The images of my ion counts (e.g., 12C14N and 12C15N) look beautiful, but when I make a ratio image (e.g., 12C15N/12C14N), it does not look so pretty because there are a lot of noisy pixels in areas where the ion counts are low. Could I overcome this aesthetic issue, for example, by modulating in every pixel the hue, which represents the value of the ratio according to the color map used, in such a way that the hue intensity will be proportional to the ion count? If I could do this, the noisy information would still be there but not visible in such a prominent way.
When displaying a ratio image, check the Modulate hue by intenity option in the main LANS GUI, and decide which mass will be used as the factor modulating the hue intensity.
An example of the result before and after the application of this modulation is shown in the left and right image below, respectively.
In this example we will use data kindly provided by Esther van der Ent. It is assumed that the data have been loaded into LANS, aligned and accumulated, and that we want to modify the appearance of the 15N/(14N+15N) ratio image.
4in the (mass [ ]) field in the main LANS GUI (see image above). Then, by entering
[200 2000]as the scale of the 12C14N ion counts, HI is calculated as (12C14N-200)/(2000-200), with 1 and 0 being forced in pixels where 12C14N>2000 and 12C14N<200, respectively. In this way the HI image will appear oversaturated and undersaturated at the same time, but it will help us highlight areas in the image where the biomass is high and suppress areas where the biomass is low (see left panel of the image below). By multiplying the original ratio image 12C15N/(12C14N+12C15N) with this HI image, the result will look as follows. Examples of other ratio image pairs without and with the hue modulation applied are shown below. In all cases the same source for the HI image, namely the 12C14N ion image scaled betwee 200 and 2000, was used.