An image object detection apparatus includes a noise filtering block for removing image noise an input image, an image scaling block for scaling the noise-removed input image to produce a scaled input image, an image conversion block for dividing the scaled input image into multiple regions and converting the divided image by a modified census transform (MCT) method, a data processing block for comparing MCT values of the image converted by the MCT method with a preset threshold, detecting at least one candidate region and identifying a human region from said at least one detected candidate region, and an image output block for marking the identified human region on the noise-removed input image.