It is a trend to replace the increasing shortage of natural sand with crushed sand for the development of building materials. To meet the construction requirements, it is necessary to measure the shape and gradation of crushed sand that is difficult to control. To solve this problem, a novel digital image processing methodology is proposed in this paper. Through the setting of camera resolution, lens and light source selection, the hardware platform of the measurement system was developed. The shape and gradation characterization method of dynamic falling crushed sand was studied, and the measurement software system was developed. Comparative experimental study of equivalent particle size, study of gradations repeatability experiment, comparative experimental study of dynamic digital image methodology and vibration sieving method of gradations and comparative experimental study before and after correction were conducted, respectively. The experimental results show that the equivalent elliptic Feret short diameter is suitable as the equivalent particle size. The maximum repeatability error appears in the size interval of 1.18–2.36 mm, which is 0.9%. The maximum gradation error is reduced from 6.93% before correction to 2.77% after correction. The maximum error of fineness modulus is reduced from − 0.13 to − 0.01. The accuracy of the developed measurement system can meet the actual engineering requirements, and it can realize the quality monitoring of crushed sand.

用碎砂代替天然砂的短缺是发展建筑材料的趋势。为了满足施工要求，必须测量难以控制的碎砂的形状和等级。为了解决这个问题，本文提出了一种新颖的数字图像处理方法。通过设置摄像机分辨率，镜头和光源选择，开发了测量系统的硬件平台。研究了动态落砂的形貌和等级表征方法，并开发了测量软件系统。等效粒径的对比实验研究，层次重复性实验研究 分别进行了动态数字图像方法和梯度振动筛分方法的对比实验研究以及校正前后的对比实验研究。实验结果表明等效椭圆费雷特短直径适合作为等效粒径。最大重复性误差出现在尺寸范围为1.18–2.36 mm的区域，为0.9％。最大灰度误差从校正前的6.93％降低到校正后的2.77％。细度模量的最大误差从-0.13降低至-0.01。所开发的测量系统的精度可以满足实际工程要求，并且可以实现碎石的质量监控。实验结果表明等效椭圆费雷特短直径适合作为等效粒径。最大重复性误差出现在尺寸范围为1.18–2.36 mm的区域，为0.9％。最大灰度误差从校正前的6.93％降低到校正后的2.77％。细度模量的最大误差从-0.13降低至-0.01。所开发的测量系统的精度可以满足实际工程要求，并且可以实现碎石的质量监控。实验结果表明等效椭圆费雷特短直径适合作为等效粒径。最大重复性误差出现在尺寸范围为1.18–2.36 mm的区域，为0.9％。最大灰度误差从校正前的6.93％降低到校正后的2.77％。细度模量的最大误差从-0.13降低至-0.01。所开发的测量系统的精度可以满足实际工程要求，可以实现砂粒的质量监控。细度模量的最大误差从-0.13降低至-0.01。所开发的测量系统的精度可以满足实际工程要求，并且可以实现碎石的质量监控。细度模量的最大误差从-0.13降低至-0.01。所开发的测量系统的精度可以满足实际工程要求，可以实现砂粒的质量监控。