This document discusses wavelet-based image fusion techniques. Image fusion combines information from multiple images of the same scene to create a fused image that is more informative than any single input image. The wavelet transform decomposes images into different frequency bands, and image fusion algorithms merge the corresponding bands from input images. Common fusion rules include choosing the maximum, minimum, mean, or a value from one image at each band location. The inverse wavelet transform then reconstructs the fused image. Wavelet-based fusion can integrate high spatial and high spectral information from images like panchromatic and multispectral satellite data.