Like I said below, use bwboundaries. This MATLAB function traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW. I have the following picture here: I did the following to extract the contour and. – beaker. BW2 = bwpropfilt (BW,prop,range) extracts all connected components (objects) from a binary image BW whose value of property prop is in the specified range. i want to remove it from original image also not from the displayed figure only . Hi there, I am new in image processing using MATLAB. Hello, I'm having weird trouble with the function bwboundaries. Viewed 176 times 2 In the script below I outline an object but in the final plot. For this example, select a column coordinate. Compare the circularity measurement to the threshold. visboundaries uses bwboundaries to find the boundary pixel locations in the image. B = bwboundaries(BW) traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW. A convex polygon is a polygon that does not have concave vertices, for example: x = rand (20,1); y = rand (20,1); k = convhull (x,y); plot (x (k),y (k)) title ( 'Convex Polygon') You can also create a boundary of a point set that is nonconvex. As the L is of all the. This function is based on the boundaries function presented in the first edition of Digital Image Processing Using MATLAB, by Gonzalez, R. I would like to get the coordinates or show the individual line segments that form the boundary. bwboundary uses this point as the starting location for the boundary tracing. Just pick which label you want to see, say k, and L==k will be your binary image. BW2 = imfill (BW,'holes'); EDIT: Looking at the code, it seems that it does what you want already. Axes Properties - Matlab. This issue,. Is there some output from the function itself that will give me the area values of the shapes or is there another function that I can use with the boundary output from the "bwboundaries" function as the. Essentially this is shifting your points to be strictly greater than or equal to 1. Trace the boundaries of all coins in the image by using the bwboundaries function. regionprops supports both contiguous regions and discontiguous regions. 5 will tend to cross concave gaps. Only, now this is creating a bounding box for every object in my image. bwboundaries returns a cell array, where each cell contains the row and column coordinates for an object in the image. Furthermore, the output from bwboundaries supplies each boundary as closed (ie, the first XY boundary point is coincident with the last XY boundary point), so I think you can simply pass the results of bwboundary to a Douglas Peucker function, and then use that result directly. visboundaries(BW) draws boundaries of regions in the binary image BW on the current axes. MATLAB Language Fundamentals Matrices and Arrays Matrix Indexing. Ask Question Asked 12 years, 8 months ago. Typo Walter: bwboundaries(I==8) Sign in to comment. I2 = imfill (I) fills holes in the grayscale image I. Step 2: Convert the true-color RGB image to the grayscale image. bwboundariesの色分けについて. Function. 5 will tend to cross concave gaps. 0. You could just fill holes in the binarized labeled image, then relabel if you want. The following is my code to first create the single boundary line by searching for the bottom left pixel of the black area to begin the trace. bwboundaries also traces the exterior and hole boundaries of children objects completely enclosed by parent objects. Learn more about bwboundaries regionprops MATLAB I have a requirement to find the area and perimeter of 2 circular boundaries and also to display these boundaries over a copy of the original non-binary image. As we see there the bwboundaries declared in the list: bwboundaries : The conn and options arguments must be compile-time constants and the return value A can only be a full matrix, not a sparse matrix. The function imread reads the image from a given location and stores it in the. Unlike the convex hull, the boundary can shrink towards the interior of the hull to envelop the points. To trace the boundary of a single object in the binary image, first determine the row and column coordinates of a pixel on the border of the object. % bwboundaries() returns a cell array, where each cell contains the row/column coordinates for an object in the image. Adding the 'MaxFeretProperties' option to regionprops will add three features to the output struct. Learn more about matrix, indexing MATLAB. How can Matlab be able to take the positions from bwboundaries and correctly determine the endpoints for the edge on the. 此 MATLAB 函数 跟踪二值图像 BW 中对象的外边界以及这些对象内部孔洞的边界。bwboundaries 还跟踪父对象完全包围的子对象的外边界和孔洞边界。该函数返回由边界像素位置组成的元胞数组 B。Hello, I want to extract several variables (E1,2,3, S1,2,3 etc) from a set of nodes. m in Matlab, bwboundaries 支持 C 代码生成（需要 MATLAB ® Coder™ ）。请注意，如果您选择通用的 MATLAB Host Computer 目标平台，bwboundaries 生成的代码将使用平台特定的预编译共享库。使用共享库可保留性能上的优化，但适用范围仅限于生成的代码所适用的目标平台。 Hello, I want to extract several variables (E1,2,3, S1,2,3 etc) from a set of nodes. >> B=bwboundries(bw); bwboundaries returns B, a P-by-1 cell array, where P is the number of objects and holes. If you shrink and tighten the convex hull from above, you can enclose all of the points in a nonconvex. Use bwboundaries to get a list of the (x,y) boundary coordinates. We start by padding the image with 0s on the left and top. By default the boundaries are computed using. How do I use a picture from a satellite to compute this area using bwboundaries? transforming the image into binary image? I await response. a0 = [10 10 10 10];The code below classifies objects based on their roundness using bwboundaries. 1. The reducepoly function uses the Ramer-Douglas-Peucker line simplification algorithm, removing points along straight lines and leaving only knickpoints (points where the line curves). Copy. The default of 0. 解決策はありますか？. Try cvContours () function. If you don't want the "whole image" then what do you want? Dishant's code basically does the same as bwperim() - it gives you an image where the boundaries are white/true/1 and the rest is black/false/0. "branchpoints". You can get the boundary of your binary image with bwboundaries. Step 6: Edge Detection Process (Compute Gradient approximation and magnitude of vector) Step 7:. png figure); 2) the red curve that creates the. How write Matlab code to plot boundaries of. Answers (2) B = bwboundaries (img2,'noholes');//no holes is required in case of your image. I've used the function "bwboundaries" on a binary image but I can't seem to figure out how to find the area enclosed by the boundary output, B. png) Get the bwboundaries of the binary image; Find centroid and major axis using regionprops (image2. Now i want the region under the boundary to be masked with green color. Note that if you choose the generic MATLAB Host Computer target platform, bwboundaries generates code that uses a precompiled, platform-specific shared library. img = imread. For this example, select a column coordinate. 94 so that only the pills will be classified as round. BW is a 2-D binary image where pixels that are logical true belong to the foreground region and pixels that are logical false constitute the background. For each object: Obtain the (x,y) boundary coordinates and the circularity measurement. Hot Network Questions How did the y get lost in German writing? I'm looking for C++ code (doesn't have to be in OpenCV) that gives the exact equivalent results to the Matlab bwboundaries command. Learn more about bwboundaries, image, image analysis, image acquisition, image segmentation, label2rgb, boundary, plot, plotting MATLAB Hi. png) Find centroid and major axis using regionprops (image2. % plot the contours of the edges. png'); BW = im2bw(I, graythresh(I)); B = bwboundaries(BW,'noholes'); for k = 1:length(B) boundary = B. bwboundaries also traces the exterior and hole boundaries of children objects completely enclosed by parent objects. bwboundaries関数についてです。. I have a Matlab code written here: function matchObj2Outline. Hi, I am using bwboundaries to trace the boundaries. Copy. By. [rows, columns, numberOfColorBands] = size (grayImage); if numberOfColorBands > 1. tif' ); Find the perimeters of objects in the image. The example then calculates the row coordinate of the topmost object in that column. The find () function in MATLAB is used to find the indices and values of non-zero elements or the elements which satisfy a given condition. If I understand you correctly, you have a binary image of the boundary of the kidney and now need to set the inside of the boundary to 1s. When generating code, if you specify color as a character vector, then the value must be a compile-time constant. bwperim returns the perimeter of the blobs as an image. How obtain coordinates of pixels within. . Copy. MATLAB图像处理工具箱中另外一个用来进行边界跟踪的函数是bwboundaries,它的常见调用方法如下: B=bwboundaries (BW) [B, L，N，A] =bwboundaries (BW， conn) B=bwboundaries (BW, conn, options) 其中，BW是二值图像，值为1的像素构成了目标，值为0的像素构成了背景; conn刻画了跟踪边界的. Once you have the binary image, you can use the ' bwboundaries ' function to obtain the boundary pixels. 最近正好在做APMCM2019的A题，发现了matlab一些比较好用的函数，做一个学习笔记的作用如果大家有去了解这道题目的话，会发现它其实是需要你通过图像处理等方式，将114张SIO2融化的过程照片，去建模出SIO2晶体在融化过程中的一些规. example. A pixel is part of the perimeter if it is. k = boundary (P,0); j = boundary (P,1); Compare the shrink factors by plotting the. I wrote some sample code using bwperim to get boundary image of a region then save it in png format to save lossless. This will convert the edges into defined blobs and we can then clean up and bwareaopen() will remove all blobs smaller than a predefined size—in this particular case we will use a size of 400 px, which. If objects in score are ordered in the same way as the objects generated by regionprops then this is ok, since regionprops and bwboundaries index objects in the same order. Because the variable returned from bwboundaries() is weird, I'm having a lot of difficulties implementing the algorithm. ) h = text(. Then, use the slightly decreased object to index into the main object. If I donot use subplot, when I plot the boundary objects, the figure windows gets white and the result of plotting does not appear. i used regionprops, bwboundaries and bwlabel but i cant do it, may be i m doing some kind of mistake please help me out of doing all these above mentioned tasks. All of the objects in L are labeled. Copy. I mean, the image C and the plots on the image. For 2D data, the bwboundaries function does this very well. Image segmentation in matlab. You can see this by examining it: >> BW = ~imbinarize (Image. C = intersect (A,B) returns the data common to both A and B , with no repetitions. 9. for k=1:length (B)Link. Get the outer boundaries by using matlab function: k = boundary(x,y) Use poly2mask to convert the boundary into a binary image (image2. It also descends into the. Increase edge thickness in binary?. Description. But for the second object, it actually starts at the left image border, goes to the right image border, AND THEN BACK towards the left image border. ~ is logical negation in this context. k = boundary(x,y) returns a vector of point indices representing a single conforming 2-D boundary around the points (x,y). Compare the circularity measurement to the threshold. J = imclose (I,nhood) closes the image I, where nhood is a matrix of 0 s and 1 s that specifies the structuring element neighborhood. 7 version of ncurses available to matlab. 5; % Rethreshold. BW is a 2-D binary image where pixels that are logical true belong to the foreground region and pixels that are logical false constitute the background. EDIT - The use of hist and histc is not recommended now, and histogram should be used instead. bwboundaries: Explanation of a example. The label2rgb function picks colors from the entire range of the colormap. boundaries = bwboundaries (BW_filled); Plot the borders of all of the coins over the original grayscale image. completely enclosed by the parents). The function returns B, a cell array of boundary pixel locations. Description. what i want to say is explained in attach figure. The output stats denotes different properties for each object. numCols = size (BW,2); col = ; row = find (BW (:,col),1)Get the outer boundaries by using matlab function: k = boundary (x,y) Use poly2mask to convert the boundary into a binary image (image2. % Column 1 is rows, or y. Hi, In this example below the labeled objects are shown using the jet colormap, on a gray background, with region boundaries outlined in red. Learn more about bwboundaries, arrays, multidimensional arrays Image Processing Toolbox. I2 = imfill (I,conn) fills holes in the grayscale image I, where conn specifies the connectivity. C. So matrix A1 should store the row/column numbers for the white pixels in the big object, matrix A2 should store the row/column numbers for the white pixels in the circular objectLearn more about matlab, boundary Image Processing Toolbox. BW1 = imread ( 'circbw. bwboundaries es compatible con la generación de código C (requiere MATLAB ® Coder™). It's possible you're simply looking for the L matrix returned by bwboundaries. For more information, see Code Generation for Image Processing . MATLAB user Meshooo asked a question on MATLAB Answers about a problem with the createMask function associated with impoly. binaryImage = imfill (labeledImage > 0, 'holes'); [binaryImage, numberOfBlobs] = bwlabel (binaryImage); Change connectivity from 4 to 8 or vice versa to see what effect that has. bwboundaries returns a cell array, where each cell contains the row and column coordinates for an object in the image. obj_boundaries = bwboundaries(obj_labelmap, 'noholes'); I'd expect to work in the same way. Step 1: Read the Image. El uso de una biblioteca compartida mantiene. Answers (1) Well, here is the original image, after cropping (cardiac MR scan). Theme. 2) If you can solve the problem in (2. The clockwise boundary of each object is computed by the boundary function. In your case boundaries{4} will return you the required inner boundary. If I understand you correctly, you have a binary image of the boundary of the kidney and now need to set the inside of the boundary to 1s. Use bwboundaries () to get the coordinates of the outline of your blob (human). Skip to content. BW2 = bwareaopen (BW,P) removes all connected components (objects) that have fewer than P pixels from the binary image BW , producing another binary image, BW2. I've used the function "bwboundaries" on a binary image but I can't seem to figure out how to find the area enclosed by the boundary output, B. Get the outer boundaries by using matlab function: k = boundary(x,y) Use poly2mask to convert the boundary into a binary image (image2. We’re talking about the width and height of the rotated smallest bounding box. figure. You can get the boundary of your binary image with bwboundaries. regionprops finds unique objects in binary images using 8-connected neighborhoods for 2-D images and maximal connectivity for higher. You only need the first step of the bwboundaries algorithm, which is the region labels obtained with bwlabel. (A cell array is one where each element of the array is a matrix itself). The problem may just be with either the way you save or with way you used bwboundaries. 9689. I am trying to trace boundaries of objects using a manual ROI selection and to plot there outlines back on the original image in grayscale. Only inner boundaries are obtained. 1. visboundaries uses bwboundaries to find the boundary pixel locations in the image. Image Analyst on 22 Apr 2020Learn more about binary image, boundaries, image analysis MATLAB, Image Processing Toolbox, Image Acquisition Toolbox, Computer Vision Toolbox. Syntax. is it possible to differentiate between different boundaries by use of bwboundaries in Matlab. MATLAB has bwboundaries, which produces both a label map and a list of contours at once. Display the image with the inserted recognized text. I have found the boundary of it. In the for loop, you can vectorize it and use min(). 이 함수는 경계선 픽셀 위치로 구성된 셀형 배열인 B를 반환합니다. Answers (1) This is expected. Unable to use a value of type cell as an index. (Tilt/orientation for the ellipse occurs when the term x*y. visboundaries( B ) draws region boundaries specified by B , where B is a cell array containing the boundary pixel locations of the. Feb 13, 2022 at 19:43. Description. The bwconncomp() (on newer Matlab versions), or the older bwlabel() function, both work in. Matlab- Improve code in image cropping black border. png'); BW=~im2bw (img,0. By. as boundaries of holes inside these objects. Any. visboundaries (BW) draws boundaries of regions in the binary image BW on the current axes. To my knowledge, OpenCV doesn't have that. It almost does, but only for about 80% of the labels. bwconncomp uses significantly less memory and is sometimes faster than the other functions. double axis used in matlab. The function returns B, a cell array of boundary pixel locations. i have identified boundaries from a binary image using boundaries = bwboundaries(bw); The output of the above line of code is shown below [108,69;108,69] [691,69;691,69] 23x2 double i wanted. "branchpoints". BW is a 2-D binary image where pixels that are logical true belong to the foreground region and pixels that are logical false constitute the background. Find the treasures in MATLAB Central and discover how the community can. To do this you must first crop out the original image using the ' imcrop ' function. 1 Answer. And If you don't want to try cvBlob since you will have to install another library. Because the variable returned from bwboundaries() is weird, I'm having a lot of difficulties implementing the algorithm. Or you could use a Savitzky-Golay filter along with bwboundaries () to smooth out the coordinates, then use poly2mask () if you need to turn the coordinates into. threshold = 0. . Then use poly2mask and IA/my steps from above. It's an image of a droplet laying on surface, and I would like to know how to find the x coordinate where the droplet starts. If your version of MATLAB is older than that, it will not know the 'MaxFeretProperties' option. Description. Find the treasures in MATLAB Central and discover how the community can help you! Start Hunting!A polyshape is an object that can represent shapes that are composed of polygons. help with bwboundaries() function ?. in that case it can computes only one convhull - it doesn't help a lot. The function uses the parametric representation. 1. Select a Web Site. 0. Specifying limits of axes. Then I applied otsu segmentation to differentiate the background, then bwboundaries. Basically threshold and fill the mask so you get a solid disk. We need your original image to run your code and see where it's going wrong. % using the coordinates returned by bwboundaries(). With this principal in mind we deduce that the average pixel value of an Unsigned 8-bit integer image is 127. 2. Then run around the list of (x,y) edge. 0. numCols = size (BW,2); col = ; row = find (BW (:,col),1)I also was hoping the boundary array for the right edge from `bwboundaries` would be sorted from the corrected startpoint to endpoint (like how it is for the left edge), so that for edges that don't touch the border, I can then draw a straight line connecting them (like in red in the last image), and then use `polyshape` and `area` on it, so I can find the. 2 Binary image in. bwboundaries: Explanation of a example. bwboundaries also traces the exterior and hole boundaries of children objects completely enclosed by parent objects. Learn more about image, im2bw, array, for loop, bwboundaries, thresholding, outines Image Processing Toolbox. BW2 = bwpropfilt (BW,prop,n) sorts the objects based on the value of the specified. numCols = size (BW,2); col = ; row = find (BW (:,col),1)This assumes that the score array is ordered in the same way as the objects array generated by bwboundaries. Learn more about image processing Image Processing ToolboxWiki: "If after a recent upgrade (libncurses to v 6. I am trying to search for a specific coordinate point (I want the x value for all coordinates in the boundary that have y=constant). bwboundaries also traces the exterior and hole boundaries of children objects completely enclosed by parent objects. You could just fill holes in the binarized labeled image, then relabel if you want. MATLAB functions contour: gives you the contour location in sub-pixel coordinates. . Set the first nonzero pixel as S (Starting of the boundary) Set the current pixel as p ; Add this non zero pixel into a boundary pixel list. I am using 'bwboundaries. The question relates to the tracing of a boundary in a binary image. A= [main1. Learn more about image processing Image Processing Toolbox This simple example is given in the Matlab Documentation: I = imread('rice. The function returns B, a cell array of boundary pixel locations. This moves the inner points to the outside. For timetables, intersect takes row times into account to determine equality, and sorts the output timetable C by row times. Any specific boundary can be extracted by indexing the cell array. For 2-D problems, k is a column vector of point indices representing the sequence of points around the boundary, which is a polygon. I got problem by getting a region boundary two times. Conic Ellipse representation = a*x^2+b*x*y+c*y^2+d*x+e*y+f=0. m. After finding boundaries of my regions of interest in an RGB image I want to fill them with specific color on the original picture. Yes, you can get the boundary coordinates from bwboundaries, from erosion, or from bwperim. For this i want develop algorithm dynamically. According to bwboundaries. For 2D data, the bwboundaries function does this very well. example. answered May 25, 2012 at 17:15. For this example, select a column coordinate. numCols = size (BW,2); col = ; row = find (BW (:,col),1)I also was hoping the boundary array for the right edge from `bwboundaries` would be sorted from the corrected startpoint to endpoint (like how it is for the left edge), so that for edges that don't touch the border, I can then draw a straight line connecting them (like in red in the last image), and then use `polyshape` and `area` on it, so I can find the. Description. B = bwboundaries (BW) traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW . The bwboundaries function implements the Moore-Neighbor tracing algorithm modified by Jacob's stopping criteria. Learn more about bwboundaries, arrays, multidimensional arrays Image Processing Toolbox Hello, I am trying to get the boundaries of objects in a three-dimensional array. bwboundaries es compatible con la generación de código C (requiere MATLAB ® Coder™). Then use sqrt() to find the distance of every actual boundary point to the closest fit point. I'd try adjusting the threshold. Look at the input to bwboundaries: it is just a MATLAB matrix. But if you want to perform the same task in different images, I think you can find boundaries with and without option. ' PropertyName',PropertyValue. The function returns B, a cell array of boundary pixel locations. Sign In to Your MathWorks Account; My Account; My Community Profile; Link License. bwboundaries returns a cell array, where each cell contains the row and column coordinates for an object in the image. The function returns B, a cell array of boundary pixel locations. Add the absolute values of these points + 1 to your x and y coordinates. B = bwboundaries (BW) traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW . Using the x and y data from the previous problem, and the initial guess [10 10 10 10], we can determine the ellipse with: Theme. Use this function to clear the image border or select image borders. Theme. This figure illustrates the extrema of two different 2-D regions. Then use sqrt() to find the distance of every actual boundary point to the closest fit point. Sign in to comment. For 2D data, the bwboundaries function does this very well. If you shrink and tighten the convex hull from above, you can enclose all of the points in a nonconvex. Sie haben auf einen Link geklickt, der diesem MATLAB-Befehl entspricht: Führen Sie den Befehl durch Eingabe in das MATLAB-Befehlsfenster aus. I'll update my post. B = bwboundaries(BW) traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW. I'm looking for C++ code (doesn't have to be in OpenCV) that gives the exact equivalent results to the Matlab bwboundaries command. Just use the 4 other lines of code on whatever you called your binary image. Therefore, bwboundaries knows nothing about the world coordinate system and must return the output in what we call intrinsic coordinates. bwboundaries -, in MATLAB-, preprocessing. Determine the row and column coordinates of a pixel on the border of the object you want to trace. 94; Loop over the detected boundaries. If you want to perform a morphological bottom hat operation with a different neighborhood, then use the imbothat function. Trace the boundaries of all coins in the image by using the bwboundaries function. Once you have this logical image, you can use logical indexing to fill the region inside the boundary with specified values. To ensure that bwboundaries traces only the exterior of the coins, fill the area inside each coin by using the imfill function. Elysi, now I / we think perhaps you want to extract only the second and third largest blob, considering their size after filling, which is a completely different thing than what were first answering about blob #2 and blob #3 using numbers as gotten from something like bwboundaries() and bwlabel(). regarding to the starting- and endpoint definition. After finding boundaries of my regions of interest in an RGB image I want to fill them with specific color on the original picture. . mask = poly2mask (x, y, rows, columns); bigMask = imdilate (mask, true (3)); bigBoundary = bwboundaries (bigMask); smallMask = imerode (mask, true (3));. Show -1 older comments Hide -1 older comments. 0. Column 2 is columns, or x. visboundaries (BW) draws boundaries of regions in the binary image BW on the current axes. Essentially this is shifting your points to be strictly greater than or equal to 1. ) but I am pretty sure these functions are not the right ones to do the job that I want, or I am just using these functions the wrong way. Learn more about matlab, boundary Image Processing Toolbox. B = bwboundaries (BW) traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW . To trace the boundary of a single object in the binary image, first determine the row and column coordinates of a pixel on the border of the object. – beaker Feb 13, 2022 at 19:43 Added an image. Axes like wblplot when plotting X and Y in Matlab. OpenCV only produces each piece of information individually, and there's no guarantee that the labels map from. bwboundaries: Explanation of a example. This MATLAB function traces the exterior boundaries of objects, as well as boundaries of holes inside these objects, in the binary image BW. Learn more about image processing, digital signal processing, bwboundaries Image Processing Toolbox1. mmm ssss on 30 Jan 2012CC = bwconncomp(BW) busca y cuenta los componentes conectados CC de la imagen binaria BW. Get the outer boundaries by using matlab function: k = boundary (x,y) Use poly2mask to convert the boundary into a binary image (image2. Description. % Convert it to gray scale by taking only the green channel. As the L is of all the image not of specific object, is it possible to get it for an object?. For 2D data, the bwboundaries function does this very well. 2. y = sgolayfilt (x,order,framelen) applies a Savitzky-Golay finite impulse response (FIR) smoothing filter of polynomial order order and frame length framelen to the data in vector x. g. 1. % different to that found using bwboundaries (latter is perfect), BUT it is the edge contour. example. Filling region of RGB image specified by polygon in Matlab. I haven't been able to find a. One way I can think of doing this is threshold the image so that you have a solid white object, shrink the object by a little bit. Matlab GUI axes to figure. ocrResults = ocr (I,roi); Insert the recognized text into the original image. y = sgolayfilt (x,order,framelen,weights) specifies a weighting vector to use during the least. Then run around the list of (x,y) edge. Perhaps what you should do is to first use kmeans to identify your clusters. You would first need to extract out the pixels that are along that boundary. Then subtract off the values you added. bwboundaries also traces the exterior and hole boundaries of children objects completely enclosed by parent objects. How can I get only one boundary and in center of edge pixel. Tags histogram; relative frequency; Community Treasure Hunt. This function uses the Least-Squares criterion for estimation of the best fit to an ellipse from a given set of points (x,y). You could use a higher shrink factor. Then subtract off the values you added. To give some context to the code below: I am looking for the pixel coordinates (X,Y) of the edge of the largest Blob detected with bwboundaries. MATLAB user Meshooo asked a question on MATLAB Answers about a problem with the createMask function associated with impoly. The points (x(k),y(k)) form the boundary. Theme. a = rand (200); % Create a logical image that defines a rectangular boundary. I've tried to use both bwtraceboundary and bwboundaries to identify the edge outlines and then export this file with polylines, but am not having any luck. % numberOfColorBands should be = 1. Learn more about image processing, digital signal processing, bwboundaries Image Processing ToolboxPick a point on the boundary of a second object. La estructura de salida CC contiene el número total de componentes conectados, tales como las regiones de interés (ROI), de los índices de la imagen y los píxeles asignados a cada componente. k = boundary(x,y) returns a vector of point indices representing a single conforming 2-D boundary around the points (x,y).