Abstract: In order to calculate accurate centric coordinates and radius of quasi-circular fruit rapidly, a kind of detection method for quasi-circular fruits based on improved randomized circular Hough transform was proposed. After the object was segmented from background with 2R-G, the template matching thinning algorithm was used to extract one-pixel fruit contour, from which the edge character points were abstracted. Then the edge character points were grouped according to their average tangent directions, with which the circular RHT algorithm was improved. Last, the centric coordinates and radius of quasi-circular fruits were calculated with the optimized circular RHT algorithm. The proposed method can detect the quasi-circular fruits rapidly and accurately, and can also recover the shape of part-covered fruit satisfactorily.