转贴 供参考：That chart depicts read noise, which is a proxy for dynam

Read noise is the amount of noise generated by electronics as the charge present in the pixels is transferred to the camera. It is a combination of all the noise generated by system components which convert the charge of each CCD pixel into a signal for conversion into a digital unit (ADU or grey-scale value). Since read noise is added to each pixel as it is read out, it is applied uniformly across the CCD as the data is read out.