Questions tagged [image]

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When creating a JPEG, how can I minimize the occurence of artifacts?

There are 2 main factors that seem to lead to digital artifacts when creating JPEG images: Aliasing and Compression. Example: Converting a PNG with characters on it to a JPEG or placing vector ...
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  • 555
9 votes
2 answers
4k views

What is bilateral upsampling?

I've worked with various interpolation algorithms including linear, cubic (and bilinear and bicubic), other bezier (and nurbs, etc) based interpolations, lagrange interpolation and some others, but I ...
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7 votes
3 answers
321 views

How to denoise video?

Video noise is random and not correlated in time. I assume, the best method is using wavelet denoise in this case, right? If yes, how is wavelet denoise implemented for video? Is there something to ...
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  • 576
6 votes
2 answers
129 views

Is there a image-format that support an array per pixel?

For a project dealing with deep semantic labeling of images I need a format that supports arrays of arbitrary length for each pixel of the image. The array is an array of integers. Which image ...
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  • 61
6 votes
1 answer
147 views

Bitmap-images or SVG

I'd like to create a GUI in my first Unity-game (2D). I want my GUI appear sharp in all resolutions (e.g. 1920x1200 or 3840x2160). The problem I am facing now is that I don't know if I should save my ...
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  • 163
6 votes
1 answer
3k views

Depth of Field in Path Tracing: What do I do with the secondary ray?

How can I implement Depth of Field in my Path Tracer? I have read this article which explains the theory behind everything & I already have a good understanding of what this effect needs to ...
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  • 2,413
6 votes
1 answer
2k views

What happens when you display a high resolution image on a low resolution screen?

For a non-computer graphics expert, what happens technically when you do this? Are multiple pixels merged to one to compensate for the lower resolution? And in how far will this affect the image ...
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5 votes
1 answer
2k views

LWJGL/OpenGL get BufferedImage from texture ID

I have got a texture ID and would like to retrieve its data. The data should be stored in a BufferedImage for future use. I am using the LWJGL library in Java, so ...
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  • 297
5 votes
1 answer
251 views

What algorithm to reassemble a broken image?

What algorithm can I use to reassemble a broken image? Is there any technique? algorithm? Can I use graphs? machine learning? computer graphics?
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  • 113
3 votes
1 answer
47 views

can half of a picture be processed and viewed?

Lets say i have a picture. I send it to a server. While sending it to the server half way the upload gets canceled. Now the server has half or some of the picture. Now is there a way in which this ...
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3 votes
1 answer
3k views

How can I remove aliasing in an image without introducing blur?

I am trying to reduce aliasing in an image using some filters. I tried the Gaussian variant of filters to remove the said high frequency patterns in the image, but I feel it's a bit too much of a blur....
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2 votes
1 answer
96 views

Why isn't the clear color visible on the screen between frames?

I am told that in computer graphics, the screen refreshes in number of times(in this scenario let say that it renders 60 times per second). The screen is cleared and drawn to 60 times per second. My ...
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2 votes
1 answer
225 views

Is there a way to script image creation?

I am facing a though challange - I need to perform repetitive Image formating. Firstly, I need resize picture A so that it has some fixed width in pixels. Then, I need to place picture A in the middle ...
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  • 123
2 votes
1 answer
372 views

Why BMP file format last line of image is first line on file?

I'm studying Microsoft Windows Bitmap File Format, extension BMP. I'm curious to know why scanlines are stored on file from bottom to up: the last scanline on image is the first line on file and the ...
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  • 121
2 votes
2 answers
1k views

How linear interpolation works between mipmaps?

Nearest interpolation between 2 texels means to take the texel whose center is nearest to a given coordinate to draw or, in other words, the texel the coordinate is matching. Linear interpolation ...
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  • 617
2 votes
1 answer
81 views

Mixing HSV Channel

I have a question about the saturation channel. 1.) So far I know, that saturation channel only give intensity to Hue channel, but I do not understand, how saturation channel can be dark and what is ...
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2 votes
1 answer
1k views

How does a GLSL Sampler2D read a Vec2 UV coordinate to determine UV range

I am working with an atlas shader that steps through various sprite tiles within a single png atlas page to playback an animation with sampler2D. Looking at the shader code, I would expect to have to ...
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2 votes
0 answers
197 views

How to merge multiple exr into a single multilayer exr?

Are there some tools or softwares to merge multiple exr into a single multilayer exr? I only find a tool to split a multilayer exr into multiple exr. And it seems that Blender, Mitsuba, Darktable ...
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  • 551
1 vote
3 answers
458 views

How are the colors for each pixel from a Ray Tracer stored in an Image?

I have begun learning how to create a Ray Tracer and 1 thing I am confused about is how the pixel color from a Ray Tracer is stored into an image. Do we use SetPixel...
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1 vote
2 answers
1k views

Explanation of a the transparency of an .EXR file

Simply put, what does the transparency data of an EXR file represent?
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1 vote
2 answers
38 views

splitting hue & saturating and leaving value behind

In an HSV model, the Hue is the color model. So when we split the image or remove H, should we get an image without rgb colors? Similarly, saturation is the gray shade. I read that images become more ...
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  • 113
1 vote
1 answer
157 views

How to change a RGB value using a radiance value?

I am new to this awesome community, I am currently writing a ray tracer but I hit a problem... Let's say I have a surface(material doesn't matter) of colour [1, 0, 0] in RGB, and the radiance reaching ...
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1 vote
1 answer
87 views

Description of the process involved in displaying digital images

Could someone please provide me with/point me to a description of the process involved in displaying a digital image? Starting from reading the data from a file to displaying the image on the screen. ...
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  • 113
1 vote
1 answer
63 views

Compression-friendly PNG files

How to create PNG files optimized for being compression-friendly? I.e. would it help if image is created (mostly) from 8x8 unicolor blocks?
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  • 111
1 vote
1 answer
39 views

Image made of shapes - terminology + software? [closed]

I've often seen images that look like the following example Q1) is there a term for such an image? Q2) What common software is used to convert a real photo (e.g. human face) to be composed of such ...
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  • 121
1 vote
1 answer
69 views

What does an algorithm which handles mesh-based image morphing look like?

In recent years, the technology of Live2D has become particularly popular and I have been attempting to find any papers or articles which explain what the mathematics for the mesh-based image morphing ...
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1 vote
1 answer
692 views

How do you add text dynamically to an image and export it?

Apologize for crossposting, but I posted this in Stack Overflow and thought it might be a better post here. Recently, Spotify released their 2019 Spotify wrapped web application, which is essentially ...
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  • 111
1 vote
1 answer
122 views

How to create static alpha masks of an image

I have an image of following type- I want to create mask of the following type where the inside area is white and rest of it is black. How to do it?
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  • 129
1 vote
1 answer
122 views

Artificially increase the region of interest of an image

I am solving an image segmentation problem. To increase the accuracy of the model, I came across the following preprocessing step- First, the set of pixels of the exterior border of the ROI is de- ...
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  • 129
1 vote
1 answer
365 views

Is there a general way how to specify the "image compression loss"?

For JPG, i can choose the "quality" from 100 to 0, which means that any pixel information is divided by 1 (quality = 100) or a very high number (quality = 0). This results in less or more "artifacts", ...
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  • 277
1 vote
1 answer
437 views

LWJGL/OpenGL render textured quad

So this should be easy and simple, but I still can't get it to work. All I need is a small example program that: Takes in a BufferedImage (TYPE_INT_ARGB) Renders that BufferedImage on a textured quad ...
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  • 297
1 vote
0 answers
36 views

Extract object from image and apply it to different image

SHORT BACKGROUND: I am developing a neural network based model to differentiate benign and malignant ovarian tumors. I am working with transvaginal ultrasound images, some of which contains yellow ...
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  • 111
1 vote
0 answers
113 views

What image formats support indexed color palettes with more than 256 colors?

I've been reading up on images with indexed color, and while most indexed image formats are limited to 256 colors, there are apparently image formats that support larger palettes. According to ...
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1 vote
0 answers
37 views

Are there some methods of preventing tools like FotoForensics from detecting manipulations?

I am asking this question purely our of curiosity. I do not look for step-by-step tutorial on how to manipulate a photo and making sure that it will be hard to detect it. I was wondering, because ...
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  • 111
1 vote
0 answers
1k views

OpenGL - Fit High/Low Resolution Image/Texture to a particular size Window

Consider a ray tracer written in OpenGL and using GLFW as a window toolkit. There are basically 2 options to display the ray-traced image. 1) Create a RenderBuffer ...
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1 vote
0 answers
103 views

How to make Convolved Diffuse and Specular image in C#

I am trying to take either a HDR panoramic or HDR cubeMap and from that create a Lambert Irradiance environment map and a Cook-Torrence Specular environment map. I am stuck at the proper ...
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1 vote
0 answers
51 views

How do you sample an analogue image and store it in a true-colour frame buffer? [closed]

I really cannot get my head around on this issue - how does an analogue image is sampled and then stored in a ture-colour frame buffer (e.g. in a camera) and how do you prevent noise when you do so? ...
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  • 11
0 votes
2 answers
181 views

How RGB images are formed

I have a noob level question about RGB images- Pixels in RGB images are in the range of (0-255), so technically each channel ranges from 0(black) to 1(white), then why we say that each image has a Red,...
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  • 129
0 votes
1 answer
592 views

What is the typical use case for rendering to an image through imageStore?

The typical scenario for using a texture would simply be: ...
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  • 1,447
0 votes
1 answer
60 views

Difference between Gray-Level and Gray-Scale?

What's the difference between the terms Gray-Level & Gray-Scale ? I think that Gray-Level refers to the matrix of light-intensities of the Black-White digital image itself whilst Gray-Scale refers ...
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0 votes
2 answers
659 views

Get normalized device coordinate of an image pixel

I have an image rendered to the screen, and based on the normalized device coordinates of the cursor I would like to pick the pixel of the image under the cursor. Say the image has four channels, I ...
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0 votes
1 answer
73 views

60px * 60px circle image appears pixellated when scaled down to 15px * 15px

We have a circle image with dimensions 60 by 60 px. We want to display this image in a smaller size (15 by 15) on a website using HTML / CSS. When we do so, the image looks blurry (ignore the cropped ...
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  • 103
0 votes
2 answers
51 views

Space efficient storage/compression of multiple scaled values (mip maps)

Because scaling operations are prohibitively expensive in my current rendering stack, I have to pre-render my images in all desired sizes and cache the result on disk. At the moment, I do this by ...
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  • 297
0 votes
1 answer
77 views

Paint pixels on the image around the cursor for painting application

I'm trying to create a simple painting application. And I was wondering about an efficient way to draw pixels on the screen. I have a pixel struct: ...
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0 votes
1 answer
177 views

basic of image dithering

Is just read about image-dithering ? So I tried to implement that. Here is my result. Can someone verify it? My code : ...
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0 votes
1 answer
592 views

How RGB images are formed when normalized between 0 and 1

There is a popular technique of normalising images by dividing each pixel with 255 so that it comes in the range of 0 and 1. But, then how the same colours are formed when we normalize images. for ...
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  • 129
0 votes
1 answer
2k views

Difference between Cropping, Scaling, Resizing & Changing Aspect Ration of an Image?

I've got a new task related to image processing in a website. I am too confused in understanding different terms used with sizing of an image. What is the difference between: Cropping an image ...
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0 votes
0 answers
17 views

Object, Feature, Pattern: What is the exact difference [closed]

implementing a feature extraction algorithm for medical images. However, uncertain about what circumstance a pattern may be considered a feature or an object ? found online: feature --> group of ...
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  • 1
0 votes
1 answer
39 views

How to identify images with similar content?

There's a set of pictures that if you take them literally, they're different. That is, there can be two images of the same thing among them, only in different hue. In addition, among these two, there ...
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0 votes
0 answers
28 views

Software to obtain high resolution images of a STEP geometry file

When trying to obtain high resolution images of geometry files, the only option seems to take a screenshot of the software in use (Salome, Catia, etc...). Although enough in most circumstances, it ...
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