Satellite image fusion provides a context for potential applications in several fields such as agricultural development, hydrology, environmental studies, and natural disaster actions plans. However, when dealing with large-size images, the time required for the fusion process grows significantly. To reduce processing delays, the present study proposes the use of the Brovey transform as an image-fusion technique together with a spectral richness calibration stage. The proposal makes use of a CPU/GPU heterogeneous computing architecture based on mass parallel processing, conducted with CUDA. The fusion process of a 8192-pixel image evinced a speed-up of 532X. Regarding the quality of the resulting image, a per-band average correlation coefficient of 0.9714 (spatial detail) was obtained when comparing the fused and panchromatic images in an (R,G,B) color space.