Information in this article applies to:
Article ID: NDS1215 — Created: 11 Jun 2018 — Reviewed: 2 Jul 2018
Is there a way to check to see if there is dirt or debris on the image sensor that is causing image problems?
Yes, there is. You can review the flat-field correction image for the camera in question.
The flat-field correction image is used to flatten an image due to light gradients in the illuminator, objective, or image sensor and to level out minute variations in the sensitivity of adjacent pixels on the image sensor. The flat-field image is captured in air and should be completely free of image debris or other effects caused by the slide.
It is rare, yet possible, for parts of the uScope light path to become dirty. The light path includes the following possible sources of obstruction:
Any contamination in the light path will be captured by the flat-field image which you can review.
The following flat-field images illustrate various light path effects.
This is a typical flat-field image for a uScope. There are no discernible light or dark spots on the image. The lighting is consistent with some possible vignetting at the corners (which is expected).
If your flat-field image looks anything like this, it is good. There is nothing in the light path or on the image sensor to be concerned with.
This flat-field image shows several dark spots. These are caused by very tiny debris (2-3 microns in size) on the image sensor.
These spots are not completely opaque and are not a cause for concern. You should not be able to detect these spots on images captured and filtered with flat-field correction.
This flat-field image shows several light spots (and a few dark spots). The light spots are caused by water spots on the image sensor. They are caused when too much cleaning solution is used to clean the image sensor. Some of the spots may be difficult to see.
These spots are typically no cause for concern. You should not be able to detect them on images filtered with flat-field correction.