Skip to content

Python OpenCV | cv2.imshow() method

cv2.imread() method - Python OpenCV

Last Updated : 14 Apr, 2025

OpenCV-Python is a Python library used to solve computer vision tasks. cv2.imread() method loads an image from the specified file. If the image cannot be read because of missing file, improper permissions or an unsupported/invalid format then it returns an empty matrix.

Example:

Python

import cv2

image = cv2.imread("image.png")

cv2.imshow("Image", image)

cv2.waitKey(0)

cv2.destroyAllWindows()

Output:

gfgjpg — Example Image

Syntax of cv2.imread() Method

cv2.imread(filename, flag)

Parameters:

filename: specifies the path to the image file.
flag: specifies the way how the image should be read which can be :

cv2.IMREAD_COLOR - It specifies to load a color image. Any transparency of image will be neglected. It is the default flag. Alternatively we can pass integer value 1 for this flag.
cv2.IMREAD_GRAYSCALE - It specifies to load an image in grayscale mode. Alternatively we can pass integer value 0 for this flag.
cv2.IMREAD_UNCHANGED - It specifies to load an image such as including alpha channel. Alternatively we can pass integer value -1 for this flag.

The cv2.imread() function return a NumPy array if the image is loaded successfully.

Examples of OpenCV cv2.imread() Method

Below is the sample image we will be using:

cv2.imread() image — Input Image

1. Using cv2 imread() function to read a colored image:

In this example we are reading the image as a color image. We will use cv.imread() function to take the image as an input and cv.imshow() function to display the image.

Python

import cv2
image = cv2.imread("gfg.jpeg")

cv2.imshow("Image", image)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

cv2.imread() image — Colored image

Here we can see that by default our image got read and displayed in coloured image.

2. Reading image in grayscale

In this example we are reading the image as a greyscale image. Both color and grayscale images are acceptable as input.

Python

import cv2

image = cv2.imread("gfg.jpeg",cv2.IMREAD_GRAYSCALE)

cv2.imshow("Image", image)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

cv2.imread() image — Grayscale Image

3. Reading PNG Image with Transparency

In this example we are reading the image with the transparency channel i.e the alpha channel. It represents the transparency or opacity of an image. It controls how transparent or solid each pixel is with value of 0 indicating full transparency and 255 representing full opacity.

Python

import cv2
image = cv2.imread("gfg.jpeg",cv2.IMREAD_UNCHANGED)

cv2.imshow("Image", image)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

cv2.imread() image — Image with Aplha Channel

cv2.imread() method is a fundamental function for reading image files. It loads images into memory allowing us image manipulation and analysis. By specifying the appropriate flag you can control how the image is loaded and used for analysis.

Python OpenCV | cv2.imshow() method

R

Rajnis09

Improve

Article Tags :

Practice Tags :

python

Similar Reads

Essential OpenCV Functions to Get Started into Computer Vision

Computer vision is a process by which we can understand the images and videos how they are stored and how we can manipulate and retrieve data from them. Computer Vision is the base or mostly used for Artificial Intelligence. Computer-Vision is playing a major role in self-driving cars, robotics as w

cv2.imread() method - Python OpenCV

OpenCV-Python is a Python library used to solve computer vision tasks. cv2.imread() method loads an image from the specified file. If the image cannot be read because of missing file, improper permissions or an unsupported/invalid format then it returns an empty matrix.Example:Pythonimport cv2 image

Python OpenCV | cv2.imshow() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.imshow() method is used to display an image in a window. The window automatically fits the image size.Â Syntax: cv2.imshow(window_name, image)Parameters:Â window_name: A string representing the name of the wi

Python OpenCV | cv2.cvtColor() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.cvtColor() method is used to convert an image from one color space to another. There are more than 150 color-space conversion methods available in OpenCV. We will use some of color space conversion codes be

Python OpenCV | cv2.imwrite() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.imwrite() method is used to save an image to any storage device. This will save the image according to the specified format in current working directory. Syntax: cv2.imwrite(filename, image) Parameters:file

Python OpenCV | cv2.rectangle() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.rectangle() method is used to draw a rectangle on any image. Syntax: cv2.rectangle(image, start_point, end_point, color, thickness) Parameters:image: It is the image on which rectangle is to be drawn. start

Python OpenCV | cv2.circle() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.circle() method is used to draw a circle on any image. The syntax of cv2.circle() method is: Syntax:Â cv2.circle(image, center_coordinates, radius, color, thickness) Parameters:Â image: It is the image on w

Python OpenCV | cv2.line() method

OpenCV-PythonÂ is a library of Python bindings designed to solve computer vision problems. cv2.line() method is used to draw a line on any image.Syntax:cv2.line(image, start_point, end_point, color, thickness) Parameters: image: It is the image on which line is to be drawn.Â start_point: It is the sta

Python OpenCV | cv2.putText() method

OpenCV-Python is a library of Python bindings designed to solve computer vision problems. cv2.putText() method is used to draw a text string on any image. Syntax: cv2.putText(image, text, org, font, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]]]) Parameters:image: It is the image on w

Line detection in python with OpenCV | Houghline method

The Hough Transform is a method that is used in image processing to detect any shape, if that shape can be represented in mathematical form. It can detect the shape even if it is broken or distorted a little bit.We will see how Hough transform works for line detection using the HoughLine transform m

'); // $('.spinner-loading-overlay').show(); let script = document.createElement('script'); script.src = 'https://assets.geeksforgeeks.org/v2/editor-prod/static/js/bundle.min.js'; script.defer = true document.head.appendChild(script); script.onload = function() { suggestionModalEditor() //to add editor in suggestion modal if(loginData && loginData.premiumConsent){ personalNoteEditor() //to load editor in personal note } } script.onerror = function() { if($('.editorError').length){ $('.editorError').remove(); } var messageDiv = $('

').text('Editor not loaded due to some issues'); $('#suggestion-section-textarea').append(messageDiv); $('.suggest-bottom-btn').hide(); $('.suggestion-section').hide(); editorLoaded = false; } }); //suggestion modal editor function suggestionModalEditor(){ // editor params const params = { data: undefined, plugins: ["BOLD", "ITALIC", "UNDERLINE", "PREBLOCK"], } // loading editor try { suggestEditorInstance = new GFGEditorWrapper("suggestion-section-textarea", params, { appNode: true }) suggestEditorInstance._createEditor("") $('.spinner-loading-overlay:eq(0)').remove(); editorLoaded = true; } catch (error) { $('.spinner-loading-overlay:eq(0)').remove(); editorLoaded = false; } } //personal note editor function personalNoteEditor(){ // editor params const params = { data: undefined, plugins: ["UNDO", "REDO", "BOLD", "ITALIC", "NUMBERED_LIST", "BULLET_LIST", "TEXTALIGNMENTDROPDOWN"], placeholderText: "Description to be......", } // loading editor try { let notesEditorInstance = new GFGEditorWrapper("pn-editor", params, { appNode: true }) notesEditorInstance._createEditor(loginData&&loginData.user_personal_note?loginData.user_personal_note:"") $('.spinner-loading-overlay:eq(0)').remove(); editorLoaded = true; } catch (error) { $('.spinner-loading-overlay:eq(0)').remove(); editorLoaded = false; } } var lockedCasesHtml = `You can suggest the changes for now and it will be under 'My Suggestions' Tab on Write.

You will be notified via email once the article is available for improvement. Thank you for your valuable feedback!`; var badgesRequiredHtml = `It seems that you do not meet the eligibility criteria to create improvements for this article, as only users who have earned specific badges are permitted to do so.

However, you can still create improvements through the Pick for Improvement section.`; jQuery('.improve-header-sec-child').on('click', function(){ jQuery('.improve-modal--overlay').hide(); $('.improve-modal--suggestion').hide(); jQuery('#suggestion-modal-alert').hide(); }); $('.suggest-change_wrapper, .locked-status--impove-modal .improve-bottom-btn').on('click',function(){ // when suggest changes option is clicked $('.ContentEditable__root').text(""); $('.suggest-bottom-btn').html("Suggest changes"); $('.thank-you-message').css("display","none"); $('.improve-modal--improvement').hide(); $('.improve-modal--suggestion').show(); $('#suggestion-section-textarea').show(); jQuery('#suggestion-modal-alert').hide(); if(suggestEditorInstance !== null){ suggestEditorInstance.setEditorValue(""); } $('.suggestion-section').css('display', 'block'); jQuery('.suggest-bottom-btn').css("display","block"); }); $('.create-improvement_wrapper').on('click',function(){ // when create improvement option clicked then improvement reason will be shown if(loginData && loginData.isLoggedIn) { $('body').append('

'); $('.spinner-loading-overlay').show(); jQuery.ajax({ url: writeApiUrl + 'create-improvement-post/?v=1', type: "POST", contentType: 'application/json; charset=utf-8', dataType: 'json', xhrFields: { withCredentials: true }, data: JSON.stringify({ gfg_id: post_id }), success:function(result) { $('.spinner-loading-overlay:eq(0)').remove(); $('.improve-modal--overlay').hide(); $('.unlocked-status--improve-modal-content').css("display","none"); $('.create-improvement-redirection-to-write').attr('href',writeUrl + 'improve-post/' + `${result.id}` + '/', '_blank'); $('.create-improvement-redirection-to-write')[0].click(); }, error:function(e) { showErrorMessage(e.responseJSON,e.status) }, }); } else { if(loginData && !loginData.isLoggedIn) { $('.improve-modal--overlay').hide(); if ($('.header-main__wrapper').find('.header-main__signup.login-modal-btn').length) { $('.header-main__wrapper').find('.header-main__signup.login-modal-btn').click(); } return; } } }); $('.left-arrow-icon_wrapper').on('click',function(){ if($('.improve-modal--suggestion').is(":visible")) $('.improve-modal--suggestion').hide(); else{ } $('.improve-modal--improvement').show(); }); const showErrorMessage = (result,statusCode) => { if(!result) return; $('.spinner-loading-overlay:eq(0)').remove(); if(statusCode == 403) { $('.improve-modal--improve-content.error-message').html(result.message); jQuery('.improve-modal--overlay').show(); jQuery('.improve-modal--improvement').show(); $('.locked-status--impove-modal').css("display","block"); $('.unlocked-status--improve-modal-content').css("display","none"); $('.improve-modal--improvement').attr("status","locked"); return; } } function suggestionCall() { var editorValue = suggestEditorInstance.getValue(); var suggest_val = $(".ContentEditable__root").find("[data-lexical-text='true']").map(function() { return $(this).text().trim(); }).get().join(' '); suggest_val = suggest_val.replace(/\s+/g, ' ').trim(); var array_String= suggest_val.split(" ") //array of words var gCaptchaToken = $("#g-recaptcha-response-suggestion-form").val(); var error_msg = false; if(suggest_val != "" && array_String.length >=4){ if(editorValue.length { jQuery('.ContentEditable__root').focus(); jQuery('#suggestion-modal-alert').hide(); }, 3000); } } document.querySelector('.suggest-bottom-btn').addEventListener('click', function(){ jQuery('body').append('

'); jQuery('.spinner-loading-overlay').show(); if(loginData && loginData.isLoggedIn) { suggestionCall(); return; } // script for grecaptcha loaded in loginmodal.html and call function to set the token setGoogleRecaptcha(); }); $('.improvement-bottom-btn.create-improvement-btn').click(function() { //create improvement button is clicked $('body').append('

'); $('.spinner-loading-overlay').show(); // send this option via create-improvement-post api jQuery.ajax({ url: writeApiUrl + 'create-improvement-post/?v=1', type: "POST", contentType: 'application/json; charset=utf-8', dataType: 'json', xhrFields: { withCredentials: true }, data: JSON.stringify({ gfg_id: post_id }), success:function(result) { $('.spinner-loading-overlay:eq(0)').remove(); $('.improve-modal--overlay').hide(); $('.create-improvement-redirection-to-write').attr('href',writeUrl + 'improve-post/' + `${result.id}` + '/', '_blank'); $('.create-improvement-redirection-to-write')[0].click(); }, error:function(e) { showErrorMessage(e.responseJSON,e.status); }, }); });

Continue without supporting

`; $('body').append(adBlockerModal); $('body').addClass('body-for-ad-blocker'); const modal = document.getElementById("adBlockerModal"); modal.style.display = "block"; } function handleAdBlockerClick(type){ if(type == 'disabled'){ window.location.reload(); } else if(type == 'info'){ document.getElementById("ad-blocker-div").style.display = "none"; document.getElementById("ad-blocker-info-div").style.display = "flex"; handleAdBlockerIconClick(0); } } var lastSelected= null; //Mapping of name and video URL with the index. const adBlockerVideoMap = [ ['Ad Block Plus','https://media.geeksforgeeks.org/auth-dashboard-uploads/abp-blocker-min.mp4'], ['Ad Block','https://media.geeksforgeeks.org/auth-dashboard-uploads/Ad-block-min.mp4'], ['uBlock Origin','https://media.geeksforgeeks.org/auth-dashboard-uploads/ub-blocke-min.mp4'], ['uBlock','https://media.geeksforgeeks.org/auth-dashboard-uploads/U-blocker-min.mp4'], ] function handleAdBlockerIconClick(currSelected){ const videocontainer = document.getElementById('ad-blocker-info-div-gif'); const videosource = document.getElementById('ad-blocker-info-div-gif-src'); if(lastSelected != null){ document.getElementById("ad-blocker-info-div-icons-"+lastSelected).style.backgroundColor = "white"; document.getElementById("ad-blocker-info-div-icons-"+lastSelected).style.borderColor = "#D6D6D6"; } document.getElementById("ad-blocker-info-div-icons-"+currSelected).style.backgroundColor = "#D9D9D9"; document.getElementById("ad-blocker-info-div-icons-"+currSelected).style.borderColor = "#848484"; document.getElementById('ad-blocker-info-div-name-span').innerHTML = adBlockerVideoMap[currSelected][0] videocontainer.pause(); videosource.setAttribute('src', adBlockerVideoMap[currSelected][1]); videocontainer.load(); videocontainer.play(); lastSelected = currSelected; }