Image Definition and 1000 Threads

I have a difficult to articulate question about digital microscopes. I was reminded by my post in the STEM toys thread when I mentioned the Eyeclops. How does one define what strength something is magnified at when you can cast the live image onto monitors of various sizes? An image magnified...

Hi, I just have a quick question regarding image processing. What is the correct form of the Laplacian for image processing? I have seen different versions online and don't understand which one is meant to be the conventional one. I know that: \nabla^2 f(x, y) = \frac{\partial^2 f}{\partial...

I have a spherical concave mirror with focal length of 65cm, radius of curvature of 130cm. I hold the mirror close to the eye at approximate 45 degrees and I reflect an object below it as shown in the image. The distance between the object and the mirror is 90cm, that is more than the focal...

from PIL import ImageGrab from win32gui import GetWindowRect def find_img_loc(): k=1 folder=sep.join((getcwd(),'screenshots')) initial_file='screenshot'+str(k) filename=lambda x: sep.join((folder,x+'.png')) while exists(filename(initial_file)): k+=1...

I was reading the following webpage on Gaussian kernel but couldn't understand few details: https://www.imageeprocessing.com/2014/04/gaussian-filter-without-using-matlab.html . Would really appreciate it if you could guide me. Thanks in advance! Here you can find the high-res screenshot of the...

I have to do a MATLAB assignment but when it comes to the report (the theory) I am having quite a lot of problems. My tutor used this formula that I am going to attach: However, I don't know if that equation is the Laplace equation, the 2D Heat Diffusion equation, or what exactly that is as I...

Hello, Is it possible to take a picture/image using a digital camera and then obtain the intensity/irradiance (##W/m^2##) of the composing pixels? Should the image be exported in a particular format into a graphics software like photoshop to be able to obtain the irradiance information? Or...

Hello to all forum members, Here is a page from the F-104 flight manual. It shows the flight envelope for the F-104 Starfighter with the powerful -19 turbojet engine: I have a question regarding the shape of the afterburner envelope. In Aerodynamics for Naval Aviators, published in 1965...

Hi, I was just looking at some conceptual problems on the internet and wanted to check whether my thought process on this question was correct. Question: The two texture images shown below are quite different, but their histograms are identical. Both images have size 80 × 80, with black (0)...

Hello guys, if I have an image with 11x11 pixels and in the center of the image is a square of 5x5 pixels, with the gray level of the background 0 and the gray level of the square is 50. How can I compute the result of the magnitude of edges(intensity of the contour) given by the compass...

Hello guys, if I have an image with 11x11 pixels and in the center of the image is a square of 5x5 pixels, with the gray level of the background 0 and the gray level of the square is 50. How can I compute the result of the magnitude of edges(intensity of the contour) or better said the gradient...

Hi all, I am trying to figure out a way to simplify this problem to give the image of the map. I have not seen this function before and I am having trouble figuring out what the image should come out as. I have tried graphing u and v separately as a function of x and y in R3 and both surfaces...

I have been doing some reading about birefringence in order to understand colors observed in different birefringent crystals when I came across the following page in connection with calcite crystal birefringence. https://www.microscopyu.com/tutorials/birefringence-in-calcite-crystals I think I...

In gravitational lensing, the image magnification is defined as the image area over the source area. But many texts also give it as the inverse of the determinant of the jacobian, A, of the of the lens equation. My question is how these are equivalent. The lens equation is...

Hi, So my question is perhaps better asked as: - What is the point of convolution (in 2D image processing)? - Why would we use that operation in image processing? - What is so special about that flipped version of the kernel? Context: In an image processing class, I was learning about the...

I am studying the classic image problem (griffins, p. 124) Suppose a point charge ##q## is held a distance ##d## above an infinite grounded conducting plane. Question: What is the potential in the region above the plane? boundary conditions: 1. V = 0 when z = 0 (since the conducting plane is...

The graph of y=x^2 was transformed to the graph of y=-3(x+5)-2. The point (-3, 9) lies on the graph of y=x^2. Determine its image point after the transformations.

A conducting sphere of radius a is made up of 3 different shells, upper part a/2 z -a/2, the middle part -a/2 z a, the lower part -a z -a/2 where the center of the sphere is at the origin. The upper part V and the lower part has -V potentials, while the mid part is grounded. Find the...

First image is an object for the concave lens so won't +ve direction change from right to left?! In that case, object distance will be -ve (from concave lens towards right side). Any ideas? Solution in the book takes first image's distance to be +ve. See attached ray diagram for clarification...

I know how to solve the problem but the only thing that's bothering me is what is A? According to me A is should be 2F ie 2 times the focal length distance. I thought of it like this: 1. First there will be an image formed due to the lens. 2. The image will be formed below the lens but the...

I have used my entry-level Zwo colour camera to get movies of planets and, subject to my limited skills, those movies (Avi format) are handled quite happily by Autostakkert and Registax. I have used my DSLR successfully to take multiple long exposure images and they have stacked fine (of...

Hi PF! Each element of an ##n\times m## matrix is complex valued. In the following code, I call this "domain". There is also an ##n\times m## matrix that is real valued, below I call this "f". I'd like to plot a 3D image where the ##x-y## plane is the complex plain given by the coordinates...

All are used to finding the image charge induced by a source charge outside a conducting sphere. The solution is supposed to also work for the case where the source charge is inside the conducting sphere, in which case the sphere is now a conducting cavity. But the solution suggests the image...

Hi, I have seen people adding watermark in Lyx. I have looked around and found few codes, even tried but unsuccessful. I have installed xwatermark. Can someone help me adding watermark to my report on few pages? Thanks in advance.

Seeing the Unseeable: Capturing an Image of a Black Hole A Free Science Lecture Led by Dr. Sheperd Doeleman, the Event Horizon Telescope (EHT) project made history by capturing an image of the event horizon of a black hole, where gravity is so strong that even light cannot escape. You are...

Summary

[Moderator's note: Moved from a technical forum and thus no template. Own effort in next post.]

Here is the documentation for the 2DFFT: https://www.mathworks.com/help/matlab/ref/fft2.html how would I go about creating this formula on MATLAB to apply it on an image? My guess is that I need to create the equation and then multiply it to the image I need such as: $$U = VI$$ where V is my...

The other day I was trying to visualize a field using line integral convolution. I thought I kept failing for days since Pillow was giving me outputs similar to this one (img = Image.fromarray(output_image, 'L')): I thought I was making some mistake until I tried Pyplot...

Merged thread deleted first post next post is the first post.

. . . I'm not programmer, although I do have a basic knowledge of programming and have passed one college course in it. But this could be a foot in the door for me to become useful at something my company might want to expand into in the future. Here is what I am being asked to do. I...

I have an plano-convex lens with focal length 75 mm. The object is 325mm from the lens. a) Where is the location of the image after the lens? b) Where is the location of the image if an beamsplitter is placed after the lens? My solution, questions: a) a = 325 mm b = ? mm f = 75 mmm...

Full article: https://www.aura-astronomy.org/news/nsfs-newest-solar-telescope-produces-first-images/

Hello everyone this was a problem on one of the exams from last year and I'm having trouble with the last point ##3## my solution for ##1## $$\frac{1}{2\pi i}\int_{|z|=r}\frac{f(z)}{z}(1+\frac{z}{2re^{i\theta}}+\frac{re^{i\theta}}{2z})dz =$$ I divided this integral into 3 different ones and...

Are there any good images that can be used as a hook for an elementary number theory course?

Are there any good images that can be used as a hook for an elementary number theory course?

A thin lens has an upper radius of curvature 𝑅1 and a lower radius of curvature 𝑅2. When the lens is completely surrounded by air, it has a focal distance 𝑓. The lens is then placed in the interface between air and water inside a vessel (see figure). Calculate the refractive index for the glass...

I am trying to use the Method of images for this configuration, But somehow I don't know where should I put the imaginary charge. I know the on the surface of the conductor the potential must be zero and the imaginary charge should be other side of the conductor but that's all I cay..

## \dfrac{1}{2} \left(\begin{array}{rrrr} 0 & 2 & -2 & 0 \\ 3 & -2 & 2 & -3 \\ 3 & -4 & 4 & -3 \\ -2 & 2 & -2 & 2 \end{array}\right)## The matrix satisfies ##A^2=A##, so it is a projection. To find ##U'##, one can find the ##\text{ker} \ (A-I)=\text{ker} \ (I-A)=\text{im} \ (A)=U'##. Also...

So I was reading Jackson's discussion on Image charge method of a grounding sphere. He first assumed an image charge q inside Sphere with radius a, so the potential for real change and image charge is . The by set potential equal to 0 at x=a, he solved q' and y' Then he can get potential...

I have a response matrix for my 4pi imager to perform MLEM that has dimensions: (16 x 16 x 18) x (72 x 36) which is Observation Bins x Source Bins. I'm told that I can use MLEM to create an image by feeding in a 1x3 vector of det1, det2, theta into the MLEM algorithm. Where det1, det2 are...

In concave mirror, when object is beyond C ( centre of curvature) our traditional Ray diagrams show a real and inverted image formed between C and F. But at the same time, if we look directly into the mirror and remove the screen, we see an inverted image which appears to be inside the mirror...

Hi there I am teaching resonance and standing waves in stringed instruments at the moment at high school. The theory states that a number of standing waves simultaneously (harmonics) exist in a naturally vibrating musical string, but with varying amplitudes, the 1 st harmonic being loudest...

I have pasted the image below after copying it from my desktop. The image becomes visible in the Post Composer as soon as you paste it. It also works if you copy from another web page. I assume that JavaScript is able to grab the data from the clipboard and create an IMG element on the fly, and...

image_data = fits.getdata(alma_image, ext=0) plt.figure() plt.imshow(image_data, cmap='viridis', vmin=-4, vmax=4) plt.xlim(540,640) plt.ylim(540,640) plt.colorbar(extend='both') plt.clim(0, 1) plt.show()

I need to implement a decent image compression algorithm in a day or two, without using libraries. So it can't be anything with multiple layers, like jpeg. I was thinking huffman encoding, Which would be a good algorithm I can learn to implement in a day or two that is not terrible at it's job.

Consider two opposing mirrors. If they are exactly parallel planes I think there is only a single image in each but if they are slightly angled there appears an "infinite" number of reflections. Similarly, suppose we have grounded conducting planes instead of mirrors with a charge in between...

Hi I see there are several articles about how CNN's are used to isolate and classify an object within an nxm rectangular region. While I know how to classify an image into one of p classes, I am not sure how to segment an image into rectangular regions which contain certain objects and, let's...