Embodiments of the present disclosure relate to reducing line banding artifacts in raw image data. If the same line of pixel sensors (e.g., in a row) in an image sensor includes a subset of pixel sensors that receive bright light and another subset of pixel sensors that receive low light, line banding artifacts may appear in the capture raw image data. To reduce or eliminate the line banding artifacts, the raw image data is normalized by adding offset values to its pixel values. The offset values are determined from the pixel values obtained from masked pixel sensors on one or both sides of the image sensor.