A method applied to a BJT pixel of an image sensor apparatus includes: obtaining at least one of a surface quality signal of a first image sensed by the BJT pixel and a shutter turn-on time corresponding to the first image; and adaptively adjusting a pre-flash time of the BJT pixel for sensing of a second image according to the at least one of the surface quality signal of the first image and the shutter turn-on time corresponding to the first image; wherein the second image follows the first image.