IDS Software Suite 4.96.1

Definition

Hot pixels (or in a broader sense, defective pixels) are pixels that do not react linearly to incident light – or do not react at all. They occur for various reasons, such as contamination during sensor production or sensor age. CCD sensors generally have fewer hot pixels than CMOS sensors under the same operating conditions. With darkened sensors and prolonged exposure times, hot pixels are visible as individual bright dots in the image. The following factors promote the occurrence of hot pixels:

•Long exposure times

•High gain settings

•High sensor operating temperature

Hot pixel correction

During the manufacture of our cameras, all sensors that will be used in uEye cameras are checked for hot pixels. In the process, images are taken with a darkened sensor and long exposure times. Pixels with a brightness higher than a specific value are classified as hot pixels. A list of the coordinates of each hot pixel is stored in the camera memory. The hotpixel correction is done in the uEye driver. However, some sensors also provide an internal hotpixel correction.

The maximum number of hot pixels stored in a uEye camera is:

How many hot pixels are on the camera's internal list depends above all on the defined threshold values. It is not an indication of the quality of the sensors used.

When you enable the "Hotpixel correction" function, the software automatically corrects the hot pixels in the captured image by calculating the average from the brightness value of two neighboring pixels. When using color sensors, the hot pixel is corrected with the appropriate color in raw Bayer format, i.e. before color conversion. The correction does not work with activated subsampling and binning factors greater than 2x.

Defining additional hot pixels

If additional hot pixels occur during use of the camera, you can add them to the camera's internal hot pixel list. To do this, use the API function given below.