A stereoscopic visualization system for endoscope using shape-from-shading algorithm, comprising: a monoscopic endoscope capturing a two-dimensional image; a three-dimensional display; and an image conversion device connected between the monoscopic endoscope and the 3D display, and having: an input port for endoscope connected to the monoscopic endoscope to receive the 2D image from the monoscopic endoscope; a 2D-to-3D conversion unit; an image output port connected with the 2D-to-3D image conversion unit and the three-dimensional display to receive the stereo image and display the stereo image on the 3D display; wherein the 2D-to-3D conversion unit is configured to apply a shape-from-shading algorithm adapted to calculate a light direction of a light source and a camera position for the 2D image, and to calculate a depth map based upon information of light distribution and shading of the 2D image, and to apply a depth image based rendering algorithm to convert the 2D image to a stereoscopic image with the depth map, wherein a disparity map is created by using the depth map, disparity values in the disparity map are inversely proportional to the corresponding pixel intensity values of the depth maps and are proportional to a focal length of the monoscopic endoscope and an interorbital width of the 3D display, and the stereoscopic image is generated by using the disparity map; and wherein the shape-from-shading algorithm combines the light direction and an iterative approach to solve equations involving a gradient variation of pixel intensity values in the 2D image. a monoscopic endoscope capturing a two-dimensional image; a three-dimensional display; and an image conversion device connected between the monoscopic endoscope and the 3D display, and having: an input port for endoscope connected to the monoscopic endoscope to receive the 2D image from the monoscopic endoscope; a 2D-to-3D conversion unit; an image output port connected with the 2D-to-3D image conversion unit and the three-dimensional display to receive the stereo image and display the stereo image on the 3D display; wherein the 2D-to-3D conversion unit is configured to apply a shape-from-shading algorithm adapted to calculate a light direction of a light source and a camera position for the 2D image, and to calculate a depth map based upon information of light distribution and shading of the 2D image, and to apply a depth image based rendering algorithm to convert the 2D image to a stereoscopic image with the depth map, wherein a disparity map is created by using the depth map, disparity values in the disparity map are inversely proportional to the corresponding pixel intensity values of the depth maps and are proportional to a focal length of the monoscopic endoscope and an interorbital width of the 3D display, and the stereoscopic image is generated by using the disparity map; and wherein the shape-from-shading algorithm combines the light direction and an iterative approach to solve equations involving a gradient variation of pixel intensity values in the 2D image. an input port for endoscope connected to the monoscopic endoscope to receive the 2D image from the monoscopic endoscope; a 2D-to-3D conversion unit; an image output port connected with the 2D-to-3D image conversion unit and the three-dimensional display to receive the stereo image and display the stereo image on the 3D display; wherein the 2D-to-3D conversion unit is configured to apply a shape-from-shading algorithm adapted to calculate a light direction of a light source and a camera position for the 2D image, and to calculate a depth map based upon information of light distribution and shading of the 2D image, and to apply a depth image based rendering algorithm to convert the 2D image to a stereoscopic image with the depth map, wherein a disparity map is created by using the depth map, disparity values in the disparity map are inversely proportional to the corresponding pixel intensity values of the depth maps and are proportional to a focal length of the monoscopic endoscope and an interorbital width of the 3D display, and the stereoscopic image is generated by using the disparity map; and wherein the shape-from-shading algorithm combines the light direction and an iterative approach to solve equations involving a gradient variation of pixel intensity values in the 2D image.