Calculate the cone angle of a spray image

IMCLEARBORDER Suppress light structures connected to image border. IM2 = IMCLEARBORDER(IM) suppresses structures that are lighter than their surroundings and that are connected to the image border. IM can be an intensity or binary image. The output image, IM2, is intensity or binary, respectively. The default connectivity is 8 for two dimensions, 26 for three dimensions, and CONNDEF(NDIMS(BW),'maximal') for higher dimensions. For intensity images, IMCLEARBORDER tends to reduce the overall intensity level in addition to suppressing border structures. IM2 = IMCLEARBORDER(IM,CONN) specifies the desired connectivity. CONN may have the following scalar values: 4 two-dimensional four-connected neighborhood 8 two-dimensional eight-connected neighborhood 6 three-dimensional six-connected neighborhood 18 three-dimensional 18-connected neighborhood 26 three-dimensional 26-connected neighborhood Connectivity may be defined in a more general way for any dimension by using for CONN a 3-by-3-by- ... -by-3 matrix of 0s and 1s. The 1-valued elements define neighborhood locations relative to the center element of CONN. CONN must be symmetric about its center element. Class Support ------------- IM can be a numeric or logical array of any dimension, and it must be nonsparse and real. IM2 has the same class as IM. Note ---- A pixel on the edge of the input image might not be considered to be a "border" pixel if a nondefault connectivity is specified. For example, if CONN = [0 0 0; 1 1 1; 0 0 0], elements on the first and last row are not considered to be border pixels because, according to that connectivity definition, they are not connected to the region outside of the image. References: ----------- P. Soille, Morphological Image Analysis: Principles and Applications, Springer, 1999, pp. 164-165. Example 1 --------- % This example shows how to clear the border of an intensity image: I = imread('rice.png'); I2 = imclearborder(I); montage({I,I2}) Example 2 --------- % This example shows how to clear the border of a binary image: BW = imbinarize(imread('rice.png')); BW2 = imclearborder(BW); montage({I,I2}) Example 3 --------- % This example shows how to retain some borders while clearing: I = imread('rice.png'); % Specify border, in order from: top, right, bottom, left. bordersToKeep = [0 1 0 1]; % keep right and left % Top and left Ipad = padarray(I, [bordersToKeep(1), bordersToKeep(4)], 'pre'); % Bottom and right Ipad = padarray(Ipad, [bordersToKeep(3), bordersToKeep(2)], 'post'); I2 = imclearborder(Ipad); % Unpad topLeft = [bordersToKeep(1) bordersToKeep(4)]+1; botRight = topLeft + [size(I,1), size(I,2)] - 1; I2 = I2(topLeft(1):botRight(1), topLeft(2):botRight(2)); montage({I,I2}) See also IMRECONSTRUCT. Documentation for imclearborder doc imclearborder