Patent ID: 7773141

Claim:
A control apparatus for controlling a monitor provided in an optical device, said control apparatus comprising: a brightness control processor that controls a brightness of said monitor; and a detecting processor that detects an amount of change in movement of an object produced as an image and indicated on said monitor; said brightness control processor setting an economy mode, in which said brightness is decreased to a level lower than that of a normal mode when the amount of change in movement of said object produced as said image on said monitor is greater than a threshold value; and said detecting processor comprising: an average value calculating processor that divides said image into a plurality of blocks, and calculates an average value of luminance values for each of said blocks according to a formula: BL ⁡ ( m , n ) = 1 a * b ⁢ ∑ x = 0 y = 0 y = b - 1 x = a - 1 ⁢ ⁢ Y ⁡ [ x , y ] , ⁢ wherein m corresponds to a coordinate along a first coordinate axis in the image, n corresponds to a coordinate along a second coordinate axis in the image, a corresponds to a number of pixels along said first coordinate axis in a block of pixels, and b corresponds to a number of pixels along said second coordinate axis in said block of pixels; and a change amount calculating processor that controls said average value calculating processor so that said average values are obtained for different images, to calculate the amount of change in movement of said object produced as said image on said monitor according to a formula: VR = ∑ m = 0 n = 0 n = d - 1 m = c - 1 ⁢  ⁢ BL 1 ⁡ ( m , n ) - BL 2 ⁡ ( m , n )  , ⁢ wherein m corresponds to a coordinate along a first coordinate axis in the image, n corresponds to a coordinate along a second coordinate axis in the image, c corresponds to a number of blocks along said first coordinate axis in the image, and d corresponds to a number of blocks along said second coordinate axis in the image.