1. A management system comprising: a plurality of labels disposed on a management target at respective positions different from each other in a direction separating from an imaging device, each of the labels including a plurality of display parts, the plurality of display parts being configured to change respective colors depending on different levels of temperature or humidity with each other, the plurality of display parts being arranged so as to change coloring positions depending on level of temperature or humidity; an imaging device configured to output image data indicating an image of the labels captured by the imaging device; an image processor configured to perform first image processing or second image processing, the first image processing being configured to transform the image data in a manner such that a difference in a number of pixels corresponding to each of the labels among the labels in image data after the transformation is less than a difference in the number of pixels corresponding to each of the labels among the labels in the image data before the transformation, the second image processing being configured to recognize an image of the plurality of display parts by using information of the number of pixels corresponding to each of the labels in the image data; and a level detector configured to detect the level of temperature or humidity based on brightness information of pixels corresponding to the display parts, the brightness information obtained by performing the first image processing or the second image processing by the image processor on the image data output from the imaging device.