[opencv] applyColorMap

功能

转化为热力图，因为热力图我们看的变化更加细微，在很多地方都用到了热力图。

最近在看CAM，所以记一记这个函数。

感觉还是很有用的。

代码

>>> import cv2 as cv
>>> import numpy as np
>>> img = cv.imread("./res.jpg")
>>> color_zero = np.zeros(shape = img.shape).astype(np.uint8)
>>> color_zero[0:50,0:50,:] = 254
>>> color_img = color_zero
>>> color_gray = cv.cvtColor(color_img,cv.COLOR_BGR2GRAY)
>>> color_app = cv.applyColorMap(color_gray,2)
>>> out = cv.addWeighted(img,0.5,color_app,0.5,0)
>>> cv.imwrite("out.jpg",out)
True

一般需要img为灰度图，然后根据灰度图亮度的大小转化为热力图。

函数参数

Enumerator
COLORMAP_AUTUMN Python: cv.COLORMAP_AUTUMN	autumn
COLORMAP_BONE Python: cv.COLORMAP_BONE	bone
COLORMAP_JET Python: cv.COLORMAP_JET	jet
COLORMAP_WINTER Python: cv.COLORMAP_WINTER	winter
COLORMAP_RAINBOW Python: cv.COLORMAP_RAINBOW	rainbow
COLORMAP_OCEAN Python: cv.COLORMAP_OCEAN	ocean
COLORMAP_SUMMER Python: cv.COLORMAP_SUMMER	summer
COLORMAP_SPRING Python: cv.COLORMAP_SPRING	spring
COLORMAP_COOL Python: cv.COLORMAP_COOL	cool
COLORMAP_HSV Python: cv.COLORMAP_HSV	HSV
COLORMAP_PINK Python: cv.COLORMAP_PINK	pink
COLORMAP_HOT Python: cv.COLORMAP_HOT	hot
COLORMAP_PARULA Python: cv.COLORMAP_PARULA	parula
COLORMAP_MAGMA Python: cv.COLORMAP_MAGMA	magma
COLORMAP_INFERNO Python: cv.COLORMAP_INFERNO	inferno
COLORMAP_PLASMA Python: cv.COLORMAP_PLASMA	plasma
COLORMAP_VIRIDIS Python: cv.COLORMAP_VIRIDIS	viridis
COLORMAP_CIVIDIS Python: cv.COLORMAP_CIVIDIS	cividis
COLORMAP_TWILIGHT Python: cv.COLORMAP_TWILIGHT	twilight
COLORMAP_TWILIGHT_SHIFTED Python: cv.COLORMAP_TWILIGHT_SHIFTED	twilight shifted

官网API

Python:
	dst	=	cv.applyColorMap(	src, colormap[, dst]	)
	dst	=	cv.applyColorMap(	src, userColor[, dst]	)

Parameters

src	The source image, grayscale or colored of type CV_8UC1 or CV_8UC3.
dst	The result is the colormapped source image. Note: Mat::create is called on dst.
userColor	The colormap to apply of type CV_8UC1 or CV_8UC3 and size 256

Python:
	dst	=	cv.applyColorMap(	src, colormap[, dst]	)
	dst	=	cv.applyColorMap(	src, userColor[, dst]	)

Parameters

src	The source image, grayscale or colored of type CV_8UC1 or CV_8UC3.
dst	The result is the colormapped source image. Note: Mat::create is called on dst.
colormap	The colormap to apply, see ColormapTypes