Introduction

What is a digital image?

A digital image is an array of numbers. Each element of the array is called a pixel. Each pixel carries the value recorded by a single cell of a digital camera, a line  scan camera, a CCD camera, etc. The value of the pixel indicates the amount of radiation received by the sensor from all  the points inside its field of view.

What is a panchromatic image?

A panchromatic image is a grey image and is formed by sensors with cells that are sensitive to a wide range of wavelengths.

What is a multi spectral image?

A multispectral image is a collection of grey images, all depicting the same scene. Each grey image in the collection has been formed by sensors sensitive to a narrow range of wavelengths.

What is image resolution?

Image resolution is the size of the patch on the imaged scene that is inside the field of view of a single sensor.