Hello I have this kind of bounding box annotations.
Bouding box with left,top,width,height coordinates
How to convert given coordiantes as yolo format like this
Yolo format coordiantes of bounding box
as well is there any solution to add class column as start with A to be class 0, startwith class 1 and others ?
Related
Using QGIS 3.16, I have drawn polygons around shapes and found their areas in units of meters2. Next I have created a shapefile for bounding boxes around these polygons. When I click on the shapefile for the bounding boxes just created, and open the attribute table, I expect to see units for height, width, area, and perimeter in units of meters or meters2. The units displayed in the image below is unknown. How do I convert all these measurements into meters or meters**2?
to answer at your question it's necessary to know Coordinate systems worldwide EPSG code or your data reference system (SR).
Maybe that your data are in WGS84 or in other Geographic coordinate system,and so data have measure unit in degrees (or in grads).
You can recalculate your measures in field calculator using transform() function, that reprojects your data in a Projected coordinate system, that has measures in meters. For example:
transform($geometry,'EPSG:4326','EPSG:32634')
where first epsg code is you data SR e second one is the new EPSG code.
If you undestand this passage, then you can calculate
BBox area:
area( bounds( transform($geometry,'EPSG:4326','EPSG:32634')))
same formula without transform
area( bounds( $geometry))
bbox heigth
bounds_height( ( transform($geometry,'EPSG:4326','EPSG:32634')))
same formula without transform
> bounds_height( ($geometry))
bbox width:
bounds_width( ( transform($geometry,'EPSG:4326','EPSG:32634')))
same formula without transform
> bounds_width( ($geometry))
Here is what I did and want.
I have two images with small differences.
In the case of same resolution and position, to detect difference is simple.
Just subtracting two images.
Then the subtracted image has only different points valid.
How can I draw bounding boxes to those differences?
Is there any function to do it in matlab?
Given a set of 2D points X where the images are different, you can draw the bounding box on top of your image as follows.
imshow(I)
hold on
rectangle('Position', [min(X) (max(X)-min(X))])
hold off
(Depending on the data format, some transposes ' may be needed.)
Hi i am working with matlab and trying to select a region using a bounding box. The code is as shown below
BW=bwconncomp(I1);
STATS = regionprops(BW, 'FilledArea','BoundingBox','Image');
The result is as shown below
I am trying to obtain an output as shown below. Is it possible?
I found these two codes for the generation of oriented bounding boxes on the File Exchange:
orientedBox in geom2d by David Legland:
OBOX = orientedBox(PTS) Computes the oriented bounding box of a set of points.
imOrientedBox in Feret diameter and oriented box also by David Legland
OBB = imOrientedBox(IMG) Computes the minimum area oriented
bounding box of labels in image IMG.
You will probably get what you are looking for from imOrientedBox.
How to identify boundaries of a binary image to crop in matlab?
ie. the input binary image has no noises. only has one black object in white background.
You can use the edge command in MATLAB.
E = edge(I);
I would be an input grayscale or binary image. This will return a binary image with only the edges.
This can provide further assistance:
http://www.mathworks.com/help/images/ref/edge.html
If your image is just black-and-white and has a single object, you can likely make use of the Flood fill algorithm, for which Matlab has built-in support!
Try the imfill function (ref).
This should give you the extents of the object, which would allow you to crop at will.
You can also invert the image, then do regionprops to extract all of the properties for separate objects. You need to invert the image as regionprops assumes that the objects are white while the background is black. A good thing about this approach is that it generalizes for multiple objects and you only need about a few lines of code to do it.
As an example, let's artificially create a circle in the centre of an image that is black on a white background as you have suggested. Let's assume this is also a binary image.
im = true(200, 200);
[X,Y] = meshgrid(1:200, 1:200);
ind = (X-100).^2 + (Y-100).^2 <= 1000;
im(ind) = false;
imshow(im);
This is what your circle will look like:
Now let's go ahead and invert this so that it's a white circle on black background:
imInvert = ~im;
imshow(imInvert);
This is what your inverted circle will look like:
Now, invoke regionprops to find properties of all of the objects in our image. In this case, there should only be one.
s = regionProps(imInvert, 'BoundingBox');
As such, s contains a structure that is 1 element long, and has a single field called BoundingBox. This field is a 4 element array that is structured in the following way:
[x y w h]
x denotes the column/vertical co-ordinate while y denotes the row/horizontal co-ordinate of the top-left corner of the bounding box. w,h are the width and height of the rectangle. Our output of the above code is:
s =
BoundingBox: [68.5000 68.5000 63 63]
This means that the top-left corner of our bounding box is located at (x,y) = (68.5,68.5), and has a width and height of 63 each. Therefore, the span of our bounding box goes from rows (68.5,131.5) and columns (68.5,131.5). To make sure that we have the right bounding box, you can draw a rectangle around our shape by using the rectangle command.
imshow(im);
rectangle('Position', s.BoundingBox);
This is what your image will look like with a rectangle drawn around the object. As you can see, the bounding box given from regionprops is the minimum spanning bounding box required to fully encapsulate the object.
If you wish to crop the object, you can do the following:
imCrop = imcrop(imInvert, s.BoundingBox);
This should give you the cropped image that is defined by the bounding box that we talked about earlier.
Hope this is what you're looking for. Good luck!
I want to get the object's bounding box positions (x, y, width and height) in the image and save it to a text file. As shown in the below image. So if anyone could please advise.
The image can be found here
Assuming you have read the image using imread, this should work:
bwImage=~im2bw(img,0.98); %making gray pixels white and (almost) white pixels black
bndBox=regionprops(bwImage,'BoundingBox');
bndBox will have top-left corner of the bounding box and its width and height stored in the format [corner_x corner_y width height].