1. An image enhancement apparatus, comprising: a global contrast curve generator generating a global contrast curve for an input image according to a global histogram of the input image; a local contrast curve generator generating a local contrast curve for each image partition within the input image according to the global contrast curve and further a feature of the image partition; and an image generator generating an output image by enhancing a contrast of each image partition according to the local contrast curve for the image partition, the input image and further one or more local contrast curves for one or more image partitions adjacent to image partition, and merging the enhanced image partitions, and wherein the image generator further comprises: a blender obtaining a contrast adjusting value for each pixel in the image partition by blending the local contrast curves of the image partition and the one or more adjacent image partitions according to the distances between the pixel and the image partition and the one or more adjacent image partitions; and the image generator generating the output image by compensating each pixel in the image partition with the corresponding contrast adjusting value to enhance the contrast of each image partition, and merging the enhanced image partitions.