What is the length of the tape/strip from the image?

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Problem explanation: 1. tape can be in any position of the image 2. Position can vertical / horizontal for tape Condition: Is to do without using a deep learning model only with help of OpenCV

my approach is given below 1. firstly convert the image to grayscale 2. thresholding to differentiate between foreground and background 3. morphology to reduce the noise in the image 4. After that trying to find the ROI but no ability to detect the tape

please suggest me how to proceed/guidance very helpful for me