Remote Sensing Image Formation Process: Applications & Corrections

1. Data Preprocessing Dr Lewis RSU Geography UCL

2. Rationale when we view an RS image, we see a 'picture’

3. Rationale when we view an RS image, we see a 'picture’ BUT need to be aware of the 'image formation process' to: • understand and use the information content of the image and factors operating on it • spatially reference the data

4. Overview • Image formation process • Sensor scanning systems • Geometric distortions • Radiometric distortions • dealing with these effects • applications • radiometric correction • geometric correction

5. Image formation process • Generally, an RS instrument makes a measure of the radiation received at a sensor

6. Types of sensor: Source of Energy • passive sensors • receive energy from a natural external energy source • e.g. reflected energy (originating at the Sun)

7. Types of sensor: Source of Energy • passive sensors • receive energy from a natural external energy source • e.g. emitted energy (thermal or microwave)

8. Types of sensor: Source of Energy • active sensors • emit energy from on-board source, and measure reflected energy • e.g. laser devices (LiDAR)

9. Types of sensor: Source of Energy • active sensors • emit energy from on-board source, and measure reflected energy • e.g. RADAR

10. Types of sensor: Source of Energy • active sensors • emit energy from on-board source, and measure reflected energy • e.g. RADAR

11. Types of sensor: Source of Energy • Semi-active sensors • emit energy from one platform, and measure from another • e.g. target illumination