A virtual ruler can estimate the size of colorectal polyps

Colon polyps-fleshy growths that occur on the lining of the colon or rectum-are an important risk factor for colorectal cancer
.

Colonoscopy is a non-surgical method in which doctors use an endoscope to check for polyps in the colon

First, the endoscope uses a fisheye lens to obtain a wider field of view inside the tubular structure of the colon and rectum
.

Although this lens is excellent for exploration purposes, it greatly distorts the outer part of the image compared to the central part

Fortunately, researchers at Fujifilm and Okayama University have developed a simple and economical solution
.

In a paper published in the Journal of Biomedical Optics, the researchers proposed a method by simply adding a laser pointer and minimal image processing to the endoscope.

The basic principle behind their new method is the geometric concept of triangulation
.

The small red laser pointer directly below the endoscope objective lens is aimed diagonally upwards, so that in the captured image, the position of the red dot changes according to the distance between the endoscope tip and the object hit by the laser

The researchers first tested their method with graph paper, which has straight lines of 0.
5 mm at different distances and inclination angles
.

Then, they recruited three endoscopy experts, who used the device and biopsy forceps to estimate the size of 33 silicon polyp images in the colon model

The proposed method requires only minimal modification to the existing endoscope design
.

In addition, the virtual scale can be turned on or off by touching a button, so that the screen can proceed as usual, displaying the scale as needed