The document provides an overview of remote sensing concepts through three lectures presented by Dr. Safaa Mohamed Hasan. The lectures cover definitions of remote sensing, sensor types, image characteristics, and resolutions including spatial, spectral, radiometric, and temporal resolutions. Geometric distortions and corrections through registration and resampling techniques are also discussed.

1. Lectures Remote Sensing Presented by Dr. Safaa Mohamed Hasan National Authority for Remote Sensing and Space Sciences (NARSS) E-mail; safaamh2002@yahoo.com

2. Who am I? Dr. Safaa Mohamed Hasan Ph.D of Remote sensing and GIS Head of image processing department Data Reception, Analysis and Receiving Station Affairs Division. National Authority for Remote Sensing and Space Sciences (NARSS)

4. Lecture One

7. A remote sensing instrument collects information about an object or phenomenon within the instantaneous-field-of-view (IFOV) of the sensor system without being in direct physical contact with it. The sensor is located on a suborbital or satellite platform.

8. Interaction Model Depicting the Relationships of the Mapping Sciences as they relate to Mathematics and Logic, and the Physical, Biological, and Social Sciences

11. Person in photo is holding a sensor similar to the ones used on satellites. By recording a highly accurate spectral signature for this crop type using this hand-held spectrometer, scientists can then search for and extract this signature from satellite imagery and develop detailed maps of this crop type over very large areas.

13. AVHRR OLS MODIS MERIES SSM/I Seawinds SAR ASAR reflective Emissive Radiative Thermal Sensor Types The Electromagnetic Spectrum

16. Incident (I) Absorption (A) Transmission (T) Reflection (R) Specular or mirror reflection. where all (or almost all) of the energy is directed away from the surface in a single direction Diffuse reflection . the surface is rough and the energy is reflected almost uniformly in all directions Radiation - Target Interactions

17. 1.5 Radiation - Target Interactions Leaves Interactions: A chemical compound in leaves called chlorophyll strongly absorbs radiation in the red and blue wavelengths but reflects green wavelengths Water Interactions: Longer wavelength visible and near infrared radiation is absorbed more by water than shorter visible wavelengths

18. Characteristics of Images An image refers to any pictorial representation, regardless of what wavelengths or remote sensing device has been used to detect and record the electromagnetic energy

21. Active Sensor Passive Sensor Active and Passive ATMOSPHERE SURFACE Reflectance Emission Radiance

23. Lecture Two

26. Spatial Resolution, Pixel Size, and Scale spatial resolution of the sensor and refers to the size of the smallest possible feature that can be detected. Instantaneous Field of View (IFOV). The IFOV is the angular cone of visibility of the sensor (A) and determines the area on the Earth's surface which is "seen" from a given altitude at one particular moment in time (B). Pixels which are the smallest units of an image. Scale = The distance on an image or map / actual ground distance.

28. Low spatial resolution High spatial resolution

29. Spectral Resolution

30. Spectral Resolution Spectral resolution: the ability of a sensor to define fine wavelength intervals. Finer the spectral resolution  narrower wavelength range for a particular band. Black and White film Coarse spectral resolution Color film fine spectral resolution Some material may not be easily distinguishable using broad wavelength. They would require comparison at much finer spectral resolution (hyperspectral sensors)

31. Advanced Very High Resolution Radiometer (AVHRR) Bandwidths

32. Spectral Bandwidths of SPOT and Landsat Sensor Systems

34. One byte = 8bit Byte: is the smallest stored units for users Bit: is the smallest stored units for computers If we have 11 bits digital values, should be stored on………byte on our computer If we have 6 bits digital values, What ranges on the gray level put in our computer

37. High Radiometric Resolution Low Radiometric Resolution

38. Lecture Three

40. The geometric registration process involves identifying the image coordinates (i.e. row, column) of several clearly discernible points, called ground control points (or GCPs), in the distorted image (A - A1 to A4), and matching them to their true positions in ground coordinates (e.g. latitude, longitude). 1- Image-to-map registration 2- Image-to-image registration

41. Geometric Registration Process G.R. process involves identifying the image coordinates (i.e. row, column) of several clearly discernible points, called ground control points (or GCPs), in the distorted image (A - A1 to A4), and matching them to their true positions in ground coordinates (e.g. latitude, longitude). The true ground coordinates are typically measured from a map (B - B1 to B4), either in paper or digital format.

43. Nearest neighbour resampling uses the digital value from the pixel in the original image which is nearest to the new pixel location in the corrected image

44. Bilinear interpolation resampling takes a weighted average of four pixels in the original image nearest to the new pixel location.

45. Cubic convolution resampling goes even further to calculate a distance weighted average of a block of sixteen pixels from the original image which surround the new output pixel location