Allied International Home Security System manual Is it an impurity? Identifying impurities

AVT camera cleaning instructions

Is it an impurity? – Identifying impurities

If you observe any image artefacts in your video preview of your AVT camera you may have impurities either on the lens, filter/protection glass or, theo- retically on the sensor protection glass, although every AVT camera gets cleaned prior to sealing and shipment.

Impurities (dust, particles or fluids) on the sensor or optical components (Figure 3: Image with tiny dust on the filter (left) and dust on the sensor (right) on page 22) will appear as a dark area, patch or spot on the image and will remain fixed in the preview window while you rotate the camera over the target.

Do not confuse this with a pixel defect which will appear as a distinct point. It is crucial to differentiate between dust (e.g. flakes of skin, particles) and other dirt (e.g. liquids, fingerprints, grease). Particles can either rest loosely or can be more or less stuck to the optical surface.

Figure 3: Image with tiny dust on the filter (left) and dust on the sensor (right)

Where is the impurity? – Locating impurities

Before you dismount the lens you should find out if the impurity is on the filter, lens or sensor. Therefore you should view a uniform image (e.g. a white sheet of paper) with the camera. The affected optical surface is identified when a suspected optical component is moved and the dirt follows this move- ment.

1.If you move only the lens (not the camera) and the impurity moves as well, the impurity is on the lens.

2.If you move the IR cut filter/protection glass window and the impurity moves as well:

Please carefully remove the filter/protection glass (for certain camera models, indicated below, requiring a special tool which can be ordered

Hardware Installation Guide V2.0.0

22