OpenCV这么简单为啥不学——1.9、cvtColor颜色空间转换(全色值效果演示)
前言
计算机视觉市场巨大而且持续增长，且这方面没有标准API，如今的计算机视觉软件大概有以下三种：
1、研究代码（慢，不稳定，独立并与其他库不兼容）
2、耗费很高的商业化工具（比如Halcon, MATLAB+Simulink）
3、依赖硬件的一些特别的解决方案（比如视频监控，制造控制系统，医疗设备）这是如今的现状，而标准的API将简化计算机视觉程序和解决方案的开发，OpenCV致力于成为这样的标准API。
OpenCV致力于真实世界的实时应用，通过优化的C代码的编写对其执行速度带来了可观的提升，并且可以通过购买Intel的IPP高性能多媒体函数库（Integrated Performance Primitives）得到更快的处理速度。
故而我们选择学习OpenCV，我们来一步步的学习OpenCV。
cvtColor函数
语法：
cv2.cvtColor(src, code[, dst[, dstCn]]) → dst
参数：
src：img图片
code：色值代码(r,g,b)
dst：返回img
code色值表
cv::COLOR_BGR2BGRA = 0,
cv::COLOR_RGB2RGBA = COLOR_BGR2BGRA,
cv::COLOR_BGRA2BGR = 1,
cv::COLOR_RGBA2RGB = COLOR_BGRA2BGR,
cv::COLOR_BGR2RGBA = 2,
cv::COLOR_RGB2BGRA = COLOR_BGR2RGBA,
cv::COLOR_RGBA2BGR = 3,
cv::COLOR_BGRA2RGB = COLOR_RGBA2BGR,
cv::COLOR_BGR2RGB = 4,
cv::COLOR_RGB2BGR = COLOR_BGR2RGB,
cv::COLOR_BGRA2RGBA = 5,
cv::COLOR_RGBA2BGRA = COLOR_BGRA2RGBA,
cv::COLOR_BGR2GRAY = 6,
cv::COLOR_RGB2GRAY = 7,
cv::COLOR_GRAY2BGR = 8,
cv::COLOR_GRAY2RGB = COLOR_GRAY2BGR,
cv::COLOR_GRAY2BGRA = 9,
cv::COLOR_GRAY2RGBA = COLOR_GRAY2BGRA,
cv::COLOR_BGRA2GRAY = 10,
cv::COLOR_RGBA2GRAY = 11,
cv::COLOR_BGR2BGR565 = 12,
cv::COLOR_RGB2BGR565 = 13,
cv::COLOR_BGR5652BGR = 14,
cv::COLOR_BGR5652RGB = 15,
cv::COLOR_BGRA2BGR565 = 16,
cv::COLOR_RGBA2BGR565 = 17,
cv::COLOR_BGR5652BGRA = 18,
cv::COLOR_BGR5652RGBA = 19,
cv::COLOR_GRAY2BGR565 = 20,
cv::COLOR_BGR5652GRAY = 21,
cv::COLOR_BGR2BGR555 = 22,
cv::COLOR_RGB2BGR555 = 23,
cv::COLOR_BGR5552BGR = 24,
cv::COLOR_BGR5552RGB = 25,
cv::COLOR_BGRA2BGR555 = 26,
cv::COLOR_RGBA2BGR555 = 27,
cv::COLOR_BGR5552BGRA = 28,
cv::COLOR_BGR5552RGBA = 29,
cv::COLOR_GRAY2BGR555 = 30,
cv::COLOR_BGR5552GRAY = 31,
cv::COLOR_BGR2XYZ = 32,
cv::COLOR_RGB2XYZ = 33,
cv::COLOR_XYZ2BGR = 34,
cv::COLOR_XYZ2RGB = 35,
cv::COLOR_BGR2YCrCb = 36,
cv::COLOR_RGB2YCrCb = 37,
cv::COLOR_YCrCb2BGR = 38,
cv::COLOR_YCrCb2RGB = 39,
cv::COLOR_BGR2HSV = 40,
cv::COLOR_RGB2HSV = 41,
cv::COLOR_BGR2Lab = 44,
cv::COLOR_RGB2Lab = 45,
cv::COLOR_BGR2Luv = 50,
cv::COLOR_RGB2Luv = 51,
cv::COLOR_BGR2HLS = 52,
cv::COLOR_RGB2HLS = 53,
cv::COLOR_HSV2BGR = 54,
cv::COLOR_HSV2RGB = 55,
cv::COLOR_Lab2BGR = 56,
cv::COLOR_Lab2RGB = 57,
cv::COLOR_Luv2BGR = 58,
cv::COLOR_Luv2RGB = 59,
cv::COLOR_HLS2BGR = 60,
cv::COLOR_HLS2RGB = 61,
cv::COLOR_BGR2HSV_FULL = 66,
cv::COLOR_RGB2HSV_FULL = 67,
cv::COLOR_BGR2HLS_FULL = 68,
cv::COLOR_RGB2HLS_FULL = 69,
cv::COLOR_HSV2BGR_FULL = 70,
cv::COLOR_HSV2RGB_FULL = 71,
cv::COLOR_HLS2BGR_FULL = 72,
cv::COLOR_HLS2RGB_FULL = 73,
cv::COLOR_LBGR2Lab = 74,
cv::COLOR_LRGB2Lab = 75,
cv::COLOR_LBGR2Luv = 76,
cv::COLOR_LRGB2Luv = 77,
cv::COLOR_Lab2LBGR = 78,
cv::COLOR_Lab2LRGB = 79,
cv::COLOR_Luv2LBGR = 80,
cv::COLOR_Luv2LRGB = 81,
cv::COLOR_BGR2YUV = 82,
cv::COLOR_RGB2YUV = 83,
cv::COLOR_YUV2BGR = 84,
cv::COLOR_YUV2RGB = 85,
cv::COLOR_YUV2RGB_NV12 = 90,
cv::COLOR_YUV2BGR_NV12 = 91,
cv::COLOR_YUV2RGB_NV21 = 92,
cv::COLOR_YUV2BGR_NV21 = 93,
cv::COLOR_YUV420sp2RGB = COLOR_YUV2RGB_NV21,
cv::COLOR_YUV420sp2BGR = COLOR_YUV2BGR_NV21,
cv::COLOR_YUV2RGBA_NV12 = 94,
cv::COLOR_YUV2BGRA_NV12 = 95,
cv::COLOR_YUV2RGBA_NV21 = 96,
cv::COLOR_YUV2BGRA_NV21 = 97,
cv::COLOR_YUV420sp2RGBA = COLOR_YUV2RGBA_NV21,
cv::COLOR_YUV420sp2BGRA = COLOR_YUV2BGRA_NV21,
cv::COLOR_YUV2RGB_YV12 = 98,
cv::COLOR_YUV2BGR_YV12 = 99,
cv::COLOR_YUV2RGB_IYUV = 100,
cv::COLOR_YUV2BGR_IYUV = 101,
cv::COLOR_YUV2RGB_I420 = COLOR_YUV2RGB_IYUV,
cv::COLOR_YUV2BGR_I420 = COLOR_YUV2BGR_IYUV,
cv::COLOR_YUV420p2RGB = COLOR_YUV2RGB_YV12,
cv::COLOR_YUV420p2BGR = COLOR_YUV2BGR_YV12,
cv::COLOR_YUV2RGBA_YV12 = 102,
cv::COLOR_YUV2BGRA_YV12 = 103,
cv::COLOR_YUV2RGBA_IYUV = 104,
cv::COLOR_YUV2BGRA_IYUV = 105,
cv::COLOR_YUV2RGBA_I420 = COLOR_YUV2RGBA_IYUV,
cv::COLOR_YUV2BGRA_I420 = COLOR_YUV2BGRA_IYUV,
cv::COLOR_YUV420p2RGBA = COLOR_YUV2RGBA_YV12,
cv::COLOR_YUV420p2BGRA = COLOR_YUV2BGRA_YV12,
cv::COLOR_YUV2GRAY_420 = 106,
cv::COLOR_YUV2GRAY_NV21 = COLOR_YUV2GRAY_420,
cv::COLOR_YUV2GRAY_NV12 = COLOR_YUV2GRAY_420,
cv::COLOR_YUV2GRAY_YV12 = COLOR_YUV2GRAY_420,
cv::COLOR_YUV2GRAY_IYUV = COLOR_YUV2GRAY_420,
cv::COLOR_YUV2GRAY_I420 = COLOR_YUV2GRAY_420,
cv::COLOR_YUV420sp2GRAY = COLOR_YUV2GRAY_420,
cv::COLOR_YUV420p2GRAY = COLOR_YUV2GRAY_420,
cv::COLOR_YUV2RGB_UYVY = 107,
cv::COLOR_YUV2BGR_UYVY = 108,
cv::COLOR_YUV2RGB_Y422 = COLOR_YUV2RGB_UYVY,
cv::COLOR_YUV2BGR_Y422 = COLOR_YUV2BGR_UYVY,
cv::COLOR_YUV2RGB_UYNV = COLOR_YUV2RGB_UYVY,
cv::COLOR_YUV2BGR_UYNV = COLOR_YUV2BGR_UYVY,
cv::COLOR_YUV2RGBA_UYVY = 111,
cv::COLOR_YUV2BGRA_UYVY = 112,
cv::COLOR_YUV2RGBA_Y422 = COLOR_YUV2RGBA_UYVY,
cv::COLOR_YUV2BGRA_Y422 = COLOR_YUV2BGRA_UYVY,
cv::COLOR_YUV2RGBA_UYNV = COLOR_YUV2RGBA_UYVY,
cv::COLOR_YUV2BGRA_UYNV = COLOR_YUV2BGRA_UYVY,
cv::COLOR_YUV2RGB_YUY2 = 115,
cv::COLOR_YUV2BGR_YUY2 = 116,
cv::COLOR_YUV2RGB_YVYU = 117,
cv::COLOR_YUV2BGR_YVYU = 118,
cv::COLOR_YUV2RGB_YUYV = COLOR_YUV2RGB_YUY2,
cv::COLOR_YUV2BGR_YUYV = COLOR_YUV2BGR_YUY2,
cv::COLOR_YUV2RGB_YUNV = COLOR_YUV2RGB_YUY2,
cv::COLOR_YUV2BGR_YUNV = COLOR_YUV2BGR_YUY2,
cv::COLOR_YUV2RGBA_YUY2 = 119,
cv::COLOR_YUV2BGRA_YUY2 = 120,
cv::COLOR_YUV2RGBA_YVYU = 121,
cv::COLOR_YUV2BGRA_YVYU = 122,
cv::COLOR_YUV2RGBA_YUYV = COLOR_YUV2RGBA_YUY2,
cv::COLOR_YUV2BGRA_YUYV = COLOR_YUV2BGRA_YUY2,
cv::COLOR_YUV2RGBA_YUNV = COLOR_YUV2RGBA_YUY2,
cv::COLOR_YUV2BGRA_YUNV = COLOR_YUV2BGRA_YUY2,
cv::COLOR_YUV2GRAY_UYVY = 123,
cv::COLOR_YUV2GRAY_YUY2 = 124,
cv::COLOR_YUV2GRAY_Y422 = COLOR_YUV2GRAY_UYVY,
cv::COLOR_YUV2GRAY_UYNV = COLOR_YUV2GRAY_UYVY,
cv::COLOR_YUV2GRAY_YVYU = COLOR_YUV2GRAY_YUY2,
cv::COLOR_YUV2GRAY_YUYV = COLOR_YUV2GRAY_YUY2,
cv::COLOR_YUV2GRAY_YUNV = COLOR_YUV2GRAY_YUY2,
cv::COLOR_RGBA2mRGBA = 125,
cv::COLOR_mRGBA2RGBA = 126,
cv::COLOR_RGB2YUV_I420 = 127,
cv::COLOR_BGR2YUV_I420 = 128,
cv::COLOR_RGB2YUV_IYUV = COLOR_RGB2YUV_I420,
cv::COLOR_BGR2YUV_IYUV = COLOR_BGR2YUV_I420,
cv::COLOR_RGBA2YUV_I420 = 129,
cv::COLOR_BGRA2YUV_I420 = 130,
cv::COLOR_RGBA2YUV_IYUV = COLOR_RGBA2YUV_I420,
cv::COLOR_BGRA2YUV_IYUV = COLOR_BGRA2YUV_I420,
cv::COLOR_RGB2YUV_YV12 = 131,
cv::COLOR_BGR2YUV_YV12 = 132,
cv::COLOR_RGBA2YUV_YV12 = 133,
cv::COLOR_BGRA2YUV_YV12 = 134,
cv::COLOR_BayerBG2BGR = 46,
cv::COLOR_BayerGB2BGR = 47,
cv::COLOR_BayerRG2BGR = 48,
cv::COLOR_BayerGR2BGR = 49,
cv::COLOR_BayerBG2RGB = COLOR_BayerRG2BGR,
cv::COLOR_BayerGB2RGB = COLOR_BayerGR2BGR,
cv::COLOR_BayerRG2RGB = COLOR_BayerBG2BGR,
cv::COLOR_BayerGR2RGB = COLOR_BayerGB2BGR,
cv::COLOR_BayerBG2GRAY = 86,
cv::COLOR_BayerGB2GRAY = 87,
cv::COLOR_BayerRG2GRAY = 88,
cv::COLOR_BayerGR2GRAY = 89,
cv::COLOR_BayerBG2BGR_VNG = 62,
cv::COLOR_BayerGB2BGR_VNG = 63,
cv::COLOR_BayerRG2BGR_VNG = 64,
cv::COLOR_BayerGR2BGR_VNG = 65,
cv::COLOR_BayerBG2RGB_VNG = COLOR_BayerRG2BGR_VNG,
cv::COLOR_BayerGB2RGB_VNG = COLOR_BayerGR2BGR_VNG,
cv::COLOR_BayerRG2RGB_VNG = COLOR_BayerBG2BGR_VNG,
cv::COLOR_BayerGR2RGB_VNG = COLOR_BayerGB2BGR_VNG,
cv::COLOR_BayerBG2BGR_EA = 135,
cv::COLOR_BayerGB2BGR_EA = 136,
cv::COLOR_BayerRG2BGR_EA = 137,
cv::COLOR_BayerGR2BGR_EA = 138,
cv::COLOR_BayerBG2RGB_EA = COLOR_BayerRG2BGR_EA,
cv::COLOR_BayerGB2RGB_EA = COLOR_BayerGR2BGR_EA,
cv::COLOR_BayerRG2RGB_EA = COLOR_BayerBG2BGR_EA,
cv::COLOR_BayerGR2RGB_EA = COLOR_BayerGB2BGR_EA,
cv::COLOR_BayerBG2BGRA = 139,
cv::COLOR_BayerGB2BGRA = 140,
cv::COLOR_BayerRG2BGRA = 141,
cv::COLOR_BayerGR2BGRA = 142,
cv::COLOR_BayerBG2RGBA = COLOR_BayerRG2BGRA,
cv::COLOR_BayerGB2RGBA = COLOR_BayerGR2BGRA,
cv::COLOR_BayerRG2RGBA = COLOR_BayerBG2BGRA,
cv::COLOR_BayerGR2RGBA = COLOR_BayerGB2BGRA,
cv::COLOR_COLORCVT_MAX = 143
测试代码
import os import cv2 import shutil img = '800_600.jpg' save_dir = 'Demo_img/' try: # 递归删除文件夹 shutil.rmtree(save_dir) os.makedirs(save_dir) except OSError: pass img = cv2.imread(img) valid_index = [] for color_type in range(0, 256, 1): try: img_new = cv2.cvtColor(img, color_type) cv2.imwrite(os.path.join(save_dir, str(color_type) + '.jpg'), img_new) valid_index.append(color_type) except Exception: pass print("有效输出：") for item in valid_index: print(item, end=".jpg,")
实际生成：
效果展示
总结
我们替换了色值以及看到了对应的效果，cvtColor转换之后可以看去与原图的情境相同但是意境不同，不同颜色给别人的感觉也不同，具体那个合适就需要自己定夺了。
