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Click here to download the full example code This example opens an RGB JPEG image and writes out each channel as a separate FITS (image) file. This example uses
pillow to read the image, By: Erik Bray, Adrian Price-Whelan License: BSD import numpy as np from PIL import Image from astropy.io import fits Set up matplotlib and use a nicer set of plot parameters Load and display the original 3-color jpeg image: image = Image.open('Hs-2009-14-a-web.jpg') xsize, ysize = image.size print(f"Image size: {ysize} x {xsize}") print(f"Image bands: {image.getbands()}") ax = plt.imshow(image) Out: Image size: 232 x 400 Image bands: ('R', 'G', 'B') Split the three channels (RGB) and get the data as Numpy arrays. The arrays are flattened, so they are 1-dimensional: Out: Reshape the image arrays to be 2-dimensional: Out: Write out the channels as separate FITS images. Add and visualize header info Out: SIMPLE = T / conforms to FITS standard BITPIX = 64 / array data type NAXIS = 2 / number of array dimensions NAXIS1 = 400 NAXIS2 = 232 EXTEND = T LATOBS = '32:11:56' LONGOBS = '110:56 ' Delete the files created Total running time of the script: ( 0 minutes 0.204 seconds) Gallery generated by Sphinx-Gallery Main Content rgb2grayConvert RGB image or colormap to grayscale SyntaxDescriptionexample
Examplescollapse all Convert RGB Image to Grayscale ImageRead and display an RGB image, and then convert it to grayscale. Read the sample file, RGB = imread('peppers.png');
imshow(RGB) Convert the RGB image to a grayscale image and display it. I = rgb2gray(RGB); figure imshow(I) Convert RGB Colormap to Grayscale ColormapRead an indexed image with an RGB colormap. Then, convert the colormap to grayscale. Read the sample file, [X,map] = imread('corn.tif'); Display the image. Convert the RGB colormap to a grayscale colormap and redisplay the image. newmap = rgb2gray(map); imshow(X,newmap) Input Argumentscollapse all RGB — Truecolor image m-by-n-by-3 numeric arrayTruecolor image, specified as an m-by-n-by-3 numeric array. If you have Parallel Computing Toolbox installed, Data Types: map — Colormap c-by-3 numeric matrixColormap, specified as a c-by-3 numeric matrix with values in the range [0, 1]. Each row of If you have Parallel Computing Toolbox installed, Data Types: Output Argumentscollapse all I — Grayscale image m-by-n numeric arrayGrayscale image, returned as an m-by-n numeric array. If you have Parallel Computing Toolbox installed, then newmap — Grayscale colormap c-by-3 numeric matrixGrayscale colormap, returned as an c-by-3 numeric matrix with values in the range [0, 1]. The three columns of If you have Parallel Computing Toolbox installed, then Data Types: Tips
Algorithms
0.2989 * R + 0.5870 * G + 0.1140 * B These are the same weights used by the The coefficients used to calculate
grayscale values in Rec.ITU-R BT.601-7 calculates E'y using the following formula: 0.299 * R + 0.587 * G + 0.114 * B Extended CapabilitiesC/C++ Code Generation Generate C and C++ code using MATLAB® Coder™.When generating code, if you choose the generic GPU Code Generation Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.Thread-Based Environment Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment. GPU Arrays Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox). Distributed Arrays Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox). How do you convert an image to RGB in Python?“how to convert grayscale image to rgb in python” Code Answer's. import cv2.. image = cv2. imread('C:/Users/N/Desktop/Test.jpg'). gray = cv2. cvtColor(image, cv2. COLOR_BGR2GRAY). cv2. imshow('Original image',image). cv2. imshow('Gray image', gray). How do I convert JPG to RGB?How to convert JPG to RGB. Upload jpg-file(s) Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.. Choose "to rgb" Choose rgb or any other format you need as a result (more than 200 formats supported). Download your rgb.. How do I get RGB in Python?How to find the RGB value of a pixel in Python. red_image = PIL. Image. open("red_image.png") Create a PIL.Image object.. red_image_rgb = red_image. convert("RGB") Convert to RGB colorspace.. rgb_pixel_value = red_image_rgb. getpixel((10,15)) Get color from (x, y) coordinates.. Is OpenCV BGR or RGB?OpenCV follows BGR order, while matplotlib likely follows RGB order. Therefore, when we display an image loaded in OpenCV using matplotlib functions, we may want to convert it into RGB mode. If we did not switch brg order, we get rgb inverted picture.
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