1. Image Denoising
 1.1 Find the rough position of each grid line;
 1.2 Remove the noise using median filtering locally.
2. Cell Extraction Individually
 2.1 Guided boundary contour tracing;
 2.2 Cell Extraction through 4-neighborhood region growing.
3. Shape from Shading Using Linear Approximation
 3.1 Image Irradiance Equation Deductio;
 3.2 3-D Shape Reconstructing.
4. Computing RBC shape surface feature
 4.1 Compute mean curvature and Gaussian curvature using image convolution;
 4.2 Set a threshold for this two curvature.
5: Segmentation through multiscale surface fitting
 More details is in Section 6: Experiment.
Algorithm 1: