Note that the matrix has data type double with values outside of the range [0,1], including negative values.
Values in A that are greater than or equal to amax are mapped to the value 1 in I.
Values in input image A that are less than or equal to amin are mapped to the value 0 in the intensity image, I.
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I = mat2gray(A,[amin amax]) converts the matrix A to an intensity image I that contains values in the range 0 (black) to 1 (white). amin and amax are the values in A that correspond to 0 and 1 in I. Values less than amin become 0, and values greater than amax become 1.
BW = im2bw(I,level) converts the grayscale image I to binary image BW, by replacing all pixels in the input image with luminance greater than level with the value 1 (white) and replacing all other pixels with the value 0 (black).
gpuarrayI = mat2gray(gpuarrayA,___) performs the operation on a GPU. This syntax requires the Parallel Computing Toolbox™.
[counts, grayLevels] = imhist(grayImage, 256); if sum(counts(2:end-1)) > 0 % It’s not pure black and white end % Get map of non-0 and non-255 pixels grayPixels = grayImage > 0 & grayImage
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It’s my first time to know that Matlab can convert to black and white, I don’t know b w photos can be made outside of photo software, thanks for shares.
I = mat2gray(A) sets the values of amin and amax to the minimum and maximum values in A.
Output intensity image when run on a GPU, returned as a gpuArray.
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If the input image is not a grayscale image, im2bw converts the input image to grayscale using ind2gray or rgb2gray, and then converts this grayscale image to binary by thresholding.
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This range is relative to the signal levels possible for the image’s class. Therefore, a level value of 0.5 corresponds to an intensity value halfway between the minimum and maximum value of the class.
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1.If image is pure black and white matlab should tell me that image is pure black & white and if grayscale it should tell that its grayscale.
Display the result of the operation. Because the data range of the matrix is outside the default display range of imshow, every pixel with a positive value displays as white, and every pixel with a negative or zero value displays as black. It is challenging to see the edges of the grains of rice.
[amin amax] — Input black and white values 2-element numeric vector
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
BW = im2bw(X,cmap,level) converts the indexed image X with colormap cmap to a binary image.
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Perform an operation that returns a numeric matrix. This operation looks for edges.
Color map associated with indexed image X, specified as a c-by-3 numeric matrix containing the RGB values of c colors.
Input black and white values, specified as a 2-element numeric vector.
Display the result of the conversion. Pixels show a range of grayscale colors, which makes the location of the edges more apparent.
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load trees BW = im2bw(X,map,0.4); imshow(X,map), figure, imshow(BW)
Luminance threshold, specified as a number in the range [0, 1]. To compute level, you can use the graythresh function.
level — Luminance threshold 0.5 (default) | number in the range [0, 1]
BW = im2bw(RGB,level) converts the truecolor image RGB to a binary image.
gpuarrayI — Output intensity image when run on a GPU gpuArray
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Convert the matrix into an image. Display the maximum and minimum values of the image.
Output intensity image, returned as a numeric matrix with values in the range [0, 1].
2.in my grayscale image if some pure black or white part come it should save it an array and other gray scale values should be saved in another array. i am attaching a black& white image for reference. Thanks
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Note that values are still data type double, but that all values are in the range [0, 1].