\u00e1zku dal\u0161\u00ed barvy, kter\u00e9 v p\u016fvodn\u00ed barevn\u00e9 palet\u011b chyb\u00ed. Lidsk\u00e9 oko je t\u00edmto mechanismem klam\u00e1no, aby si myslelo, \u017ee je v obraze v\u00edce barev, ne\u017e ve skute\u010dnosti je. Mezi \u010dasto pou\u017e\u00edvan\u00e9 algoritmy ditheringu pat\u0159\u00ed uspo\u0159\u00e1dan\u00fd dithering, rozptyl chyb a n\u00e1hodn\u00fd dithering. Je velmi d\u016fle\u017eit\u00e9 zvolit p\u0159\u00edstup, kter\u00fdm dos\u00e1hnete po\u017eadovan\u00fdch v\u00fdsledk\u016f, proto\u017ee ka\u017ed\u00e1 strategie m\u00e1 sv\u00e9 vlastn\u00ed v\u00fdhody a p\u0159in\u00e1\u0161\u00ed pon\u011bkud odli\u0161n\u00e9 v\u00fdsledky. <\/p>\n

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Pokyny pro dithering ve Photoshopu: <\/p>\n

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Technika ditheringu obr\u00e1zku je pom\u011brn\u011b jednoduch\u00e1, pokud pou\u017e\u00edv\u00e1te aplikaci Photoshop. Zde je podrobn\u00fd n\u00e1vod: <\/p>\n

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1. Ujist\u011bte se, \u017ee je obr\u00e1zek v re\u017eimu RGB a otev\u0159ete jej ve Photoshopu. <\/p>\n

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2. V nab\u00eddce „Obr\u00e1zek“ vyberte „Re\u017eim“ a pot\u00e9 „Indexovan\u00e1 barva“. 3. V \u010d\u00e1sti „Barvy“ dialogov\u00e9ho okna Indexovan\u00e1 barva m\u016f\u017eete zadat po\u010det barev, kter\u00e9 hodl\u00e1te pou\u017e\u00edt. V\u011bt\u0161\u00ed ztr\u00e1ta barev se projev\u00ed p\u0159i ni\u017e\u0161\u00edm nastaven\u00ed. 4. V\u00fdb\u011brem mo\u017enosti „Dither“ v rozev\u00edrac\u00ed nab\u00eddce d\u00e1te programu Photoshop pokyn, aby p\u0159i p\u0159evodu pou\u017eil dithering. 5. V rozev\u00edrac\u00ed nab\u00eddce „Dither“ vyberte preferovan\u00fd algoritmus ditheringu. Vyzkou\u0161ejte r\u016fzn\u00e9 algoritmy, abyste zjistili, kter\u00fd poskytuje nejlep\u0161\u00ed v\u00fdsledky pro v\u00e1\u0161 obr\u00e1zek. 6. Klepnut\u00edm na tla\u010d\u00edtko „OK“ po proveden\u00ed v\u00fdb\u011bru p\u0159epnete obr\u00e1zek do indexovan\u00e9ho barevn\u00e9ho re\u017eimu s ditheringem. <\/p>\n

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PNG dithering: <\/p>\n

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P\u0159i ukl\u00e1d\u00e1n\u00ed nebo exportu obr\u00e1zku ve form\u00e1tu PNG (Portable Network Graphics) je dithering procesem aplikace ditheringu. PNG je obl\u00edben\u00fd bezztr\u00e1tov\u00fd form\u00e1t obr\u00e1zk\u016f na webu. V z\u00e1vislosti na sv\u00fdch pot\u0159eb\u00e1ch se m\u016f\u017eete rozhodnout, zda p\u0159i ukl\u00e1d\u00e1n\u00ed obr\u00e1zku jako PNG aktivujete nebo zak\u00e1\u017eete dithering. Pomoc\u00ed ditheringu lze zm\u00edrnit prou\u017ekov\u00e1n\u00ed a barevn\u00e9 artefakty, zejm\u00e9na v oblastech s klouzav\u00fdmi p\u0159echody. P\u0159i pou\u017eit\u00ed PNG s ditheringem je z\u00e1sadn\u00ed naj\u00edt spr\u00e1vnou rovnov\u00e1hu mezi kvalitou obrazu a velikost\u00ed souboru, proto\u017ee dithering m\u016f\u017ee tak\u00e9 v\u00e9st ke zv\u011bt\u0161en\u00ed velikosti souboru. Kdy byste m\u011bli v\u00e1hat? P\u0159i rozhodov\u00e1n\u00ed, zda obr\u00e1zek ditherovat, v\u00e1m pom\u016f\u017ee zv\u00e1\u017een\u00ed konkr\u00e9tn\u00edch pot\u0159eb va\u0161eho projektu. P\u0159i pr\u00e1ci s omezen\u00fdmi barevn\u00fdmi paletami nebo p\u0159i zmen\u0161ov\u00e1n\u00ed vzork\u016f fotografi\u00ed je dithering obzvl\u00e1\u0161t\u011b u\u017eite\u010dn\u00fd. Dithering nap\u0159\u00edklad pom\u00e1h\u00e1 redukovat barevn\u00e9 p\u00e1sy a vytv\u00e1\u0159et hlad\u0161\u00ed vzhled p\u0159i p\u0159\u00edprav\u011b fotografi\u00ed pro zobrazen\u00ed na zastaral\u00fdch po\u010d\u00edta\u010dov\u00fdch syst\u00e9mech, hern\u00edch konzol\u00edch nebo mobiln\u00edch za\u0159\u00edzen\u00edch s omezen\u00fdmi mo\u017enostmi barev. Dithering m\u016f\u017ee b\u00fdt tak\u00e9 u\u017eite\u010dn\u00fd p\u0159i p\u0159evodu slo\u017eit\u00fdch nebo fotografick\u00fdch fotografi\u00ed na \u010dernob\u00edlou, proto\u017ee dok\u00e1\u017ee zachovat detaily a zabr\u00e1nit tomu, aby byl obraz ostr\u00fd nebo rozpixelovan\u00fd. <\/p>\n

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Shrnut\u00ed: <\/p>\n

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V\u00fdkonnou metodou pro sn\u00ed\u017een\u00ed barev v obr\u00e1zku p\u0159i zachov\u00e1n\u00ed vizu\u00e1ln\u00ed kvality je dithering. Vynikaj\u00edc\u00edch v\u00fdsledk\u016f lze dos\u00e1hnout pou\u017eit\u00edm n\u011bkolika technik ditheringu, nap\u0159\u00edklad uspo\u0159\u00e1dan\u00e9ho ditheringu, rozptylu chyb nebo n\u00e1hodn\u00e9ho ditheringu. Porozum\u011bn\u00ed tomu, jak ditherovat obr\u00e1zek a kdy jej pou\u017e\u00edt, v\u00e1m pom\u016f\u017ee zachovat v\u011brnost barev i v obt\u00ed\u017en\u00fdch situac\u00edch, a\u0165 u\u017e pou\u017e\u00edv\u00e1te aplikaci Photoshop nebo pracujete se soubory PNG.<\/p><\/div>\n

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FAQ<\/div>\n
\n
M\u00e1 dithering n\u011bjak\u00fd v\u00fdznam?<\/div>\n

Dithering m\u00e1 vliv na zpracov\u00e1n\u00ed obr\u00e1zk\u016f, to je pravda. Dithering je metoda pro simulaci odst\u00edn\u016f nebo barevn\u00fdch odst\u00edn\u016f, kter\u00e9 nejsou reprezentov\u00e1ny velk\u00fdm po\u010dtem barev. Pro navozen\u00ed dojmu v\u011bt\u0161\u00edho po\u010dtu odst\u00edn\u016f se p\u0159id\u00e1v\u00e1 vzor pixel\u016f nebo bod\u016f v r\u016fzn\u00fdch barv\u00e1ch. <\/p>\n

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Pokud je t\u0159eba sn\u00ed\u017eit barevnou hloubku obr\u00e1zku, nap\u0159\u00edklad kdy\u017e je t\u0159eba p\u0159ev\u00e9st v\u011brn\u00fd barevn\u00fd obr\u00e1zek na omezenou barevnou paletu pro zobrazen\u00ed na za\u0159\u00edzen\u00ed s m\u00e9n\u011b pokro\u010dil\u00fdmi barevn\u00fdmi schopnostmi, m\u016f\u017ee b\u00fdt dithering obzvl\u00e1\u0161t\u011b u\u017eite\u010dn\u00fd. Bez ditheringu by obraz mohl vypadat znateln\u011b pok\u0159iven\u011b nebo by v d\u016fsledku men\u0161\u00edho po\u010dtu dostupn\u00fdch barev ztratil n\u011bkter\u00e9 detaily. <\/p>\n

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Dithering pom\u00e1h\u00e1 rozpt\u00fdlit dostupn\u00e9 barvy tak, aby se vizu\u00e1ln\u011b v\u00edce podobaly p\u016fvodn\u00edmu obr\u00e1zku, a to p\u0159id\u00e1n\u00edm dob\u0159e napl\u00e1novan\u00e9ho vzoru bod\u016f nebo pixel\u016f. Omezuje v\u00fdrazn\u00e9 prou\u017ekov\u00e1n\u00ed a n\u00e1hl\u00e9 p\u0159echody barev, ke kter\u00fdm by mohlo doch\u00e1zet p\u0159i pouh\u00e9m sn\u00ed\u017een\u00ed barevn\u00e9 hloubky bez ditheringu. <\/p>\n

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Je d\u016fle\u017eit\u00e9 si uv\u011bdomit, \u017ee prodlu\u017eov\u00e1n\u00ed nen\u00ed v\u017edy nutn\u00e9 ani \u017e\u00e1douc\u00ed. Dithering m\u016f\u017ee ob\u010das vytv\u00e1\u0159et ne\u017e\u00e1douc\u00ed vizu\u00e1ln\u00ed odchylky nebo naru\u0161ovat po\u017eadovanou estetiku, zejm\u00e9na p\u0159i pr\u00e1ci s vysoce kvalitn\u00edmi fotografiemi nebo ur\u010dit\u00fdm um\u011bleck\u00fdm stylem. Pou\u017eit\u00ed ditheringu proto z\u00e1vis\u00ed na konkr\u00e9tn\u00edch po\u017eadavc\u00edch sn\u00edmku a po\u017eadovan\u00e9m v\u00fdsledku. <\/p>\n<\/div>\n

\n
Jak se prov\u00e1d\u00ed dithering?<\/div>\n

P\u0159id\u00e1n\u00edm \u0161umu nebo vzor\u016f do obrazu, kter\u00e9 simuluj\u00ed dal\u0161\u00ed barvy, sni\u017euje dithering barevnou hloubku obrazu. Obvykle se toho dos\u00e1hne rozd\u011blen\u00edm obrazu na mal\u00e9 pixely a zm\u011bnou hodnoty barvy ka\u017ed\u00e9ho pixelu v z\u00e1vislosti na okoln\u00edch pixelech. T\u00edm se vytvo\u0159\u00ed dojem v\u00edce barev, ne\u017e ve skute\u010dnosti umo\u017e\u0148uje dostupn\u00e1 paleta barev. A\u010dkoli existuje mnoho r\u016fzn\u00fdch algoritm\u016f pro dithering, mezi obl\u00edben\u00e9 pat\u0159\u00ed uspo\u0159\u00e1dan\u00fd dithering, rozptyl chyb a n\u00e1hodn\u00fd dithering.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

P\u0159edstavte se: Ve zpracov\u00e1n\u00ed obrazu je dithering metoda pro sn\u00ed\u017een\u00ed po\u010dtu barev v obr\u00e1zku p\u0159i zachov\u00e1n\u00ed vzhledu barevn\u00e9 hloubky. V p\u0159\u00edpad\u011b, \u017ee je barevn\u00fd prostor omezen, jako nap\u0159\u00edklad p\u0159i p\u0159evodu obr\u00e1zku na ni\u017e\u0161\u00ed bitovou hloubku nebo p\u0159i zobrazov\u00e1n\u00ed obr\u00e1zk\u016f na za\u0159\u00edzen\u00edch s omezenou barevnou paletou, je obzvl\u00e1\u0161t\u011b u\u017eite\u010dn\u00e1. C\u00edlem t\u00e9to str\u00e1nky je p\u0159edstavit d\u016fkladn\u00fd n\u00e1vod, … \u010c\u00edst d\u00e1l<\/a><\/p>\n","protected":false},"author":1382,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2654],"tags":[],"class_list":["post-10716","post","type-post","status-publish","format-standard","hentry","category-zpracovani-obrazku"],"_links":{"self":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts\/10716","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/users\/1382"}],"replies":[{"embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/comments?post=10716"}],"version-history":[{"count":0,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts\/10716\/revisions"}],"wp:attachment":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/media?parent=10716"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/categories?post=10716"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/tags?post=10716"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}