[Cause]
The specified area contains multiple colours. This may be due to:
1. A portion of the designated area is mirrored.
2. Specular reflection from the lighting in part of the specified region makes it appear white in the image.
3. Several colours were taken within the designated area.
4. Colored lighting is being used.
5. The color changes according to the unevenness of the object being measured.
[Countermeasure]
For their respective reasons, the response is as follows:
1. Please change the lighting configuration to avoid a shadow.
2. Change the lighting arrangement to avoid specular reflection.
3. Cover the colours other than those you are going to measure.
4. Use white lighting and reduce brightness unevenness throughout the field of view when arranging the lighting.
5. Mask colors that appear darker because of surface unevenness.