In this paper, we present new applications of the Spectral Edge image fusion method. The Spectral Edge image fusion algorithm creates a result which combines details from any number of multispectral input images with natural color information from a visible spectrum image. Spectral Edge image fusion is a derivative–based technique, which creates an output fused image with gradients which are an ideal combination of those of the multispectral input images and the input visible color image. This produces both maximum detail and natural colors. We present two new applications of Spectral Edge image fusion. Firstly, we fuse RGB–NIR information from a sensor with a modiﬁed Bayer pattern, which captures visible and near–infrared image information on a single CCD. We also present an example of RGB–thermal image fusion, using a thermal camera attached to a smartphone, which captures both visible and low–resolution thermal images. These new results may be useful for computational photography and surveillance applications.
In this paper, we compare four methods of fusing visible RGB and near-infrared (NIR) images to produce a
color output image, using a psychophysical experiment and image fusion quality metrics. The results of the
psychophysical experiment show that two methods are significantly preferred to the original RGB image, and
therefore RGB-NIR image fusion may be useful for photographic enhancement in those cases. The Spectral Edge
method is the most preferred method, followed by the dehazing method of Schaul et al.
We then investigate image fusion metrics which give results correlated with the psychophysical experiment
results. We extend several existing metrics from 2 to 1 to M to N channel image fusion, as well as introducing
new metrics based on output image colorfulness and contrast, and test them on our experimental data. While
none of the individual metrics gives a ranking of the algorithms which exactly matches that of the psychophysical
experiment, through a combination of two metrics we accurately rank the two leading fusion methods.