{"id":38812,"date":"2024-11-02T00:57:15","date_gmt":"2024-11-02T00:57:15","guid":{"rendered":"http:\/\/atmokpo.com\/w\/?p=38812"},"modified":"2024-11-26T06:43:16","modified_gmt":"2024-11-26T06:43:16","slug":"opencv-%ea%b0%95%ec%a2%8c-clahecontrast-limited-adaptive-histogram-equalization","status":"publish","type":"post","link":"https:\/\/atmokpo.com\/w\/38812\/","title":{"rendered":"OpenCV \uac15\uc88c, CLAHE(Contrast Limited Adaptive Histogram Equalization)"},"content":{"rendered":"

<\/p>\n

\n
\n

\uc774 \uae00\uc5d0\uc11c\ub294 OpenCV\ub97c \uc0ac\uc6a9\ud558\uc5ec CLAHE(Contrast Limited Adaptive Histogram Equalization)\uc5d0 \ub300\ud55c \ubc29\ubc95\uacfc \uac1c\ub150\uc744 \ub2e4\ub8f0 \uac83\uc785\ub2c8\ub2e4. CLAHE\ub294 \uc774\ubbf8\uc9c0\uc758 \ub300\ube44\ub97c \ud5a5\uc0c1\uc2dc\ud0a4\uae30 \uc704\ud574 \uc8fc\ub85c \uc0ac\uc6a9\ub418\ub294 \uae30\uc220\ub85c, RETINEX \uae30\ubc18\uc758 \ubc29\ubc95\uc744 \uc774\uc6a9\ud574 \uc774\ubbf8\uc9c0\ub97c \ubcf4\uc815\ud569\ub2c8\ub2e4.<\/p>\n<\/header>\n

\n

1. CLAHE\ub780 \ubb34\uc5c7\uc778\uac00?<\/h2>\n

CLAHE\ub294 Contrast Limited Adaptive Histogram Equalization\uc758 \uc57d\uc790\ub85c, \uc804\ud1b5\uc801\uc778 \ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654\uc758 \ud55c\uacc4\ub97c \uadf9\ubcf5\ud558\uae30 \uc704\ud574 \uc81c\uc548\ub41c \uae30\ubc95\uc785\ub2c8\ub2e4. \ubcf8 \uae30\ubc95\uc740 \uc774\ubbf8\uc9c0\uc758 \uba85\uc554\ube44\ub97c \ub192\uc5ec \uc791\uc740 \uc138\ubd80\uc0ac\ud56d\uc758 \uac00\uc2dc\uc131\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\uba74\uc11c, “\uacfc\ub3c4\ud55c \ub300\ube44”\ub97c \ubc29\uc9c0\ud569\ub2c8\ub2e4. \uc77c\ubc18\uc801\uc73c\ub85c \ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654\ub294 \uc804\uccb4 \uc774\ubbf8\uc9c0\uc5d0 \ub300\ud574 \ub3d9\uc77c\ud55c \ubcc0\ud654\uc728\uc744 \uc801\uc6a9\ud558\uc9c0\ub9cc, CLAHE\ub294 \uc774\ubbf8\uc9c0\uc758 \uc5ec\ub7ec \uc9c0\uc5ed\uc5d0 \ub2e4\ub978 \ubcc0\ud654\uc728\uc744 \uc801\uc6a9\ud558\uc5ec \ub354 \ud6a8\uacfc\uc801\uc778 \uacb0\uacfc\ub97c \uc0dd\uc131\ud569\ub2c8\ub2e4.<\/p>\n

1.1 CLAHE\uc758 \uc6d0\ub9ac<\/h3>\n

CLAHE\ub294 \uc774\ubbf8\uc9c0\ub97c \uc5ec\ub7ec \uac1c\uc758 \uc791\uc740 \ube14\ub85d\uc73c\ub85c \ub098\ub204\uace0, \uac01 \ube14\ub85d\uc5d0 \ub300\ud574 \ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654\ub97c \uc218\ud589\ud569\ub2c8\ub2e4. \uadf8\ub7f0 \ub2e4\uc74c, \ube14\ub85d\uc5d0\uc11c \uc5bb\uc740 \uacb0\uacfc\ub97c \ubcd1\ud569\ud558\uc5ec \uc804\uccb4 \uc774\ubbf8\uc9c0\ub97c \uc0dd\uc131\ud569\ub2c8\ub2e4. \uc774 \uacfc\uc815\uc5d0\uc11c, \ub300\ube44\uac00 \uc9c0\ub098\uce58\uac8c \ucee4\uc9c0\ub294 \uac83\uc744 \ubc29\uc9c0\ud558\uae30 \uc704\ud574 ‘\ub300\ube44 \uc81c\ud55c’\uc744 \uc124\uc815\ud569\ub2c8\ub2e4. \uc774\ub85c \uc778\ud574 \uacfc\ub3c4\ud55c \ub300\ube44\uac00 \ubc1c\uc0dd\ud558\uc9c0 \uc54a\uace0 \ub354 \uc790\uc5f0\uc2a4\ub7ec\uc6b4 \uc774\ubbf8\uc9c0\ub97c \uc5bb\uc744 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n<\/section>\n

\n

2. OpenCV\uc5d0\uc11c CLAHE \uad6c\ud604\ud558\uae30<\/h2>\n

OpenCV\uc5d0\uc11c\ub294 CLAHE\ub97c \uc27d\uac8c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub2e4\uc74c\uc740 Python\uc744 \uc0ac\uc6a9\ud574 CLAHE\ub97c \uad6c\ud604\ud558\ub294 \ubc29\ubc95\uc5d0 \ub300\ud55c \ub2e8\uacc4\ubcc4 \uc124\uba85\uc785\ub2c8\ub2e4.<\/p>\n

2.1 OpenCV \uc124\uce58<\/h3>\n

CLAHE\ub97c \uc0ac\uc6a9\ud558\uae30 \uc704\ud574 OpenCV \ud328\ud0a4\uc9c0\ub97c \uc124\uce58\ud574\uc57c \ud569\ub2c8\ub2e4. \ud130\ubbf8\ub110\uc5d0\uc11c \uc544\ub798\uc758 \uba85\ub839\uc5b4\ub97c \uc785\ub825\ud558\uc5ec OpenCV\ub97c \uc124\uce58\ud569\ub2c8\ub2e4.<\/p>\n

pip install opencv-python<\/code><\/pre>\n
2.2 CLAHE \uad6c\ud604 \uc608\uc81c<\/h3>\n
\ub2e4\uc74c\uc740 CLAHE\ub97c \uc0ac\uc6a9\ud55c \uc774\ubbf8\uc9c0 \ub300\ube44 \ud5a5\uc0c1 \uc608\uc81c\uc785\ub2c8\ub2e4.<\/p>\n
python\nimport cv2\nimport numpy as np\nimport matplotlib.pyplot as plt\n\n# \uc774\ubbf8\uc9c0 \ub85c\ub4dc\nimage = cv2.imread('input_image.jpg', cv2.IMREAD_GRAYSCALE)\n\n# CLAHE \uac1d\uccb4 \uc0dd\uc131\nclahe = cv2.createCLAHE(clipLimit=2.0, tileGridSize=(8, 8))\n\n# CLAHE \uc801\uc6a9\nclahe_image = clahe.apply(image)\n\n# \uc6d0\ubcf8 \uc774\ubbf8\uc9c0\uc640 CLAHE \uc774\ubbf8\uc9c0 \ube44\uad50\nplt.figure(figsize=(12, 6))\nplt.subplot(1, 2, 1)\nplt.title('\uc6d0\ubcf8 \uc774\ubbf8\uc9c0')\nplt.imshow(image, cmap='gray')\nplt.axis('off')\n\nplt.subplot(1, 2, 2)\nplt.title('CLAHE \uc774\ubbf8\uc9c0')\nplt.imshow(clahe_image, cmap='gray')\nplt.axis('off')\n\nplt.show()\n<\/code><\/pre>\n
\uc704\uc758 \ucf54\ub4dc\ub294 ‘input_image.jpg’ \ud30c\uc77c\uc744 \uc77d\uace0 CLAHE\ub97c \uc801\uc6a9\ud558\uc5ec \uc6d0\ubcf8 \uc774\ubbf8\uc9c0\uc640 \ub300\ube44 \ud5a5\uc0c1\ub41c \uc774\ubbf8\uc9c0\ub97c \ube44\uad50\ud558\uc5ec \ubcf4\uc5ec\uc90d\ub2c8\ub2e4. \uac01 \ube14\ub85d\uc740 8×8 \ud06c\uae30\ub85c \ub098\ub204\uc5b4\uc838 \uc788\uc73c\uba70, clipLimit\ub294 \ub300\ube44 \uc81c\ud55c\uc758 \uac12\uc785\ub2c8\ub2e4.<\/p>\n<\/section>\n
\n
3. \ub9e4\uac1c\ubcc0\uc218 \uc870\uc815<\/h2>\n
CLAHE\uc758 \uc131\ub2a5\uc740 \uba87 \uac00\uc9c0 \ub9e4\uac1c\ubcc0\uc218\uc5d0 \ub530\ub77c \ub2ec\ub77c\uc9c8 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc8fc\uc694 \ub9e4\uac1c\ubcc0\uc218\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
3.1 clipLimit<\/h3>\n
clipLimit\ub294 \ub300\ube44\ub97c \uc81c\ud55c\ud558\ub294 \uac12\uc785\ub2c8\ub2e4. \uc774 \uac12\uc774 \ucee4\uc9c8\uc218\ub85d \uc774\ubbf8\uc9c0\uc758 \ub300\ube44\uac00 \uc99d\uac00\ud558\uc9c0\ub9cc, \uacfc\ub3c4\ud55c \ub300\ube44\uac00 \ubc1c\uc0dd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc77c\ubc18\uc801\uc73c\ub85c 2.0 \ub610\ub294 3.0\uc758 \uac12\uc744 \uc0ac\uc6a9\ud569\ub2c8\ub2e4. \uc801\uc808\ud55c clipLimit \uac12\uc744 \uc124\uc815\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4.<\/p>\n
3.2 tileGridSize<\/h3>\n
tileGridSize\ub294 CLAHE\uac00 \uc801\uc6a9\ub420 \ube14\ub85d\uc758 \ud06c\uae30\uc785\ub2c8\ub2e4. \uc791\uc740 \ud06c\uae30\uc758 \ube14\ub85d\uc740 \uc138\ubd80\uc0ac\ud56d\uc744 \ub354 \uc798 \ubcf4\uc874\ud558\uc9c0\ub9cc, \ub178\uc774\uc988\ub97c \uc99d\uac00\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubc18\uba74, \ud070 \ube14\ub85d \ud06c\uae30\ub294 \ub35c \ud6a8\uacfc\uc801\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc77c\ubc18\uc801\uc73c\ub85c 8×8\uc774\ub098 16×16\uc758 \uac12\uc744 \uc120\ud0dd\ud569\ub2c8\ub2e4.<\/p>\n
3.3 \uc870\ud569 \uc608\uc81c<\/h3>\n
\ub2e4\uc591\ud55c \ub9e4\uac1c\ubcc0\uc218\ub97c \uc870\uc815\ud558\uc5ec \uc774\ubbf8\uc9c0\ub97c \ucc98\ub9ac\ud558\uace0 \uacb0\uacfc\ub97c \ube44\uad50\ud574\ubcf4\uc138\uc694.<\/p>\n
python\n# \uc5ec\ub7ec clipLimit\uc640 tileGridSize \ud14c\uc2a4\ud2b8\nclip_limits = [1.0, 2.0, 3.0]\ntile_sizes = [(8, 8), (16, 16), (32, 32)]\n\nplt.figure(figsize=(15, 10))\nfor i, clip_limit in enumerate(clip_limits):\n    for j, tile_size in enumerate(tile_sizes):\n        index = i * len(tile_sizes) + j\n        clahe = cv2.createCLAHE(clipLimit=clip_limit, tileGridSize=tile_size)\n        clahe_image = clahe.apply(image)\n\n        plt.subplot(len(clip_limits), len(tile_sizes), index + 1)\n        plt.imshow(clahe_image, cmap='gray')\n        plt.title(f'clipLimit {clip_limit}, tileGridSize {tile_size}')\n        plt.axis('off')\n\nplt.tight_layout()\nplt.show()\n<\/code><\/pre>\n<\/section>\n
\n
4. CLAHE\uc758 \uc801\uc6a9 \uc0ac\ub840<\/h2>\n
CLAHE\ub294 \uc5ec\ub7ec \ubd84\uc57c\uc5d0\uc11c \ub110\ub9ac \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \ud2b9\ud788 \uc758\ub8cc \uc601\uc0c1 \ucc98\ub9ac \ubc0f \uc704\uc131 \uc774\ubbf8\uc9c0 \ucc98\ub9ac\uc5d0 \uc720\uc6a9\ud558\uac8c \uc0ac\uc6a9\ub429\ub2c8\ub2e4.<\/p>\n
4.1 \uc758\ub8cc \uc601\uc0c1 \ucc98\ub9ac<\/h3>\n
\uc758\ub8cc \uc601\uc0c1\uc5d0\uc11c\ub294 \uc138\ubd80\uc0ac\ud56d\uc774 \uc911\uc694\ud55c \uc5ed\ud560\uc744 \ud569\ub2c8\ub2e4. CLAHE\ub97c \ud1b5\ud574 CT \ub610\ub294 MRI \uc774\ubbf8\uc9c0\uc5d0\uc11c \uc138\ubd80\uc0ac\ud56d\uc744 \ub354 \uc798 \ubcf4\uc874\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
4.2 \uc704\uc131 \uc774\ubbf8\uc9c0 \ucc98\ub9ac<\/h3>\n
\uc704\uc131 \uc774\ubbf8\uc9c0\uc5d0\uc11c\ub3c4 CLAHE\ub294 \ub300\ube44\ub97c \ud5a5\uc0c1\uc2dc\ucf1c \uc9c0\ud615\uc744 \ub354 \uc120\uba85\ud558\uac8c \ub9cc\ub4e4\uc5b4 \uc90d\ub2c8\ub2e4. \uc9c0\ud615 \ubd84\uc11d \ubc0f \uc790\uc6d0 \ud0d0\uc0ac\uc5d0\uc11c \uc911\uc694\ud55c \uc5ed\ud560\uc744 \ud569\ub2c8\ub2e4.<\/p>\n<\/section>\n
\n
5. \uc131\ub2a5 \ube44\uad50<\/h2>\n
CLAHE\uc758 \ud6a8\uacfc\ub97c \ub2e4\ub978 \ub300\ube44 \ud5a5\uc0c1 \uae30\ubc95\uacfc \ube44\uad50\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4, \uc804\ud1b5\uc801\uc778 \ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654\uc640 CLAHE\uc758 \uacb0\uacfc\ub97c \ube44\uad50\ud574\ubcfc \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
python\n# \uc804\ud1b5\uc801\uc778 \ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654\nhist_equalized = cv2.equalizeHist(image)\n\n# \uacb0\uacfc \ube44\uad50\nplt.figure(figsize=(12, 6))\nplt.subplot(1, 3, 1)\nplt.title('\uc6d0\ubcf8 \uc774\ubbf8\uc9c0')\nplt.imshow(image, cmap='gray')\nplt.axis('off')\n\nplt.subplot(1, 3, 2)\nplt.title('\ud788\uc2a4\ud1a0\uadf8\ub7a8 \ud3c9\ud65c\ud654')\nplt.imshow(hist_equalized, cmap='gray')\nplt.axis('off')\n\nplt.subplot(1, 3, 3)\nplt.title('CLAHE \uc774\ubbf8\uc9c0')\nplt.imshow(clahe_image, cmap='gray')\nplt.axis('off')\n\nplt.show()\n<\/code><\/pre>\n<\/section>\n