{"id":575704,"date":"2026-08-05T08:57:18","date_gmt":"2026-08-05T01:57:18","guid":{"rendered":"https:\/\/hoanghamobile.com\/tin-tuc\/?p=575704"},"modified":"2026-08-05T08:57:18","modified_gmt":"2026-08-05T01:57:18","slug":"pixel-la-gi","status":"publish","type":"post","link":"https:\/\/hoanghamobile.com\/tin-tuc\/pixel-la-gi\/","title":{"rendered":"Pixel l\u00e0 g\u00ec? \u0110i\u1ec3m \u1ea3nh, \u0111\u1ed9 ph\u00e2n gi\u1ea3i v\u00e0 m\u1eadt \u0111\u1ed9 \u0111i\u1ec3m \u1ea3nh PPI"},"content":{"rendered":"

Pixel (\u0111i\u1ec3m \u1ea3nh) l\u00e0 \u0111\u01a1n v\u1ecb nh\u1ecf nh\u1ea5t c\u1ea5u t\u1ea1o n\u00ean h\u00ecnh \u1ea3nh hi\u1ec3n th\u1ecb tr\u00ean c\u00e1c m\u00e0n h\u00ecnh k\u1ef9 thu\u1eadt s\u1ed1. M\u1ed7i m\u00e0n h\u00ecnh \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb h\u00e0ng tri\u1ec7u \u0111i\u1ec3m \u1ea3nh li ti, v\u00e0 m\u1ed7i pixel \u0111\u1ea3m nh\u1eadn nhi\u1ec7m v\u1ee5 hi\u1ec3n th\u1ecb m\u1ed9t m\u00e0u s\u1eafc ri\u00eang bi\u1ec7t; khi ph\u1ed1i h\u1ee3p c\u00f9ng nhau, ch\u00fang t\u00e1i t\u1ea1o n\u00ean b\u1ee9c \u1ea3nh ho\u00e0n ch\u1ec9nh m\u00e0 b\u1ea1n nh\u00ecn th\u1ea5y. S\u1ed1 l\u01b0\u1ee3ng pixel (\u0111\u1ed9 ph\u00e2n gi\u1ea3i) c\u00e0ng nhi\u1ec1u th\u00ec h\u00ecnh \u1ea3nh c\u00e0ng tr\u1edf n\u00ean chi ti\u1ebft v\u00e0 s\u1eafc n\u00e9t. “Pixel” l\u00e0 kh\u00e1i ni\u1ec7m n\u1ec1n t\u1ea3ng kh\u00f4ng th\u1ec3 thi\u1ebfu trong c\u00f4ng ngh\u1ec7 hi\u1ec3n th\u1ecb, nhi\u1ebfp \u1ea3nh v\u00e0 \u0111\u1ed3 h\u1ecda s\u1ed1. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd gi\u1ea3i th\u00edch chi ti\u1ebft pixel l\u00e0 g\u00ec, m\u1ed1i li\u00ean h\u1ec7 gi\u1eefa pixel v\u1edbi \u0111\u1ed9 ph\u00e2n gi\u1ea3i, m\u1eadt \u0111\u1ed9 \u0111i\u1ec3m \u1ea3nh c\u0169ng nh\u01b0 c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf.<\/p>\n

Pixel l\u00e0 g\u00ec?<\/h2>\n

Pixel (vi\u1ebft t\u1eaft c\u1ee7a picture element \u2013 ph\u1ea7n t\u1eed h\u00ecnh \u1ea3nh) l\u00e0 \u0111i\u1ec3m \u1ea3nh nh\u1ecf nh\u1ea5t c\u1ea5u t\u1ea1o n\u00ean m\u1ed9t b\u1ee9c \u1ea3nh k\u1ef9 thu\u1eadt s\u1ed1 tr\u00ean m\u00e0n h\u00ecnh. B\u1ea1n c\u00f3 th\u1ec3 h\u00ecnh dung m\u00e0n h\u00ecnh hi\u1ec3n th\u1ecb gi\u1ed1ng nh\u01b0 m\u1ed9t l\u01b0\u1edbi g\u1ed3m r\u1ea5t nhi\u1ec1u \u00f4 vu\u00f4ng c\u1ef1c nh\u1ecf, trong \u0111\u00f3 m\u1ed7i \u00f4 ch\u00ednh l\u00e0 m\u1ed9t pixel c\u00f3 kh\u1ea3 n\u0103ng ph\u00e1t ra m\u1ed9t m\u00e0u s\u1eafc nh\u1ea5t \u0111\u1ecbnh. Khi h\u00e0ng tri\u1ec7u pixel mang m\u00e0u s\u1eafc kh\u00e1c nhau \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp li\u1ec1n k\u1ec1, m\u1eaft ng\u01b0\u1eddi s\u1ebd ghi nh\u1eadn s\u1ef1 h\u00f2a quy\u1ec7n \u0111\u00f3 th\u00e0nh m\u1ed9t h\u00ecnh \u1ea3nh li\u1ec1n m\u1ea1ch, ch\u00e2n th\u1ef1c.<\/p>\n

V\u1ec1 c\u1ea5u tr\u00fac, m\u1ed7i pixel th\u01b0\u1eddng \u0111\u01b0\u1ee3c ph\u1ed1i h\u1ee3p t\u1eeb ba m\u00e0u s\u1eafc c\u01a1 b\u1ea3n (Red – Green – Blue \/ RGB) nh\u1eb1m pha tr\u1ed9n v\u00e0 t\u1ea1o ra v\u00f4 s\u1ed1 gam m\u00e0u kh\u00e1c nhau. S\u1ed1 l\u01b0\u1ee3ng pixel hi\u1ec7n di\u1ec7n tr\u00ean m\u00e0n h\u00ecnh \u0111\u00f3ng vai tr\u00f2 quy\u1ebft \u0111\u1ecbnh \u0111\u1ebfn \u0111\u1ed9 chi ti\u1ebft c\u1ee7a h\u00ecnh \u1ea3nh: c\u00e0ng s\u1edf h\u1eefu nhi\u1ec1u pixel, h\u00ecnh \u1ea3nh hi\u1ec3n th\u1ecb c\u00e0ng m\u1ecbn m\u00e0ng v\u00e0 s\u1eafc n\u00e9t. B\u00ean c\u1ea1nh m\u00e0n h\u00ecnh, pixel c\u0169ng l\u00e0 \u0111\u01a1n v\u1ecb \u0111o l\u01b0\u1eddng c\u01a1 b\u1ea3n trong b\u1ee9c \u1ea3nh ch\u1ee5p k\u1ef9 thu\u1eadt s\u1ed1 (th\u01b0\u1eddng bi\u1ebft \u0111\u1ebfn qua th\u00f4ng s\u1ed1 megapixel tr\u00ean camera) c\u0169ng nh\u01b0 trong thi\u1ebft k\u1ebf \u0111\u1ed3 h\u1ecda. \u0110\u00e2y l\u00e0 ki\u1ebfn th\u1ee9c c\u1ed1t l\u00f5i c\u1ea7n n\u1eafm khi t\u00ecm hi\u1ec3u v\u1ec1 c\u00f4ng ngh\u1ec7 m\u00e0n h\u00ecnh, m\u00e1y \u1ea3nh v\u00e0 x\u1eed l\u00fd h\u00ecnh \u1ea3nh s\u1ed1.<\/p>\n

\"pixel-la-gi-1\"<\/p>\n

Pixel v\u00e0 \u0111\u1ed9 ph\u00e2n gi\u1ea3i m\u00e0n h\u00ecnh<\/h2>\n

\u0110\u1ed9 ph\u00e2n gi\u1ea3i (resolution) l\u00e0 th\u00f4ng s\u1ed1 th\u1ec3 hi\u1ec7n t\u1ed5ng s\u1ed1 l\u01b0\u1ee3ng pixel x\u1ebfp theo chi\u1ec1u ngang v\u00e0 chi\u1ec1u d\u1ecdc c\u1ee7a m\u00e0n h\u00ecnh<\/strong>, \u0111\u1ea1i di\u1ec7n cho m\u1ee9c \u0111\u1ed9 chi ti\u1ebft c\u1ee7a h\u00ecnh \u1ea3nh hi\u1ec3n th\u1ecb. V\u00ed d\u1ee5, chu\u1ea9n \u0111\u1ed9 ph\u00e2n gi\u1ea3i Full HD (1920 x 1080) \u0111\u1ed3ng ngh\u0129a v\u1edbi vi\u1ec7c m\u00e0n h\u00ecnh s\u1edf h\u1eefu 1920 pixel theo chi\u1ec1u ngang v\u00e0 1080 pixel theo chi\u1ec1u d\u1ecdc, t\u01b0\u01a1ng \u1ee9ng v\u1edbi t\u1ed5ng c\u1ed9ng h\u01a1n 2 tri\u1ec7u \u0111i\u1ec3m \u1ea3nh.<\/p>\n

\u0110\u1ed9 ph\u00e2n gi\u1ea3i c\u00e0ng cao (c\u00e0ng t\u00edch h\u1ee3p nhi\u1ec1u pixel) th\u00ec h\u00ecnh \u1ea3nh thu \u0111\u01b0\u1ee3c c\u00e0ng s\u1eafc n\u00e9t v\u00e0 r\u00f5 chi ti\u1ebft. M\u1eb7c d\u00f9 v\u1eady, \u0111\u1ed9 s\u1eafc n\u00e9t th\u1ef1c t\u1ebf m\u00e0 m\u1eaft ng\u01b0\u1eddi c\u1ea3m nh\u1eadn \u0111\u01b0\u1ee3c v\u1eabn ph\u1ee5 thu\u1ed9c l\u1edbn v\u00e0o k\u00edch th\u01b0\u1edbc v\u1eadt l\u00fd c\u1ee7a m\u00e0n h\u00ecnh \u2013 v\u1edbi c\u00f9ng m\u1ed9t \u0111\u1ed9 ph\u00e2n gi\u1ea3i, m\u00e0n h\u00ecnh k\u00edch th\u01b0\u1edbc nh\u1ecf s\u1ebd cho \u0111\u1ed9 m\u1ecbn t\u1ed1t h\u01a1n m\u00e0n h\u00ecnh k\u00edch th\u01b0\u1edbc l\u1edbn (do c\u00e1c \u0111i\u1ec3m \u1ea3nh \u0111\u01b0\u1ee3c x\u1ebfp d\u00e0y \u0111\u1eb7c h\u01a1n). \u0110\u00e2y ch\u00ednh l\u00e0 l\u00fd do v\u00ec sao gi\u1edbi c\u00f4ng ngh\u1ec7 th\u01b0\u1eddng s\u1eed d\u1ee5ng th\u00eam th\u00f4ng s\u1ed1 m\u1eadt \u0111\u1ed9 \u0111i\u1ec3m \u1ea3nh (PPI) \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 \u0111\u1ed9 s\u1eafc n\u00e9t th\u1ef1c t\u1ebf c\u1ee7a t\u1eebng thi\u1ebft b\u1ecb.<\/p>\n

\"pixel-la-gi-2\"<\/p>\n

M\u1eadt \u0111\u1ed9 \u0111i\u1ec3m \u1ea3nh (PPI) l\u00e0 g\u00ec?<\/h2>\n

PPI (Pixels Per Inch \u2013 s\u1ed1 \u0111i\u1ec3m \u1ea3nh tr\u00ean m\u1ed7i inch) l\u00e0 ch\u1ec9 s\u1ed1 \u0111o l\u01b0\u1eddng m\u1eadt \u0111\u1ed9 ph\u00e2n b\u1ed5 c\u1ee7a pixel tr\u00ean b\u1ec1 m\u1eb7t m\u00e0n h\u00ecnh, ph\u1ea3n \u00e1nh m\u1ee9c \u0111\u1ed9 san s\u00e1t c\u1ee7a c\u00e1c \u0111i\u1ec3m \u1ea3nh. Ch\u1ec9 s\u1ed1 PPI c\u00e0ng cao th\u1ec3 hi\u1ec7n c\u00e1c pixel \u0111\u01b0\u1ee3c thu nh\u1ecf v\u00e0 x\u1ebfp c\u00e0ng s\u00e1t nhau, gi\u00fap h\u00ecnh \u1ea3nh \u0111\u1ea1t \u0111\u1ed9 m\u1ecbn m\u00e0ng v\u01b0\u1ee3t tr\u1ed9i v\u00e0 khi\u1ebfn m\u1eaft th\u01b0\u1eddng r\u1ea5t kh\u00f3 ph\u00e1t hi\u1ec7n ra t\u1eebng \u0111i\u1ec3m \u1ea3nh ri\u00eang bi\u1ec7t.<\/p>\n

Ch\u1eb3ng h\u1ea1n, m\u1ed9t m\u00e0n h\u00ecnh \u0111i\u1ec7n tho\u1ea1i k\u00edch th\u01b0\u1edbc 6 inch mang \u0111\u1ed9 ph\u00e2n gi\u1ea3i Full HD s\u1ebd \u0111\u1ea1t ch\u1ec9 s\u1ed1 PPI r\u1ea5t cao (h\u00ecnh \u1ea3nh hi\u1ec3n th\u1ecb c\u1ef1c k\u1ef3 m\u1ecbn); trong khi \u0111\u00f3, m\u1ed9t chi\u1ebfc tivi k\u00edch th\u01b0\u1edbc l\u1edbn s\u1edf h\u1eefu c\u00f9ng \u0111\u1ed9 ph\u00e2n gi\u1ea3i Full HD l\u1ea1i c\u00f3 ch\u1ec9 s\u1ed1 PPI th\u1ea5p h\u01a1n \u0111\u00e1ng k\u1ec3 (k\u00edch th\u01b0\u1edbc t\u1eebng pixel l\u1edbn h\u01a1n). Do \u0111\u00f3, ch\u1ec9 s\u1ed1 PPI gi\u00fap ng\u01b0\u1eddi d\u00f9ng so s\u00e1nh chu\u1ea9n x\u00e1c \u0111\u1ed9 s\u1eafc n\u00e9t th\u1ef1c t\u1ebf gi\u1eefa c\u00e1c d\u00f2ng m\u00e0n h\u00ecnh c\u00f3 k\u00edch th\u01b0\u1edbc v\u00e0 \u0111\u1ed9 ph\u00e2n gi\u1ea3i kh\u00e1c bi\u1ec7t.<\/p>\n

\u0110\u1ed1i v\u1edbi smartphone hi\u1ec7n \u0111\u1ea1i, ch\u1ec9 s\u1ed1 PPI th\u01b0\u1eddng \u0111\u1ea1t m\u1ee9c cao (tr\u00ean 300 – 400 PPI), \u0111em \u0111\u1ebfn tr\u1ea3i nghi\u1ec7m h\u00ecnh \u1ea3nh si\u00eau m\u1ecbn. Khi ch\u1ecdn mua thi\u1ebft b\u1ecb, ch\u1ec9 s\u1ed1 PPI l\u00e0 y\u1ebfu t\u1ed1 r\u1ea5t \u0111\u00e1ng c\u00e2n nh\u1eafc b\u00ean c\u1ea1nh \u0111\u1ed9 ph\u00e2n gi\u1ea3i, v\u00ec n\u00f3 ph\u1ea3n \u00e1nh tr\u1ef1c ti\u1ebfp ch\u1ea5t l\u01b0\u1ee3ng hi\u1ec3n th\u1ecb th\u1ef1c t\u1ebf tr\u00ean k\u00edch th\u01b0\u1edbc m\u00e0n h\u00ecnh c\u1ee5 th\u1ec3.<\/p>\n

\"pixel-la-gi-3\"<\/p>\n

C\u00e1c m\u1ee9c \u0111\u1ed9 ph\u00e2n gi\u1ea3i ph\u1ed5 bi\u1ebfn<\/h2>\n\n\n\n\n\n\n\n\n
\u0110\u1ed9 ph\u00e2n gi\u1ea3i<\/th>\nS\u1ed1 pixel (ngang x d\u1ecdc)<\/th>\n<\/tr>\n<\/thead>\n
HD<\/td>\n1280 x 720<\/td>\n<\/tr>\n
Full HD (1080p)<\/td>\n1920 x 1080<\/td>\n<\/tr>\n
2K \/ QHD<\/td>\n2560 x 1440<\/td>\n<\/tr>\n
4K \/ UHD<\/td>\n3840 x 2160<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Xem th\u00eam:\u00a0Mapping L\u00e0 G\u00ec? C\u00e1c Lo\u1ea1i Mapping Trong Thi\u1ebft K\u1ebf, C\u00f4ng Ngh\u1ec7 V\u00e0 \u0110\u1eddi S\u1ed1ng<\/a><\/strong><\/p>\n

Pixel trong nhi\u1ebfp \u1ea3nh v\u00e0 \u0111\u1ed3 h\u1ecda<\/h2>\n

Kh\u00f4ng ch\u1ec9 gi\u1edbi h\u1ea1n \u1edf m\u00e0n h\u00ecnh hi\u1ec3n th\u1ecb, pixel c\u00f2n gi\u1eef vai tr\u00f2 tr\u1ee5 c\u1ed9t trong l\u0129nh v\u1ef1c nhi\u1ebfp \u1ea3nh v\u00e0 thi\u1ebft k\u1ebf \u0111\u1ed3 h\u1ecda s\u1ed1.<\/p>\n

Trong nhi\u1ebfp \u1ea3nh, \u0111\u1ed9 ph\u00e2n gi\u1ea3i c\u1ee7a m\u1ed9t b\u1ee9c \u1ea3nh c\u0169ng \u0111\u01b0\u1ee3c \u0111o l\u01b0\u1eddng b\u1eb1ng pixel. C\u1ea3m bi\u1ebfn camera<\/a><\/strong> th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 qua th\u00f4ng s\u1ed1 “megapixel” (t\u01b0\u01a1ng \u1ee9ng v\u1edbi m\u1ed9t tri\u1ec7u \u0111i\u1ec3m \u1ea3nh) \u2013 v\u00ed d\u1ee5, camera 12MP c\u00f3 kh\u1ea3 n\u0103ng ch\u1ee5p ra b\u1ee9c \u1ea3nh ch\u1ee9a kho\u1ea3ng 12 tri\u1ec7u pixel. S\u1ed1 l\u01b0\u1ee3ng megapixel cao gi\u00fap b\u1ee9c \u1ea3nh ghi l\u1ea1i nhi\u1ec1u chi ti\u1ebft h\u01a1n, h\u1ed7 tr\u1ee3 t\u1ed1t cho nhu c\u1ea7u in \u1ea5n kh\u1ed5 l\u1edbn ho\u1eb7c c\u1eaft tr\u00edch (crop) khung h\u00ecnh m\u00e0 v\u1eabn gi\u1eef \u0111\u01b0\u1ee3c \u0111\u1ed9 n\u00e9t. M\u1eb7c d\u00f9 v\u1eady, ch\u1ea5t l\u01b0\u1ee3ng t\u1ed5ng th\u1ec3 c\u1ee7a b\u1ee9c \u1ea3nh v\u1eabn ph\u1ee5 thu\u1ed9c v\u00e0o nhi\u1ec1u y\u1ebfu t\u1ed1 kh\u00e1c nh\u01b0 k\u00edch th\u01b0\u1edbc c\u1ea3m bi\u1ebfn, ch\u1ea5t l\u01b0\u1ee3ng \u1ed1ng k\u00ednh hay thu\u1eadt to\u00e1n x\u1eed l\u00fd h\u00ecnh \u1ea3nh.<\/p>\n

Trong thi\u1ebft k\u1ebf \u0111\u1ed3 h\u1ecda, c\u00e1c \u0111\u1ecbnh d\u1ea1ng \u1ea3nh l\u01b0\u1edbi (bitmap\/raster nh\u01b0 JPG, PNG) \u0111\u1ec1u \u0111\u01b0\u1ee3c c\u1ea5u t\u1ea1o t\u1eeb c\u00e1c h\u1ea1t pixel. Khi b\u1ea1n th\u1ef1c hi\u1ec7n ph\u00f3ng to b\u1ee9c \u1ea3nh qu\u00e1 m\u1ee9c cho ph\u00e9p, hi\u1ec7n t\u01b0\u1ee3ng “v\u1ee1 h\u00ecnh” s\u1ebd xu\u1ea5t hi\u1ec7n do c\u00e1c \u00f4 pixel b\u1ecb k\u00e9o gi\u00e3n v\u00e0 l\u1ed9 r\u00f5. Vi\u1ec7c n\u1eafm r\u00f5 b\u1ea3n ch\u1ea5t c\u1ee7a pixel s\u1ebd gi\u00fap b\u1ea1n l\u1ef1a ch\u1ecdn \u0111\u1ed9 ph\u00e2n gi\u1ea3i chu\u1ea9n x\u00e1c khi ch\u1ee5p \u1ea3nh, thi\u1ebft k\u1ebf c\u0169ng nh\u01b0 \u0111\u00e1nh gi\u00e1 ch\u1ea5t l\u01b0\u1ee3ng h\u00ecnh \u1ea3nh m\u1ed9t c\u00e1ch chuy\u00ean nghi\u1ec7p.<\/p>\n

\"pixel-la-gi-4\"<\/p>\n

\u0110i\u1ec3m \u1ea3nh ch\u1ebft (dead pixel) v\u00e0 c\u00e1ch ki\u1ec3m tra<\/h2>\n

Trong qu\u00e1 tr\u00ecnh s\u1eed d\u1ee5ng thi\u1ebft b\u1ecb, ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 g\u1eb7p ph\u1ea3i s\u1ef1 c\u1ed1 hi\u1ec7n t\u01b0\u1ee3ng \u0111i\u1ec3m \u1ea3nh ch\u1ebft (dead pixel) ho\u1eb7c \u0111i\u1ec3m \u1ea3nh b\u1ecb k\u1eb9t (stuck pixel):<\/p>\n