public void setStrength(float strength) {
        this.strength = strength;
        if (material != null) {
            material.setFloat("Strength", strength);
        }
    }
Sets current strength value, i.e. influence on final image

@param strength the desired influence factor (default=1)
jme3-effects/src/main/java/com/jme3/post/filters/PosterizationFilter.java