Introduction to Video and Image Processing

Point Processing (Introduction to Video and Image Processing) Part 5

Programming Point Processing Operations When implementing one of the point processing operations in software the following is done. Fig. 4.28 The order in which the pixels are visited. Illustrated for a 10 x 10 image Remember that each pixel is individually processed meaning that it does not matter in which order the pixels are processed. […]

Neighborhood Processing (Introduction to Video and Image Processing) Part 1

In the previous topic we saw that a pixel value in the output was set according to a pixel value in the input at the same position and a point processing operation. This principle has many useful applications (as we saw), but it cannot be applied to investigate the relationship between neighboring pixels. For example, […]

Neighborhood Processing (Introduction to Video and Image Processing) Part 2

Correlation Correlation is an operation which also works by scanning through the image and applying a filter to each pixel. In correlation, however, the filter is denoted a kernel and plays a more active role. First of all the kernel is filled by numbers—denoted kernel coefficients. These coefficients weight the pixel value they are covering […]

Neighborhood Processing (Introduction to Video and Image Processing) Part 3

Gradients To enable edge detection we utilize the concept of gradients. We first present gradients for a general curve and then turn to gradients in images. In the 1D case we can define the gradient of a point as the slope of the curve at this point. Concretely this corresponds to the slope of the […]

Morphology (Introduction to Video and Image Processing) Part 1

One important branch of neighborhood processing is mathematical morphology— or simply morphology. It is applicable to both gray-scale images as well as binary images, but in this text only operations related to binary images are covered. Morphology on binary images has a number of applications and in Fig. 6.1 three typical ones are illustrated. The […]

Morphology (Introduction to Video and Image Processing) Part 2

Level 3: Compound Operations Combining dilation and erosion in different ways results in a number of different image processing tools. These are denoted compound operations. Here we present three of the most common compound operations, namely Opening, Closing, and Boundary Detection. Fig. 6.8 Erosion with different sized structuring elements Fig. 6.9 Closing of the binary […]

BLOB Analysis (Introduction to Video and Image Processing) Part 1

Before describing what is meant by the somewhat strange title of this topic, let us look at a few examples. In the first example the task is to design an algorithm which can figure out how many circles are present in the image to the left (see Fig. 7.1). Obviously the answer is three, but […]

BLOB Analysis (Introduction to Video and Image Processing) Part 2

BLOB Classification Each of the objects in Fig. 7.6 has now been identified as separate BLOBs using, for example, the Grass-Fire algorithm. The task is now to determine which BLOB is a circle and which is not. As suggested above we can use the circularity feature for this purpose. In Fig. 7.6 the values of […]

Segmentation in Video Data (Introduction to Video and Image Processing) Part 1

A video sequence is in principle a sequence of images. The methods presented in the previous topics therefore apply equally well to a video sequence as an image. We simply process one image at a time. There are, however, two differences between a video sequence and an image. First, working with video allows us to […]

Segmentation in Video Data (Introduction to Video and Image Processing) Part 2

Background Subtraction Background subtraction is a simple and yet efficient method of extracting an object in a scene. This is especially true if the background can be designed to be uniform. In indoor and controlled setups this is indeed realistic, but for more complicated scenarios, other methods might be necessary. Even in the case of […]

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