Questions tagged [opencv]

Open Source Computer Vision Library (OpenCV) is an open source machine learning library used primarily for computer visions applications. OpenCV contains over 2,500 optimized algorithms (including state of the art computer vision ones).

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851 views

Skin Detection From a Face Image

I have photos of people's faces, and I want to detect each person's skin color for later use. I don't want to use predetermined color ranges, instead I want to determine each person's color and then ...
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1answer
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illumination problem for face landmark detection

I trained dlib face landmark detection model using ibug and yaleB datasets. Accuracy of the model is dropping when a bright light or a shadow appears on the side face. Used default parameters and ...
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2answers
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shapes recognition for shapes formed by dotted points

In the image, below right corner there is circle shape and triangle shape made with set of co-ordninates.I have searched extensively in the net for algorithm or approach to classify shape correctly ....
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1answer
1k views

Detect blur image using ssdmobilenet and tensorflowlite

I have clear images of cards vs blurry images of card. My task is to capture photo when the image is not blurry, as you can see from the description I need this code to run in real time on android ...
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701 views

How to convert photo to a vector drawing

I am using the following code to convert photo to a drawing: ...
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3answers
28k views

I get this error Expected Ptr<cv::UMat> for argument '%s' while resizing image in open cv2

This is my code: ...
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1answer
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What is difference between "cv2.filter2D" vs Keras "Conv2D" function

When I have to sharpen an image using opencv, I use: ...
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2answers
340 views

How to Extract Information from the Image(PNG)

I'm trying to extract some particular information from the image(png). I tried to extract the text using the below code ...
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1k views

Implement and train YOLO 3 with Opencv and C++

I want to implement and train YOLO 3 with my dataset using Opencv and C++. I can't find an example to start with, or a tutorial to explain how to train YOLO with my own data. All of the tutorials I ...
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Orange widget with OpenCV setMouseCallback

I am designing an Orange Widget for facial recognition. I would like to draw a rectangle around faces captured in video by setting mouse events with ...
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0answers
45 views

Semantic Segmentation using Scipy or Scikit-image

Many days ago I saw a user using scipy function to get region of interest (RoI) in an image using different colors. I believe it was some sort of filter. Now I'm trying to do the same but I'm not able ...
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0answers
140 views

How to detect only the lane boundaries using Hough transform?

This is my code to detect the lane boundaries. But only one line(left most) is detected here. Is there a way to remove other objects from the picture (remove bushes and trees) and detect only the ...
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1answer
346 views

What's the difference between Haar-like Features and Haar Cascades?

Are they the same in terms of their algorithm? Or do they differ in their respective detection methods?
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1answer
70 views

Is there a way (like planning algorithms) to draw a successive polyline to fill a specific shape (like triangle)?

there is a specific shape (like triangle) area, i am trying to develop an program to draw a successive polyline inside the triangle to fill the triangle, one line 3 layers this post demonstrates some ...
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1answer
676 views

Prerequisites for openCV [closed]

I am looking to start learning openCV to perform a car detection program. Should I know data science and/or machine learning stuff before going for openCV? If not, where can I start learning openCV ...
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1answer
65 views

Train ML algorithm to find edges

I have input RGB images as follows: I have a dataset of manually annotated images highlighting the outline(edges) from the input images I am attaching an example. My aim is to train a ML algorithm ...
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1answer
58 views

Detecting unique icon on video in real time

For a project I am working on I'd like to be able to detect unique icons/barcodes in video footage. Suppose you have 10 people in the frame where each person is wearing a t-shirt with a similar but ...
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1answer
147 views

People detection methods

In my problem I want to distinguish people from other shapes in images e.g I want to accurately know how many people are in specific region of image (at least for small number of people, for crowded ...
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1answer
7k views

TypeError: 'tuple' object cannot be interpreted as an integer

I have an image (480,640,3) and I am trying to resize it to (150,150,1). Since my Keras model has been trained on images of shape (150,150,1), unfortunately I cannot seem to resize it using the PIL ...
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2answers
2k views

Why image is more blurred through PIL?

I was using PIL library to open an image and then convert it into array later on for DL operations. However I found out that image opened was blurry as opposed to the original image. Why is the image ...
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2answers
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How can I detect blocks of text from scanned document images

ORIGINAL IMAGE: GOAL: I want to separate texts into individual paragraphs by placing bounding boxes over them (as shown above). I tried it do this via traditional computer vision approach using ...
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1answer
414 views

How can I detect partially obscured objects using Python?

I'm building a computer vision application using Python (OpenCV, keras-retinanet, tensorflow) which requires detecting an object and then counting how many objects are behind that front object. So, ...
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1answer
2k views

Identify credit card shape using machine learning

I have to approach this task: identify credit card from an image. I am attaching example image below: I have to identify and localize the credit card from this image. The real challenge is that the ...
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1answer
168 views

does tensorflow use opencv to covert image to numpy array

Does tensorflow use opencv to covert image to numpy array ? How is feature extraction done in tensorflow ? How is it different from opencv model ?
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2answers
35k views

cv2.error: OpenCV(3.4.3) (-215:Assertion failed) !empty() in function

Would anyone have a tip on how to fix this empty function error in OpenCV? I am attempting to follow the guides on OpenCV.org The script will detect a face in an image and draw boxes around ...
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1answer
794 views

Calculate image width

In this code below, a picture can be loaded into openCV and then the region of interest RIO can be created by just selecting a box around something with the mouse, then press ...
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0answers
530 views

Detecting blinking light on a device

Can anyone tell me good approaches to detect blinking light in a video? The background may change constantly. As of now, the color would remain same but the intensity and angle of vision can change. ...
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2answers
1k views

how to apply similarity algorithm(or comparision) of over one million vectors with other one million vectors?

How can I apply similarity algorithm (or comparison) of over one million vectors with another one million vectors? I am following this pyimage search tutorial but don't know how to scale up the ...
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1answer
2k views

Uniformity of color and texture in an image

I am new to the field of deep learning and have a problem in determining whether two images have uniform color and texture. For example, I have a Master image - Now, with respect to this image i ...
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1answer
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FREAK feature extraction OpenCV

I want to know how to use FREAK feature extraction in python, I read the documentation but I need some examples. I wrote this code : ...
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1answer
1k views

Keypoint matching using HoG and SIFT

I have two images and I've found their keypoints using sift keypoint detector, Now I have to match their keypoints with HoG features, I know how to extract HoG description, but I dont know how to ...
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2answers
42 views

Classifier not predicting real data

I'm trying to train a classifier to recognize my own signature. This is how I built my classifier How did I collect data? Signed on a piece of paper for 50 times and created 50 images out of it. for ...
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1answer
388 views

Opencv kmeans predict equivalent

I'm moving my project from Python's libraries to opencv, and I have one big problem. In Python skylearn, I have kmeans object, which has two useful methods: fit_predict and fit, which both are ...
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70 views

Image processing algorithm [closed]

Can you give me a idea about image processing segmentation algorithm invariant to light that can be implemented in Opencv in Jupyter Notebook?Please!
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1answer
514 views

Bounding box coordinates prediction

How to pass multiple bounding boxes coordinates to CNN model?My goal is to predict the coordinates of texts in an image.
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3answers
731 views

Is it possible to detect a person using facial recognition on the fly?

I am working on a small app for face detection in Python using face_recognition and opencv libraries. I have trained the data ...
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0answers
304 views

Importing TensorFlow trained model in OpenCV

I want to import a TensorFlow pretrained model in OpenCV dnn C++ module. How can this be done? Are there any examples available?
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Python : Feature Matching + Homography to find Multiple Objects

I'm trying to use OpenCV via Python to find multiple objects in a train image and match it with the key points detected from a query image. For my case, I'm trying to detect the tennis courts in the ...

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