Accessory device and imaging device

An image-capturing device for capturing a skin image of a subject's skin, wherein the image-capturing device has a light source and a single image sensor configured to detect light emitted by the light source, both the light source and the single image sensor adjacently positioned on or within a surface of the image-capturing device, and further comprising:

• an accessory device, said accessory device comprising:
• a tubular member comprising a first opening at its first end configured to surround, when the accessory device is detachably mounted to the image-capturing device, the light source and the image sensor included in the image-capturing device, the tubular member further comprising a second opening at its second end configured to surround a skin portion;
• and
• first and second mirrors arranged within the second end of the tubular member, wherein the first mirror is arranged to reflect, when the accessory device is detachably mounted to the image-capturing device, light emitted by the light source towards the skin portion and the second mirror is arranged to reflect, when the accessory device is detachably mounted to the image-capturing device, light reflected from the skin portion towards the image sensor, wherein each of the first and second mirrors is provided with one or more markers that are detectable in images of the subject's skin taken by the image sensor, and wherein the one or more markers of the first and second mirrors are the same or different;
• a processor configured to process the image to determine a skin parameter of the skin portion from which the light has been received by the image sensor, wherein the skin parameter comprises skin gloss and the processor is configured to determine a gloss score indicating an amount or a character of skin gloss based on determination of:
• (i) an amount of white pixels in the skin portion;
• (ii) a number of clusters of white pixels in the skin portion, wherein a cluster is 4 or more adjacent white pixels;
• (iii) an average size of the number of clusters of white portions in the skin portion, where a size of a cluster is a number of white pixels in the cluster;
• and (iv) a largest cluster, by size of the cluster, in the skin portion, and further wherein the gloss score is determined using the following equation:
• C0+C1*pixel count+C2*cluster count+C3*average cluster size+C4*max cluster size
• where pixel count is the determination of the amount of white pixels in the skin portion, cluster count is the determination of the number of clusters of white pixels in the skin portion, average cluster size is the determination of the average size of the number of clusters of white portions in the skin portion, max cluster size is the determination of the largest cluster in the skin portion, and C0, C1, C2, C3, and C4 are constants.