Image Quality Assessment Methods - An Overview

Images have gradually taken over the whole internet. Anywhere you go online, you see tons of images. Apart from the internet, we also capture a lot of images to cherish our beautiful moments, incredible landscapes, and anything we see unusual. These images provide many benefits to users, like creating emotional appeals and getting others’ attention. However, not all images are equal. 

Some are great, and people love to watch them again and again. And others are awful, and people don’t want to see them. Have you ever considered why it happens? Mostly, it is because of the image quality.

If you don’t know how to assess an image’s quality, this article is for you. Here are the best methods for assessing an image’s quality.

1. Resolution

Resolution generally refers to the number of pixels in an image. It directly affects the image quality, clarity, and details. That’s why people first talk about the resolution when they look at a picture. It is the most crucial element that can help people assess images.

Resolution impacts the quality in different ways. For example, it directly influences image clarity. The higher the resolution is, the clearer the picture will be. Higher resolution means the individual pixels are close to each other, and their density is high. Ultimately, it increases the clarity of the images, even edges and curves.

Moreover, higher resolution can also help in printing and image enlargements. If an image is designed for printing, it must have a higher resolution so it doesn’t distort when enlarged. On the other hand, images with a low resolution quickly distort, and they get blurry and unclear.

2. Scaling

Scaling is a key factor defining image quality, as it directly affects the resolution and visual artifacts. The perfectly scaled images are usually detailed and clear, which helps people enjoy the creation. On the other hand, the images that are not appropriately scaled look awful because of low resolution and noise.

Scaling is the process of resizing an image, either making it larger (upscaling) or smaller (downscaling), in the context of images. It entails adjusting the image's dimensions while maintaining its aspect ratio or proportions. 

Nowadays, we can resolve the scaling-images issue without compromising quality by using various online tools for reducing, compressing, and resizing images.

The availability of online image resizer solves the problem of image scaling without sacrificing image quality. Resize images as per your choice.

There are principally two kinds of scaling:

• Upscaling: 

This entails making an image larger. When an image needs to be displayed at a size bigger than its original proportions, it is frequently employed. Upscaling, however, sometimes produces fuzzy or pixelated images because it adds extra pixels to fill in the gaps, which degrades the quality and sharpness of the original image.

To reduce the quality loss during scaling, advanced upscaling techniques like interpolation or deep learning-based approaches are applied. 

• Downscaling

Reducing the size of an image is known as downscaling. Downscaling is frequently used to reduce the size of an image, which can be beneficial for reducing storage requirements, speeding up website loading times, or producing thumbnails. 

In order to reduce the amount of detail in an image, downscaling may also involve smoothing and simplification. It's necessary to balance the size reduction while maintaining crucial visual components because excessive downscaling can result in the loss of important information. Reduce image size in KB online with perfect scaling, so that the image looks fabulous.

3. Originality 

Many people don’t consider originality a factor in determining image quality. However, it is one of the most critical factors that can help you assess an image, especially in creative contexts. For example, if you are a designer and want to design a beautiful landscape. 

In that case, using your imagination and creativity can help you get recognition and appreciation for your work. On the other hand, if you copy other designers’ ideas and design your image, no one will appreciate you. Instead, people may label you as a plagiarist. In that case, it doesn’t matter whether your images are more detailed; if they are copied, you will still be crucified for your act of plagiarism.

As a designer make sure your work is original and no one is copying your design. Just upload your creative work to reverse image search, the tool analyzes its elements and shows similar pictures. The results aid in distinguishing the uniqueness of your work or identifying potential instances of copying.

4. Color Accuracy

To assess an image’s quality, look at its color accuracy. The best images are those that portray the actual colors that people see in real life. Color accuracy depends on the hues, shades, tones, and many other factors that combine to create an image. When all these things are perfectly balanced and image creators achieve color accuracy, the results will undoubtedly be outstanding.

Color accuracy affects pictures in different ways. First of all, it helps creators depict reality through their work. For example, there are lush green fields with a few mountains surrounding them and a water stream coming from the mountains and running through the fields. In images, this scene will only look great if all the colors are accurately used as they are in real life. 

Otherwise, the pictures may not portray the real beauty of the scene. Similarly, colors help image creators set a specific mood and convey different emotions. The proper use of colors can help designers and editors change the overall meaning of the pictures. As you may know, every color impacts viewers differently, so creators should know about color psychology before creating pictures.

5. Sharpness

Sharpness refers to image clarity and detail. A high sharpness will result in a more detailed and clear image. On the other hand, lower sharpness means less clarity and details.

Multiple factors affect an image’s sharpness. The most significant of them is the focus. When the focus of an image is accurate, the subjects look clear, sharp, and well-defined. It can ultimately make an image look much better and clear.

Apart from focus, camera stability is also an important thing that can impact the sharpness of an image. For example, if the camera shakes while capturing pictures, the result won’t be good, and the image will look blurry and unclear. That’s why many people use different equipment to stabilize the camera movement.

6. Noise

Noise and grain ruin the beauty of images. The lesser the noise is, the better it is for your images. People don’t want to look at images with a lot of noise. As a photographer or designer, you must consider the noise while capturing or designing images.

While capturing photographs, if there is a lot of noise, you should experiment with various camera settings and identify the best. That’s how you can easily reduce noise and bring more clarity to your photographs.

On the other hand, when designing or editing images, you must look at different factors enhancing noise and try to minimize them as much as possible. That’s how you can make your work much better and get a wow from viewers.

There are four kinds of noise:

• Gaussian noise:

Random fluctuations in pixel values define this sort of noise

• Salt-and-pepper noise:

This kind of noise adds errant black and white pixels to the image that resemble salt and pepper grains.

• Speckle noise:

Images captured with ultrasound or synthetic aperture radar (SAR) may contain speckle noise, a grainy pattern brought on by random changes in pixel values.

• Poisson noise:

Poisson noise, which results from the stochastic character of photon arrival at the sensor, is frequently linked to low-light imaging circumstances.

 

7. Artifacts

When it comes to images, artifacts are unwanted distortions, noise, and anomalies. The artifacts can come in images in any phase, including capturing, designing, editing, compression, or uploading. Artifacts can completely ruin a picture and damage its quality. Whenever you have to assess an image, you must consider visual artifacts. Artifacts can also damage clarity. Different artifacts can make images blurrier and reduce pixels.

There are different types of artifacts that can ruin a picture. The most common artifacts include noise artifacts, compression artifacts, motion blur, chromatic aberration, etc. While capturing or editing pictures, you must take care of all the artifacts and try to reduce them to enhance the quality of your images.

Conclusion

Images with greater resolution aren’t always great. Many other things matter a lot when it comes to image quality. This article has briefly discussed all elements that determine the overall quality of images. If an image has an outstanding balance of all these things, it can be considered great. So, next time, when you have to assess an image’s quality, make sure to consider all these things.