Image processing device and image processing method

The present invention provides an image processing device and an image processing method, which can suppress the degradation of the detection accuracy of objects, such as a person and a vehicle, which are imaged in a frame image of an imaging area taken with an infrared camera, with the change in weather of the imaging area of the infrared camera. An image processing part (4) employs a background model to determine whether each pixel of a frame image inputted into an image input part (3) is a foreground pixel or a background pixel and generates a background difference image. The background model corresponding to each pixel is stored in a memory (4a). In addition, the image processing part (4) sets a threshold D taken as a reference used to determine whether the pixel is the background pixel or the foreground pixel for each pixel of the frame image inputted into the image input part. The image processing part (4) calculates and sets the threshold D in the generated background difference image according to the