You can read the original ITU-R Recommendation 709 6th edition. You need to convert your image to a numpy array this way: import numpy import PIL img ('foo.jpg').convert ('L') imgarr numpy.array (img) Share Improve this answer Follow answered at 9:18 Billal Begueradj 20.1k 43 110 129 This way of conversion retains the image but results in a loss of colors. To convert between other modes, you may have to use an intermediate image (typically an RGB image). L = R * 2125/10000 + G * 7154/10000 + B * 0721/10000 from PIL import Image with Image.open('hopper.ppm') as im: im im.convert('L') The library supports transformations between each supported mode and the L and RGB modes. You can read the original ITU-R Recommendation 601 7th edition. f r'c:/Users/t/Desktop/IMG5510.jpg' img Image.open(f) Now, img is your image. All you need is to assign an image path and then open it with Image using: Image.open(f) where f is the path. ITU-R 601 7th Edition Construction of Luminance formula: L = R * 299/1000 + G * 587/1000 + B * 114/1000īy iterating through each pixel you can convert 24-bit to 8-bit or 3 channel to 1 channel for each pixel by using the formula above. from PIL import Image At this point you are ready to open an image file. One of the standards that can be used is Recommendation 601 from ITU-R (Radiocommunication Sector of International Telecommunication Union or ITU) organization which is also used by pillow library while converting color images to grayscale. The numpy. So, how do we achieve one value from those three pixel values? We need some kind of averaging. If we want to convert an image read by the PIL library to a NumPy array, we can use the numpy.array () function. Parameters: obj Object with array interface mode Optional mode to use when reading obj. This means that P and PA mode images will lose their palette. L mode on the other hand only uses one value between 0-255 for each pixel (8-bit). from PIL import Image import numpy as np im Image.open('hopper.jpg') a np.asarray(im) When converting Pillow images to arrays however, only pixel values are transferred. This marks the end of the Python Pillow Image Convert Tutorial. It adds some kind of blur effect onto the image, which adds a unique look to it, which kind of looks nice. In summary, color images usually use the RGB format which means every pixel is represented by a tuple of three value (red, green and blue) in Python. from PIL import Image img Image.open('C://Users/Shado/Desktop/kitten.jpg') newimg img.convert ('1') newimg.show () Here’s the output. There are different image hashes that can be used to transform color images to grayscale.
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