I am an academician in Faculty of Agriculture, Department of Field Crops. Therefore I am associated with plants. In our experiments, especially if you work on physiology of plants, you need to determine alteration of leaf area in field. This is one of the important physiological parameter. There are some methods which are time consuming and need labor. For example sampling of some plant leaves and estimate it by width-height-coefficient method. It is hard, time consuming and also not give healthy results in terms of all plant leaves in an area. Also there are some devices such as LI-COR leaf area meter, but all of them determine the leaf area one by one. If you work in breeding program, maybe you will have a hundred or a thousand different plants and think about you have to compare them with regard to leaf area. I mean it is necessity that using a more practical and almost accurate method that estimate the leaf area in field.
Don't limit yourself, you can also estimate to area of everything, but you need a reference object that you know its area.
Step 1: What You Need for Estimation
- reference object (you have to know its area)
- an object for estimating its area
- a camera (high resolution)
- computer and Photoshop software (I have used to CS6)
Step 2: Taking Photograph
- Be sure that you take photograph perpendicularly. If you couldn't get it as far as perpendicular, you will have bigger error margin.
- Show attention that reference object and measured object have contrast color due to It's easy to separate in selection stage.
- It will be better if you take photo more than one and replicate it when you edit in Photoshop for getting real-like value.
Step 3: How to Estimate in Photoshop
I have prepared a video about estimation leaf area (or an object area) in Photoshop.
I hope it is clear enough.