A mesh-candidate-based online 3D measurement method is proposed for reconstruction of the cement clinker in the grate cooler. The binocular stereo system is consist of two cameras with intersection of the optical axes. The wavelet multi-resolution algorithm is applied for improving the efficiency of measuring system. The few candidates were rematched using larger or smaller window according to histogram if the confidence coefficient value was low

and it reduced the measurement error caused by ambiguity. The measurement system reconstructed the surface of the cement clinker in grate cooler with high accuracy and efficiency.