# Tag Info

Accepted

### Application of the projection matrix: Removing perspective distortion

You're very close: First, ImageTransformation by default assumes that the range of the coordinate system for the input image is [...] {{0,1},{0,a}}, where a is ...
• 36.2k
Accepted

### Extracting data from analog screen photograph

Doing this with basic image processing can be done. In comparison to the post you have linked, your situation is more complicated because you have a monochrome image with no option to separate colors. ...
• 113k
Accepted

### Polar contour plot in Mathematica?

You can use TransformedField to get a function that can be used as the first argument of ContourPlot: ...
• 399k

### How to find the conformal mapping between two regions

We can use PI algorithm described in the paper Numerical Conformal Mapping with Rational Functions.The function for conformal mapping can be computed as follows ...
• 47.4k
Accepted

### Lens on a map. Realistic imitation of magnifying glass on images with text and other small features

In your code you use constant strength: (r/strength). You can change it to depend on r: ...
• 20.3k
Accepted

### How to plot a sphere with Cartesian coordinate axes?

For instance, you can do the following: ...
• 19.1k

### How to find the conformal mapping between two regions

Updated We use schwarz christoffel formula for triangle. $$\int_{0}^{z} (\zeta-a_1)^{\alpha_1-1} (\zeta-a_1)^{\alpha_2-1}\,\mathrm{d}\zeta$$ To integrate such ...
• 78.4k
Accepted

### Calculating the volume of a sphere after switching to spherical coordinates?

Employing most of your own code; ...

• 67.2k
Accepted

### How to create a pin cushion (or barrel) distortion from the square function on Cartesian coordinate?

Here is an example how to distort images (cushion or barrel): ...
• 54k
Accepted

### Does Mathematica 11 have spherical coordinate unit vectors?

Mathematica does all its computations in an orthonormal basis. You simply need to specify what coordinate system you're working in. So for your example, you just multiply by ...
• 14.2k

### How to do nonlinear substitution?

I am assuming you have a field in Spherical Coordinates given by your function and you want to transform it in Cartesian Coordinates: ...

### Convert RotationMatrix to RotationTransform

One only needs to apply AffineTransform[] to the result of RotationMatrix[]; e.g. ...

### Integrating Hamilton's equations for the Schwarzschild metric

After debugging, the code works ...
• 47.4k

### VectorDensityPlot,

• 2,166
Here is an alternative way. We can solve for r and plot $[\theta,r]$. Solve[(r^2 - a^3/r) Sin[θ]^2 == g, r] \$\left\{\left\{...