1. An image process apparatus, comprising: an image capture device capturing an original image comprising at least one target object and generating a first depth map corresponding to the original image; a filter selecting the at least one target object from the original image according to the first depth map, and generating a temporary image comprising the at least one target object, wherein the temporary image has a depth information of the at least one target object; a depth estimation circuit generating a second depth map corresponding to an input image according to the input image; and a mixture circuit blending the temporary image into a predetermined field depth of the input image to generate a blending image comprising the input image and the at least one target object according to the depth information of the at least one target object and the second depth map, and a depth test method.