{"id":6473,"date":"2019-03-23T09:24:05","date_gmt":"2019-03-23T00:24:05","guid":{"rendered":"http:\/\/www.gisdeveloper.co.kr\/?p=6473"},"modified":"2020-05-28T12:36:21","modified_gmt":"2020-05-28T03:36:21","slug":"python%ea%b3%bc-opencv-8-image-thresholding-1-2","status":"publish","type":"post","link":"http:\/\/www.gisdeveloper.co.kr\/?p=6473","title":{"rendered":"Python\uacfc OpenCV \u2013 9 : Image Thresholding (1\/2)"},"content":{"rendered":"<p>\uc774 \uae00\uc758 \uc6d0\ubb38\uc740 https:\/\/opencv-python-tutroals.readthedocs.io\/en\/latest\/py_tutorials\/py_imgproc\/py_thresholding\/py_thresholding.html \uc785\ub2c8\ub2e4.<\/p>\n<p>\uc774 \uae00\uc5d0\uc11c\ub294 Simple thresholding, Adaptive thresholding, Otsu\u2019s thresholding \uc911 \ucc98\uc74c 2\uac00\uc9c0\uc5d0 \ub300\ud574 \uc5b8\uae09\ud569\ub2c8\ub2e4. \uadf8\ub9ac\uace0 \uae00\uc744 \ub098\ub220 Otsu\u2019s thresholding\uc744 \uc124\uba85\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p>Image Thresholding \uc989, \uc774\ubbf8\uc9c0\uc758 \uc784\uacc4\uac12 \ucc98\ub9ac\ub780 \ud53d\uc140\uac12(\ub300\ubd80\ubd84\uc740 Grayscale \uac12)\uc774 \uc5b4\ub5a4 \uc870\uac74(\uc784\uacc4 \uc870\uac74)\uc744 \ub9cc\uc871\ud560\ub54c \ud574\ub2f9 \ud53d\uc140\uc758 \uac12\uc744 \uc5b4\ub5a4 \uac12\uc73c\ub85c \uce58\ud658\ud560 \uac83\uc778\uac00\ub97c \uacb0\uc815\ud558\ub294 \uac83\uc778\ub370, \uba3c\uc800 Simple thresholding\uc5d0 \ub300\ud55c \uc608\uc81c\ub97c \uc0b4\ud3b4\ubcf4\uba74..<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"python\">\r\nimport cv2\r\nimport numpy as np\r\nfrom matplotlib import pyplot as plt\r\n\r\nimg = cv2.imread('.\/data\/gray-gradient.jpg', cv2.IMREAD_GRAYSCALE)\r\n\r\nret,thresh1 = cv2.threshold(img, 180, 255, cv2.THRESH_BINARY)\r\nret,thresh2 = cv2.threshold(img, 180, 255, cv2.THRESH_BINARY_INV)\r\nret,thresh3 = cv2.threshold(img, 180, 255, cv2.THRESH_TRUNC)\r\nret,thresh4 = cv2.threshold(img, 180, 255, cv2.THRESH_TOZERO)\r\nret,thresh5 = cv2.threshold(img, 180, 255, cv2.THRESH_TOZERO_INV)\r\n\r\ntitles = ['Original Image', 'BINARY', 'BINARY_INV', 'TRUNC', 'TOZERO', 'TOZERO_INV']\r\nimages = [img, thresh1, thresh2, thresh3, thresh4, thresh5]\r\n\r\nfor i in range(6):\r\n    plt.subplot(2,3,i+1), plt.imshow(images[i], 'gray')\r\n    plt.title(titles[i])\r\n    plt.xticks([]), plt.yticks([])\r\n\r\nplt.show()\r\n<\/pre>\n<p>\uacb0\uacfc\ub97c \uba3c\uc800 \ubcf4\uace0 \ucf54\ub4dc\uc5d0\uc11c \uc911\uc694\ud55c \ubd80\ubd84\uc744 \uc5b8\uae09\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.gisdeveloper.co.kr\/wp-content\/uploads\/2019\/03\/opencv-simple-threshold.png\" alt=\"\" width=\"1444\" height=\"1228\" class=\"aligncenter size-full wp-image-6474\" \/><\/p>\n<p>Original Image\uac00 \uc785\ub825 \uc774\ubbf8\uc9c0\uc778 \uc6d0\ubcf8\uc778\ub370, 5\uac1c\uc5d0 \ub300\ud55c Simple thresholding\uc5d0 \ub300\ud55c \uacb0\uacfc\uac00 \ud45c\uc2dc\ub418\uace0 \uc788\uc2b5\ub2c8\ub2e4. Simple thresholding \ucc98\ub9ac\uc5d0 \ub300\ud55c \ud568\uc218\ub294 cv.threshold \uc778\ub370, \uccab\ubc88\uc9f8 \uc778\uc790\ub294 \uc785\ub825 \uc774\ubbf8\uc9c0, \ub450\ubc88\uc9f8\ub294 \uc870\uac74\uac12\uc5d0 \ub300\ud55c \ud53d\uc140\uac12\uc758 \ucd5c\uc18c\uac12, \uc138\ubc88\uc9f8\ub294 \uc870\uac74\uac12\uc5d0 \ub300\ud55c \ud53d\uc140\uac12\uc758 \ucd5c\ub300\uac12, \ub124\ubc88\uc9f8\ub294 thresholding \uc870\uac74\uc5d0 \ub300\ud55c \uacb0\uacfc\uac12 \ucc98\ub9ac \ubc29\uc2dd\uc778\ub370 \uc0b4\ud3b4\ubcf4\uba74..<\/p>\n<ul>\n<li>cv2.THRESH_BINARY &#8211; \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud53d\uc140\uac12\uc744 255\ub85c \ub9cc\uc871\ud558\uc9c0 \uc54a\ub294 \ud53d\uc140\uac12\uc744 0\uc73c\ub85c \uc124\uc815<\/li>\n<li>cv2.THRESH_BINARY_INV &#8211; \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud53d\uc140\uac12\uc744 0\ub85c \ub9cc\uc871\ud558\uc9c0 \uc54a\ub294 \ud53d\uc140\uac12\uc744 255\uc73c\ub85c \uc124\uc815<\/li>\n<li>cv2.THRESH_TRUNC &#8211; \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud53d\uc140\uac12\uc744 255\ub85c \ub9cc\uc871\ud558\uc9c0 \uc54a\ub294 \ud53d\uc140\uac12\uc744 \uc6d0\ubcf8\uac12\uc73c\ub85c \uc124\uc815<\/li>\n<li>cv2.THRESH_TOZERO &#8211; \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud53d\uc140\uac12\uc744 \uc6d0\ubcf8\uac12\uc73c\ub85c \ub9cc\uc871\ud558\uc9c0 \uc54a\ub294 \ud53d\uc140\uac12\uc744 0\uc73c\ub85c \uc124\uc815<br \/>\ncv2.THRESH_TOZERO_INV &#8211; \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud53d\uc140\uac12\uc744 0\ub85c \ub9cc\uc871\ud558\uc9c0 \uc54a\ub294 \ud53d\uc140\uac12\uc744 \uc6d0\ubcf8\uac12\uc73c\ub85c \uc124\uc815<\/li>\n<\/ul>\n<p>\uc774\uc81c \ub2e4\uc74c\uc740 Adaptive thresholding\uc778\ub370\uc694. Simple thresholding\uc758 \ubb38\uc81c\uc810\uc740 \uc774\ubbf8\uc9c0\uac00 \uc804\uccb4\uc801\uc73c\ub85c \ub3d9\uc77c\ud55c \ubc1d\uae30\ub97c \uac00\uc838\uc57c \ud55c\ub2e4\ub294 \uac83\uc778\ub370.. \uc608\ub97c \ub4e4\uc5b4\uc11c \ud558\ub098\uc758 \uc774\ubbf8\uc9c0\uc5d0 \uc5b4\ub290 \ubd80\ubd84\uc740 \uadf8\ub9bc\uc790\uac00 \ub4e4\uc5b4\uac00 \uc788\uc744 \uacbd\uc6b0 \uc774 \uadf8\ub9bc\uc790 \ubd80\ubd84\uc5d0 \ub300\ud55c \ucc98\ub9ac\uac00 \uc81c\ub300\ub85c \ub418\uc9c0 \uc54a\uc2b5\ub2c8\ub2e4. \uc774\ub97c \uac1c\uc120\ud558\uae30 \uc704\ud55c \ubc29\uc2dd\uc774 Adaptive thresholding\uc774\uba70 \uc608\uc81c \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"python\">\r\nimport cv2\r\nimport numpy as np\r\nfrom matplotlib import pyplot as plt\r\n\r\nimg = cv2.imread('.\/data\/srcThreshold.png', 0)\r\nimg = cv2.medianBlur(img, 5) # \uc7a1\uc74c\uc81c\uac70\r\n\r\nret,th1 = cv2.threshold(img, 127, 255, cv2.THRESH_BINARY)\r\n\r\nth2 = cv2.adaptiveThreshold(img, 255, cv2.ADAPTIVE_THRESH_MEAN_C, cv2.THRESH_BINARY, 11, 2)\r\n\r\nth3 = cv2.adaptiveThreshold(img, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 11, 2)\r\n\r\ntitles = ['Original Image', 'Simple Thresholding (v = 127)', 'Adaptive Mean Thresholding', 'Adaptive Gaussian Thresholding']\r\nimages = [img, th1, th2, th3]\r\n\r\nfor i in range(4):\r\n    plt.subplot(2, 2, i+1), plt.imshow(images[i], 'gray')\r\n    plt.title(titles[i])\r\n    plt.xticks([]), plt.yticks([])\r\nplt.show()\r\n<\/pre>\n<p>\uacb0\uacfc\ub97c \ubcf4\uba74..<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/www.gisdeveloper.co.kr\/wp-content\/uploads\/2019\/03\/opencv-adaptive-threshold.png\" alt=\"\" width=\"1444\" height=\"1228\" class=\"aligncenter size-full wp-image-6478\" \/><\/p>\n<p>\ucd1d 4\uac1c\uc758 \uc601\uc0c1\uc774 \ud45c\uc2dc\ub418\ub294\ub370 Original Image\ub294 \uc785\ub825 \uc6d0\ubcf8 \uc601\uc0c1, Simple Threshold\ub294 \uc55e\uc11c \uc0b4\ud3b4\ubcf8 cv2.threshold\uc5d0 \uc758\ud55c \ucc98\ub9ac \uc601\uc0c1\uc785\ub2c8\ub2e4. \uc6d0\ubcf8 \uc774\ubbf8\uc9c0\uc5d0\uc11c \ub2e4\ub978 \ubd80\ubd84\ubcf4\ub2e4 \uc0c1\ub300\uc801\uc73c\ub85c \uc5b4\ub450\uc6b4 \ubd80\ubd84\uc5d0 \ub300\ud574\ub3c4 \uc6d0\ud558\ub294 \ucc98\ub9ac\uac00 \ub41c\uac83\uc744 \ube44\uad50\ud574 \ubcfc \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub098\uba38\uc9c0 2\uac1c\uac00 Adaptive thresholding\uc778\ub370 \uccab\ubc88\uc9f8\ub294 \ub2e8\uc21c \ud3c9\uade0\uac12, \ub450\ubc88\uc9f8\ub294 \uac00\uc911\uce58\uc5d0 \uc758\ud574 \ucc98\ub9ac\ub41c \uac12\uc774 \ud569\uc785\ub2c8\ub2e4. \uc774\ub294 cv.adaptiveThreshold \ud568\uc218\uc758 \uc138\ubc88\uc9f8 \uc778\uc790\uc5d0 \uc758\ud574 \uc9c0\uc815\ub418\uba70 \uc544\ub798\uc640 \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n<ul>\n<li>cv2.ADAPTIVE_THRESH_MEAN_C &#8211; \ub300\uc0c1 \ud53d\uc140\uac12 \uc8fc\uc704\uc758 \ud53d\uc140\uac12\ub4e4\uc758 \ud3c9\uade0\uac12\uc5d0 C \uac12\uc744 \ub354\ud568<\/li>\n<li>cv2.ADAPTIVE_THRESH_GAUSSIAN_C &#8211; Gaussian Window\uc5d0 \uc758\ud574 \uac00\uc911\uce58 \uac12\uc774 \uc801\uc6a9\ub41c \ud53d\uc140\uac12\ub4e4\uc758 \ud569\uc5d0 C \uac12\uc744 \ub354\ud568<\/li>\n<\/ul>\n<p>cv.adaptiveThreshold\uc758 \uc804\uccb4 \uc778\uc790\ub97c \uc0b4\ud3b4\ubcf4\uba74 \uccab\ubc88\uc9f8\ub294 \uc785\ub825 \uc774\ubbf8\uc9c0, \ub450\ubc88\uc9f8\ub294 \ud53d\uc140\uac12\uc758 \ucd5c\ub300\uac12, \uc138\ubc88\uc9f8\uc640 \ub124\ubc88\uc9f8\ub294 \uc55e\uc11c \uc124\uba85\ud55c \ubc14\uac00 \uac19\uc73c\uba70, \ub2e4\uc12f\ubc88\uc9f8\ub294 \uc8fc\uc758\uac12\uc758 \ud53d\uc140\uc744 \uc5bb\uc744 Window\uc758 \ud06c\uae30, \uc5ec\uc12f\ubc88\uc9f8\ub294 C \uac12\uc785\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\uc774 \uae00\uc758 \uc6d0\ubb38\uc740 https:\/\/opencv-python-tutroals.readthedocs.io\/en\/latest\/py_tutorials\/py_imgproc\/py_thresholding\/py_thresholding.html \uc785\ub2c8\ub2e4. \uc774 \uae00\uc5d0\uc11c\ub294 Simple thresholding, Adaptive thresholding, Otsu\u2019s thresholding \uc911 \ucc98\uc74c 2\uac00\uc9c0\uc5d0 \ub300\ud574 \uc5b8\uae09\ud569\ub2c8\ub2e4. \uadf8\ub9ac\uace0 \uae00\uc744 \ub098\ub220 Otsu\u2019s thresholding\uc744 \uc124\uba85\ud558\uaca0\uc2b5\ub2c8\ub2e4. Image Thresholding \uc989, \uc774\ubbf8\uc9c0\uc758 \uc784\uacc4\uac12 \ucc98\ub9ac\ub780 \ud53d\uc140\uac12(\ub300\ubd80\ubd84\uc740 Grayscale \uac12)\uc774 \uc5b4\ub5a4 \uc870\uac74(\uc784\uacc4 \uc870\uac74)\uc744 \ub9cc\uc871\ud560\ub54c \ud574\ub2f9 \ud53d\uc140\uc758 \uac12\uc744 \uc5b4\ub5a4 \uac12\uc73c\ub85c \uce58\ud658\ud560 \uac83\uc778\uac00\ub97c \uacb0\uc815\ud558\ub294 \uac83\uc778\ub370, \uba3c\uc800 Simple thresholding\uc5d0 \ub300\ud55c \uc608\uc81c\ub97c \uc0b4\ud3b4\ubcf4\uba74.. import cv2 import &hellip; <\/p>\n<p class=\"link-more\"><a href=\"http:\/\/www.gisdeveloper.co.kr\/?p=6473\" class=\"more-link\">\ub354 \ubcf4\uae30<span class=\"screen-reader-text\"> &#8220;Python\uacfc OpenCV \u2013 9 : Image Thresholding (1\/2)&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[130,131],"tags":[],"class_list":["post-6473","post","type-post","status-publish","format-standard","hentry","category-opencv","category-python"],"_links":{"self":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/6473","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6473"}],"version-history":[{"count":6,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/6473\/revisions"}],"predecessor-version":[{"id":9484,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/6473\/revisions\/9484"}],"wp:attachment":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6473"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6473"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6473"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}