An image processing device which is connected to an imaging unit, the imaging unit: being configured to sequentially capture images of a plurality of workpieces conveyed on a conveying device, and having an imaging range such that the sequentially captured images overlap, the image processing device comprising: an interface that receives the sequentially captured images obtained by the imaging unit; measurement means for acquiring a position of each workpiece by performing measurement processing to a respective sequentially captured image; synthesis means for generating a synthesized image by synthesizing the sequentially captured images into a panoramic image such that the sequentially captured images overlap with one another within an overlapping range in an imaging order; output means for outputting the synthesized image, information indicating the overlapping range correlated with the synthesized image, and information indicating the position of each workpiece; and means for outputting information on a ratio of the time necessary for acquiring the position of each workpiece to a time between the capture of respective sequentially captured images, wherein the ratio is acquired with respect to each of the sequentially captured images of the synthesized image, and the ratio is output while correlated with the synthesized image at a position corresponding to the position of each sequentially captured image of the synthesized image. being configured to sequentially capture images of a plurality of workpieces conveyed on a conveying device, and having an imaging range such that the sequentially captured images overlap, the image processing device comprising: an interface that receives the sequentially captured images obtained by the imaging unit; measurement means for acquiring a position of each workpiece by performing measurement processing to a respective sequentially captured image; synthesis means for generating a synthesized image by synthesizing the sequentially captured images into a panoramic image such that the sequentially captured images overlap with one another within an overlapping range in an imaging order; output means for outputting the synthesized image, information indicating the overlapping range correlated with the synthesized image, and information indicating the position of each workpiece; and means for outputting information on a ratio of the time necessary for acquiring the position of each workpiece to a time between the capture of respective sequentially captured images, wherein the ratio is acquired with respect to each of the sequentially captured images of the synthesized image, and the ratio is output while correlated with the synthesized image at a position corresponding to the position of each sequentially captured image of the synthesized image. an interface that receives the sequentially captured images obtained by the imaging unit; measurement means for acquiring a position of each workpiece by performing measurement processing to a respective sequentially captured image; synthesis means for generating a synthesized image by synthesizing the sequentially captured images into a panoramic image such that the sequentially captured images overlap with one another within an overlapping range in an imaging order; output means for outputting the synthesized image, information indicating the overlapping range correlated with the synthesized image, and information indicating the position of each workpiece; and means for outputting information on a ratio of the time necessary for acquiring the position of each workpiece to a time between the capture of respective sequentially captured images, wherein the ratio is acquired with respect to each of the sequentially captured images of the synthesized image, and the ratio is output while correlated with the synthesized image at a position corresponding to the position of each sequentially captured image of the synthesized image.