Hot pixel (telescopes)
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A hot pixel or bright dot defect is a pixel that outputs many more electrons than others at the same input signal in a charge-coupled device (CCD) or CMOS sensor. In the simulated image,{{Cite journal |last=Hroch |first=Filip |date=2000-02-23 |title=The robust detection of stars on CCD images |journal= Experimental Astronomy|volume=9 |issue=4 |pages=251–259 |doi=10.1023/A:1008195518637 |arxiv=astro-ph/0002435 |s2cid=13504731 }} the hot pixels are the sources of the salt-and-pepper noise. In the definition of the HST ACS, A pixel above 0.14 e¯/pixel/second is considered a "hot" pixel.{{Cite web |title=4.3 Dark Current, Hot Pixels, and Cosmic Rays - HST User Documentation |url=https://hst-docs.stsci.edu/acsdhb/chapter-4-acs-data-processing-considerations/4-3-dark-current-hot-pixels-and-cosmic-rays |access-date=2023-03-09 |website=hst-docs.stsci.edu}}
A warm pixel is a pixel that has negative bias values. In the definition of the Hubble Space Telescope, a pixel below the hot pixels range but above 0.06 e¯/pixel/second is considered a "warm" pixel.