Can anyone give me an idea on how to proceed? I was able to run the code, but is not showing any results. In your code you are using a for loop which is time consuming. You could rather make use of the fast and agile numpy library. EDIT: i had to read up on what Chris commenting on the post meant by XY Problem but i agree, is there something youve tried and hasnt worked that youd like us to help fix?
Learn more. Finding all the X and Y coordinates of an image in python opencv Ask Question. Asked 2 years, 10 months ago. Active 1 year, 11 months ago. Viewed 26k times. Image for detecting all the X and Y coordinates The sample code i wrote is written below, import cv2 import numpy as np import matplotlib.
Harikrishnan R Harikrishnan R 25 1 1 gold badge 1 1 silver badge 6 6 bronze badges. I'm confused. What does "all the X and Y coordinates of pixels" mean? What are you trying to accomplish here?
This sounds like an XY problem. X, Y coordinates of what??? YvesDaoust of all pixels of the image or entire image.Services section navigation. Print this page. For example the following XY mouse coordinates were recorded by clicking the image circumference. Recorded XY mouse coordinates: ,47, 99, 74, 58, 49, 52, 65, 86,95,, How it works: Upload any of the following image filetypes:.
If the uploaded image has a width larger than px, it will be automatically resized to px. Each time you click your mouse on the image the corresponding XY mouse coordinate is recorded. You can manually add new coordinates by entering the XY values or change or delete existing coordinates. The coordinate origin is positioned in the top left corner coordinate 0,0. When you are done recording, press the Finalize button.
This will copy the recorded values to the output area. If the image was resized the recorded mouse coordinates are recalculated to its original image scale. In the output area you can: Change the final coordinates or even erase all coordinates and enter your own.
Scale all coordinates by entering a multiply factor. These points can be connected by lines and even the formed shape can be filled. The created image can be downloaded. The download functionality is not available if you use Internet Explorer. For problems or assistance with this site, send an email to Mobilefish. Record XY mouse coordinates on an uploaded image. This free online service allows you to upload an image and record all XY mouse coordinates by mouse clicks.
Recorded XY mouse coordinates: ,47, 99, 74, 58, 49, 52, 65, 86,95,, Points only Lines only do not connect start point with end point Lines only connect start point with end point Fill the shape Points and lines do not connect start point with end point Points and lines connect start point with end point Fill the shape include points.Convert, Edit, or Compose Bitmap Images Consider posting your issue or question on our new discussion forum.
Privacy Terms. Skip to content. Quick links. Usage questions are like "How do I use ImageMagick to create drop shadows? For example if I have a black and white image of a hand drawn circle, I would like to get back some sort of coordinates that can be used to accurately redraw the circle in say a spreadsheet.
I have not yet downloaded ImageMajick. Is there a script written to do something like this? I don't know that IM has that kind of ability. But will defer to the IM experts. You have the idea and this is getting very close. Can all of what you said be done with just ImageMagick, or do I need something else like the perl interface. I haven't used this program yet. I didn't want to invest the time if it couldn't do what I am looking for. Another way to solve this: Many graphical image editing programs have a magic wand that will select something if it stands out well.
That portion of the image gets highlighted with a marquee. Is there a way to get the coordinates based on a magic wand selection, if there is one in ImageMagick? Fred's ImageMagick Scripts. In excel I was able to make the original data you supplied a little more to my liking ideally only one set of coordinates at each step around the perimeter.
An excel macro would speed up the task.
Calculate X, Y, Z Real World Coordinates from Image Coordinates using OpenCV
You have some fascinating scripts on your linked page. I expect to use some of them for some other things I have been trying.
Any other expert advice from others? One solution may be covert your image to a bitmap and then filter it though a raster to vector program such as 'autotrace'. This will contain fewer coordinates, but will have them in sequence around the edge.
For example using the IM Example output of "autotrace" from But my day is ending now and the work week begins.The method of image charges also known as the method of images and method of mirror charges is a basic problem-solving tool in electrostatics. The name originates from the replacement of certain elements in the original layout with imaginary charges, which replicates the boundary conditions of the problem see Dirichlet boundary conditions or Neumann boundary conditions.
The validity of the method of image charges rests upon a corollary of the uniqueness theoremwhich states that the electric potential in a volume V is uniquely determined if both the charge density throughout the region and the value of the electric potential on all boundaries are specified.
Possessing knowledge of either the electric potential or the electric field and the corresponding boundary conditions we can swap the charge distribution we are considering for one with a configuration that is easier to analyze, so long as it satisfies Poisson's equation in the region of interest and assumes the correct values at the boundaries.
This situation is equivalent to the original setup, and so the force on the real charge can now be calculated with Coulomb's law between two point charges. The surface charge density on the grounded plane is therefore given by.
In addition, the total charge induced on the conducting plane will be the integral of the charge density over the entire plane, so:. The total charge induced on the plane turns out to be simply —q. This can also be seen from the Gauss's lawconsidering that the dipole field decreases at the cube of the distance at large distances, and the therefore total flux of the field though an infinitely large sphere vanishes.
Because electric fields satisfy the superposition principlea conducting plane below multiple point charges can be replaced by the mirror images of each of the charges individually, with no other modifications necessary. The dipole experiences a force in the z direction, given by. Similar to the conducting plane, the case of a planar interface between two different dielectric media can be considered. It can be shown that the resulting electric field inside the dielectric containing the particle is modified in a way that can be described by an image charge inside the other dielectric.
Inside the other dielectric, however, the image charge is not present. It may even have the same sign, if the charge is placed inside the stronger dielectric material charges are repelled away from regions of lower dielectric constant.
This can be seen from the formula. The method of images may be applied to a sphere as well. In the figure, this is represented by the green point. Let q be the charge of this point. The image of this charge with respect to the grounded sphere is shown in red.
The potential inside the sphere is thus given by the above expression for the potential of the two charges. The potential outside the grounded sphere will be determined only by the distribution of charge outside the sphere and will be independent of the charge distribution inside the sphere. Note that the reciprocal problem is also solved by this method. The potential inside the sphere will be dependent only upon the true charge distribution inside the sphere.
The image of an electric point dipole is a bit more complicated. If the dipole is pictured as two large charges separated by a small distance, then the image of the dipole will not only have the charges modified by the above procedure, but the distance between them will be modified as well. The method of images for a sphere leads directly to the method of inversion. From Wikipedia, the free encyclopedia.
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Lost your phone? Our Technology.In mathematicsthe image of a function is the set of all output values it may produce. More generally, evaluating a given function f at each element of a given subset A of its domain produces a set called the " image of A under or through f ".
The inverse image or preimage of a given subset B of the codomain of f is the set of all elements of the domain that map to the members of B. Image and inverse image may also be defined for general binary relationsnot just functions. The word "image" is used in three related ways.
When there is no risk of confusion, f [ A ] is simply written as f A. This convention is a common one; the intended meaning must be inferred from the context. This makes f [. See Notation below. The image of a function is the image of its entire domain. Let f be a function from X to Y. The set of all the fibers over the elements of Y is a family of sets indexed by Y.
The traditional notations used in the previous section can be confusing. An alternative  is to give explicit names for the image and preimage as functions between powersets:.
The results relating images and preimages to the Boolean algebra of intersection and union work for any collection of subsets, not just for pairs of subsets:. Here, S can be infinite, even uncountably infinite. With respect to the algebra of subsets, by the above the inverse image function is a lattice homomorphism while the image function is only a semilattice homomorphism it does not always preserve intersections.
From Wikipedia, the free encyclopedia. The set of all values of a function. For other uses, see Image disambiguation.
Record XY mouse coordinates on an uploaded image
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Just in case you want to dive right in, you can access the code via my Github HTA0 robot project. You can read through my Medium post on the overview of the robot and watch the video of it in operation in Youtube. This illustration will be crucial to understand the code and how you can use it on your own projects which may have different frames of reference based on your application.
The main reference I have used for this, is the OpenCV 2. The main challenge I found with this pinhole model, is that if you want to solve for X Y Z, it cannot be done, because you cannot calculate the inverse of the R t matrix as it is not square. Before I dive into the solution, it is important to understand the pinhole camera model and coordinates:. And this is important, because if your setup has a z value that is not equal to zero, the pinhole camera model simplifies to:.How to Get data from image ( graph, results etc) │ Digitize your image │Easiest way
To make it work, I added the scaling factor and camera matrix, to arrive at u, v which now enabled to solve for X Y Z in the following manner:. This was a crucial step that enable me to get to a working solution and while working through this another interesting aspect popped-up. The first step to calibrate your setup, is to find what is called the intrinsic parameters of your camera, which are based on how the camera is build and one of the key factors to calibrate, is the distortion that is caused by the curvature of the camera lens.
I followed the steps from the OpenCV Camera Calibration and even used a lot of the example code, but I did find something interesting. You can find the Python script for this Initial calibration here. To get to this point, It involved a series of more steps to get it to work reliably, which I will explain. If you refer to the pinhole model, these are equivalent to u and v pixel values.
Our sheet looks like this:. We then use the 9 circle template I created to calculate the Image points, which is the information we need for the perspective calculation.
And after running the Perspective calibration, it is important to check the scaling factor s. This is a crucial step, given that your Intrinsic Camera Calibration results drive a lot of variablity in the reliability of the X Y Z calculation, and you should look to iterate and get the scaling factor error as small as possible.
Z calculations, and my hypothesis is this is base primarily on how the frames of reference for the plane vs. You can find the Python script for this process here.