The Left Move button 42 is an operation button for moving the indicator 41 leftward on the indicator guide 46. The Right Move button 43 is an operation button for moving the indicator 41 rightward on the indicator guide 46. The hue value after the indicator is moved is a temporary hue value and is not a determined value until the OK button 44 is pressed.

The OK button 44 is an operation button for setting the temporary hue value described above and making it the present hue value. The Cancel button 45 is an operation button for canceling the temporary hue value described above.

On the indicator guide 46, characters such as Red, Blue, and Green indicate the color ranges of the image displayed on the image display unit 11. Accordingly, the user can change (set) the tint of the image displayed on the image display unit 11 according to a relative position of the indicator 41 rather than by inputting a numerical value indicating the hue value.

(1-2) Operation

FIG. 9 shows an operation from when the display control unit 14 constructs the color component screen data until when an image (e.g., a set temperature) is displayed on the image display unit 11 by using the constructed color component image data in the first embodiment.

In step S1, the display control unit 14 reads component image data from the component image database 16, reads a color palette from the color palette database 17, and saves them in a temporary memory. The temporary memory can be a memory (not shown) in the display control unit 14 or another memory such as the storage device 18 shown in FIG. 1.