I would like to ask on how calculate vessel density in Adobe photosop.
But no further explanation on how it was calculated
I found below information from the Journal:
Vessel area density was represented as the number of vessel-overlaid pixels relative to the total number of picture area pixels, expressed as a percentage. The vessel density was calculated with Adobe Photoshop software on a Macintosh computer. Vessel length density was represented as the length (in millimeters) of blood vessels in a given area (1 mm2) of tissue and reflected the total length of vessels independent of vessel size from Journal: Increased Airway Vascularity in Newly Diagnosed Asthma Using a High-magnification Bronchovideoscope
You have all the answers there: You need a calibration marker on your image and then calculate the actual lengths and areas based e.g. on a selection with the info palette telling you how many pixels are in the selection or measuring blood vessels' lenghts and diameters with the measuring tools and fetching thme to the measurement log or writing them down in an Excle table/ on paper. The rest is just math based on known factors like the size of certain bload cells correlating to the measurements. The rest would require specific info on what the article actually reports on the methodology used, your own imagery and so on. Very few users here will even have experience with such scenarios and scientific publications are usually behind paywalls, so you have to provide that info/ links to the publication if possible.