Remote sensing

What are the Four types of image resolution

1. What are the Four types of image resolution

2. INTRODUCTION Remote sensing: is the collection of information relating to objects without being in physical contact with the object (Abdurrahman 2010) Remote sensing is the process of acquiring data or information about substances not in direct contact with the sensor, by gathering its inputs using electromagnetic radiation or acoustical waves that are from the target of interest

3. Introduction cont.. Sensor – is the device that detects and responds to some type of input from physical environment, the specific input could be light, heat, motion, moisture, pressure or any other environmental phenomena (Channel 1999) Resolution is the term used to describe the number of dots or pixels used to display an image.

4. Introduction cont.. High resolution means that more pixels are used to create the image resulting in cleaner image. Low resolution means that fewer pixels are used to create the image resulting in less cleaner image. This display is indicated by a number of combinations such as 800 X 600.

5. TYPES OF RESOLUTION Spatial resolution : this is the ability of the sensor to record distinctively clear image of smallest object on the earth’s surface. It describes the ability of a sensor to identify the smallest size detail of a pattern on an image.

6. spatial cont..

7. Spatial cont.. That is the first image has low spatial resolution in which smallest object cannot clearly seen while the second image has a high spatial resolution in smallest object to be seen clearly.

8. Spectral resolution Spectral resolution is the sensitivity of a sensor to respond to a specific frequency range The frequency ranges covered often include not only visible light but also non-visible light and electromagnetic radiation.

9. Spectral cont.. High spectral resolution means that the sensor distinguishes between very narrow bands of wavelength. low spectral resolution means the sensor records the energy in a wide band of wavelengths as a single measurement.

10. Spectral cont..

11. Spectral cont.. Color film is individually sensitive to the reflected energy at the blue, green, and red wavelengths of the spectrum. Color film has higher spectral resolution when compared to black and white film.(Reddy, 2001)

12. Radiometric Resolution Refers to the ability of a sensor to detect differences in energy magnitude. Sensors with low radiometric resolution are able to detect only relatively large differences in the amount of energy received, sensors with high radiometric resolution are able to detect relatively small differences in the amount of energy received.

13. Radiometric cont.. Radiometric resolution is the sensitivity of a sensor system to differentiate signal strength as weak or strong radiation in micro and macro radiation in the electromagnetic spectrum (EMS), it is determined by the frequency band (Hz).

14. Radiometric cont.. 2-bit image 8-bit image

15. Radiometric cont.. By comparing a 2-bit image with an 8-bit image, one can see that there is a large difference in the level of discernible details. The more sensitive a sensor is to the reflectance of an object as compared to its surroundings, the smaller an object that can be detected and identified.

16. Temporal Resolution Temporal Resolution is the frequency at which data is captured for a specific place on the earth. The more frequently they are captured, the better or finer is the temporal resolution. The ability to collect imagery of the same area of the Earth's surface at different periods of time is one of the most important elements for applying remote sensing data.

17. Temporal cont.. For example, during the growing season, most species of vegetation are in a continual state of change and our ability to monitor those subtle changes using remote sensing is dependent on when and how frequently we collect imagery.

18. C onclusion The resolution gives accuracy to the images and it is important to the image because it gives well, clear and observable objects on the image, also higher resolution of the image can help to analyze and interpret details of the image for the best information.