1. A method of sensing device characteristics of pixels, comprising: analyzing an input image to at least determine gray level difference in a first direction at different portions of the input image, the different portions including a first portion with a first level of gray level difference in the first direction and a second portion with a second level of gray level difference in the first direction, the second level of gray level difference higher than the first level of gray level difference; selecting a subset of pixels in a display panel based on the analysis of the input image, wherein the selected subset of pixels displaying the first portion is separated in the first direction by a first sensing interval, wherein the selected subset of pixels displaying the second portion is separated in the first direction by a second interval shorter than the first interval; sensing the device characteristics of the selected subset of pixels in a first sensing period; and estimating the device characteristics of unselected pixels based on the sensed device characteristics of the pixels.