# Quality assessment of data from CHRIS/PROBA

Polina Lemenkova

► To cite this version:

Polina Lemenkova. Quality assessment of data from CHRIS/PROBA. [University works] 'Calibration and Validation of Earth Observation Data' MSc student course report, University of Southampton. 2009, pp.1. hal-02023009

HAL Id: hal-02023009

https://hal.science/hal-02023009

Submitted on 18 Feb 2019

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
CHRIS/PROBA images characteristics:

* 18 bands

* 7th Oct 2004

* 17m ground resolution

* region: Thorney Island

Quality of CHRIS images is affected by two types of noises (J.C.Garcia, J. Moreno):

* vertical noise (vertical stripes; can be corrected by comparing values of neighbouring pixels)

* horizontal noise (easy to detect and correct using the horizontal profile of each file)

Correction of noises can be made through DIELMO 3D Methodology (J.C.Garcia, J. Moreno)

<figure><img src="image_2.png" /><figcaption>Fig4. Example of vertical noises in CHRIS image
Photo taken from Removal of noises (J.C.Garcia, p.3)</figcaption></figure>

<figure><img src="image_3.png" /><figcaption>Fig.5. Example of horizontal noises in CHRIS image
Photo taken from Removal of noises (J.C.Garcia, p.1)</figcaption></figure>

For the quality of CHRIS images .hdr files were examined:

1) **CHRIS...47A0_41.hdr** (taken at +36°)

3) **CHRIS...47A2_41.hdr** (taken at +55°)

2) **CHRIS...47A1_41.hdr** (taken at -36°)

4) **CHRIS...47A3_41.hdr** (taken at -55°)

5) **CHRIS...479F_41.hdr** (taken at nadir)

Images taken at the nadir are of good quality, while those at different angles have defects:

<figure><img src="image_4.png" /><figcaption>Comparing images taken at +55° dgr (47A2_41) and nadir images (479F_41) right</figcaption></figure>

<figure><img src="image_5.png" /><figcaption>Images taken at +36° dgr (47A0_41), left and nadir images (479F_41) right.</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>Images taken at +36° and -36°dgr (CHRIS 47A0_41 and CHRIS 47A1_41) both have inverted direction.</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Inverted Image received from bands
Combination 13-12-11, Envi</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>Inverted Image received from bands
Combination 9(red)-10(green)-11(blue).</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>Image received from bands
Combination 11(R)-4(G)-2(B)</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>Image received from bands
Combination 6(R)-5(G)-2(B)</figcaption></figure>

<figure><img src="image_11.png" /><figcaption>Image received from bands
Combination 15(R)-4(G)-1(B)</figcaption></figure>

Quality assessment of data from CHRIS/PROBA

CHRIS (Compact High Resolution Imaging Spectrometer) - new imaging spectrometer

carried on board a space platform PROBA (Project for On Board Autonomy)

The satellite was successfully launched in late October 2001, Shriharikota (India)

Region of interest – Thorney Island (UK), Chichester harbour

Chichester harbour has unique wetland environment : place for rare bird colonies.

Monitoring this place - important ecological task for environmental managers

To obtain a good-quality natural-coloured image of wetlands we need: nadir-taken colour CHRIS image with bands combination of corresponding spectral channels:

<table><thead><tr><td>Number of spectral channel</td><td>Corresponding colour</td></tr></thead><tbody><tr><td>1</td><td>Indigo blue (cyan)</td></tr><tr><td>2</td><td>blue</td></tr><tr><td>3</td><td>green</td></tr><tr><td>4</td><td>green</td></tr><tr><td>5</td><td>green</td></tr><tr><td>6</td><td>red</td></tr><tr><td>7</td><td>red</td></tr><tr><td>8</td><td>red</td></tr><tr><td>9</td><td>red</td></tr><tr><td>10</td><td>red</td></tr><tr><td>11</td><td>red</td></tr><tr><td>12</td><td>red</td></tr><tr><td>13</td><td>NIR</td></tr><tr><td>14</td><td>NIR</td></tr><tr><td>15</td><td>NIR</td></tr><tr><td>16</td><td>NIR</td></tr><tr><td>17</td><td>NIR</td></tr><tr><td>18</td><td>NIR</td></tr></tbody></table>

<figure><img src="image_12.png" /><figcaption>Inverted Image received from bands
Combination 4(R)-2(G)-1(B)</figcaption></figure>

<figure><img src="image_13.png" /><figcaption>CHRIS Superspectral Land:
Many narrow bands around
the red-edge (Barnsley M.J. p.5)</figcaption></figure>

<figure><img src="image_14.png" /><figcaption>CHRIS Superspectral Water:
many narrow bands in the visible
wavelengths (Barnsley M.J., p.5)</figcaption></figure>

<figure><img src="image_15.png" /><figcaption>Fig. 3. Viewing angles in a CHRIS / PROBA acquisition (J.C.Garcia, p.3)</figcaption></figure>

<figure><img src="image_16.png" /><figcaption>CHRIS_CH_041007_479F_41
Bands_12-8-1</figcaption></figure>

<figure><img src="image_17.png" /><figcaption>Fig. 1. Vertical air photo of Thorney Island</figcaption></figure>

<figure><img src="image_18.png" /><figcaption>Fig.2. Oblique air photo Thorney island</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>CHRIS_CH_041007_479F_41_Bands_7-4-1,
best natural-colours band combination
for Thorney Island wetlands monitoring</figcaption></figure>

References:

* Barnsley M.J. et al. *The PROBA/CHRIS Mission: A Low-Cost Smallsat for Hyperspectral, Multi-Angle, Observations of the Earth Surface and Atmosphere.*

* Bermin J. PROBA – Project for On-Board Autonomy

* Cutter M.A., Lobb D.R. Cockshott R. (2000) *Compact High Resolution Imaging Spectrometer*. Elsevier Science Ltd, Kent, UK

* Garcia J.G., Moreno J. *Removal of noises in CHRIS/PROBA images: Application to the Sparc Campaign Data*

* http://www.chris-proba.org.uk/

* http://earth.esa.int/missions/thirdpartymission/proba.html

* Kuusk A., Kuusk J., Lang M.. *A dataset for the validation of reflectance models*. Remote Sensing of Environment 113 (2009) 889–892