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MICRO MEASURING

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How to mesure the HFOV ?

Now you can take the picture of the specimen or make a

 

 

For trying this for the first time the simple way is :

first test of your scale image by making a proportional

 

 

after taking a good picture of a specimen take another one of a scale.

resample of :  4500 x 3375 pixels.

 

 

If the objective is 40x or more use a stage micrometer of 1 mm

You have now a calibrated image where each 10 pixels,

 

 

If the objective is 2x, 4x or 10x you can use a micrometer of 10 mm

on the specimen picture, is equal to 1 μm .

 

 

design for eyepiece. It is better if your scale cover all the horizontal

Now you are ready for crop a small or big object 

 

 

view of the picture.

in the picture for evaluate the dimension in micron.

 

 

 

 

 

 

Never crop the picture of the specimen before making mesurement.

 

 

With a software like Photoshop make a high resample 

 

 

of the picture of the scale  by  8000 x 6000 pixels.

 

 

Crop the scale image for showing a round number of divisions :

 

 

10 divisions = 0.1 mm    or    20 divisions = 0.2 mm 

 

 

Now look on the property of the image for see the number of pixels

 

 

for the width. If the picture of your scale was taken with a 40x

 

 

you will obtain about 3555 pixels for 20 divisions or for 0.2 mm.

 

 

3555 pixels = 0.2 mm    then    8000 pixels = 0.450 mm

New resample of a scale

       Crop picture

 

 

The HFOV  for this lens in this particular condition is :  450 μm 

Objective 40x

       20 divisions : 200 μm

 

 

 

4500 x 3375 pixels

       2000 pixels

 

 

   

 

   

 

   

 

   

 

   

 

   

 

   

 

   

 

 Full picture of a scale

        Crop picture

       

 

 Objective 40x

   20 divisions : 0.2 mm =  200 μm

   

 

 8000 x 6000 pixels

        3555 pixels