Enhance Your Pictures—Discover Top 5 Online Free Picture Upscaler Tools in 2023

In a world where digital photography dominates, with over one trillion photos taken yearly, our lives are deeply intertwined with these visual representations. To grab attention and make an impact, it is crucial to utilize high-quality images. However, most online images suffer from low quality and digital noise. Fortunately, AI technology has made significant strides in image upscaling in recent years. This advancement enables low-resolution images to be transformed into professional-grade visuals of superior quality. This blog will introduce you to five free Picture Upscaler online tools available.

free picture upscale

I. What is Picture Upscaler?

Picture Upscaler is an advanced image processing technique that enhances the resolution and quality of low-resolution images. It utilizes sophisticated algorithms to extrapolate missing details and improve image sharpness, resulting in a visually enhanced output1.1 By upscaling the resolution, these tools produce higher-quality visuals suitable for various purposes, including printing, web publishing, and digital displays.

II. Who Needs a Picture Upscaler?

Picture Upscalers can benefit a wide range of individuals and professionals alike:

– Artists and Designers: Artists and graphic designers often work with images and require high-resolution visuals for their projects. A picture upscaler can help them improve the quality of their artwork and create stunning designs.

-Photographers: Photographers dealing with old or low-resolution photographs can utilize picture upscalers to revive these images and showcase them in print, exhibitions, or social media.

– Content Creators: Video editors, bloggers, and content creators need high-quality visuals to engage their audience. Picture upscalers enable them to enhance the resolution of images used in videos, blog posts, and social media content.

– Businesses: Companies aiming to create impactful marketing campaigns rely on high-resolution images. Picture upscalers empower businesses to improve the quality of product images, advertisements, and promotional materials.

III. Top 5 Free Picture Upscaler Online Tools:

While numerous image upscaling tools are available nowadays, online tools are highly favored. Here are a few reasons why online tools offer advantages over offline software:

Web-based picture upscalers are readily accessible on a wide range of devices, including computers and mobile phones, through web browsers. Since there is no need for lengthy installations with online tools, they can save you valuable time, money, and storage space on your device. Let us introduce the top five free picture upscaler online tools in 2023.

1.Icons8 Upscaler

Icons8 Upscaler is a cutting-edge image enhancement tool that harnesses the power of AI technology. It offers a convenient online platform where you can effortlessly upload your images and experience upscale and enhanced results without any loss in quality. With the ability to upscale images by 2x or 4x, Icons8 Upscaler ensures remarkable enhancements while preserving the original integrity of your images.


Key features

  • Easily and quickly enhance your photos to high-definition quality up to 4 times, with automatic and efficient processing.
  • Experience an impressive 100% improvement in photo quality while upscaling.
  • Witness the transformation of blurry subjects into sharper images while removing any unwanted artifacts.
  • Utilizing cutting-edge AI technology, Icons8 Upscaler ensures the highest level of excellence in making images HD.
+Without quality getting compromised, you get things done.
+You can upscale the image four times.
-Limited scale options.

2. Fotor

Fotor, an AI-powered online picture upscaler tool, is free and aims to enhance images. This tool can effortlessly provide high-resolution and improved-quality pictures with just a single click. Utilizing its advanced AI algorithm, Fotor ensures instant image upscaling with minimal effort.


Key features:

  • Batch editing capability for efficient image enhancement.
  • The option to compare the results with the original file, enables better evaluation.
+Easy to use.+Instant image quality improvement.+High quality image output.– For extra advanced service, additional payment plans are required.


Media.io is one of the best web-based picture upscaler; you can use this tool to enlarge, enhance, and upscale photos without much trouble. This AI-powered tool can also upscale photos up to 4K resolution. With multi-format support and a user-friendly interface, Media.io is the go-to online AI picture upscaler.


Key features

  • Media.io is a free online web-based editing tool that can deblur images instantly and is compatible with all devices.
  • The tool can remove blur from a photo, such as motion blur caused by a shaky camera, and improve image quality with enhancements such as color adjustments and exposure balancing.
  • You can upscale your Image from a range of options up to 2x, 4x, or 8x.
+Offers a significant number of features and tools for free.
+It can process images reasonably quickly as compared to other tools.
– The UI of the website can be improved in terms of presentation and functionality.

4. Aiseesoft

Aiseesoft picture upscaler is a highly effective tool that utilizes AI technology to enhance your images. With this tool, you can effortlessly restore blurry images, recover lost pixels, enhance colors, and bring out intricate textures and details. Aiseesoft is capable of upscaling your images for both print and web applications, ensuring optimal results for any purpose.


Key features

  • Aiseesoft picture upscaler allows you to increase the size of images by 200%, 400%, 600%, or 800%.
  • This software supports many image file formats, including JPG, PNG, BMP, and more.
  • Benefit from advanced denoising capabilities: Aiseesoft Picture Upscaler includes a robust tool that eliminates image noise, improving overall quality.
+The picture upscaler can deliver high-quality results in a matter of seconds.
+It offers other image editing tools on the same platform, which increases the overall efficiency for the user.
-Limited resolution that you can not cross when upscaling an image.


Waifu2x is a great tool for upscaling anime-style art images. It is specifically designed for enhancing and enlarging anime-style images. This AI-powered tool also supports online image processing, allowing users to enhance and upscale their images effortlessly. The image enhancement functions are highly effective, delivering impressive results.


Key features:

  • Upscaling: Waifu2x has the capability to increase the resolution of images by four times their original size. For instance, a 100×100 pixel image can be upscaled to 400×400 pixels.
  • Noise reduction: Waifu2x effectively reduces picture noise and artifacts, resulting in smoother and more detailed images.
  • Style preservation: Waifu2x aims to maintain the original appearance and feel of the photos. This means that the images will retain their anime or manga-like characteristics even after upscaling.
  • Open-source and free: Waifu2x is open-source software, available for free to anyone who wants to use it and contribute to its development.
+Image enhancement functions are good.
+Supports the image noise reduction.
+It also gives batch conversion.+Free and is easy to use.
-Limited scale options.

IV. imageenhan AI Upscaler – Your Top Choice as a Free Alternative

Discover the Power of imageenhan – Enhanced by PicUP.Ai, a respected pioneer in AI-driven graphics design and computer vision technology. In imageenhan AI AI Image Upscaler, you can:

imageenhan picture upscaler tutorial 0

1. Unleash the Brilliance of Your Images – Experience Crystal-Clear Details

imageenhan is an unparalleled image enhancer that brings out the best in your pictures. With cutting-edge technology, this platform lets you witness every intricate detail with utmost clarity, ensuring your images shine like never before.

2. A Remarkable Image Enhancer for Everyone – Elevate Your Photos in an Instant

No matter your skill level, imageenhan is here to revolutionize your photo editing experience. Seamlessly enhancing pixelated, blurry, and low-quality photos, this online image enhancer is perfect for printing, social media, marketing campaigns, presentations, and many other purposes. Say goodbye to subpar visuals and hello to stunning, professional-grade images in just a few clicks.

3. Free Tool without any additional charges

The tool is entirely free, and users are not required to pay additional fees or worry about hidden charges.

Whether you’re an amateur or an expert, imageenhan offers a wide range of free features tailored to suit all skill levels. Give imageenhan a try and unlock your creative potential today!

V. How to use imageenhan AI Upscaler?

Now let’s quickly go over the basic steps for using imageenhan AI Image Upscaler online application.

Step 1.

Go to the Image Enhancer website and access the AI Image Upscaler. Use the Upload Image button to select and upload an image. Alternatively, you can click on any of the images below to use them instead.

imageenhan picture upscaler tutorial 1

Step 2.

After selecting the image you want to use from your device, navigate to the right sidebar and click on any feature you wish to use. Adjust the settings according to your preferences.

imageenhan picture upscaler tutorial 2

Step 3.

Once satisfied with the adjustments, click the Download button to save the edited image. Choose the desired format (JPG or PNG) and adjust the image quality if needed before clicking the Download button.

imageenhan picture upscaler tutorial 3

In conclusion, High-quality images are crucial for effectively conveying statements and making a memorable impact. Online image upscaler tools offer a convenient solution for enhancing low-resolution visuals. Whether you’re an artist, photographer, content creator, or business owner, the previous top five picture upscaler tools can help you turn your images into impactful visual assets. Why not try them and boost the quality of your images today?

If you want to use a free picture upscaler, visit our site


1 Samuel Schulter, Christian Leistner, Horst Bischof; Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015, pp. 3791-3799

2023-12-17 15:50:46

Improve Your Visual Experience with the Top 5 Image Upscalers in 2023

Have you ever found yourself in a situation where you needed to create a poster, but when you enlarged the image, it became distorted and unclear? Or maybe you wanted to bring new life to precious old photographs? If youre seeking improved image enlargement and picture quality restoration, AI Image Upscaler online free is here to help.AI-powered image upscalers have revolutionized the way we enlarge images without compromising on quality. The days are gone when you had to rely on complex software to achieve this; now, with the incredible power of AI, you can effortlessly enhance your images for professional and personal purposes. With this in mind, we will explore the top-notch AI image upscaler online free in this article that you can integrate into your photo editing workflow today.I. What is an image upscaler?Software/tools designed to enhance the resolution and overall quality of a picture. It analyses existing pixels and intelligently adds new ones to create sharper, more detailed images using advanced AI algorithms. Use Super Resolution to create a single image with twice (or more) the linear resolution if you have old or low-resolution photos that you want to bring up to print quality. That is, the enhanced image is double the width and height of the original, and the number of pixels is quadruple.II. The Image Upscaler is designed forDesigners and Photographers: To enhance the quality and professionalism of their work, designers and photographers can use Image Upscaler to enlarge low-resolution images and enhance details.Media and advertising companies: Advertising and media production often require images to be resized for different media channels. Upscaling allows media and advertising organisations to increase the size of low-resolution images while maintaining clarity and detail.Social media users and bloggers: For social media users and bloggers who share photos on social media, Image Upscaler can also help to improve the quality and visual effects of photos, thereby increasing their appeal and engagement.Website and e-commerce owners: Web sites and e-commerce platforms with large databases of images can benefit from the Image Upscaler. In this case, upscaling their product images allows them to provide customers with a more detailed and immersive visual experience, leading to increased sales and customer satisfaction.III. Top five AI Image Upscaler Online free1. HitPaw Photo EnhancerHitPaw AI Image Upscaler HitPaw Photo Enhancer is a PC and Mac-based computer program that allows you to upscale your images without reducing their quality. Like most upscalers on our list, HitPaw’s Photo Enhancer can work on many photos, including landscapes, animations, buildings, and nature. This enhancer is also equipped with a face enhancer. So you don’t need to crack open a secondary image editing software after upscaling your photos in HitPaw.You can also colorize and bring your old photos back to life using one click, saving old memories and making new ones together. HitPaw’s denoise model allows you to automatically remove noise from low-quality photos while also fixing their low-lighting issues without causing harm to the original photo. As a desktop app, HitPaw is an excellent solution for those who want a little more out of their photo upscaler.Key FeaturesAvailable for Android, PC, and MacRemove noise and sharpen photos while enlarging themUpscale images with no quality lossUpscale to HD, 2K, 4K, and 8KBatch processing for a large number of imagesPriceFree PlanMonthly PlanAnnual PlanFree$19.99/month$79.99/monthPros ConsProsCons+Clean and easy user interface+Available in 16 languages+Free version available+Packed with editing features-The subscription is quite expensive -Doesnt offer multi-user capability (e.g. teams).2. Adobe Photoshop (Firefly)Adobe unveiled an impressive generative AI engine called Adobe Firefly, which has now been seamlessly integrated into Photoshop. With this intention, leveraging the power of AI, Photoshops capabilities have expanded to include automatic subject selection, generative fill, and neural filters, enabling significant transformations in image style and mood. Also, incorporating this exciting AI integration will enhance the familiar Photoshop tools that designers and photographers have relied on for years, such as blending modes, image scaling, and GIF creation.Instead of solely relying on the original pixels of an image, Photoshop can now utilize a neural network to generate new contextual material or pixels. This groundbreaking development takes photo editing to an entirely new level. One of Photoshops standout features, the AI Smart Portrait Neural Filter, and Adobes AI Generative Fill elevates these advancements even further. With generative fill, users can select a specific portion of an image and input a text-based prompt to transform that aspect of the picture.Key FeaturesIncorporated generative AI into Adobe Firefly.Utilized AI-powered subject selection.Leveraged Generative Fill to edit images with AI based on prompts.Employed AI neural filters to apply stylistic transformations to images.PriceFree TrialMonthly Plan7 Days$20.99/monthPros ConsProsCons+Thought to Composition Instantly+Highly Safe and Ethical-The subscription is quite expensive -Poor Quality of Image Generations3. Zyro Image UpscalerZyro, developed by Hostinger, is a widely used AI website builder that provides an online AI image upscaler. The user-friendly interface ensures a seamless experience when uploading and enhancing your images. Unlike most image upscalers on our list, Zyros upscaler only supports two file formats, which may be limiting. However, this interface is best suited for hobbyists and individuals who do not require advanced upscaling features for their work.Key FeaturesCompatible with PNG and JPG file formatsSimple and user-friendly interfaceAllows downloading of results without watermarksNo limitations on the number of photos to be upscaledPriceFreePros ConsProsCons+Free and easy to use+No need to register or sign in-The output quality is low Upscale image only by 2x Limited file size4. CanvaCanva is a widely used and user-friendly web-based graphic design tool offering various powerful features. In addition to its AI upscaler, which allows users to upscale images to 4K resolution, Canva also boasts an extensive collection of templates for designing banners and logos. Furthermore, users can purchase premium stock images and paid templates, with prices starting at $1.Key featuresPhoto EditingBackground ScreeningCrop ImageCustomizationDesign TemplatesPriceFree PlanCanva ProCanva Team3 credits/month$14.99 /month$29.99/monthPros ConsProsCons+Seamless workflow.+Easy to use+User friendly-Have to subscribe to a paid account because its template collection doesnt have any high-quality layouts-Search function5. Upscale PicsUpscale Pics is a website that offers a unique feature the ability to increase image resolution without compromising quality. Whats remarkable about this image upscaler is its capability to enlarge pictures to any desired size, up to 2X.Powered by advanced AI upscaling algorithms, Upscale Pics enhances your images by adding intricate details, giving them a professional photographer-like appearance. The website provides a free trial plan for users to experience its features. One of its outstanding qualities is its ability to identify and prioritize important elements, such as text or faces, during the upscaling process.Key featuresEnlarge your images without losing quality with AI. Any resolution up to 8X worksRemove the Background and paste the custom background.Remove JPEG noiseOn-Device Al image upscaler ensuring full privacy crop image.PriceUpscalePics TrialUpscalepics PlusFree$3 /monthPros ConsProsCons+Eliminates JPEG artifacts+Allows online resizing of images up to 8X+Enhances image tonality and adds extra detail-Displays advertisements-Processing time can be relatively longIV. imageenhan AI Upscaler Your Top Choice as a Free AlternativeDiscover the Power of imageenhan Enhanced by PicUP.Ai, a respected pioneer in AI-driven graphics design and computer vision technology. In imageenhan AI AI Image Upscaler, you can:1. Unleash the Brilliance of Your Images Experience Crystal-Clear DetailsBringing out the best in your images, imageenhan is an unparalleled image enhancement platform. Using the latest technology, this platform allows you to see every intricate detail with the utmost clarity, ensuring your images shine like never before.2. A Remarkable Image Enhancer for Everyone Elevate Your Photos in an InstantNo matter what your level of skill, imageenhan is here to revolutionise the way you edit your photos. This online image enhancer is perfect for printing, social media, marketing campaigns, presentations and a myriad of other uses by seamlessly improving pixelated, blurry and low-quality photos. In just a few clicks, you can say goodbye to subpar visuals and hello to stunning, professional-quality images.3. Free Tool without any additional chargesThe tool is completely free and users pay no additional fees or worry about hidden charges.It doesnt matter if you are an amateur or an expert, imageenhan offers a wide range of free features that are tailored to suit all skill levels. Give imageenhan a try and start unlocking your creative potential today!V. How to use imageenhan AI Upscaler?Lets take a quick look at the basic steps involved in using the imageenhan AI ImageUpscaler online program.Step 1.Access the AI Image Upscaler from the Image Enhancer website. Select and upload an image using the Upload Image button. As an alternative, you can also click on one of the images provided below to use it as an image instead.Step 2.Navigate to the right sidebar and click on any of the features you want to use after selecting the image from your device. You can also tweak the settings to suit how you want to use them.Step 3.Once you are happy with the settings, click the Download button. This will save your edited image. Before clicking the Download button, select the desired format (JPG or PNG) and adjust the image quality if necessary.Image upscalers have become indispensable tools for professionals and enthusiasts alike, as visuals now play a crucial role in communication. These innovative solutions allow you to turn your images into stunning masterpieces, whether youre a photographer, designer, content creator or simply someone who wants to enhance their visual experience. So take your visual content to new heights of quality and impact by exploring the top 5 free AI image upscaler online mentioned above.

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2023-09-15 11:11:52

12 Python AI Upscaling Methods for Image Enhancement

Why Image EnhancementIn the realm of Python and AI, image enhancement is especially crucial.During the process of generating, transmitting or transforming an image, it is affected by a number of factors such as light source, imaging system, and channel bandwidth and noise, which may result in degradation of quality such as low contrast, insufficient dynamic range, loss of clarity, and the inclusion of significant noise. Therefore, image enhancement is required. This is a field where Python and AI technologies are increasingly being applied.Definition of Image EnhancementImage enhancement is to improve the quality of an image for some application purpose, and the result of the processing is more suitable for human visual characteristics or machine recognition systems.Enhancement does not increase the information of the original image, but only improves the ability to recognize certain information, and such processing may cause partial loss of other information. Python and AI techniques contribute to achieving this goal effectively.Methods of image enhancement1.Image enhancement methods can be categorized into spatial domain methods and frequency domain methods according to the domain of action. This method can be effectively implemented using Python and AI for upscaling the image quality.Spatial domain method refers to the image spatial domain directly on the pixel gray value operation processing, commonly used gray scale transformation, histogram correction, template convolution, pseudo-color processing, etc..Frequency domain method is to enhance the transformed value of the image in some kind of transform domain of the image, and then obtain the enhanced image by inverse transformation, which is an indirect processing method. AI algorithms can also be used for these frequency domain methods.2. According to the analysis of the frequency characteristics of the image, it is generally believed that the contrast and dynamic range of the entire image depends on the image informationThe contrast and dynamic range of the whole image depend on the low-frequency part of the image information (referring to the overall image), while the edge contour and local details in the image depend on the high-frequency part. Therefore, two-dimensional digital filtering methods are used for image processing, such asHigh-pass filters are used, which help to emphasize the edge contours and detailed parts of the image.Low-pass filters are used to smooth the image and reduce noise.3. Image enhancement methods can be divided into smoothing and sharpening according to the purpose and effect of processing. Python and AI algorithms can help in the effective implementation of these methods for image upscalingSmoothing has a blurring effect on the image, making the image transition natural and soft, suppressing noise; based on the frequency characteristics of the image from the frequency point of view to understand, smoothing is to maintain or strengthen the low-frequency components of the image, weakening or eliminating the high-frequency components of the image.Sharpening can be seen as the inverse operation of smoothing, the effect and purpose is to highlight the details, so that the image outline is clear, contrast; from the perspective of frequency domain processing, sharpening is to enhance the high-frequency components of the image.These methods are based on Python and AI technologies.Next, I introduce 12 ai upscaling methods via python12 python ai upscaling methodsHere, we introduce 12 AI-driven upscaling methods implemented in Python.1.Contrast and brightness enhancementUsage scenario: bright spot (white spot) detection for dark (black) backgroundsRealization,This enhancement can be automated using Python and AI:void adjust(const cv::Mat src, cv::Mat dst, const float brightness, const float contrast){double B = brightness / 255.; double c = contrast / 255.;double k = tan((45 + 44 * c) / 180 * M_PI);double alpha = k;double beta = 127.5 * (1 + B) - k * 127.5 * (1 - B);src.convertTo(dst, -1, alpha, beta);}2.Histogram equalizationHistogram equalization is a whole image mapping, and will not be mapped locally to certain regions, for those parts of the region is dark or light image is not applicable. At the same time, histogram equalization reduces the gray level of the image, causing some details of the image to disappear. Histogram equalization can be effectively performed using Python libraries.It is more suitable for an overall dark or light image. It can make the gray value of the whole image evenly distributed in the whole dynamic range [0,255], so as to increase the contrast of the image.1).Customized cumulative frequency equalization method:Steps:Count the number of pixels per gray value in the imageCalculate the frequency of each gray value pixel and calculate the cumulative frequencyMap the image and the gray value of the image = original gray value of the image * cumulative frequencySingle channel:bool MyEqualizeHist(Mat gray, Mat result) { //Count the number of pixel values ​​from 0 to 255 mapint, intmp; for (int i = 0; i gray.rows; i++) { uchar* ptr = gray.data + i * gray.cols; for (int j = 0; j gray.cols; j++) { int value = ptrj]; mpvalue]++; } } //Count the frequency of 0~255 pixel values, and calculate the counting frequency mapint, double valuePro; int sum = gray.cols*gray.rows; double sumPro = 0; for (int i = 0; i 256; i++) { sumPro += 1.0*mpi] / sum; valueProi] = sumPro; } //Convert based on cumulative frequency for (int i = 0; i gray.rows; i++) { uchar* ptr1 = gray.data + i*gray.cols; for (int j = 0; j gray.cols; j++) { int value = ptr1j]; double p = valueProvalue]; result.atuchar(i, j) = p*value; } } return true;}Multi-channel (RGB):void MyEqualizeHistRgb(Mat image){Mat imageRGB3];split(image, imageRGB);for (int i = 0; i 3; i++){MyEqualizeHist(imageRGBi], imageRGBi]);}merge(imageRGB, 3, image);imshow("result", image);}2).opencv comes with equalizeHist():equalizeHist(Mat src, Mat dst).Steps:Calculate the histogram H of the input image (8-bit);Normalize the histogram H so that the histogram bins sum to 255;Calculate the integral of the histogram; H′i=∑ 0≤ji H(j);Transform the image using H′ as a look-up table (look-uptable), the transformation formula for specific pixel values is: dst(x,y)=H(src(x,y))This algorithm normalizes the brightness and increases the contrast of the image,the result will be different from the customized one.3).Adaptive local histogram equalizationLocal histogram process:Set a template (rectangular neighborhood) of a certain size and move it along the image pixel by pixel;For each pixel position, calculate the histogram of the template region, and perform histogram equalization or histogram matching transformation on this local region, and the transformation result is only used for the gray value correction of the center pixel point of the template region;The template (neighborhood) moves row by row and column by column in the image, traverses all pixel points, and completes the local histogram processing of the whole image.python and AI make it easier to adapt histograms locally for upscaling.c++ code://C++cvtColor(img,gray,COLOR_BGR2GRAY);PtrCLAHE clahe = createCLAHE();clahe-apply(gray, dst);Python code://pythonclahe = cv2.createCLAHE(clipLimit=2.0, tileGridSize=(4,4)) # Create CLAHE objectimgLocalEqu = clahe.apply(img) # Adaptive local histogram equalizationtitleGridSize: template (neighborhood) size for local histogram equalization, optional, default (8,8)clipLimit: threshold for color contrast, optional, default 83.Exponential transformation enhancementExponential transformation (Power-Law) formula: S = c * R ^ r, through a reasonable choice of c and r can be compressed grayscale range, the algorithm to c = 1.0/255.0, r = 2 to achieve.Tested with a darker image, the actual effect is darker. Consistent with the formulas reasoning, the actual pixel value is replaced with the smaller value from the lookup table.Custom index enhancement algorithm:void Enhance::ExpEnhance(IplImage* img, IplImage* dst){ // Since oldPixel:1,256], you can save a lookup table first uchar lut256] ={0}; double temp = 1.0/255.0; for ( int i =0; i255; i++) { luti] = (uchar)(temp*i*i+0.5); } for( int row =0; row img-height; row++) { uchar *data = (uchar*)img-imageData+ row* img-widthStep; uchar *dstData = (uchar*)dst-imageData+ row* dst-widthStep; for ( int col = 0; colimg-width; col++) { for( int k=0; kimg-nChannels; k++) { uchar t1 = datacol*img-nChannels+k]; dstDatacol*img-nChannels+k] = lutt1]; } } } }// OpenCV versions before 2.1 used the IplImage* data structure to represent images, and versions after 2.1 used the image container Mat to store them.//Mat dstImage = cvarrToMat(dst1); // Convert IplImage format to Mat format// IplImage dst1= (IplImage)(dst);// Convert Mat type image to IplImage// The following is the original version using Mat.void Enhance::ExpEnhance(Mat img,double c, int r){ if(img.channels() != 1) { cvtColor(img,img,COLOR_BGR2GRAY); } uchar lut256] ={0}; for ( int i =0; i255; i++) { luti] = (uchar)( c * pow(i,r) +0.5); cout c*i*i+0.5endl; } for(int i = 0;i img.rows; i++) { for(int j = 0;j img.cols; j++) { int pv = img.atuchar(i,j); img.atuchar(i,j) = lutpv]; } }}Note:Some blogs use expf(n) to calculate the nth power of e. Personally, I think it is wrong. expf(100) is already inf infinity. Implemented in Python, AI algorithms can further optimize exponential transformation.srcmat.atuchar(i, j) = (unsigned char)(255.0 *(expf(srcmat.atuchar(i, j) - low_bound) / expf(up_bound - low_bound))); 4.Gamma enhancementSpecial exponential enhancement, Gamma correction based on power transformation is a very important nonlinear transformation in image processing, it is the opposite of the logarithmic transformation, it is the gray value of the input image for the exponential transformation, which corrects the deviation in brightness. Python and AI methods provide more options for gamma correction and enhancement. Usually, Gamma correction is used to expand the details of dark tones. Generally speaking, when the value of Gamma correction is greater than 1, the highlights of the image are compressed and the dark tones are expanded; when the value of Gamma correction is less than 1, on the contrary, the highlights of the image are expanded and the dark tones are compressed.output = L^γWhen γ is less than 1, the low grayscale interval is stretched and the high grayscale interval is compressed;When γ is greater than 1, the low grayscale interval is compressed and the high grayscale interval is stretched;When γ is equal to 1, it simplifies to a constant transform.1. Fixed cubic enhancement:void Enhance::gammaEhance(Mat image){Mat imageGamma(image.size(), CV_32FC3);for (int i = 0; i image.rows; i++){for (int j = 0; j image.cols; j++){imageGamma.atVec3f(i, j)0] = (image.atVec3b(i, j)0])*(image.atVec3b(i, j)0])*(image.atVec3b(i, j)0]);imageGamma.atVec3f(i, j)1] = (image.atVec3b(i, j)1])*(image.atVec3b(i, j)1])*(image.atVec3b(i, j)1]);imageGamma.atVec3f(i, j)2] = (image.atVec3b(i, j)2])*(image.atVec3b(i, j)2])*(image.atVec3b(i, j)2]);}}//Normalized to 0~255 normalize(imageGamma, imageGamma, 0, 255, CV_MINMAX);//Convert to 8bit image display convertScaleAbs(imageGamma, imageGamma);imshow("gammacubic enhancement", imageGamma);}2. Custom coefficient enhancement:Mat Enhance::gammaWithParameter(Mat img, float parameter){//Create lookup table file LUTunsigned char LUT256];for (int i = 0; i 256; i++){//Gamma transform definitionLUTi] = saturate_castuchar(pow((float)(i / 255.0), parameter)*255.0f);}Mat dstImage = img.clone();//When the input image is a single channel, Gamma transformation is performed directlyif (img.channels() == 1){MatIterator_uchariterator = dstImage.beginuchar();MatIterator_uchariteratorEnd = dstImage.enduchar();for (; iterator != iteratorEnd; iterator++)*iterator = LUT(*iterator)];}else{//When the input channel is 3 channels, each channel needs to be transformed separatelyMatIterator_Vec3biterator = dstImage.beginVec3b();MatIterator_Vec3biteratorEnd = dstImage.endVec3b();//Conversion by lookup tablefor (; iterator!=iteratorEnd; iterator++){(*iterator)0] = LUT((*iterator)0])];(*iterator)1] = LUT((*iterator)1])];(*iterator)2] = LUT((*iterator)2])];}}return dstImage;}5.Log conversion enhancementEffective. Test transparent items blurred boundary enhancement after obtaining good results.Logarithmic transformation can expand the low gray value and compress the high gray level value, so that the gray level distribution of the image is more in line with the visual characteristics of the human eye.After proper processing, the contrast of low gray areas in the original image will be increased and dark details will be enhanced.python libraries often have built-in functions for logarithmic transformation, useful in AI upscaling.The logarithmic transformation formula is:y = log(1+x)/bwhere b is a constant used to control the degree of curvature of the curve, where the smaller b is the closer it is to the y-axis and the larger b is the closer it is to the x-axis. The x in the expression is the pixel value in the original image and y is the transformed pixel value.Realization:void logEhance(Mat image){Mat imageLog(image.size(), CV_32FC3); for (int i = 0; i image.rows; i++){for (int j = 0; j image.cols; j++){imageLog.atVec3f(i, j)0] = log(1 + image.atVec3b(i, j)0]);imageLog.atVec3f(i, j)1] = log(1 + image.atVec3b(i, j)1]);imageLog.atVec3f(i, j)2] = log(1 + image.atVec3b(i, j)2]);}}//Normalized to 0~255 normalize(imageLog, imageLog, 0, 255, CV_MINMAX);//Convert to 8bit image display convertScaleAbs(imageLog, image);//imshow("Soure", image);imshow("Log", image); }6.Laplace Ehance enhancementHas a sharpening effect, more sensitive to noise, need to do the smoothing process first.Used to improve the blurring due to diffusion effect is particularly effective, because it is consistent with the model of downscaling. Diffusion effect is a phenomenon that often occurs in the imaging process.The Laplacian operator is generally not used in its original form for edge detection because, as a second-order derivative, the Laplacian operator has an unacceptable sensitivity to noise; at the same time, its magnitude produces an arithmetic edge, which is an undesired result of complex segmentation; and lastly, the Laplacian operator does not detect the direction of the edge. AI algorithms can mitigate the noise sensitivity of the Laplacian operator.Realization:void Enhance::laplaceEhance(Mat image){Mat imageEnhance;Mat kernel = (Mat_float(3, 3) 0, -1, 0, 0, 5, 0, 0, -1, 0); //A variety of convolution kernels are available. //Mat kernel = (Mat_float(3, 3) 0, 1, 0, 1, -4, 1, 0, 1, 0); //Mat kernel = (Mat_float(3, 3) 0, -1, 0, -1, 4, -1, 0, -1, 0); //Mat kernel = (Mat_float(3, 3) 0, 1, 0, 1, 3, 1, 0, 1, 0); //Mat kernel = (Mat_float(3, 3) 0, -1, 0, -1, 5, -1, 0, -1, 0);filter2D(image, imageEnhance, CV_8UC3, kernel);imshow("laplaceEhance", imageEnhance);}7.Linear transformationTheres not much to say, its just a straightforward linear transformation. Linear transformations are straightforward to implement in Python for upscaling purposes.y = kx+b.Realization:Mat Enhance::linearTransformation(Mat img, const float k, const float b){ Mat dst = img.clone(); for(int i=0; iimg.rows; i++) { for(int j=0; jimg.cols; j++) { for(int c=0; c3; c++) {float x =img.atVec3b(i, j)c];dst.atVec3b(i, j)c] = saturate_castuchar(k* x + b); } } }return dst;}8.Segmented linear stretching algorithmA commonly used algorithm in image grayscale transformation, which also has a corresponding function in the commercial image editing software Photoshop. Segmented linear stretching is mainly used to improve image contrast, highlighting the image details. Python and AI are effective tools for segmented linear stretching, which improves image contrast.Customized enhancement, weakened pixel intervals:void Enhance::PiecewiseLinearTrans(cv::Mat matInput, float x1, float x2, float y1, float y2){//Calculate straight line parameters//L1float K1 = y1 / x1;//L2float K2 = (y2 - y1) / (x2 - x1);float C2 = y1 - K2 * x1;//L3float K3 = (255.0f - y2) / (255.0f - x2);float C3 = 255.0f - K3 * 255.0f;//build lookup table uchar LUT256] ={0};for (int m = 0; m 256; m++){if (m x1){LUTm] = m * K1;}else if (m x2){LUTm] = m * K3 + C3;}else{LUTm] = m * K2 + C2;}}//grayscale mapfor (int j = 0; j matInput.rows; j++){for (int i = 0; i matInput.cols; i++){//Lookup table gamma transformation int x = matInput.atuchar(j,i); matInput.atuchar(j,i) = LUTx];}}}9.Gray level layeringThe simplest example is the commonly used opencv binarization algorithm: thresh, inRange can be. Python libraries like OpenCV offer functions for gray level layering in AI upscaling.10.Overexposure to the image inverseJust do a 255-x operation on the value. This is easily achieved using Python code and can be part of an AI upscaling pipeline.Realization:void ExporeOver(IplImage* img, IplImage* dst){for( int row =0; row height; row++){uchar *data = (uchar*)img-imageData+ row* img-widthStep;uchar *dstData = (uchar*)dst-imageData+ row* dst-widthStep;for ( int col = 0; colwidth; col++){for( int k=0; knChannels; k++){uchar t1 = datacol*img-nChannels+k];uchar t2 = 255 - t1;dstDatacol*img-nChannels+k] = min(t1,t2);}}}}11.High contrast retentionHigh-contrast retention is mainly the image of the color, dark and light contrast between the two parts of the junction retained, such as the image of a person and a stone, then the outline of the stone and the outline of the line of the person and the face, clothing, and other obvious lines of the place will be changed to be retained, the child of the other large-scale changes in dark and dark without obvious changes in the place of generation of medium-gray. python and AI algorithms make high-contrast retention more accurate.The expression form is:dst = r*(img Blur(img)).Realization:Mat HighPass(Mat img){Mat temp;GaussianBlur(img, temp,Size(7,7),1.6,1.6); int r=3;Mat diff = img + r*(img-temp); //High contrast preservation algorithmreturn diff;}12.Masaic algorithm (mosaic)In the daily sometimes confidential or other needs to mosaic the image, the following algorithm to achieve the image mosaic function (principle: the center pixel to represent the neighboring pixels).uchar getPixel( IplImage* img, int row, int col, int k){ return ((uchar*)img-imageData + row* img-widthStep)col*img-nChannels +k];} void setPixel( IplImage* img, int row, int col, int k, uchar val){ ((uchar*)img-imageData + row* img-widthStep)col*img-nChannels +k] = val;}//nSize: is the size, odd number//Replace the value of the neighborhood with the value of the center pixelvoid Masic(IplImage* img, IplImage* dst, int nSize){ int offset = (nSize-1)/2; for ( int row = offset; row img-height - offset; row= row+offset) { for( int col= offset; colimg-width - offset; col = col+offset) { int val0 = getPixel(img, row, col, 0); int val1 = getPixel(img, row, col, 1); int val2 = getPixel(img, row, col, 2); for ( int m= -offset; moffset; m++) { for ( int n=-offset; noffset; n++) { setPixel(dst, row+m, col+n, 0, val0); setPixel(dst, row+m, col+n, 1, val1); setPixel(dst, row+m, col+n, 2, val2); } } } }}ConclusionThe above many methods in practice sometimes are not used alone, filtering and the combination of each method with each other often achieve better results.If you have a need for image enhancement, you can also use the tools on our website to realize it!The use of Python and AI for image upscaling and enhancement is highly effective and offers a range of methods to improve image quality.

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2023-09-15 11:09:59

Free Image Search Sites with CC0 Licenses: The Ultimate Resource for All Your Creative Needs in 2023

IntroductionAre you a designer struggling to find the perfect image references? Or perhaps a content creator concerned about copyright infringement when sourcing images from Google? Whether youre a graphic designer, blogger, marketer, or someone in need of visually compelling images, the quest for the right visuals can be challenging. Thankfully, theres a wide array of free image search sites that offer a variety of creative solutions. In this article, well explore the top 10 free image search sites, highlighting their unique features, advantages, and disadvantages.Why Opt for Professional Free Image Search Sites?Finding high-quality images is crucial, whether for personal or commercial projects. However, to avoid legal complications, its essential to use professional free image search sites that offer legally licensed and copyright-compliant images. These platforms collaborate with photographers and artists who have explicitly permitted the distribution of their work. By sourcing images from these sites, you can confidently sidestep any legal pitfalls related to copyright infringement.In todays digital landscape, where copyright infringement is a pressing issue, relying on professional free image search sites is indispensable. Most images on these platforms come with a Creative Commons Zero (CC0) license, allowing users to freely use, share, and modify the content. This ensures peace of mind when it comes to copyright compliance.Top 10 Free Image Search Sites for CC0-Licensed and Public Domain Images in 20231. Adobe StockAdobe Stock offers an intuitive interface, making it easy to find the visuals you need. While some assets are premium, there are also free options, catering to various budgets without the need to scour multiple platforms.ProsCons+Well-designed interface+Broad selection of content+Free media available-Expensive-Best used as part of Adobe Creative Cloudadobe stock overview2. UnsplashUnsplash is a prominent online photography community that boasts a staggering number of over 50,000 contributing photographers. Their API has seamlessly integrated with more than 500 products, including Apple TV, the App Store, and the Chrome web store.Renowned for its exceptional quality and Creative Commons Zero (CC0) licensing, Unsplash has become a go-to destination for stunning photographs. This popular platform continuously updates its content by releasing 10 new photos every 10 days. Furthermore, it offers a comprehensive search feature, allowing users to easily find images across a wide range of themes, such as business, nature, and restaurants.ProsCons+Free online service+Millions of photos to choose from+High quality downloads+New optional subscription service-Photographers may not benefit from much remuneration-Anyone can use the same photosunsplash overview3. ShutterstockShutterstock stands as one of the most sought-after platforms for stock media. Its vast media library boasts an impressive collection of over 200 million images, catering to the diverse needs of users. However, its worth noting that a significant portion of these images come with a pay-per-use scheme or require proper attribution, unlike the media offered by Pexels.ProsCons+Vast gallery+Free trial+Easy to find content-Large subscription-Premium content not hidden by defaultshutterstock overview4. PexelsPexels is an exceptionally well-curated and extensive compilation of public domain photographs. With its user-friendly interface, you can effortlessly navigate through various categories or utilize the search feature to find exactly what youre looking for. The best part is, all images on Pexels are entirely free to use, requiring no attribution whatsoever.ProsCons+The images are royalty-free. +Don’t have to create an account, we just download the image and it’s ready to go.+The images are very friendly to people who like to use Adobe Photoshop.-Most of photos are photoshopped-Depending on what you search for on Pexels you’ll only find a few images that match your searchpexels overview5. Public Domain PicturesPublic Domain Pictures is a platform that provides an extensive collection of free, high-quality images, graphics, and vectors available for download. The platform efficiently organizes these visuals into various categories, facilitating convenient browsing and selection.ProsCons+Free online service +The wealth of choices +public domain-The picture is easy to be the same as others, not special enough. -Picture quality variespublic domain pictures overviewConclusionWhen it comes to finding the perfect visual content, these Top 10 Excellent Sources for CCO-Licensed and Free Public Domain Images provide a wide range of choices for every creative need. From free stock photos to premium licensed content, these platforms cater to diverse budgets and requirements. If you find suitable images from the websites mentioned above that require super-resolution or watermark removal, you can visit our website.While each website has its own unique features and limitations, they all serve as valuable resources for enhancing your visual projects and communication endeavors.

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