Sample images for opencv

Sample images for opencv. One of the common feature extraction techniques is edge detection using the Canny algorithm. See emscripten Module API for more details. Let’s start reading an image. 3 : –match_conf 0. It is the extraction of meaningful information from videos or images. Aug 16, 2021 · With the usual OpenCV procedure, we extract the image, in this case, Messi1. OpenCV. 3 days ago · As a first step, we read the image "starry_night. cpp; samples/cpp/tutorial_code/HighGUI/AddingImagesTrackbar. They get a frame from camera, do some processing with OpenCV and visualize the frame on a device screen. Jan 8, 2013 · If the scaling parameter alpha=0, it returns undistorted image with minimum unwanted pixels. As you can tell, EAST is quite accurate and relatively fast taking approximately 0. The word, “ALTO” is correctly detected by OpenCV and EAST. Jan 8, 2013 · fld_lines. OpenCv library can be used to perform multiple operations on videos. The first step is to read in the image, using the imread() function in OpenCV. 4 days ago · Introduction. This may be: IMREAD_COLOR loads the image in the BGR 8-bit Feb 25, 2020 · What is camera calibration? The process of estimating the parameters of a camera is called camera calibration. So, we take a new image (left12. cuda. pyplot as plt import matplotlib. Problems using the math. Below we will see an example of how to change a particular region of an image. Specify a single frame Sep 15, 2020 · By default, each of the OpenCV CUDA algorithms uses a single GPU. An example in python Jan 8, 2013 · cout << "\nThis program demonstrates the use of cv::CascadeClassifier class to detect objects (Face + eyes). In the last session, we saw basic concepts like epipolar constraints and other related terms. We are now ready to apply image alignment and registration using OpenCV! Use the “Downloads” section of this tutorial to download the source code and example images. Sep 17, 2018 · Figure 5: A more complicated picture of a sign with white background is OCR’d with OpenCV and Tesseract 4. Sample – image-manipulations – this example demonstrates how OpenCV can be used as an image processing and manipulation library. Given this thresholded image, it’s simple to apply contour detection to to find the outlines of these white regions (Lines 58 May 7, 2024 · In OpenCV Python, the normalize() function from the cv2 module is used to normalize images. Actually, if you check the type of the img, it will give you the following result: >>>print(type(img)) <class 'numpy. How it works ? Using PIL library we are opening 3 days ago · Warning. Can't compile . Introduction to Object Detection with OpenCV. Goals. 1 without prior Gaussian smoothing (which is performed by pyrDown C++ function). imread function to load an input image from disk, determine the image’s width, height, and number of channels, display the loaded image to our screen, and write the image back out to disk as a different image filetype. There are also several sample applications written mostly in Java. Aug 12, 2024 · 4. They may have variations with slightly different backgrounds, dimensions, feature additions/subtractions, or transformations (scaled, rotated, skewed). : –conf_thresh 0. Sometimes, you will have to play with certain regions of images. So use it only if necessary. e. py file and copy all input images in an input subfolder. In the epipolar geometry & stereo vision article of the Introduction to spatial AI series, we discussed two essential requirements to estimate the depth (the 3D structure) of a given scene: point correspondence and the cameras’ relative position. We use image hashing for CBIR, near-duplicate detection, and reverse image search engines. 4 days ago · Bitwise Operations. polyline() function to generate same image as above. Template Matching. imshow, our images must be unsigned 8-bit integers in the range [0, 255] — Lines 81 and 82 take care of that operation for us. C++ version only: intensity. Jan 8, 2013 · The explanation below belongs to the book Learning OpenCV by Bradski and Kaehler. -bg <background_file_name>: Background description file. Since in OpenCV images are represented by the same structure as matrices, we use the same convention for both cases - the 0-based row index (or y-coordinate) goes first and the 0-based column index (or x-coordinate) follows it. This function takes an image and resizes it to the specified dimensions. Well, here you adjust the values of histograms along with its bin values to look like x,y coordinates so that you can draw it using cv. \n" Mar 22, 2021 · # draw the bounding box on the image cv2. The cross-platform library sets its focus on real-time image processing and includes patent-free implementations of the latest computer vision algorithms. In this tutorial, we will focus on training your own models using OpenCV’s machine learning module. May 21, 2023 · Feature Detection and Extraction. OpenCV-Python is the Python API for OpenCV. Jul 24, 2023 · import matplotlib. ) using imread. Compile OpenCV with samples by setting BUILD_EXAMPLES to ON in cmake configuration. The Hough Line Transform is a transform used to detect straight lines. OpenCV or open-source Computer Vision Library is a Python library designed to help developers seamlessly integrate computer vision applications with machine 4 days ago · For some cameras we may need to flip the input image. Save all frames of the video as image files; Save given frames as image files. Then we do the “face encoding” with the functions of the Face recognition library. Go to bin folder and use imagelist_creator to create an XML/YAML list of your images. After reading the image, we also blur it, using the GaussianBlur() function. Python OpenCV cv2 Tutorial covers basic and intermediate Image Processing techniques like: read image, working with color channels, finding contours, resizing, capturing video, etc. OpenCV comes with a function cv. watershed() Theory . Double-click the Visual Studio Solution (. onRuntimeInitialized() when its ready. The resulting component is then added to our list of images for visualization. Sample file attached . Below are some of the examples by which we can understand about normalizing images in OpenCV Python: Example 1: Normalizing Sep 3, 2018 · Captured images of each of the patterns on the object being scanned - around 44 images if projector was 1024 x 768 resolution Known projector resolution Calibration files containing intrinsic and extrinsic information for the setup that acquired the pattern images on the two cameras. For eye detection in images, first face detection is done over the entire image. Stitcher_create functions. Feature extraction and detection is the first and most important stage in the image stitching pipeline. This sample calculates the minimum Hamming distance for the generated dictionary and also allows you to create markers that are resistant to reflection. This tutorial will teach us how to detect objects using the OpenCV library. Threshold for two images are from the same panorama confidence is 0. image as mpimg # prepare object points nx = 8 3 days ago · Confidence for feature matching step is 0. Below is an image and some simple mathematical formulas which prove that Oct 19, 2022 · If you simply want to save a video as a frame-by-frame still image, you can do so with ffmpeg commands, but if you want to do some image processing before saving, Python and OpenCV are useful. To learn more about face recognition with OpenCV, Python, and deep learning, just keep reading! Jun 21, 2023 · Starting in the folder where you unzipped the samples, go to the Samples subfolder, then the subfolder for this specific sample, then the subfolder for your preferred language (C++, C#, or JavaScript). Annotating Images Using OpenCV. LPF helps in removing noise, blurring images, etc. 6 days ago · After obtaining face features feature1 and feature2 of two facial images, run codes below to calculate the identity discrepancy between the two faces. resize(image, (width, height)) What are the parameters for resizing Nov 12, 2018 · images/: This folder contains four static images which we’ll perform object detection on for testing and evaluation purposes. Let's see how to create video using multiple images using OpenCV. -numPos <number_of_positive_samples>: Number of positive samples used in training for every classifier stage. C++ double cos_score = faceRecognizer->match(feature1, feature2, FaceRecognizerSF::DisType::FR_COSINE); May 10, 2021 · Simple — our eigenvalue decomposition results in real-valued feature vectors, but in order to visualize images with OpenCV and cv2. We discuss OpenCV functions, their syntax and options. 14 seconds on average per image. rectangle on Line 38 draws the bounding box on the image. To switch active device use cv::cuda::setDevice (cv2. cpp; samples/cpp/connected_components. Jan 8, 2013 · Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below). Common and Video are simple data handling and opening routines that you can find in the OpenCV Python Samples directory or from the github repo linked above. This is Jan 8, 2013 · Goal . jpg') # Resize the image resized_image = cv2. fastNlMeansDenoising() - works with a single grayscale images; cv. cpp; samples/cpp/pca. Open Source Computer Vision Library https://opencv. In OpenCV you can easily read in images with different file formats (JPG, PNG, TIFF etc. cu file when including opencv. Image ROI . OpenCV is used for all sorts of image and video analysis, like facial recognition and detection, license plate reading, photo editing, advanced robotic vision, optical character recognition, and a whole lot more. In this chapter, We will learn to use marker-based image segmentation using watershed algorithm; We will see: cv. OpenCV template matching results -vec <vec_file_name>: vec-file with positive samples (created by opencv_createsamples utility). You can decrease this value if you have some difficulties to match images. It supports several Jan 8, 2013 · Several algorithms were designed for this purpose and OpenCV provides two of them. py and detect_edges_video. Jan 8, 2013 · Use the OpenCV class cv::PCA to calculate the orientation of an object. All the time you are working with a NumPy array. Hello Readers!! OpenCV – Open Source Computer Vision. Now , I went to test this code with my own image , on the left is an image of a flash drive , and on the right is an image of a scissor with an usb drive . Your upscaled image is located in 'img_new'. 3 You can decr␂ease this value if you have some difficulties to match images Sep 21, 2020 · In this tutorial, you will build a basic Automatic License/Number Plate Recognition (ANPR) system using OpenCV and Python. imwrite() function of OpenCV python library. It is one of the most widely used tools for computer vision and image processing tasks. If you need to utilize multiple GPUs, you have to manually distribute the work between GPUs. jpg' # image = cv2. To save an image to the local file system, use cv2. In this article, we will learn how to use contours to detect the text in an image and save it to 6 days ago · We will learn to create a depth map from stereo images. The array of sub-images the split_images function returns is of size (50, 100, 20, 20). 04. OpenCV in python helps to process an image and apply various functions like resizing image, pixel manipulations, object detection, etc. 2 days ago · You can deduct from the above graph that, blue has some high value areas in the image (obviously it should be due to the sky) 2. Run the sample Jan 30, 2024 · Crops an image patch of equivalent size to the sub-images that feature the digits (i. Hough Line Transform. webp, and convert it into RGB color format. The second argument is optional and specifies the format in which we want the image. To learn more refer: Read, Display and Write an Image using OpenCV. line() or cv. The most basic morphological operations are: Erosion and Dilation. This stage entails locating different keypoints in each Jan 8, 2013 · The method cv::ml::SVM::predict is used to classify an input sample using a trained SVM. Learn to: Blur images with various low pass filters; Apply custom-made filters to images (2D convolution) 2D Convolution ( Image Filtering ) As in one-dimensional signals, images also can be filtered with various low-pass filters (LPF), high-pass filters (HPF), etc. Feeds the HOG descriptors into the trained SVM to obtain a label prediction. This function also returns an image ROI which can be used to crop the result. Using OpenCV. Thanks. Learn how to Read, Display and Write an Image using OpenCV. Then simple upscale. Data like this. imread('image. Welcome to a tutorial series, covering OpenCV, which is an image and video processing library with bindings in C++, C, Python, and Java. Subscribe to the OpenCV YouTube Channel featuring OpenCV Live, an hour-long streaming show; Follow OpenCV on LinkedIn for daily posts showing the state-of-the-art in computer vision & AI; Apply to be an OpenCV Volunteer to help organize events and online campaigns as well as amplify them; Follow OpenCV on Mastodon in the Fediverse; Follow May 3, 2012 · Is there a built-in way to downsample an image in OpenCV 2. Mar 11, 2018 · In this post, we will learn how to perform feature-based image alignment using OpenCV. org OpenCV samples (Images) | Kaggle Kaggle uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Is there a repository of those images somewhere? 2 days ago · OpenCV offers support for the image formats Windows bitmap (bmp), portable image formats (pbm, pgm, ppm) and Sun raster (sr, ras). In the above input images we can see heavy overlap between the two input images. The hsplit and vsplit methods are then used to split the NumPy array horizontally and vertically, respectively. sln) file. Jan 8, 2013 · For some cameras we may need to flip the input image. This directory contains four sample videos for you to test with. It simply slides the template image over the input image (as in 2D convolution) and compares the template and patch of input image under the template image. OpenCV (Open Source Computer Vision) is a popular computer vision library started by Intel in 1999. Histograms in OpenCV. When resizing an image: Various interpolation techniques come into play to accomplish these operations. The Canny edge detection algorithm smooths the image to reduce noise, calculates the gradient to find edge strength and direction, applies non-maximum suppression to thin edges, and uses hysteresis for final edge tracking, resulting in a black and white image with edges in Jun 18, 2018 · As we’ll see, the deep learning-based facial embeddings we’ll be using here today are both (1) highly accurate and (2) capable of being executed in real-time. cpp; samples/cpp/convexhull. Reading and Writing Videos using OpenCV. rectangle(image, (startX, startY), (endX, endY), (255, 0, 0), 3) # show the output image cv2. Install the following libraries: PIL cv2 Also, check the path before running the code otherwise you will be full with errors. So it may even remove some pixels at image corners. 3 days ago · Also you could use aruco_dict_utils. This is the file containing the negative sample images. ndarray'> It’s a NumPy array! That why image processing using OpenCV is so easy. inpaint() First algorithm is based on the paper **"An Image Inpainting Technique Based on the Fast Marching Method"** by Alexandru Telea in 2004. Jan 8, 2013 · As a first step, we read the image "starry_night. Reading, displaying, and writing images are basic to image processing and computer vision. val[0] contains a value from 0 to 255. png and box_in_scene. videos/: After performing object detection with YOLO on images, we’ll process videos in real time. 3’s brand new (totally overhauled) dnn module to detect objects in images. build problems for android_binary_package - Eclipse Indigo, Ubuntu 12. Jan 4, 2023 · In current scenario, techniques such as image scanning, face recognition can be accomplished using OpenCV. In short: A set of operations that process images based on shapes. However, I am hoping to find the images they used in the tutorials so that I can reproduce results. We will share code in both C++ and Python. They will be highly useful while extracting any part of the image (as we will see in coming chapters), defining and working with non-rectangular ROI's, and etc. If alpha=1, all pixels are retained with some extra black images. 3 days ago · For some cameras we may need to flip the input image. 2 days ago · samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo. Image Transforms in OpenCV. Jul 1, 2021 · Introduction. Hough Line Transform . imread(image_path) # Uncomment this line if using OpenCV # image For color images, image is converted to CIELAB colorspace and then it separately denoise L and AB components. Aug 31, 2020 · OpenCV image alignment and registration results. jpg in this case. Delete image window from the memory after displaying using destroyAllWindows() function. import cv2 # Load the image image = cv2. imshow("Output", image) cv2. Image Resizing with OpenCV. Again, notice how our OpenCV OCR pipeline was able to correctly localize and recognize the text; however, in our terminal output we see a registered trademark Unicode symbol — Tesseract was likely confused here as the bounding box reported by OpenCV’s EAST text detector bled into May 24, 2023 · OpenCV (Open source computer vision) is a library of programming functions mainly aimed at real-time computer vision. Use square size equal to 3cm. Theory Note The explanation below belongs to the book Learning OpenCV by Bradski and Kaehler. createStitcher and cv2. The main addition to the panorama is towards the right side of the stitched images where we can see more of the “ledge” is added to the output. Meet different Image Transforms in OpenCV like Fourier Transform, Cosine Transform etc. jpg" from the OpenCV samples. SetDevice) function. Load color or grayscale JPG, transparent PNG / TIFF, and 16-bit / channel images. Image Analysis is a very common field in the area of Computer Vision. Aug 9, 2024 · How to resize images using OpenCV? To resize an image using OpenCV, you use the cv2. Image Translation and Rotation Using OpenCV. We also saw that if we have two images of same scene, we can get depth information from that in an intuitive way. The final result of the image is just a dummy atm and the script isn't complete yet. Jun 20, 2024 · Step 4: Use Edge Detection. OpenCV provides samples on how to work with already implemented methods with GPU support using Nov 27, 2017 · Figure 1: Image hashing (also called perceptual hashing) is the process of constructing a hash value based on the visual contents of an image. Jul 5, 2023 · The image is now treated as a matrix with rows and columns values stored in img. 4 days ago · Test data: use images in your data/chess folder. Then, run calibration sample to get camera parameters. Reading and writing videos in OpenCV is very similar to reading and writing images. Morphological Operations . Feb 8, 2019 · After applying findChessboardCorners() and drawChessboardCorners() import numpy as np import cv2 import matplotlib. This may be: IMREAD_COLOR loads the image in the BGR 8-bit 3 days ago · If the scaling parameter alpha=0, it returns undistorted image with minimum unwanted pixels. In order to do so, a call to the cv::imread function loads the image using the file path specified by the first argument. Sample Demo. Mar 30, 2024 · For context, refer to this article on image recognition with AI. Learn to search for an object in an image using Template Matching. h class with OpenCV (c++, VS2012) How to reduce false positives for face detection. cpp; samples/cpp/cout_mat. Image Denoising in OpenCV . cv. Mar 26, 2020 · Paste the code into a . HPF filters help in finding edges in images. All about histograms in OpenCV. This includes the bitwise AND, OR, NOT, and XOR operations. Typically, two images will not be exactly the same. Stores the image patch coordinates whenever a detection is found. You can use Haar or LBP features. To apply the Transform, first an edge detection pre-processing is desirable. To read the images cv2. From there, open up a terminal, and execute the following command: Nov 1, 2013 · I downloaded the two images at the bottom box. Sep 11, 2017 · Specifically, we used both MobileNets + Single Shot Detectors along with OpenCV 3. cpp sample inside the opencv/samples/cpp. Cropping an Image using OpenCV. Extracts the HOG descriptors of every image patch. py scripts. Normalize an Image in OpenCV Python. Jan 8, 2013 · Introduction . OpenCV, short for Open Source Computer Vision Library, is a powerful library that provides tools and functionalities for various computer vision tasks, including image and video processing, feature extraction, and machine learning. Press Ctrl+Shift+B, or select Build > Build Solution. cpp; samples/cpp/contours2. What is PCA? Principal Component Analysis (PCA) is a statistical procedure that extracts the most important features of a dataset. Otherwise go for Numpy indexing. cpp Jun 19, 2018 · I have been following tutorials from the official OpenCV documentations. May 25, 2015 · Figure 4: Thresholding the frame delta image to segment the foreground from the background. This function allows us to specify the desired range for the pixel intensity values. An ANPR-specific dataset, preferably with plates from various countries and in different conditions, is essential for training robust license plate recognition systems, enabling the model to handle real-world diversity and complexities. Modules Needed: import cv2 Jan 8, 2013 · img. So, all you need to do is loop over all the frames in a video sequence, and then process one frame at a time. 2 days ago · Template Matching is a method for searching and finding the location of a template image in a larger image. 3 days ago · Now we can upscale any image. Video On Label OpenCV Qt :: hide cvNamedWindows. Find the pattern in the current input. copyMakeBorder(). split() is a costly operation (in terms of time). imread() method is used. In other words, an image is traversed interpreting its pixels as points of the Cartesian plane. Feb 26, 2024 · OpenCV(Open Source Computer Vision) is an open-source library for computer vision, machine learning, and image processing applications. Apr 7, 2015 · OpenCV C++ and Python examples for reading images (imread). 3. And by the end of the tutorial you’ll be putting together a complete project to count basic objects in images using contours. hpp 6 days ago · All about Contours in OpenCV. Color spaces in OpenCV (C++ / Python) Image Filtering Using Convolution in OpenCV Jul 19, 2018 · Inside this guide, you’ll learn basic image processing operations using the OpenCV library using Python. Learn to detect lines in an image Aug 20, 2018 · This scene contains a Spanish stop sign. resize() function. The image has dimensions (540, 960, 3), representing the height, width, and three color . Making Borders for Images (Padding) If you want to create a border around an image, something like a photo frame, you can use cv. cpp; samples/cpp/camshiftdemo. 4 days ago · Whenever you work with video feeds you may eventually want to save your image processing result in a form of a new video file. Dec 17, 2018 · In this tutorial, you will learn how to perform image stitching using Python, OpenCV, and the cv2. js form the current folder, and, as said previously emscripten will call Module. Basics. Jul 18, 2012 · Method #2: Dense Vector Representations. To install it, open the command prompt and execute the command in the command line: pip install opencv-python Build sample OCR Script Reading a sample Image import cv2 Introduction . The following sample code is shown here. Working with images . Manual dictionary definition. For simple video outputs you can use the OpenCV built-in cv::VideoWriter class, designed for this. Note the ordering of x and y. I'll try to continue it in the next couple of days. Come, let’s learn about image resizing with OpenCV. How to create a video file with OpenCV; What type of video files you can create with OpenCV Apr 5, 2021 · Demo video of obstacle avoidance with stereo vision Using OAK-D (source link) Recap of learning from the first two posts of this series. Pose estimation Jan 8, 2013 · In this case we load the file opencv. We would like to show you a description here but the site won’t allow us. Today most digital images and imaging devices use 8 bits per channel thus limiting the dynamic range of the device to two orders of magnitude (actually 256 levels), while human eye can adapt to lighting conditions varying by ten orders of magnitude. The script will create a debug subfolder where it'll save some images that show the current detection state. To resize an image, scale it along each axis (height and width), considering the specified scale factors or just set the desired height and width. In this example we have used this method in order to color the space depending on the prediction done by the SVM. Jan 30, 2024 · The function subsequently applies the OpenCV imread method to load a grayscale version of the image into a NumPy array. fastNlMeansDenoisingColored() - works with a color image. Mar 4, 2019 · I’ve provided a number of sample images/ including one of myself, my dog, and a sample cat image I found on the internet. Lines 41 and 42 then show our output image on our screen. Feb 28, 2024 · Sample applications. We will demonstrate the steps by way of an example in which we will align a photo of a form taken using a mobile phone to a template of the form. Using today’s code you’ll be able to stitch multiple images together, creating a panorama of stitched images. It provides a wide sense of image processing. Mar 20, 2017 · Great! Now we have an image in memory which we can now manipulate however we like in our python script. dtype is very important while debugging because a large number of errors in OpenCV-Python code are caused by invalid datatype. C:\fakepath Jan 20, 2021 · In this tutorial, you will learn how to use OpenCV and the cv2. OpenCV provides four variations of this technique. waitKey(0) A call to cv2. This means we have all the information (parameters or coefficients) about the camera required to determine an accurate relationship between a 3D point in the real world and its corresponding 2D projection (pixel) in the image captured by that calibrated camera. When working with OpenCV Python, images are stored in NumPy ndarray. pyplot as plt # Load and read the image using PIL or OpenCV image_path = '/content/Lata. Today we’re going to review the detect_edges_image. png to validate the correctness of this code , I was alright . 32-bit float 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel) If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way. A video is nothing but a series of images that are often referred to as frames. js doesn't support image formats so we can't load png or jpeg images directly. Load an image via the standard 'imread' function and create a new Mat for the destination image. cpp; samples/cpp/tutorial_code First we need to import the relevant libraries: OpenCV itself, Numpy, and a couple of others. Any grayscale image can be viewed as a topographic surface where high intensity denotes peaks and hills while low intensity denotes valleys. Jul 30, 2024 · As we know OpenCV is a widely used library for image processing. Here, we read in the color image as a grayscale image because you do not need color information to detect edges. Finally, the dictionary can be configured manually, so that any encoding can be used. Area of a single pixel object in OpenCV. As a computer vision and deep learning community we owe a lot to the contributions of Aleksandr Rybnikov, the main contributor to the dnn module for making deep learning so accessible Jan 8, 2013 · Use the OpenCV functions HoughLines() and HoughLinesP() to detect lines in an image. While working with images in Image Processing applications, quite often, you may need to store intermediate results of image transformations or save the final resulting image. Again, note that the background of the image is black, whereas the foreground (and where the motion is taking place) is white. , 20 $\times$ 20 pixels) from the test image at every iteration. Here we do this too. Both can be accessed by the same function, cv. matchTemplate() for this purpose. 3 days ago · cv::String findFile(const cv::String &relative_path, bool required=true, bool silentMode=false) Sep 3, 2018 · Figure 3: Semantic segmentation with OpenCV reveals a road, sidewalk, person, bycycle, traffic sign, and more! Notice how accurate the segmentation is — it clearly segments classes and accurately identifies the person and bicycle (a safety issue for self-driving cars). May 23, 2021 · Here is a list of tutorials in this series: Read, Display and Write an Image using OpenCV. Morphological operations apply a structuring element to an input image and generate an output image. Both scripts share the same edge detection process, so we’ll be spending most of our time on the HED image script. using cv2. Dec 14, 2019 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand Jan 11, 2016 · Figure 4: Applying image stitching and panorama construction using OpenCV. The formation of the equations I mentioned above aims to finding major patterns in the input: in case of the chessboard this are corners of the squares and for the circles, well, the circles themselves. mutaz gqbe nbaos faif nth qbnqq vrutbu fmemg ubryb lbbsp