An Introduction to Digital Image Analysis

An Introduction to Digital Image Analysis: 4 Important Characteristics | The Lifesciences Magazine

Digital image is the process of transforming an image into a digital form for performing certain operations. It provides us with useful information. The digital image analysis has synonyms attached to it. Image morphometry, automated cytophotometry, static image analysis, and many more. Digital Image Analysis is a method of quantifying the microscopic images of a cell. It is obtained by a digital conversion and computer analysis of the features of the image. 

The algorithms of digital image analysis improve the visual quality of the image making them sharper, clearer, and more informational. These algorithms can provide more accurate results than humans, especially for those tasks that require accurate measurements. Digital image analysis helps us to critically analyze an image and understand its exact meaning. The applications of image analysis are mainly earth sciences, remote sensing, cell biology, and medicine. 

Understanding Digital Images

Digital image processing is the mechanism of using a computer to convert a digital image from its numerical representation to its output image. The numerical image can be presented in various ways as per the needs of the viewer. It can also be influenced to enhance the diagnostic breakdown. It is now a part of the regular workflow of managing images. It is a routine day of work for radiologists and technologists. 

Let’s Have a Look at 4 Characteristics of Digital Image Analysis:

A digital image has four basic characteristics: Matrix, Pixels, Voxels, and Bit Depth.

1. Matrix

A digital image is made up of a 2D formation of numbers called a matrix. A matrix is a rectangular arrangement of numbers, symbols or expressions arranged in rows and columns. Generally, diagnostic images are rectangular in shape and the matrix size or field of view (FOV) must be selected by the operator. The larger the image, the larger the matrix, and the more time it takes to process the image. 

2. Pixel

The boxes in the matrix are known as Pixel. Each pixel contains a discrete value that represents the brightness level. It reflects the tissue characteristics that are being photographed. The larger the matrix size, the smaller the pixel size and the better the spatial resolution. 

The pixel size can be calculated as Pixel Size= FOV/Matrix

3. Voxel

The pixels in the automated image represent the information existing in the volume of tissue in a patient. Such a volume is referred to as a volume element or voxel. The volume element information is converted into a numerical value and expressed in the pixel. 

4. Bit Depth

The number of bits or binary digits is called the bit depth. They encode the signal intensity of each pixel for the digital image.  Digital images can be produced in black, white, or bitonal. A color image is typically represented by a bit depth ranging from 8 to 24 or higher. 

Different Types of Digital Images (E.g., Grayscale, Color, Binary)

A digital image pertains to a finite set of elements called pixels. They are also known as picture elements or image elements. An image is represented in the form of a matrix where each element consists of a single pixel. Each pixel is the smallest point on the image that takes on a particular opaqueness, shade, or color. 

Some Types of Digital Images Are:

1. Binary images

Binary images are the simplest type of images. These can take up two values, mostly 0 and 1, or black and white. A binary image is addressed as a 1-bit image as it takes only 1 binary digit to illustrate each pixel. This type of information is used in applications where the only information required is genera shape or outline. E.g. Optical Character Recognition (OCR)

2. Gray-Scale Images

These images are also known as monochrome (single-color) images. This does not use any color information, only gray-level information is available. The conventional gray-scale image contains 8 bits/pixel data, which allows us to have 256 different grayscale levels. The extra gray levels become useful when a small section of the image is made much larger to detect details. 

3. Color images

Color images can be modeled as three-band monochrome image data, where each band of data corresponds to a different color. The actual information stored in the digital image data is the gray-level information in each spectral band. Color images are represented as red, blue, and green. Using the 8-bit monochrome standard as a model, the corresponding image would have 24-bits/pixel. 

4. Multi-spectral images

Multispectral images normally contain information outside the normal human perceptual range. This includes X-ray, infrared, ultraviolet, and radar data. These are not images in the usual sense because the information presented is not directly visible to the human eye. The information is often shown in visual form by mapping the different spectral bands to RGB components.  

Basics of Digital Image Analysis

How is digital image processed?

Digital image processing is done by the use of algorithms and mathematical models to process and analyze digital images. The goal of digital image processing is to enhance the quality of images, extract significant content, and automate image-based tasks. 

The Steps Involved in Digital Image Processing Are:

  1. Image acquisition
  2. Image enhancement
  3. Image Restoration
  4. Image segmentation
  5. Image representation and description
  6. Image analysis
  7. Image synthesis and compression

Common Challenges in Digital Image Analysis

Picture classification goes through a set of challenges too. Some of them are as follows:

1. Intra-class variation

Intra-class variance is the difference in images from the same class. Having cars of various types in the dataset is an example of intra-class variance. They could be different models of various companies. This problem of intra-class variation can be solved using the picture categorization method. 

2. Variation in perspective

Humans have a perspective variation. It allows an item to be rotated in several dimensions depending on how it is shot. The object, of course, remains the same regardless of the angle from which it is snapped. 

3. Illumination

The picture categorization system should be able to cope with variations in illumination as well. Picture this. If you have a painting of the same painting, each with a different amount of pixel intensity. The picture categorization system should be able to adapt to lighting changes. So, if we offer our image classification system a picture of the same item with varying brightness levels, the system should be able to assign the same levels. 

4. Clutter in the background

It signifies that the image contains a large number of things, making it difficult for the observer to locate the desired project. These photographs have a lot of “noise” to them. It is difficult to distinguish owing to the noise. It is a challenging assignment for a human. So you can think how difficult it is to process the same for a machine that has no conceptual knowledge about the image. 

Advantages of Artificial Intelligence and Machine Learning on Digital Image Analysis:

1. Enhanced efficiency

One of the vital benefits of artificial intelligence and machine learning is its ability to automate image processing tasks. The automation is done via machine learning algorithms. This enables you to handle a large amount of data, and complex image-processing tasks that would otherwise not be possible for humans alone. Machine learning improves the ability to gain fast results. 

2. Capable of handling large amounts of data

The quantity of data that machine learning or artificial intelligence can handle is immense. Using algorithms, large amounts of data processing happen very quickly, which is not possible to do manually. For eg. You can use a deep-learning algorithm to detect faces or objects in an image without having to manually draw boxes around each face or object. 

3. Ability to learn and adapt

With more training data and additional processing power, you can create better algorithms. An important benefit of using machine learning is its ability to improve results over time. When a deep neural network is in use, the model gains access to a larger variety of information about every pixel in an image. Thus, it makes more accurate decisions as compared to other types of models. 


Digital images have made our lives a lot easier in many ways. The amount of accuracy and precision it provides has helped many sectors of work blossom over time. Some applications in which digital image processing can be used are medical image retrieval, traffic sensing technologies, image reconstruction, and face recognition. Digital image analysis helps these areas of work and has brought about significant changes making the functioning easier. The implementation of this technology has had a massive impact on many sectors of work. Almost all of the technical fields are impacted by it. As readers, we can explore the world of digital image processing more as it is a helpful source to detect any issues in our daily life. 

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