A method performed by a computer for image analyzation includes: receiving, by a processor of the computer, an image captured by an imaging device； specifying, by the processor of the computer, first and second areas in the image； detecting, by the processor of the computer, a target object from the image in accordance with a certain pattern indicating a range of color saturation in an analysis of a color of the target object； and extending, by the processor of the computer, the range of color saturation in processing of the detecting the target object, when luminance of the first area in the image is lower than a first threshold and luminance of the second area in the image is equal to or higher than a second threshold.
