Raw dataを復号可能なJPEGデータの生成方法

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(1)2006−CVIM−156（16） 2006／11／10. 社団法人情報処理学会研究報告 IPSJ SIG Technical Report ‫ޓ‬ ‫ޓ‬. ‫ޓ‬ ‫ޓ‬ ‫ޓ‬. Raw data ࠍᓳภน⢻ߥ JPEG ࠺࡯࠲ߩ↢ᚑᣇᴺ 㨪 ᣂߒ޿ Raw data ࿶❗ 㨪 ↰ਛ ᱜⴕ㧘ᅏን ᱜᢅ ᧲੩Ꮏᬺᄢቇ ᄢቇ㒮ℂᎿቇ⎇ⓥ⑼ ᯏ᪾೙ᓮࠪࠬ࠹ࡓኾ᡹ ᧲੩ㇺ⋡㤥඙ᄢጟጊ 2-12-1. [email protected], [email protected]. ᭎ⷐ. ㄭᐕ㧘ࠞ࡜࡯ࡈࠖ࡞࠲ࠕ࡟ࠗࠍ᦭ߒߚන᧼ᑼࠞ࡜࡯᠟௝⚛ሶߩ᥉෸߇⪺ߒ޿㧚߹ߚ㧘න᧼ᑼࠞ. ࡜࡯᠟௝⚛ሶߩ಴ജߢ޽ࠆ RAW ࠺࡯࠲ࠍല₸ࠃߊ࿶❗ߒߚ޿ߣ޿߁ⷐ᳞߽㜞߹ߞߡ޿ࠆ㧚ߘߎߢ㧘ᧄ ⺰ᢥߢߪ㧘RAW ࠺࡯࠲ࠍ⋥ធ࿶❗ߔࠆᣂߒ޿ᣇᴺࠍឭ᩺ߔࠆ㧚߹ߕ㧘JPEG-RAW ࠺࡯࠲ߣ޿߁ RAW ࠺࡯࠲ࠍᓳภน⢻ߥ JPEG ࠺࡯࠲ߣ޿߁⠨߃ᣇߣ↢ᚑᣇᴺࠍឭ᩺ߔࠆ㧚ߎߩ JPEG-RAW ࠺࡯࠲ߣߪ㧘 ᣢሽߩ JPEG ᓳภེߢᓳภߒ㧘ߐࠄߦ࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦࠃࠅ㧘RAW ࠺࡯࠲߇ᓳภߢ߈ࠆ ࠺࡯࠲ߢ޽ࠆ㧚JPEG-RAW ࠺࡯࠲ߪ㧘RAW ࠺࡯࠲߇ᓳภߢ߈ࠆ߫߆ࠅߢߪߥߊ㧘↹௝࠺࡯࠲ࠍ JPEG ᓳภེߢᓳภߔࠆߎߣߦࠃࠅ㧘◲ଢߦ࠺࡯࠲ࠍ↹௝ߣߒߡ⏕⹺ߔࠆߎߣ߇ߢ߈ࠆ㧚޿ߊߟ߆ߩ↹௝ߦኻ ߒߡ㧘ឭ᩺ᚻᴺߣᓥ᧪ᴺࠍᲧセߒ㧘ឭ᩺ᚻᴺ߇ RAW ࠺࡯࠲ࠍല₸⊛ߦ࿶❗ߢ߈ࠆߎߣࠍ␜ߔ㧚. Raw data decodable JPEG data 㨪 A novel raw data compression 㨪 Masayuki TANAKA and Masatoshi OKUTOMI Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan [email protected], [email protected] Abstract A single color CCD with color filter array has been became very popular. An e&ective compression of the raw data captured by the single color CCD is highly demanded. This paper proposes a novel raw data compression. We show the concept of the JPEG data from which the raw data can be extracted. An preview functionality is realized by using this JPEG data. We can preview by the normal JPEG decorder. Experiments using standard image and real image demonstrate that the proposed method can e&ectively compress the raw data. −125−.

(2) 1. ߹߃߇߈. ᄙߊߩૐࠦࠬ࠻ߥࠞ࡜࡯࠺ࠖࠫ࠲࡞ࠞࡔ࡜ߦߪ㧘ࠞ ࡜࡯ࡈࠖ࡞࠲ࠕ࡟ࠗࠍ᦭ߔࠆන᧼ᑼࠞ࡜࡯᠟௝⚛ሶ ߇೑↪ߐࠇߡ޿ࠆ㧚ࡌࠗࡗ࡯ࡄ࠲࡯ࡦߪࠞ࡜࡯ࡈࠖ࡞ ࠲ࠕ࡟ࠗߣߒߡᦨ߽ᐢߊ᥉෸ߒߡ޿ࠆ [1]㧚ࡌࠗࡗ࡯ ࡄ࠲࡯ࡦߩࠞ࡜࡯ࡈࠖ࡞࠲ࠕ࡟ࠗࠍ᦭ߔࠆන᧼ᑼࠞ ࡜࡯᠟௝⚛ሶߢߪ㧘1 ߟߩ↹⚛ߪ R,G, ߹ߚߪ B ߩ 1 ߟߩ⦡ߒ߆᷹ⷰߔࠆߎߣ߇ߢ߈ߥ޿㧚න᧼ᑼࠞ࡜࡯ ᠟௝⚛ሶߩ಴ജߪ㧘⦡࠴ࡖࡀ࡞ߪ⇣ߥࠆ߽ߩߩ 1 ߟ ߩ↹⚛ߦኻߒߡ 1 ߟߩ↹⚛୯ߢ޽ࠅ㧘1 ᨎߩࠣ࡟ࠗ↹ ௝ߢ޽ࠆߣ⠨߃ࠆߎߣ߽ߢ߈ࠆ㧚ߎߩන᧼ᑼࠞ࡜࡯ ᠟௝⚛ሶߩ಴ജ↹௝ߪ㧘RAW ࠺࡯࠲ߣ๭߫ࠇࠆ㧚ߎ ߩࠃ߁ߥ RAW ࠺࡯࠲߆ࠄ㧘ࡈ࡞ࠞ࡜࡯↹௝ࠍ↢ᚑ ߔࠆᣇᴺߪ࠺ࡕࠩࠗࠠࡦࠣಣℂߣ๭߫ࠇ㧘ᢙᄙߊߩ ᣇᴺ߇ឭ᩺ߐࠇߡ޿ࠆ [9]㧚ㄭᐕ㧘RAW ࠺࡯࠲߆ࠄ㧘 ࡈ࡞ࠞ࡜࡯↹௝ࠍ↢ᚑߔࠆᣇᴺߪ “RAW ⃻௝” ߣ߽ ๭߫ࠇߡ߅ࠅ㧘RAW ࠺࡯࠲ࠍ଻ሽߒߡ߅߈㧘PC ╬ ߢᓟ߆ࠄ࠺ࡕࠩࠗࠠࡦࠣಣℂ╬ࠍⴕ߁ߣ޿߁ᣇᴺ߽ ೑↪ߐࠇߟߟ޽ࠆ㧚߹ߚ㧘ⶄᢙߩૐ⸃௝ᐲ↹௝߆ࠄ 1 ߟߩࠞ࡜࡯㜞⸃௝ᐲ↹௝ࠍ↢ᚑߔࠆಣℂߢ޽ࠆࠞ ࡜࡯⿥⸃௝ಣℂߦ߅޿ߡ߽㧘ౣ᭴ᚑߦ⋥ធ RAW ࠺࡯ ࠲ࠍ೑↪ߔࠆߎߣߦࠃࠅ㧘ലᨐ⊛ߦ⿥⸃௝ಣℂࠍⴕ ߁ߎߣ߇ߢ߈ࠆ [10, 11]㧚 ߣߎࠈ߇㧘ല₸⊛ߦ RAW ࠺࡯࠲ࠍ଻ሽߔࠆᣇᴺ ߿㧘ㆡಾߥ଻ሽᒻᑼߪ⏕┙ߐࠇߡ߅ࠄߕ㧘㕖࿶❗ߩ ߹߹ RAW ࠺࡯࠲߇଻ሽߐࠇߡ޿ࠆߩ߇⃻⁁ߢ޽ࠆ㧚 ߐࠄߦ㧘RAW ࠺࡯࠲ߩ଻ሽᒻᑼ߽⛔৻ߐࠇߡ߅ࠄ ߕ㧘㜞࿶❗߆ߟૐᱡߺߢ RAW ࠺࡯࠲ࠍ଻ሽߔࠆᣇᴺ ߇ᦸ߹ࠇߡ޿ࠆ㧚৻ᣇ㧘ࡈ࡞ࠞ࡜࡯↹௝ߦኻߒߡߪ㧘 ᢙᄙߊߩ଻ሽᒻᑼ߇ឭ᩺ߐࠇߡ޿ࠆ㧚․ߦ㧘JPEG[2] ߪ㕖Ᏹߦ᥉෸߇ㅴࠎߢ߅ࠅ㧘࠺ࡈࠔࠢ࠻ࠬ࠲ࡦ࠳࡯ ࠼ߩ 1 ߟߣ߽⸒߃ࠆ㧚JPEG-LS[3] ߿ JPEG-2000[4] ߣ޿ߞߚᣂߒ޿଻ሽᒻᑼ߇ឭ᩺ߐࠇߡ޿ࠆ߽ߩߩ㧘 JPEG ߩ᥉෸ߦ㆙ߊ෸߫ߥ޿㧚 ߎߎߢ㧘න᧼ᑼࠞ࡜࡯᠟௝⚛ሶࠍ᦭ߒߚ࠺ࠖࠫ࠲ ࡞ࠞࡔ࡜ࠍ೑↪ߒߡ㧘↹௝ࠍ᠟ᓇ㧘଻ሽߒ㧘↹௝ࠍ ⴫␜ߔࠆ߹ߢߩᮡḰ⊛ߥᣇᴺࠍ⏕⹺ߔࠆ㧚৻⥸⊛ߦ㧘 න᧼ᑼࠞ࡜࡯᠟௝⚛ሶߦࠃࠅ᷹ⷰߐࠇߚ RAW ࠺࡯ ࠲ߪ㧘࠺ࡕࠩࠗࠠࡦࠣಣℂߦࠃࠅࡈ࡞ࠞ࡜࡯ൻߐࠇ㧘 ߐࠄߦ࠺࡯࠲࿶❗߇ⴕࠊࠇ㧘↹௝࠺࡯࠲ߣߒߡ଻ሽ ߐࠇࠆ㧚ߘߒߡ㧘଻ሽߐࠇߚ࠺࡯࠲ߪᓳภེߦࠃߞ ߡ㧘ࡈ࡞ࠞ࡜࡯↹௝ߦᓳరߐࠇ㧘⴫␜ߐࠇࠆ㧚ㄭᐕ㧘ല₸⊛ߦ RAW ࠺࡯࠲ࠍ࿶❗ߔࠆߚ߼ߩᣂ ߒ޿ᣇᴺ߇ឭ᩺ߐࠇߡ޿ࠆ [5, 6, 7, 8]㧚ߎࠇࠄߩᣇᴺ ߪ㧘RAW ࠺࡯࠲ࠍ⦡࠴ࡖࡀ࡞ߏߣߦಽ㔌ߒ㧘ߘߩᓟ㧘 ฦ⦡࠴ࡖࡀ࡞ߩ↹௝ࠍࠣ࡟ࠗ↹௝ߣߣࠄ߃㧘ᣢሽߩ ↹௝࿶❗ᣇᴺࠍㆡ↪ߔࠆߣ޿߁౒ㅢὐ߇޽ࠆ㧚ߎߩ ࠃ߁ߥᣇᴺࠍ೑↪ߔࠆߎߣߦࠃࠅ㧘㜞࿶❗߆ߟૐᱡ ߺߢ RAW ࠺࡯࠲ࠍ࿶❗ߒ㧘଻ሽߔࠆߎߣ߇น⢻ߢ ޽ࠆ㧚ࡈ࡞ࠞ࡜࡯↹௝ࠍᓳภߔࠆ㓙ߦߪ㧘RAW ࠺࡯ ࠲ߩᓳภ㧘ࠞ࡜࡯ࡕࠩࠗࠢ↹௝ߩౣ᭴ᚑ߅ࠃ߮࠺ࡕ ࠩࠗࠠࡦࠣಣℂ߇ᔅⷐߢ޽ࠆ㧚 ߣߎࠈߢ㧘↹௝࠺࡯࠲ߩ଻ሽߦ߅޿ߡߪ㧘㜞࿶❗. ߆ߟૐᱡߺߢ࠺࡯࠲ࠍ࿶❗ߢ߈ࠆߎߣߪ߽ߜࠈࠎߩ ߎߣ㧘࠺࡯࠲ࠍ◲ଢߦ↹௝ߣߒߡ⏕⹺ߢ߈ࠆߎߣ߽ ㊀ⷐߢ޽ࠆ㧚ᧄ⺰ᢥߢߪ㧘଻ሽ࠺࡯࠲ࠍ◲ଢߦ↹௝ߣ ߒߡ⏕⹺ߔࠆߎߣࠍࡊ࡟ࡆࡘ࡯ߣ๭߱ߎߣߦߒ㧘ࡊ ࡟ࡆࡘ࡯ߩߚ߼ߦ↢ᚑߐࠇࠆ↹௝ࠍࡊ࡟ࡆࡘ࡯↹௝ ߣ๭߱ߎߣߦߔࠆ㧚ᣢሽߩ RAW ࠺࡯࠲࿶❗ᚻᴺߢ ߪ㧘࠺࡯࠲ࠍ↹௝ߣߒߡ⏕⹺ߔࠆ႐วߪ㧘ኾ↪ߩ↹ ௝ᓳరಣℂࠍⴕ߁ᔅⷐ߇޽ࠆ㧚ߘߩߚ߼㧘ᣢሽߩᓳ ภེߢ◲ଢߦࡊ࡟ࡆࡘ࡯ߔࠆߎߣ߇ߢ߈ߕ㧘᥉෸ߩ ᅹߍߦߥࠆ߽ߩߣᕁࠊࠇࠆ㧚 ߘߎߢ㧘ᧄ⺰ᢥߢߪ㧘ᦨ߽ᐢߊ᥉෸ߒߡ޿ࠆ JPEG ߦၮߠ޿ߚ RAW ࠺࡯࠲࿶❗ᣇᴺࠍᣂߒߊឭ᩺ߔࠆ㧚 ߹ߕ㧘RAW ࠺࡯࠲ࠍᓳภน⢻ߥ JPEG ࠺࡯࠲ߣ޿ ߁⠨߃ᣇࠍዉ౉ߔࠆ㧚ߎߩ JPEG ࠺࡯࠲ࠍ JPEGRAW ࠺࡯࠲ߣ๭߱ߎߣߦߔࠆ㧚ߟ߹ࠅ㧘ឭ᩺ᚻᴺߪ ᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߦၮߠ߈ JPEG-RAW ࠺࡯ ࠲ࠍ↢ᚑߔࠆᣇᴺߢ޽ࠆ㧚JPEG-RAW ࠺࡯࠲ߣߪ㧘 JPEG ᓳภེߢᓳภߒߚࡈ࡞ࠞ࡜࡯↹௝ߦኻߒߡ㧘࠳ ࠙ࡦࠨࡦࡊ࡝ࡦࠣߩࠃ߁ߥ◲නߥᠲ૞ߦࠃࠅ㧘RAW ࠺࡯࠲ࠍᓳภߢ߈ࠆ JPEG ࠺࡯࠲ߢ޽ࠆ㧚න⚐ߦ JPEG-RAW ࠺࡯࠲ࠍ JPEG ᓳภེߢᓳภߒߚ↹௝ ߪࡊ࡟ࡆࡘ࡯↹௝ߣߒߡ೑↪น⢻ߢ޽ࠆ㧚 ឭ᩺ᚻᴺߢߪ㧘JPEG ᓳภེߩᓳภㆊ⒟ࠍቯᑼ ൻߒ㧘ᓳภߐࠇࠆ RAW ࠺࡯࠲ߣታ㓙ߦ᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߣߩ⺋Ꮕ߇ዊߐߊߥࠆࠃ߁ߦ㧘JPEGRAW ࠺࡯࠲ࠍ↢ᚑߔࠆ㧚ߎߩࠃ߁ߦ JPEG-RAW ࠺࡯࠲ࠍ↢ᚑߔࠆߎߣߦࠃࠅ㧘RAW ࠺࡯࠲ࠍ㜞࿶❗ ߆ߟૐᱡߺߢ࿶❗ߔࠆߎߣ߇ߢ߈㧘ࡊ࡟ࡆࡘ࡯߽น ⢻ߣߥࠆ㧚߹ߚ㧘ឭ᩺ᚻᴺߪ RAW ࠺࡯࠲ࠍ⋥ធ࿶ ❗ߔࠆᣇᴺߢ޽ࠆߚ߼㧘࿶❗೨ߦ࠺ࡕࠩࠗࠠࡦࠣಣ ℂߦࠃࠅࡈ࡞ࠞ࡜࡯ൻߔࠆᔅⷐ߽ߥ޿㧚ᧄ⺰ᢥߢߪ㧘 ᮡḰ↹௝߅ࠃ߮ታ↹௝ߦኻߒߡ㧘ឭ᩺ᚻᴺࠍㆡ↪ߒ㧘 ᓥ᧪ߩᣇᴺߣᲧセߒ㧘ឭ᩺ᚻᴺߩ᦭ലᕈࠍ␜ߔ㧚. 2 2.1. JPEG ࿶❗᭎ⷐ JPEG ╓ภൻ. JPEG ࿶❗ߪ㧘ࡈ࡞ࠞ࡜࡯↹௝ߦኻߔࠆ࿶❗ᣇᴺ ߣߒߡᐢߊ⍮ࠄࠇߡ޿ࠆ㧚࿑ 1 ߦ JPEG ╓ภൻߩ᭎ ⷐࠍ␜ߔ㧚߹ߕ㧘න᧼ᑼࠞ࡜࡯᠟௝⚛ሶߦࠃࠅ᷹ⷰߐ ࠇߚ RAW ࠺࡯࠲ߪ㧘࠺ࡕࠩࠗࠠࡦࠣಣℂߐࠇ㧘ࡈ ࡞ࠞ࡜࡯↹௝ߦᄌ឵ߐࠇࠆ㧚ߎߩࡈ࡞ࠞ࡜࡯↹௝ߪ㧘 YCrCb ⦡ⓨ㑆ߦᄌ឵ߐࠇ㧘㔌ᢔࠦࠨࠗࡦᄌ឵ߐࠇߚ ᓟߦ㧘㊂ሶൻಣℂ߇ⴕࠊࠇࠆ㧚ߎߩࠃ߁ߦ㊂ሶൻߐ ࠇߚ㔌ᢔࠦࠨࠗࡦᄌ឵ߩ࠺࡯࠲ࠍ㊂ሶൻ DCT ଥᢙ ߣ๭߱ߎߣߦߔࠆ㧚㊂ሶൻ DCT ଥᢙߪ㧘࡜ࡦ࡟ࡦࠣ ࠬ߅ࠃ߮ࡂࡈࡑࡦ╓ภൻߐࠇ㧘JPEG ࠺࡯࠲߇↢ᚑ ߐࠇࠆ㧚⦡Ꮕ (Cr,Cb) ߪⓨ㑆ᣇะߦ㑆ᒁ߈ߐࠇࠆߎ ߣ߇ᄙ޿㧚ឭ᩺ᚻᴺߪ⦡Ꮕ㑆ᒁ߈ߦ߽ኻᔕߒߡ޿ࠆ ߇㧘ᧄ⺰ᢥߢߪ◲නߩߚ߼⦡Ꮕ㑆ᒁ߈ࠍ⠨ᘦߒߥ޿ ߎߣߦߔࠆ㧚JPEG ╓ภൻߢߪ㧘ᦨዊ╓ภൻ࡙࠾࠶ ࠻ (MCU) ߏߣߦ╓ภൻߐࠇࠆ߇㧘⦡Ꮕ㑆ᒁ߈ࠍߒ ߥ޿႐ว㧘MCU ߪ 8 × 8 ߩᄢ߈ߐߦߥࠆ㧚. −126−.

(3) 3.1. Fig. 1. Block diagram of JPEG encoding process.. Fig. 2. Block diagram of JPEG decoding process.. 2.2. JPEG ᓳภߩቯᑼൻ. JPEG ࠺࡯࠲ࠍᓳภߔࠆᣇᴺߩ᭎ⷐࠍ࿑ 2 ߦ␜ߔ㧚 ᓳภ߽ MCU ߏߣߦⴕࠊࠇࠆߚ߼㧘ߎߎߢߪ 1 ߟߩ MCU ࠍᓳภߔࠆߎߣߩߺࠍ⠨߃ࠆ㧚߹ߕ㧘JPEG ࠺࡯࠲ߪ࡜ࡦ࡟ࡦࠣࠬ߅ࠃ߮ࡂࡈࡑࡦᓳภൻߐࠇ㧘㊂ሶൻ DCT ଥᢙ f ߣߥࠆ㧚㊂ሶൻ DCT ଥᢙߪ㧘ㅒ 㔌ᢔൻ㧘ㅒ㔌ᢔࠦࠨࠗࡦᄌ឵㧘߅ࠃ߮⦡ᄌ឵߇ᣉߐ ࠇ㧘ࡈ࡞ࠞ࡜࡯↹௝߇ᓳภߐࠇࠆ㧚ߘࠇߙࠇߩಣℂ ߪ㧘ⴕ೉Ṷ▚ߢ⴫⃻ߔࠆߎߣ߇ߢ߈㧘ߎࠇࠄߩᓳภ ߪᑼ (1) ߩࠃ߁ߦ޽ࠄࠊߐࠇࠆ㧚 h. =. A1 W1 Q f = P f. (1). ߎߎߢ㧘ࡌࠢ࠻࡞ h ߪࡈ࡞ࠞ࡜࡯↹௝ߩࡌࠢ࠻࡞⴫ ⃻ࠍ⴫ߒ㧘ⴕ೉ Q ߪㅒ㊂ሶൻࠍ㧘ⴕ೉ W1 ߪㅒ㔌 ᢔࠦࠨࠗࡦᄌ឵ࠍ㧘ⴕ೉ A1 ߪ⦡ᄌ឵ࠍ㧘ߘࠇߙࠇ ⴫ߔⴕ೉ߢ޽ࠆ㧚੹㧘MCU ࠍ 8 × 8 ߣ⠨߃ߡ޿ࠆߩ ߢ㧘㊂ሶൻ DCT ଥᢙ f ߅ࠃ߮ࡈ࡞ࠞ࡜࡯↹௝ h ߪ 192 ᰴరߩࡌࠢ࠻࡞ߢ޽ࠅ㧘ⴕ೉ A1 , W1 , Q , P ߪ 192 × 192 ᰴరߩⴕ೉ߢ޽ࠆ㧚. 3. JPEG-RAW ࠺࡯࠲ߩឭ᩺. ᧄ┨ߢߪ㧘߹ߕ㧘RAW ࠺࡯࠲࿶❗ߦ᳞߼ࠄࠇߡ ޿ࠆ․ᓽࠍㅀߴࠆ㧚ߟ޿ߢ㧘RAW ࠺࡯࠲ࠍᓳภน ⢻ߥ JPEG ࠺࡯࠲ߢ޽ࠆ JPEG-RAW ࠺࡯࠲ࠍឭ᩺ ߒ㧘ߘߩ․ᓽࠍㅀߴࠆ㧚. RAW ࠺࡯࠲࿶❗ߦ᳞߼ࠄࠇࠆ․ᓽ. RAW ࠺࡯࠲ࠍ㕖นㅒ࿶❗ߔࠆߎߣࠍ⠨߃ࠆ㧚ߎ ߩߣ߈㧘RAW ࠺࡯࠲࿶❗ߦ᳞߼ࠄࠇࠆ․ᓽߣߒߡ ߪ㧘߹ߕ╙৻ߦ㧘ߢ߈ࠆߛߌዋߥ޿ᖱႎ㊂ߢ㧘RAW ࠺࡯࠲ࠍዊߐߥ⺋Ꮕߢᓳภߢ߈ࠆߎߣ߇޽ࠆ㧚ߎߩ ࠃ߁ߥᕈ⾰ࠍḩ⿷ߒߡ޿ࠇ߫㧘࿶❗ല₸߇㜞޿ߣ⸒ ߁ߎߣߦߔࠆ㧚߹ߚ㧘RAW ࠺࡯࠲ࠍ㧘↹௝ߣߒߡ◲ ଢߦ⏕⹺ߢ߈ࠆߎߣ߽㊀ⷐߢ޽ࠆ㧚ߎߩࠃ߁ߦ࿶❗ ߐࠇߚ࠺࡯࠲ࠍ↹௝ߣߒߡ⏕⹺ߔࠆᯏ⢻ߩߎߣࠍࡊ ࡟ࡆࡘ࡯ߣ๭߱ߎߣߦߔࠆ㧚ࡊ࡟ࡆࡘ࡯↪ߩ↹௝ߦ ߪ㧘㜞޿↹⾰ߪᔅⷐߥ޿߽ߩߩ㧘ᣢߦ᥉෸ߒߡ޿ࠆ ᓳภེߢ◲ଢߦ↹௝ൻߢ߈ࠆߎߣ߇ᔅⷐߢ޽ࠆ㧚࠺ࠖ ࠫ࠲࡞ࠞࡔ࡜਄ߢߩ↹௝ߩ⏕⹺߿↹௝ߩᬌ⚝ߥߤࠍ ⠨߃ߚ႐ว㧘ߎߩࡊ࡟ࡆࡘ࡯ᯏ⢻ߪ㕖Ᏹߦ㊀ⷐߥᔅ 㗇ߩᯏ⢻ߢ޽ࠆߣ⠨߃ࠄࠇࠆ㧚 ߣߎࠈߢ㧘න᧼ᑼࠞ࡜࡯᠟௝⚛ሶߦࠃࠅ᠟ᓇߐࠇ ߚ RAW ࠺࡯࠲ߪ㧘৻⥸ߦ࿑ 3 ߩࠃ߁ߦಣℂߐࠇࠆ㧚 ߎߩ࿑߆ࠄ߽ࠊ߆ࠆࠃ߁ߦ㧘න᧼ᑼࠞ࡜࡯᠟௝⚛ሶ ߩ಴ജߢ޽ࠆ RAW ࠺࡯࠲ࠍ㜞޿࿶❗ല₸ߢ଻ሽߔ ࠆߣ⸒߁ߎߣߪ⠨ᘦߐࠇߡ߅ࠄߕ㧘޽ߊ߹ߢ࿶❗ߪ ࠺ࡕࠩࠗࠠࡦࠣߐࠇߚࠞ࡜࡯↹௝ࠍ࿶❗࡮଻ሽߔࠆ ߎߣߩߺ߇⠨ᘦߐࠇߡ޿ࠆ㧚߹ߚ㧘⃻࿷೑↪ߐࠇߡ ޿ࠆ RAW ࠺࡯࠲ߩ଻ሽᣇᴺߪ㧘㕖࿶❗ߢ޽ࠅ㧘ᣢ ሽߩᓳภེߢࡊ࡟ࡆࡘ࡯↪ߩ↹௝ࠍ↢ᚑߔࠆߎߣߪ ߢ߈ߥ޿㧚ߎࠇ߹ߢߦឭ᩺ߐࠇߡ޿ࠆ RAW ࠺࡯࠲ ߩ࿶❗ᣇᴺߪ㧘࿑ 4 ߦಣℂߩᵹࠇࠍ␜ߔࠃ߁ߦ㧘޿ ߕࠇ߽ RAW ࠺࡯࠲ࠍฦ࠴ࡖࡀ࡞ߦⓨ㑆⊛ߦಽ㔌ߔ ࠆߎߣࠍၮᧄߣߒߡ޿ࠆ [5, 6, 7, 8]㧚ߎߩߚ߼㧘ࡊ ࡟ࡆࡘ࡯↹௝ࠍ◲ଢߦ↢ᚑߔࠆߎߣߪߢ߈ߥ޿㧚 ࿶❗ല₸ߩߺࠍ⠨ᘦߒߚ႐ว㧘นㅒ࿶❗ߢ޽ࠆ ZIP ᒻᑼ߿ RAR ᒻᑼࠍ೑↪ߒߡ㧘RAW ࠺࡯࠲ࠍ࿶❗ߔ ࠆᣇᴺߪ㧘㜞޿࿶❗ല₸߇ᦼᓙߢ߈ࠆ㧚࿶❗ല₸ࠍ 㜞߼ࠆࠃ߁ߦ㕖นㅒ⊛ߥ೨ಣℂࠍߒߚߩߜߦ㧘ZIP ᒻᑼ߿ RAR ᒻᑼࠍ೑↪ߔࠆߎߣߦࠃࠅ㧘㕖นㅒ࿶ ❗߽น⢻ߢ޽ࠆߣ⠨߃ࠄࠇࠆ㧚ߒ߆ߒ㧘ߎߩࠃ߁ߥ ࿶❗ᒻᑼߪ㧘ᒰὼ㧘ࡊ࡟ࡆࡘ࡯↹௝ࠍ◲ଢߦ↢ᚑߔ ࠆߎߣߪߢ߈ߥ޿㧚 ߐࠄߦ㧘࿶❗ᒻᑼߩ᥉෸ࠍ⠨߃ߚ႐ว㧘⃻࿷ᐢߊ ᥉෸ߐࠇߡ޿ࠆᓳภེߢᓳภߢ߈ࠆߎߣߪ㧘ታ↪⊛ ߦ㊀ⷐߥߎߣߢ޽ࠆ㧚ߘߎߢ㧘RAW ࠺࡯࠲ࠍᓳภ น⢻ߥ JPEG ࠺࡯࠲ߢ޽ࠆ JPEG-RAW ࠺࡯࠲ࠍᰴ ▵ߢឭ᩺ߔࠆ㧚 3.2. JPEG-RAW ࠺࡯࠲ߩ․ᓽ. ޽ࠆ JPEG ࠺࡯࠲ࠍᓳภߔࠆߎߣߦࠃࠅࡈ࡞ࠞ ࡜࡯↹௝߇ᓧࠄࠇࠆ㧚ߎߩᓧࠄࠇߚࡈ࡞ࠞ࡜࡯↹௝ ࠍ㧘࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦࠃࠅ RAW ࠺࡯ ࠲ࠍ᛽಴ߔࠆ1 㧚ߎߩࠃ߁ߦ᛽಴ߐࠇߚ RAW ࠺࡯࠲ ߇㧘᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߦኻߒߡ⺋Ꮕ߇ዊߐ޿ߣ ߈㧘ర‫ ߩޘ‬JPEG ࠺࡯࠲ࠍ RAW ࠺࡯࠲ࠍᓳภน⢻ 1 ࡈ࡞ࠞ࡜࡯↹௝߆ࠄ RAW ࠺࡯࠲ࠍ᛽಴ߔࠆᠲ૞ߪછᗧߦ⸳ ⸘น⢻ߢ޽ࠆ߇㧘ߎߎߢߪ◲නߩߚ߼࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣࠍ⠨߃ ࠆߎߣߦߔࠆ㧚. −127−.

(4) Fig. 3. Image data flow of normal JPEG format.. ࠲ࠍ㧘JPEG-RAW ࠺࡯࠲ߣ๭߱ߎߣߦߔࠆ㧚ߎߩ ࠃ߁ߥ․ᓽࠍ᦭ߔࠆ JPEG ࠺࡯࠲ߪ㧘RAW ࠺࡯࠲ ࠍᓳภߢ߈ࠆ߫߆ࠅߢߪߥߊ㧘ㅢᏱߩ JPEG ᓳภེ ߦࠃࠅࡈ࡞ࠞ࡜࡯↹௝߇ᓧࠄࠇࠆ㧚. 4. Fig. 4. Image data flow of existing raw data compression.. Fig. 5. Image data flow of proposed method.. ߥ JPEG ࠺࡯࠲ߣ๭߱ߎߣߦߔࠆ㧚ߎߩࠃ߁ߥ RAW ࠺࡯࠲ࠍᓳరน⢻ߥ JPEG ࠺࡯࠲ߪ㧘JPEG ᓳภེ ߢන⚐ߦᓳภߔࠆߎߣߦࠃࠅ㧘ࡊ࡟ࡆࡘ࡯↹௝߇↢ ᚑߐࠇࠆߣ޿߁․ᓽ߇޽ࠆ㧚߹ߚ㧘ࡊ࡟ࡆࡘ࡯↹௝ ࠍ࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦࠃࠅ RAW ࠺࡯࠲ ߇ᓳภߐࠇࠆ㧚 ᰴߦ㧘RAW ࠺࡯࠲ࠍᓳภน⢻ߥ JPEG ࠺࡯࠲ߢ ޽ࠆ JPEG-RAW ߩ․ᓽࠍቯᑼൻߔࠆ㧚߹ߕ㧘޽ࠆ JPEG ࠺࡯࠲ࠍᓳภߒ㧘࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߦࠃࠅ㧘 RAW ࠺࡯࠲ࠍ↢ᚑߔࠆߎߣࠍ⠨߃ࠆ㧚߽ߒ㧘↢ᚑߐ ࠇߚ RAW ࠺࡯࠲߇᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߣ৻⥌ ߒߡ޿ࠇ߫㧘RAW ࠺࡯࠲ࠍ↢ᚑߔࠆߚ߼ߦ೑↪ߒߚ JPEG ࠺࡯࠲ߪ㧘RAW ࠺࡯࠲ࠍᓳరน⢻ߥ JPEG ࠺࡯࠲ߢ޽ࠆߣ⸒߃ࠆ㧚ߎߩ᧦ઙߪ㧘ᑼ (1) ߩⴕ೉ P ࠍ೑↪ߒߡ㧘ᑼ (2) ߩࠃ߁ߦ⴫ߐࠇࠆ㧚. g. =. DPf = Tf. (2). ߎߎߢ㧘ࡌࠢ࠻࡞ g ߪ RAW ࠺࡯࠲ࠍ⴫ߔࡌࠢ࠻࡞ ࠍ㧘ⴕ೉ D ߪࡈ࡞ࠞ࡜࡯↹௝߆ࠄ RAW ࠺࡯࠲ࠍ↢ ᚑߔࠆߚ߼ߩ࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣࠍ⴫ߔⴕ೉ࠍ㧘ⴕ ೉ T ߪ㊂ሶൻ DCT ଥᢙ߆ࠄ RAW ࠺࡯࠲ࠍᓳภߔ ࠆߚ߼ߩᓳภⴕ೉ࠍ㧘ߘࠇߙࠇ⴫ߔ㧚ᑼ (2) ࠍḩ⿷ ߒߡ޿ࠇ߫㧘JPEG ࠺࡯࠲߆ࠄ⺋Ꮕήߒߢ᷹ⷰߐࠇ ߚ RAW ࠺࡯࠲ࠍᓳภߔࠆߎߣ߇ߢ߈ࠆ㧚߽ߒ㧘ߎ ߩࠃ߁ߥ JPEG ࠺࡯࠲ࠍ╓ภൻߔࠆߎߣ߇ߢ߈ࠇ߫㧘 RAW ࠺࡯࠲ࠍนㅒ࿶❗ߒߡ޿ࠆߣ⠨߃ࠆߎߣ߽ߢ߈ ࠆ㧚ߎߩ RAW ࠺࡯࠲ߩนㅒ࿶❗ߩ⠨߃ᣇߪ㧘RAW ࠺࡯࠲ߩ㕖นㅒ࿶❗ߦ᜛ᒛߔࠆߎߣ߇ߢ߈ࠆ㧚㕖นㅒ ࿶❗ߪ㧘ᑼ (3) ߩ⺋Ꮕ߇චಽዊߐߊߥࠆࠃ߁ߦ JPEG ࠺࡯࠲ࠍ╓ภൻߔࠆߎߣߢ޽ࠆ㧚. E. =. ||g T f ||22. (3). ߎߎߢ㧘|| · ||2 ߪ L2 ࡁ࡞ࡓࠍ⴫ߔ㧚ᑼ (3) ߩ⺋Ꮕ߇ዊ ߐ޿ࠃ߁ߥ㊂ሶൻ DCT ଥᢙߦኻᔕߔࠆ JPEG ࠺࡯. JPEG-RAW ࠺࡯࠲ߩ↢ᚑᣇᴺ. ೨┨ߢߪ㧘JPEG-RAW ࠺࡯࠲ߩ․ᓽࠍㅀߴߚ㧚ᧄ ┨ߢߪ㧘᷹ⷰߐࠇߚ RAW ࠺࡯࠲߆ࠄ㧘JPEG-RAW ࠺࡯࠲ࠍ↢ᚑߔࠆᣇᴺࠍౕ૕⊛ߦㅀߴࠆ㧚 ߹ߕ㧘DCT ଥᢙ߇ㅪ⛯ߩ႐วߦߟ޿ߡᬌ⸛ߔࠆ㧚 ߟ޿ߢ㧘㊂ሶൻ DCT ଥᢙߦኻᔕߔࠆߚ߼ߩ➅ࠅ㄰ ߒ⸘▚ᣇᴺࠍឭ᩺ߔࠆ㧚ߐࠄߦ㧘㊂ሶൻ DCT ଥᢙ ߩࡄ࡜ࡔ࡯࠲ᢙ೥ᷫᣇᴺ߅ࠃ߮㊂ሶൻ࠹࡯ࡉ࡞ߩౣ ⸳⸘ᣇᴺࠍឭ᩺ߔࠆ㧚 ߥ߅㧘㊂ሶൻ DCT ଥᢙߣ JPEG ࠺࡯࠲ߪ㧘࡜ࡦ ࡟ࡦࠣࠬ߅ࠃ߮ࡂࡈࡑࡦ╓ภൻߢ৻ኻ৻ߦኻᔕߒߡ ޿ࠆߚ߼㧘ᧄ┨ߢߪ㊂ሶൻ DCT ଥᢙࠍ↢ᚑߔࠆᣇ ᴺߦߟ޿ߡㅀߴࠆ㧚. 4.1. ㅪ⛯ DCT ଥᢙߩ႐ว. ᄢ߈ߐ 8 × 8 ߩ MCU ߏߣߦᑼ (3) ߩ⺋Ꮕࠍ㧘ߘࠇ ߙࠇᦨዊߦߔࠆߎߣࠍ⠨߃ࠆ㧚ߎߎߢߪ㧘߹ߕ㧘DCT ଥᢙߩ㊂ሶൻߪ⠨ᘦߖߕ㧘ㅪ⛯ DCT ଥᢙߦߟ޿ߡ⠨ ߃ࠆ㧚߹ߕ㧘ਥⷐߥⴕ೉ߣࡌࠢ࠻࡞ߩᰴరࠍ⏕⹺ߔ ࠆ㧚᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߢ޽ࠆࡌࠢ࠻࡞ g ߪ 64 ᰴర㧘᳞߼ࠆߴ߈ࡈ࡞ࠞ࡜࡯↹௝ߩ DCT ଥᢙߢ޽ ࠆࡌࠢ࠻࡞ f ߪ 192 ᰴర㧘ᓳภൻⴕ೉ T ߪ 192 × 64 ᰴరߢ޽ࠆ㧚ߟ߹ࠅ㧘᳞߼ࠆߴ߈ᧂ⍮ᢙߩᢙ (192) ߇ ᜔᧤ᑼߩᢙ (64) ࠃࠅ߽ᄙ޿ߚ߼㧘ᑼ (3) ߩ⺋Ꮕࠍ࠯ ࡠߦߔࠆㅪ⛯ DCT ଥᢙ f ߪήᢙߦ޽ࠆ㧚 DCT ଥᢙߩ㊂ሶൻࠍ⠨ᘦߒߥߌࠇ߫㧘⺋Ꮕࠍ࠯ ࡠߦߔࠆ DCT ଥᢙߩ 1 ߟߪ㧘ᑼ (2) ߩᦨዊੑਸ਼ᦨ ዊࡁ࡞ࡓ⸃ߣߒߡਈ߃ࠄࠇࠆ㧚ߎߩᦨዊੑਸ਼ᦨዊࡁ ࡞ࡓ⸃ߪ㧘Moore-Penrose ߩ৻⥸ൻㅒⴕ೉ࠍ೑↪ߒ ߡ㧘ᑼ (4) ߩࠃ߁ߦ৻ᗧߦ᳞߼ࠄࠇࠆ㧚. fc. =. T+ g. (4). ߎߎߢ㧘ⴕ೉ T+ ߪⴕ೉ T ߩ Moore-Penrose ߩ৻⥸ ൻㅒⴕ೉ࠍ⴫ߔ㧚ߒ߆ߒߥ߇ࠄ㧘JPEG ࠺࡯࠲ࠍ↢ ᚑߔࠆߚ߼ߦߪ㧘ㅪ⛯ DCT ଥᢙ f c ࠍ㊂ሶൻߔࠆᔅ ⷐ߇޽ࠆ㧚㊂ሶൻߦ઻޿㧘㊂ሶൻ⺋Ꮕ߽หᤨߦ⊒↢ ߒߡߒ߹߁㧚. 4.2. ㊂ሶൻ DCT ଥᢙߩߚ߼ߩ➅ࠅ㄰ߒ⸘▚. ೨▵ߢ⼏⺰ߒߚࠃ߁ߦ৻⥸ൻㅒⴕ೉ࠍ೑↪ߒߡ㧘 DCT ଥᢙࠍ᳞߼ࠆߎߣ߇ߢ߈ࠆ㧚ߒ߆ߒߥ߇ࠄ㧘 JPEG ࠺࡯࠲ࠍ↢ᚑߔࠆߚ߼ߦߪ DCT ଥᢙࠍ㊂ሶ ൻߒߥߌࠇ߫ߥࠄߕ㧘㊂ሶൻ⺋Ꮕ߇⊒↢ߔࠆ㧚ߎߩ㊂ ሶൻ⺋Ꮕࠍૐᷫߐߖࠆߚ߼㧘ᧄ▵ߢߪ➅ࠅ㄰ߒ⸘▚ ߦࠃࠅ㧘㊂ሶൻ DCT ଥᢙࠍ᳞߼ࠆᣇᴺࠍឭ᩺ߔࠆ㧚 ࿑ 6 ߦ㧘➅ࠅ㄰ߒ⸘▚ߩᚻ㗅ࠍ␜ߔ㧚㊂ሶൻ⺋Ꮕ ࠍ⋧Ვߔࠆࠃ߁ߦ㧘㊂ሶൻ DCT ଥᢙࠍᦝᣂߔࠆᣇ. −128−.

(5) 1. Initialize DCT coe&ecients as f0 = 0. 2. f c = T+ (g T Q fn1 ). 3. fnc = Q fn1 + f c . 4. fn is quantization of fnc . 5. Repeat from 2 to 4.. Fig. 7. Used DCT data: 1 and 0 represent used data and unused data, respectively.. Fig. 6. Iterative estimation of quantized DCT data.. ᴺߢ޽ࠆ㧚ߎߩࠃ߁ߦ㧘➅ࠅ㄰ߒ⸘▚ࠍⴕ߁ߎߣߦ ࠃࠅ㧘㊂ሶൻ⺋Ꮕࠍૐᷫߔࠆߎߣ߇ߢ߈ࠆ㧚. 4.3. 4.4. ࡄ࡜ࡔ࡯࠲ᢙߩ೥ᷫ. ᳞߼ࠆߴ߈ DCT ଥᢙߩᢙ (ᧂ⍮ᢙ) ߇ 192 ߢ޽ࠅ㧘 RAW ࠺࡯࠲ߩ࠺࡯࠲ᢙ (᜔᧤ᑼߩᢙ) ߇ 64 ߢ޽ࠆߩ ߢ㧘DCT ଥᢙߩ㊂ሶൻࠍ⠨ᘦߒߥߌࠇ߫㧘ᑼ (3) ߩ ⺋Ꮕࠍ 0 ߦߢ߈ࠆߎߣߪᣢߦㅀߴߚ㧚߹ߚ㧘ోߡߩ DCT ଥᢙࠍ೑↪ߔࠆᔅⷐߪߥ޿㧚ߘߎߢ㧘ᑼ (5) ߩ ࠃ߁ߥᓳภㆊ⒟ࠍ⠨߃ࠆ㧚. g. =. T diag(s) f. (5). ߎߎߢ㧘ⴕ೉ diag(s) ߪኻⷺⷐ⚛߇ s ߢ޽ࠆኻⷺⴕ ೉ࠍ㧘ࡌࠢ࠻࡞ s ߪⷐ⚛߇ 0 ߹ߚߪ 1 ߩࡌࠢ࠻࡞ࠍ㧘 ⴫ߔ㧚ߥ߅㧘ࡌࠢ࠻࡞ s ߩᰴరߪ㧘ࡌࠢ࠻࡞ f ߩᰴ రߣหߓ 192 ߢ޽ࠆ㧚 ᑼ (5) ߩᦨዊੑਸ਼ᦨዊࡁ࡞ࡓ fsc ߪᑼ (6) ߦ⴫ߐ ࠇࠆ㧚. fsc. =. [T diag(s)]+ g. ߩߣ߈㧘ⴕ೉ T diag(s) ߩ࡜ࡦࠢ߇ࡌࠢ࠻࡞ g ߣ╬ ߒ޿ߎߣࠍ⏕⹺ߒߡ޿ࠆ㧚㊂ሶൻ࠹࡯ࡉ࡞ߩౣ⸳⸘. ࿖㓙㔚᳇ㅢାㅪว (ITU) ߪ㧘ੱߩⷞⷡߦၮߠ޿ߚ DCT ଥᢙߩߚ߼ߩ㊂ሶൻ࠹࡯ࡉ࡞ࠍ൘๔ߒߡ޿ࠆ㧚 ߎߩ㊂ሶൻ࠹࡯ࡉ࡞ߪᐢߊ೑↪ߐࠇߡ߅ࠅ㧘ߎߩ㊂ ሶൻ࠹࡯ࡉ࡞ࠍቯᢙ୚ߔࠆߎߣߦࠃߞߡ㧘࿶❗₸߇ ᄌᦝߐࠇߡ޿ࠆ㧚 ߣߎࠈߢ㧘㊂ሶൻߪ DCT ଥᢙߦኻߒߡⴕࠊࠇ㧘 DCT ଥᢙߩ㊂ሶൻ⺋Ꮕ߇ RAW ࠺࡯࠲ߩ㊂ሶൻ⺋Ꮕ ߳ߣવ៝ߔࠆ㧚߹ߚ㧘㊂ሶൻ⺋Ꮕߪ㧘DCT ଥᢙߩⷐ ⚛ߦଐሽߖߕߦ㧘หߓࠃ߁ߦ⊒↢ߔࠆ㧚ᓥߞߡ㧘ᧄ ⺰ᢥߢߪ㧘DCT ଥᢙߩ㊂ሶൻ⺋Ꮕ߇ RAW ࠺࡯࠲߳ ਈ߃ࠆᓇ㗀߇㧘ⷐ⚛ߦࠃࠄߕ╬ߒߊߥࠆࠃ߁ߦ㊂ሶ ൻ࠹࡯ࡉ࡞ࠍౣ⸳⸘ߔࠆߎߣߦߔࠆ㧚 ߹ߕ㧘ㅪ⛯୯ߩ DCT ଥᢙ߆ࠄ RAW ࠺࡯࠲߳ߩ ᓳภㆊ⒟߆ࠄ㧘RAW ࠺࡯࠲ߦ߅ߌࠆ㊂ሶൻ⺋Ꮕࠍ ᳞߼ࠆ㧚ㅪ⛯୯ߩ DCT ଥᢙ߆ࠄ RAW ࠺࡯࠲߳ߩ ᓳภㆊ⒟ߪᑼ (8) ߩࠃ߁ߦᄌᒻߢ߈ࠆ㧚. (6). ߐߡ㧘ࡌࠢ࠻࡞ s ߩ޽ࠆⷐ⚛߇ 0 ߢ޽ࠇ߫㧘ᦨዊੑ ਸ਼ᦨዊࡁ࡞ࡓ⸃ fsc ߩኻᔕߔࠆⷐ⚛ߪ 0 ߦߥࠆ㧚߹ߚ㧘 ⴕ೉ T diag(s) ߩ࡜ࡦࠢ߇ࡌࠢ࠻࡞ g ߣ╬ߒߌࠇ߫㧘 ᑼ (3) ߩ⺋Ꮕࠍ࠯ࡠߦߔࠆㅪ⛯ DCT ଥᢙࠍ᳞߼ࠆ ߎߣ߇ߢ߈ࠆ㧚 ߣߎࠈߢ㧘㊂ሶൻ DCT ଥᢙࠍ࡜ࡦ࡟ࡦࠣࠬ߅ࠃ ߮ࡂࡈࡑࡦ╓ภൻߔࠆߎߣߦࠃࠅ㧘JPEG ࠺࡯࠲߇ ᓧࠄࠇࠆ㧚ߘߩߚ߼㧘㜞޿࿶❗ല₸ࠍታ⃻ߔࠆߚ߼ ߦߪ㧘ㅪ⛯ߒߚ 0 ߇ᄙᢙ฽߹ࠇࠆࠃ߁ߦࡌࠢ࠻࡞ s ࠍ⸳⸘ߔࠇ߫ࠃ޿㧚JPEG ߢߪ㧘DCT ଥᢙࠍ଻ሽߔ ࠆߣ߈ߦࠫࠣࠩࠣ⿛ᩏ߇ណ↪ߐࠇߡ޿ࠆߎߣ㧘⦡Ꮕ ߩ㜞๟ᵄᚑಽߪੱߩⷞⷡߪ޽߹ࠅ⍮ⷡߒߥ޿ߎߣ߆ ࠄ㧘࿑ 7 ߦኻᔕߔࠆࡌࠢ࠻࡞ s ࠍ೑↪ߒߚ㧚ߎߩࠃ ߁ߥࡌࠢ࠻࡞ s ࠍ೑↪ߔࠆߎߣߦࠃࠅ㧘࿑ 7 ਛߢ 1 ߦኻᔕߔࠆ๟ᵄᢙߩ DCT ଥᢙߩߺ߇೑↪ߐࠇࠆߎ ߣߦߥࠆ㧚ߎߩࠃ߁ߥᣇᴺߦࠃࠅ㧘ታ⾰⊛ߦ೑↪ߔ ࠆࡄ࡜ࡔ࡯࠲ᢙࠍ 196 ߆ࠄ 67 ߳೥ᷫߒߚ㧚߹ߚ㧘ߎ. g. =. Y Q fc =. n X. yi qi fi +. i=1. n X. yi qi ei (7). i=1. ߎߎߢ㧘. Y. =. D W1 A1. (8). ߢ޽ࠅ㧘ࡌࠢ࠻࡞ yi ߪⴕ೉ Y ߩ i ⇟⋡ߩ೉ࡌࠢ࠻ ࡞ࠍ㧘fi ߪࡌࠢ࠻࡞ f ߩ i ⇟⋡ߩⷐ⚛ࠍ㧘Qi ߪ i ⇟ ⋡ߩⷐ⚛ߩ㊂ሶൻ㑆㓒ࠍ㧘ei ߪ i ⇟⋡ߩ DCT ଥᢙ ߩ㊂ሶൻ⺋Ꮕࠍ㧘n ߪࡌࠢ࠻࡞ f ߩⷐ⚛ᢙࠍ㧘ߘࠇ ߙࠇ⴫ߔ㧚ߥ߅㧘೨▵ߩࡄ࡜ࡔ࡯࠲೥ᷫࠍ೑↪ߒߚ ႐ว㧘ⴕ೉ Y ߪࡄ࡜ࡔ࡯࠲೥ᷫࠍ⠨ᘦߒߚᒻᑼߦߥ ࠆ㧚ߎߩߣ߈㧘RAW ࠺࡯࠲ߦ߅ߌࠆ㊂ሶൻ⺋Ꮕ g ߪᑼ (9) ߩࠃ߁ߦ⴫ߐࠇࠆ㧚. −129−. g. =. n X i=1. yi qi ei. (9).

(6) ฦ DCT ଥᢙߩⷐ⚛ߩ㊂ሶൻ⺋Ꮕ ei ߇㧘RAW ࠺࡯ ࠲ߦਈ߃ࠆᓇ㗀ࠍ╬ߒߊߔࠆߚ߼ߦ㧘ฦⷐ⚛ߩ㊂ሶ ൻ㑆㓒 qi ࠍᑼ (10) ߩࠃ߁ߦ⸳⸘ߔࠆ㧚. qi. =. z ||yi ||. (10). ߎߎߢ㧘z ߪ࿶❗₸ࠍ⺞▵ߔࠆߚ߼ߩቯᢙߢ޽ࠆ㧚. 5. ታ㛎 Fig. 8. Ground truth.. ᮡḰ↹௝߅ࠃ߮ታ↹௝ߦኻߒߡឭ᩺ᚻᴺࠍㆡ↪ߒ㧘 ឭ᩺ᚻᴺߩ᦭ലᕈࠍ⏕⹺ߔࠆ㧚߹ߕ㧘4.3 ▵ߢㅀߴߚ ࡄ࡜ࡔ࡯࠲ᢙߩ೥ᷫߣ 4.4 ▵ߢㅀߴߚ㊂ሶൻ࠹࡯ࡉ ࡞ߩౣ⸳⸘ߩലᨐࠍ⏕⹺ߔࠆ㧚4.2 ▵ߢㅀߴߚ➅ࠅ㄰ ߒ⸘▚ߩ➅ࠅ㄰ߒ࿁ᢙࠍ 3 ࿁ߦ࿕ቯߒߡ㧘ࡄ࡜ࡔ࡯ ࠲ᢙ೥ᷫ߅ࠃ߮㊂ሶൻ࠹࡯ࡉ࡞ߩౣ⸳⸘ࠍ㧘ߘࠇߙ ࠇ೑↪ߔࠆ႐วߣߒߥ޿႐วߢ㧘4 ⒳㘃ߩᣇᴺࠍᬌ ⸛ߒߚ㧚࿑ 8 ߦ␜ߔේ↹௝ࠍ࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߒ㧘 Bayer ࠞ࡜࡯ࡈࠖ࡞࠲࡯ࠕ࡟ࠗߦኻᔕߔࠆ RAW ࠺࡯ ࠲ࠍ↢ᚑߒߚ㧚ߎߩ RAW ࠺࡯࠲ߦኻߒߡ㧘4 ⒳㘃ߩ ᣇᴺߢ JPEG ࠺࡯࠲ࠍ↢ᚑߒߚ㧚㊂ሶൻ㑆㓒ࠍᄌൻ ߐߖߥ߇ࠄ㧘࿶❗₸ߣ RAW ࠺࡯࠲ߦኻߔࠆ CPSNR ࠍ᳞߼ߚ⚿ᨐ߇࿑ 9 ߢ޽ࠆ㧚࿶❗₸ߪ㧘↢ᚑߐࠇߚ JPEG ࠺࡯࠲ߩࠨࠗ࠭ߣ RAW ࠺࡯࠲ߩ࠺࡯࠲ࠨࠗ ࠭ߩᲧߢ޽ࠅ㧘୯߇ᄢ߈޿߶ߤ㧘㜞࿶❗ߢ޽ࠆߎߣࠍ ␜ߔ㧚CPSNR ߪ㧘ᓳภߐࠇߚ RAW ࠺࡯࠲ߣේ↹௝ ߩ RAW ࠺࡯࠲ߣߩᐔဋੑਸ਼⺋Ꮕࠍ࠺ࠪࡌ࡞ߢ޽ࠄ ࠊߒߚ߽ߩߢ޽ࠅ㧘୯߇ᄢ߈޿߶ߤరߩ RAW ࠺࡯ ࠲ߦㄭ޿ߎߣࠍ⴫ߒߡ޿ࠆ㧚ߔߥࠊߜ㧘࿑ 9 ߦ߅޿ ߡ㧘ฝ਄ߦ࠺࡯࠲߇ሽ࿷ߒߡ޿ࠆ߶ߤ㧘㜞࿶❗₸߆ ߟૐᱡߺߢ RAW ࠺࡯࠲߇࿶❗ߐࠇߡ޿ࠆߎߣࠍ␜ ߔ㧚࿑ 9 ߆ࠄ㧘ࡄ࡜ࡔ࡯࠲ᢙߩ೥ᷫߣ㊂ሶൻ࠹࡯ࡉ ࡞ߩౣ⸳⸘ࠍߣ߽ߦⴕ߁ᣇᴺ߇ᦨ߽ല₸⊛ߦ RAW ࠺࡯࠲ࠍ࿶❗ߒߡ޿ࠆߎߣ߇⏕⹺ߐࠇࠆ㧚 ߹ߚ㧘࿑ 10 ߦ࿶❗₸߇߅ࠃߘ 4 ઃㄭߦ߅ߌࠆ 4 ⒳㘃ߩ࿶❗ᣇᴺߦࠃࠅ↢ᚑߐࠇߚ JPEG ࠺࡯࠲ߩࡊ ࡟ࡆࡘ࡯↹௝ࠍ␜ߔ㧚࿑೽㗴ߦ CPSNR ߣ࿶❗₸ࠍ㧘 ߘࠇߙࠇ␜ߔ㧚޿ߕࠇߩࡊ࡟ࡆࡘ࡯↹௝߽㧘㜞ຠ⾰ߥ ↹௝ߢ޽ࠆߣߪ⸒߃ߥ޿㧚ߒ߆ߒߥ߇ࠄ㧘ࡊ࡟ࡆࡘ࡯ ↹௝ߪ޽ߊ߹ߢ߽㧘࠺࡯࠲ࠍ⏕⹺ߔࠆߎߣ߇⋡⊛ߢ ޽ࠆ㧚࿑ 10 ߩ↹௝߆ࠄචಽ㧘࠺࡯࠲ࠍ↹௝ߣߒߡ⏕ ⹺ߔࠆߎߣ߇ߢ߈㧘ࡊ࡟ࡆࡘ࡯ߩᓎഀࠍᨐߚߔߎߣ ߇ࠊ߆ࠆ㧚ߐࠄߦ㧘4 ⒳㘃ߩࡊ࡟ࡆࡘ࡯↹௝ߩਛߢ ߪ㧘ࡄ࡜ࡔ࡯࠲ᢙߩ೥ᷫߣ㊂ሶൻ࠹࡯ࡉ࡞ߩౣ⸳⸘ ࠍߣ߽ߦ೑↪ߒߚ (d) ߩ↹⾰߇ᦨ߽⦟޿㧚એ਄ߩℂ ↱߆ࠄ㧘ࡄ࡜ࡔ࡯࠲ᢙߩ೥ᷫߣ㊂ሶൻ࠹࡯ࡉ࡞ߩౣ ⸳⸘ࠍߣ߽ߦ೑↪ߒߚᣇᴺࠍឭ᩺ᚻᴺߣߔࠆ㧚 ᰴ ߦ 㧘ឭ ᩺ ᚻ ᴺ ࠍ 㧘৻ ⥸ ⊛ ߦ ೑ ↪ ߐ ࠇߡ ޿ ࠆ JPEG, JPEG-LS ߅ࠃ߮ JPEG-2000 ߣᲧセߔࠆ㧚߹ ߕ㧘࿑ 8 ࠍ࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦࠃࠅᓧࠄࠇ ߚ RAW ࠺࡯࠲ࠍ Adams ࠄߩᚻᴺ [12] ߦࠃࠅ࠺ࡕࠩ ࠗࠠࡦࠣಣℂࠍߒ㧘ࡈ࡞ࠞ࡜࡯↹௝ࠍᓧࠆ㧚ᓧࠄࠇߚ ࡈ࡞ࠞ࡜࡯↹௝ߦኻߒߡ㧘JPEG ࠺࡯࠲㧘JPEG-LS ࠺࡯࠲߅ࠃ߮ JPEG-2000 ࠺࡯࠲ࠍ㧘㊂ሶൻ㑆㓒ࠍ. Fig. 9. Comparision of CPSNR of four different proposd methods.. ᄌൻߐߖߥ߇ࠄ㧘ߘࠇߙࠇ↢ᚑߒߚ㧚ߘࠇߙࠇߩ↹ ௝࠺࡯࠲ࠍᓳภߒ㧘࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦ ࠃࠅ㧘RAW ࠺࡯࠲߇ᓧࠄࠇࠆ㧚࿑ 11 ߦឭ᩺ᚻᴺߣ㧘 ᣢሽߩ↹௝࿶❗ᣇᴺࠍ೑↪ߒߚ RAW ࠺࡯࠲࿶❗ᣇ ᴺߩᲧセࠍ␜ߔ㧚࿑ 11 ߆ࠄ㧘ߤߩ࿶❗₸ߦ߅޿ߡ߽ ឭ᩺ᚻᴺߩ CPSNR ߇ᦨ߽㜞޿୯ߢ޽ࠆߎߣ߇⏕⹺ ߐࠇࠆ㧚 ห᭽ߩᲧセࠍ࿑ 12 ߦ␜ߔታ㓙ߦ᠟ᓇߐࠇߚ↹௝ ߦኻߒߡⴕߞߚ㧚ߥ߅㧘᠟ᓇߦߪන᧼ᑼࠞ࡜࡯᠟௝ ⚛ሶࠍ᦭ߔࠆࠞࡔ࡜ࠍ೑↪ߒߡ޿ࠆ㧚ߘߩߚ߼㧘࿑ 12 ߪࡈ࡞ࠞ࡜࡯ൻߐࠇߚ↹௝ࠍ␜ߒߡ޿ࠆ㧚ᓥ᧪ߩ ᣇᴺߢ࿶❗ߔࠆ㓙ߦߪ㧘Adams ࠄߩᚻᴺ [12] ߦࠃࠅ ࠺ࡕࠩࠗࠠࡦࠣಣℂߦࠃࠅᓧࠄࠇߚࡈ࡞ࠞ࡜࡯↹௝ ߦኻߒߡฦ⒳࿶❗ᚻᴺࠍㆡ↪ߒߚ㧚࿑ 12 ߦኻߔࠆ㧘 ࿶❗ᣇᴺߩᲧセࠍ࿑ 13 ߦ␜ߔ㧚ᮡḰ↹௝ߩ႐วߣߪ ௑ะߪᄙዋ⇣ߥࠆ߽ߩߩ㧘࿑ 13 ߦ߅޿ߡ߽㧘ឭ᩺ᚻ ᴺ߇޿ߕࠇߩ࿶❗₸ߦ߅޿ߡ߽ᦨ߽㜞޿ CPSNR ࠍ ␜ߒߡ޿ࠆ㧚ߟ߹ࠅ㧘ឭ᩺ᚻᴺߪ RAW ࠺࡯࠲ࠍല ₸⊛ߦ࿶❗ߢ߈㧘߆ߟࡊ࡟ࡆࡘ࡯↹௝ࠍ◲ଢߦ↢ᚑ น⢻ߢ޽ࠆߎߣ߇⏕⹺ߐࠇߚ㧚 ࠞࡔ࡜਄ߢ㧘RAW ࠺࡯࠲ࠍᚻ᩺ᚻᴺߦࠃࠅ࿶❗࡮ ଻ሽߒ㧘PC ╬ߦ࠺࡯࠲ࠍォㅍߒߚᓟ㧘⸘▚ᤨ㑆߇߆ ߆ࠆ߇㜞♖ᐲߥ࠺ࡕࠩࠗࠠࡦࠣಣℂࠍ೑↪ߔࠆߣ޿ ߁ᔕ↪߇⠨߃ࠄࠇࠆ㧚࿑ 14 ߦ࿑ 12 ߩ࿶❗⚿ᨐࠍ␜ ߔ㧚࿑ 14(a) ߅ࠃ߮ (b) ߪ㧘Adams ࠄߩᣇᴺߦࠃࠅ ࠺ࡕࠩࠗࠠࡦࠣಣℂߒߚ⚿ᨐࠍ JPEG ߅ࠃ߮ JPEG2000 ߢ࿶❗ߒߚ⚿ᨐࠍ㧘࿑ 14(c) ߪ㧘RAW ࠺࡯࠲ ࠍឭ᩺ᚻᴺߦࠃࠅ࿶❗ߒߚ⚿ᨐߩࡊ࡟ࡆࡘ࡯↹௝ࠍ㧘. −130−.

(7) (a) Non dimension reduction & Non quantization redesign.. (b) Non dimension reduction & Quantization redesign.. (CPSNR: 36.3[dB],. (CPSNR: 37.5[dB],. Comp. ratio: 4.1). Comp. ratio: 3.7). (c) Dimension reduction & Non quantization redesign.. (d) Dimension reduction & Quantization redesign.. (CPSNR: 35.7[dB],. Comp. ratio: 3.9). Fig. 11. Comparison of CPSNR vs. pression ratio with Lena image.. com-. ࠺࡯࠲ࠍ↢ᚑߔࠆᣇᴺࠍឭ᩺ߒߚ㧚ߎߩ↢ᚑᣇᴺߪ㧘 JPEG ߩᓳภㆊ⒟ࠍቯᑼൻߒ㧘ᓳภߐࠇࠆ RAW ࠺࡯ ࠲ߣ᷹ⷰߐࠇߚ RAW ࠺࡯࠲ߩ⺋Ꮕ߇ዊߐߊߥࠆࠃ ߁ߦ JPEG ࠺࡯࠲ࠍ↢ᚑߔࠆߣ޿߁⠨߃ᣇߦၮߠ޿ ߡ޿ࠆ㧚㊂ሶൻߩᓇ㗀ࠍ⠨ᘦߒߚ➅ࠅ㄰ߒṶ▚㧘ࡄ ࡜ࡔ࡯࠲ᢙߩ౬㐳ߐࠍ೑↪ߒߚࡄ࡜ࡔ࡯࠲ᢙ೥ᷫ߅ ࠃ߮㊂ሶൻ࠹࡯ࡉ࡞ߩౣ⸳⸘ࠍⴕ߁ߎߣߦࠃࠅ㧘ឭ ᩺ᚻᴺߪ㜞࿶❗߆ߟૐᱡߺߢ RAW ࠺࡯࠲ࠍ࿶❗ߔ ࠆߎߣ߇น⢻ߢ޽ࠆ㧚 ᚻ᩺ᚻᴺߣ㧘ᣢሽߩ JPEG㧘JPEG-LS ߅ࠃ߮ JPEG-2000 ࠍᮡḰ↹௝߅ࠃ߮ታ↹௝ߦㆡ↪ߒ㧘ឭ ᩺ᚻᴺߩ᦭ലᕈࠍ⏕⹺ߒߚ㧚. (CPSNR: 39.2[dB],. Comp. ratio: 4.0). ෳ⠨ᢥ₂. Fig. 10. Comparision of preview images.. [1] B.E. Bayer, “Color imaging array,” US Patent 3971065, 1976.. ࿑ 14(d) ߪ㧘ឭ᩺ᚻᴺߢ࿶❗ߐࠇߚ RAW ࠺࡯࠲ߦၮ ߠ߈ Hirakawa ࠄߩᣇᴺ [13] ߢ࠺ࡕࠩࠗࠠࡦࠣಣℂ ߒߚ⚿ᨐࠍ㧘ߘࠇߙࠇ␜ߔ㧚Hirakawa ࠄߩ࠺ࡕࠩࠗ ࠠࡦࠣಣℂߪ㧘ᓥ᧪ߩᣇᴺࠃࠅ㜞♖⚦ߦ࠺ࡕࠩࠗࠠ ࡦࠣߢ߈ࠆᣇᴺߣߒߡ⍮ࠄࠇߡ޿ࠆ߽ߩߩ㧘Adams ࠄߩᣇᴺߦᲧߴߡ⸘▚ࠦࠬ࠻߇ᄢ߈޿㧚ߟ߹ࠅ㧘࿑ 14(c) ߪࠞࡔ࡜਄ߢߩ⏕⹺ߩߚ߼ߩ↹௝ࠍ㧘࿑ 14(d) ߪឭ᩺ᚻᴺࠍᔕ↪ߒߡᦨ⚳⊛ߦᓧࠄࠇࠆ↹௝ߢ޽ࠆ ߣ⠨߃ࠄࠇࠆ㧚࿑ 14(d) ࠍ࿑ 14(a) ߅ࠃ߮ (b) ߣᲧ セߒߚ႐ว㧘ឭ᩺ᚻᴺࠍᔕ↪ߒߚ࿑ 14(d) ߩ↹௝߇ ⚦ㇱ߹ߢౣ⃻ߐࠇߡ޿ࠆߎߣ߇⏕⹺ߐࠇࠆ㧚. 6. [2] G.K. Wallace, “The JPEG still picture compression standard,” Communications of the ACM, Vol. 34, No. 4, pp. 30—40, 1991. [3] M.J. Weinberger, G. Seroussi, and G. Sapiro, “The LOCO-I lossless image compression algorithm: principles andstandardization into JPEGLS,” IEEE Trans. Image Processing, Vol. 9, No. 8, pp. 1309—1324, 2000. [4] A. Skodras, C. Christopoulos, and T. Ebrahimi, “The JPEG 2000 still image compression standard,” IEEE Signal Processing Magazine, Vol. 18, No. 5, pp. 36—58, 2001.. ߻ߔ߮. ᧄ⺰ᢥߢߪ㧘RAW ࠺࡯࠲ࠍ࿶❗࡮଻ሽߔࠆߚ߼ ߩᣂߒ޿ᣇᴺࠍឭ᩺ߒߚ㧚 ߹ߕ㧘RAW ࠺࡯࠲ࠍᓳภน⢻ߥ JPEG ࠺࡯࠲ߢ ޽ࠆ JPEG-RAW ࠺࡯࠲ߣ޿߁ᣂߒ޿⠨߃ᣇࠍឭ᩺ ߒߚ㧚ߎߩ JPEG-RAW ࠺࡯࠲ߣߪ㧘ᣢሽߩ JPEG ᓳภེߢᓳภߒ㧘࠳࠙ࡦࠨࡦࡊ࡝ࡦࠣߔࠆߎߣߦࠃࠅ㧘 RAW ࠺࡯࠲߇ᓳภߢ߈ࠆ㧚߹ߚ㧘ߎߩࠃ߁ߥ JPEGRAW ࠺࡯࠲ߪ㧘ࡊ࡟ࡆࡘ࡯↹௝ࠍᣢሽߩ JPEG ᓳ ภེߢ◲ଢߦ↢ᚑߔࠆߎߣ߇ߢ߈ࠆ㧚 ᰴߦ㧘᷹ⷰߐࠇߚ RAW ࠺࡯࠲߆ࠄ㧘JPEG-RAW. [5] N. Zhang and X. Wu, “Lossless Compression of Color Mosaice Images,” IEEE Trans. Image Processing, Vol. 15, No. 6, pp. 1379—1388, 2006. [6] S.-Y. Lee and A. Ortega, “A Novel Approach of Image Compression in Digital Cameras with a Bayer Color Filter Array,” Proc. International Conference of Image Processing, Vol. 3, pp. 482— 485, 2001. [7] C.C. Koh, J. Mukherjee, and S.K. Mitra, “New E^cient Methods of Image Compression in Digital Cameras with Color Filter Array,” Trans. Consumer Electronics, Vol. 49, No. 4, pp. 1488—1456, 2003.. −131−.

(8) Fig. 12. Image captured by single color image sensor.. (a) JPEG (Compression ratio: 1.99). Fig. 13. Comparison of CPSNR vs. pression ration with captured image.. com-. (b) JPEG-2000 (Compression ratio: 1.98). [8] X. Xie, G.L. Li, Z.H. Wang, C. Zhang, D.M. Li, and X.W. Li, “A Novel Method of Lossy Image Compression for Digital Image Sensors with Bayer Color Filter Arrays,” Proc. International Symposium on Circuits and Systems, Vol. 5, pp. 4995— 4998, 2005. [9] B. K. Gunturk, J. Glotzbach, Y. Altunbasak, R. W. Schafer, and R. M. Mersereau, “Demosaicking: color filter array interpolation,” IEEE Signal Processing Magazine, Vol. 22, No. 1, pp. 44—54, 2005.. (c) Preview image of the proposed method (Compression ratio: 1.91). [10] T. Goto and M. Okutomi, “Direct SuperResolution and Registration Using Raw CFA Images,” Proc. IEEE Computer Society Conference on Computer Vision and Pattern Recognition, Vol. II, pp. 600—607, 2004. [11] ᓟ⮮⍮዁㧘ᅏንᱜᢅ㧘 න᧼ࠞ࡜࡯᠟௝⚛ሶߩ RAW ࠺࡯࠲ࠍ೑↪ߒߚ㜞♖⚦↹௝ᓳర㧘ᖱႎಣℂቇળ⺰ᢥ ⹹㧦ࠦࡦࡇࡘ࡯࠲ࡆ࡚ࠫࡦߣࠗࡔ࡯ࠫࡔ࠺ࠖࠕ㧘Vol.45㧘 No.SIG 8(CVIM 9)㧘pp. 15—25㧘2004. [12] J.E. Adams and J.F. Hamilton, “Design of practical color filter array interpolation algorithms for digital cameras,” Proc. SPIE, vol. 3028, pp. 117— 125, 1997.. (d) Reconstructed image from raw data compressed by the proposed method (Compression ratio: 1.91). [13] K. Hirakawa and T.W. Parks, “Adaptive homogeneity-directed demosaicing algorithm,” IEEE Trans. Image Processing, Vol. 14, No. 3, pp. 360—369, 2005.. −132−. Fig. 14. Comparisons of images..

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