A modified marker-extraction based watershed algorithm was proposed in this paper to deal with the over-segmentation during color image segmentation.The modified algorithm was constituted of smooth filtering

color gradient calculation

marker-extraction and watershed transformation.During smooth filtering

a novel spectrum envelope filter was designed.The new filter had a better performance on edge-preserving which was used to smooth the imported color image and gradient image.The color gradient was calculated right in the color vector space.During the course of marker-extraction

H-minima transformation was used to extract minima-marker in smoothed gradient image firstly

whose parameter was adaptively controlled by the depth information of local minima region.Then

the extracted minima-marker was updated by more information of local minima region.Finally

the updated minima-marker was imposed on the original gradient image to get the marked gradient.The final result was gotten from the watershed transformation on the marked gradient.The experimental results indicate that the modified algorithm overcomes the difficulties in getting accurate edges and detecting weak edges.Furthermore

it has a more reasonable initialization rule of parameters and a better adaptability.