How to measure Leaf Disease Damage percentage Area using ImageJ

[@nisakummi8395]

Hi sensei, I want to ask, why is my image data after the make binary process the black color is the background, not the object.. where is the error? thanks

[@nrttaye4033]

Hello thanks for reaching out. Could you please double check if during color threshold process, the threshold is selecting the object or the background. this might happen if the threshold selects the background. you can change the color of the threshold from red to black or white if your object color is red. let me know if this helps.

[@nisakummi8395]

@nrttaye4033 when I process to Threshold, the object color is red, like yours. But I don't know when I try to binary always different color with yours.

[@nrttaye4033]

Hello. Alright lets try this way now. after you click make binary, do the following. go to image, look up tables, and select invert LUT. if it still does not work let me know.

[@nisakummi8395]

@@nrttaye4033 ow thanks its worked. my diseased leaf result was just 0,056%.

[@nrttaye4033]

that is a great news. glad it worked out. all the best with the rest of your analysis

[@ranaelessawy3487]

It is really helpful.. thank you

[@nrttaye4033]

I am delighted to hear that you found the tutorial informative. If you have any questions or need clarification on anything, please ask. If you enjoyed this tutorial, please check out my other videos for more useful content. Thank you again for watching and supporting!

[@angelynfabale1719]

Hi can you help me understand about what to be inputted in "known distance" and "unit of length?" Because the sample we will be analyzing is the stomach of mice...we will analyze the total area of ulcers produced. I hope you will reply...we are now doing our experimental research.

[@nrttaye4033]

Hello, thanks for reaching out. If there is a scale image in one of your mice stomach images, that will be used as the measuring unit/length for all the subsequent images. To set the scale, first draw a line parallel to the scale. It does not matter how long it is drawn. In the above video the line is parallel to 1 cm in the scale. In the known distance input "1" since the line drawn equals 1 cm. in the unit of length input "cm" because this is a cm scale. alternatively you can also input it as 10 mm where known distance will be 10 and unit will be in mm. the distance in pixels will be set automatically. All the best with your experiment.

[@angelynfabale1719]

@@nrttaye4033 can we ask help via email? we are not really sure how to use image J software... especially the sample is the stomach of mice 🥺. We already have here the picture of stomach of mice as sample.

[@nrttaye4033]

Could you send me a sample image that contains a scale/measurement unit . Happy to help.

[@angelynfabale1719]

@@nrttaye4033 ofcourse! Thank you so much

[@angelynfabale1719]

@@nrttaye4033 can I send it through email?

[@AnneBesantyaCarroline]

hiii i love ur video, it's helping me so much. May i know how u determine that leaf disease percentage formula? Thank u so much

[@nrttaye4033]

You are very welcome. Glad you are finding it useful. the formula for leaf disease percentage is (diseased leaf area/Total leaf area) X 100.

[@AnneBesantyaCarroline]

@@nrttaye4033 but im using a fruit not leaf to measure the percentage, so is it the same formula we use?

[@nrttaye4033]

hello, the technique is the same. for the fruit it is (disease canopy area/total canopy area) X 100

[@AnneBesantyaCarroline]

@@nrttaye4033 Thankyou. But, i want to measure like only the fruit (cocoa fruit) so it just not the disease fruit area/total fruit area x 100?? why use canopy area? cause my research is The progression of disease symptoms on its surface week by week.

[@nrttaye4033]

hello . you are absolutely right. it is fruit disease area/total fruit area X 100. mine was a generalized description.