Questions tagged [image]

This tag covers signal processing where input is an image, such as a photograph or video frame and the output could be an improved or altered image, parameters related to the image or information about features within the image.

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“Image Processing” [closed]

I'm an Italian student. I'm studying Gnu Radio and I would like to upload a photo, can I upload it with "file image source" or other blocks? I need to make FFT of an a image. -> image 2D Thank you ...
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1answer
228 views

Edge detection in a crack pattern image

Here's an image of a cracked pattern. I wish to convert it to binary image where the continuous crack lines form the only discernible pixels. The main problems I am having in the lack of uniform ...
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5answers
6k views

What Is the Difference Between the Terms Color Intensity and Color Saturation?

In Digital Image Processing, what is the difference between the intensity and the saturation of a color? How would you explain the difference to a newbie?
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3answers
226 views

Ship detection from aerial image

I have an aerial image, like this I want to detect the outline of the ship without shadow. How can I do it? I tried threshold in both graylevel, RGB and HSV. It doesn't work perfectly.
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5k views

Does the cv2.waitKey argument determine the frame-rate while capturing a video?

Kinda new to image processing, so pardon me if the question is too stupid. Using the library cv2 in python to capture video from my webcam, which, so far as I can see as a programmer, is basically ...
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2answers
256 views

Selective image compression?

Forgive me if this is the wrong site for this question. Here's my problem: I am creating a game where players have to search for a hidden detail within the overall image. I downloaded an 11MB ...
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1answer
45 views

How many moments are needed for a discrete distributions

I am doing a project on imaging and I have a more general question about imaging. In general we use the moments of the distribution of the object imaged, because the capture information about the ...
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0answers
19 views

Can an untilted perspective of an object be obtained from a 2D image of a tilted object using angular transformations?

I'm trying to make a height estimation algorithm that works in tandem with a bounding box object detector. The object detector can recognise the objects in images taken at pitch/yaw angular offsets. ...
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3answers
1k views

How to determine if a pixel is inside a contour?

I have following picture which I extract the contour from. The contour looks like following I am wondering, for any pixel in the image, how do I determine if it is inside the contour or not? Say "...
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1answer
448 views

compression ratio of pixels block

I am new to image compression topic and really appreciate it if someone could help me understand how compression rati works in this case. Assuming I have JPEG lossless coder that encodes the following ...
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1answer
1k views

How Could One Imitate Photoshop's Vibrance Filter with OpenCV?

Can somebody please explain how Photoshop vibrance function can use in opencv c++ ? so that I may reproduce the same effects in my application. Here is the vibrance ...
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1answer
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Why Wavelet based Transform Is More Suitable for Image Compression Compared to DCT?

Everyone knows that JPEG2000 can obtain much better compression result than JPEG. The fundamental transform behind JPEG2000 is wavelet while the basic transform in JPEG is DCT. So my question is why ...
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1answer
102 views

Is this jumbled image due to difference between Matlab and Python slicing?

When I import an image from Matlab I get the following jumbled image rather than the (224x224x3 RGB) image of a single elephant I expected I write the image from Matlab as a binary file ...
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1answer
537 views

Estimating scaling and translation between two consecutive temporal images

I have two camera images taken from a camera mounted over a vehicle at time $t$ and $t+1$. I need to estimate the scaling and translation in the images in spatial domain itself so that information ...
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1answer
139 views

image reconstruction using a set of kernels

I try to be brief. For what I understood Convolutional Neural Network CNN for style-transfer extract/learn the main features of source Image. I think these features basically are Kernels (of different ...
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1answer
7k views

An alternative algorithm for blob detection

Here's a sample image of my experiment which is to be processed for finding the information of all the blobs (centre, dimension etc.). Basically the image contains some noise, few bold lines, and of ...
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1answer
327 views

Problems filtering image with prewitt

I'm trying to filter an image vertically to get the edges, in MATLAB, but I get very different results from convultion and correlation. CODE: ...
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1answer
499 views

why multiply grayscale images by 256

I am a newbie in image processing. in an open source code for convolution neural networks, the author is multiplying a gray scale image from MNIST dataset by 256. Please can any one tell me why? ...
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1answer
173 views

Digital Image Processing Framework

i'm looking for a free/opensource solution for digital image processing with reasonable performances processing quite large images (e.g. actual smartphones have resolutions of 8-10Mpx) and being ready ...
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1answer
112 views

opencv otsu binarization not working

I tried to apply opencv OTSU binarization on the following image, but it generate a black image. Here is the following python code: ...
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3answers
6k views

How to Calculate the Local Gradient of an Image in MATLAB

I know that the gradient function is supported by MATLAB, but the local gradient is not, so how do you calculate it? Local gradient is another texture descriptor, which is defined as: $$I_g=\...
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2answers
442 views

Is Image Noise Removal Image Enhancement or Image Restoration Operation? [closed]

I am working in digital image processing field, recently I am studying about Image Noise, I just want to know that whether this noise removal is part of image enhancement or image restoration. I ...
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2answers
63 views

What are some current algorithm(s) for finding if two images are copies of each other?

Could anyone enlighten me on what are the current best ways to detect if two images are the same (i.e. a copy or edited copy of each other)? What feature detection method do they use (SIFT, DWT, pixel ...
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2answers
33 views

Is there a way to measure each pixel's content in an image somehow?

Is there a way to measure each pixel's content in an image somehow? Like can I interpret each color as some kind of a single value, rather than a triplet? Perhaps I can think of them as $\mathbb{R}^...
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1answer
231 views

general n-dimensional name of Pixel and Voxel

In 2D images we call the smallest picture elements pixels, in 3D images we call them Voxels (for volume pixels). I was wondering if there is a word that can denote them both (pixel and voxel), and ...
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28 views

Print Image from pixel data - Matlab

I have the pixel data of an image in a 1x256 vector where each cell represents a pixel of a 16x16 image. I have written the following code in Matlab but I am not getting what is expected as an output ...
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1answer
4k views

10 bit pixels convert to RGB

I have a camera which is providing me raw, binary data with 10 bit data. It follows the Bayer pattern RGGB, and each pixel is saved using 16 bit chunks. I am able to demosaic the image almost ...
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1answer
990 views

Image Denoising with Better Edge Preservation

I have the input image : and the output of vein detection for the leaf using a Gabor filter, but the output is really noisy: I tried using Total variation denoising however the results are not good: ...
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2answers
45 views

Creating derivative images, based on original, that can only be visually understood when stacked

I've been thinking about this for a while. What I have been trying to accomplish is a way of taking an image (png specifically, or any other format that allows transparency) and generating N ...
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2answers
392 views

How to reconstruct an image from s-parameters in Matlab?

I have a set of data which is the s-parameter (s11), consisting of 2 columns ($1001 \times 2$). The first column represents the frequency and the second column is the magnitude in dB. I need to use ...
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2answers
180 views

Physical significance of resolution in image processsing

What is the physical interpretation/significance of resolution? Technically, it is the number of pixels used to denote an image but what is it that this resolution tries to convey to us?
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1answer
11k views

3D Position estimation using 2D camera

I have a camera (iPhone), I have a 3D control object in the image that I know its properties very well. (My control object). There is also a secondary object in motion. The ultimate goal is to ...
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0answers
45 views

sharpness in DCT domain image

How can we calculate the sharpness of Discrete Cosine Transform domain of an image?Is it worthy in image quality assessment?
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2answers
665 views

Method to remove small unwanted region and fill holes for specific image

I have a binary image that maintains some unwanted region (small white dot) and hole regions (in figure 1). My idea is that to fill the object after I will remove the unwanted region but I don't now ...
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2answers
2k views

Transform RGB image to *look like* Infrared

Context: I'm trying to improve a pose estimation model so that it works better when my camera is in Infrared mode. Unfortunately I only have RGB images to train on. I realize that you can't convert ...
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0answers
181 views

How to obtain the relative position (coordinates) of SIFT feature from image center coordinates?

I have extracted SIFT features (keypoints and descriptors) of training set and saved in an inverted index form. My question is how can I calculate the coordinates of each visual features in an image ...
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3answers
585 views

How to go about implementing a program to measure the “intensity”/“saturation” of a color in an image?

I have a task of developing an application to measure the intensity of a color in an image. I am researching about how to go about it. Intensity refers to the purity of a hue. Intensity is also ...
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1answer
237 views

Finding filaments in an image

I am at the moment working on images such as this one: What you see are filamentous structures / bundles. Other images coming from slightly different experiments could have more sparse / thick / ...
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1answer
547 views

Saliency Map based on itti model

i want to create a Saliency Map based on itti model via OpenCV(Python). what i'm doing is that: 1- first i change image color space from RGB to LAB color space 2- for each color channel, i create a ...
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0answers
41 views

Bitmap comparison bounded by limitations in human visual perception? [closed]

I need to do a pixel-for-pixel comparison between a 'candidate' image generated by a deep-neural-net against an 'ideal' image. Rather than just comparing RGB values, I'd like to do a comparison that ...
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1answer
145 views

What is difference between along the edge and across the edge

I am trying to implement a paper called structured tensor based image interpolation. In the paper I came across a concept called tangent direction and normal direction. What they mean is tangent ...
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1answer
330 views

How to learn image processing / computer vision in a practical way?

I am new to the field of image processing / computer vision and I find it very hard to get my hands on the subject. I read a lot about the basics/theory but I feel in no way able to use this knowledge ...
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2answers
2k views

How to calculate transfer rate and needed bandwidth

I have two questions: 1- If I want to transfer a photo via bluetooth, how should I find how long it takes to transfer? I mean the formula between the image size, bluetooth bandwidth and time. 2- If ...
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1answer
99 views

How to find derivative of an image along a radial direction with an arbitrary center of rotation?

I want to find the derivative of an image along a radial direction. For instance, in the image below I want to find the gradient at a point $P$ of the image, along the direction of the circumference ...
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2answers
12k views

What are True Positive and False Positive with reference to image processing

Say for instance, face detection algorithms - I see researchers testing their algorithms and table their results under TP and FP....
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2answers
1k views

What is Gamma correction - is my beginner's interpretation right?

I've started a course on image processing for beginners, and am trying to understand Gamma and Gamma Correction. Unfortunately, I seem to have come across conflicting explanations across multiple ...
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1answer
542 views

How would a Linear Gray Level Transform affect an image? [closed]

There are three basic gray level transformation. Linear Logarithmic Power – law The overall graph of these transitions has been shown below. I am assuming a Linear Gray Level ...
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1answer
90 views

How to express one image in terms of another one

I have two (black and white) images of identical size - let's say 128x128 pixels. I'm interested in expressing Im2 in terms of ...
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2answers
389 views

Why does gamma correction of image use two different definitions of gamma?

I've noticed that the gamma value used in level adjustment of Photoshop and Canvas is 'opposite' of gamma values defined in Wikipedia or MATLAB imadjust ...
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0answers
378 views

SSIM index: Clearly explained

I am trying to understand the SSIM index to compare two images for similarity, but I am having difficulties understanding how it is done. Therefore, I would like to ask, if someone can explain it ...

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