JPH0283538U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a relative gain graph diagram based on general color wavelengths, FIG. 2 is a block diagram of a conventional electrical white balance adjustment circuit, and FIG. 3 is a block diagram of a preferred embodiment of the present invention. FIG. 4 is a circuit diagram for implementing one example of FIG. 3, and FIG. 5 is a relative gain graph diagram showing white balance correction when a white subject is imaged. 10... Buffer means, 20... Sample holding means, 30... First reference signal supply means, 40... First comparison means, 50... Second reference signal supply means, 60... Second comparison means, 70... Optical filter control means, 80... Trigger means, 90
... Power supply means, 100 ... Rotating disk, 100
a to 100d... Optical filter, 101... Optical filter driving motor, 102... Filter position sensing means.

Claims (1)

[Claims for Utility Model Registration] (1) Buffer means for buffering input R and B gain control signals and luminance signals, respectively; and an average value of the buffered luminance signals in the buffer means, which is input. sampling means for sampling the average value of the luminance signal according to the automatic white balance set signal and the vertical drive signal; and at least one color temperature conversion reference signal according to the average value of the luminance signal sampled in the sampling. a first reference signal supply means for generating a first reference signal, and a first reference signal for determining conversion of at least one color temperature conversion filter by comparing the color temperature conversion reference signal with the R and B gain control signals buffered in the buffer means. a second reference signal supply means for generating at least one or more light amount adjustment reference signal; and a second reference signal supplying means for generating at least one or more light amount adjustment reference signal; a second comparison means for determining conversion of the light amount adjustment filter; an optical filter control means for controlling the color temperature conversion and the position conversion of the light amount adjustment filter according to the judgments of the first and second comparison means; trigger means for automatically generating a white balance set signal after the filter position is changed by the control means; and power supply means for supplying a power supply voltage to each of the means for a predetermined period of time in response to input of the white balance set signal. An automatic optical filter conversion circuit that optimizes the white balance of video cameras while minimizing power consumption. (2) The first reference signal supply means includes at least one passive resistance means and one active resistance means connected in series between the power supply voltage supply line and the ground line of the power supply means, and the active resistance The resistance value of the means is varied based on the average value of the input luminance signal, and the voltage signal divided from the supply voltage by the resistance value of the active resistance means corresponding to the amount of incident light is determined as the color temperature. 2. The optical filter automatic conversion circuit according to claim 1, wherein the optical filter automatic conversion circuit is supplied with a conversion reference signal. (3) The first comparison means includes a first comparator that compares the R gain control signal and the color temperature conversion reference signal to determine whether filter position conversion is possible on the high color temperature conversion filter side, and the B gain control. 3. The automatic optical filter conversion circuit according to claim 2, further comprising a second comparator that compares the signal with a color temperature conversion reference signal to determine whether or not the filter position can be changed on the raw color temperature conversion filter side. (4) The automatic optical filter according to any one of claims 1 to 3, wherein the second reference voltage supply means supplies first and second light amount adjustment signals having different voltage levels. conversion circuit. (5) The second comparison means includes a third comparator that compares the average value of the brightness signal with a first light amount adjustment reference signal to determine filter position conversion in the first light amount adjustment filter, and the average value of the brightness signal. 5. The automatic optical filter conversion circuit according to claim 4, further comprising a fourth comparator for comparing the second light intensity adjustment reference signal and the second light intensity adjustment reference signal to determine filter position conversion in the second light intensity adjustment filter. (6) the optical filter control signal receives the first to fourth comparator output signals and a filter position sensing signal of the currently selected optical filter, and generates an optical filter position conversion control signal based on these signals; A corresponding filter position display signal is generated in response to the filter position sensing signal, and at the same time as the position conversion control signal is generated, a trigger control signal for resetting the white balance immediately after the filter conversion is generated, and the optical filter conversion is performed. logic circuit means for generating a reset signal for resetting the power supply means when the power supply means is not required and after the conversion operation is completed and the white balance is taken again; and the filter position display means for receiving the signal and displaying the filter position. 6. The automatic optical filter conversion circuit according to claim 5, further comprising: a filter position display means for displaying the position conversion control signal; and an optical filter drive means for driving the optical filter in response to the position conversion control signal. (7) The logic circuit means includes a logic gate element;
7. The optical filter automatic conversion circuit according to claim 6, wherein the optical filter automatic conversion circuit comprises one of a programmable logic array element and a microprocessor. (8) The optical filter includes a color temperature conversion filter and a light amount adjustment filter arranged on one rotating disk that is axially coupled to an optical filter motor driven by the optical filter drive means. 7. The optical filter automatic conversion circuit according to claim 6. (9) The color temperature conversion and light amount adjustment filter is 1
9. The color temperature converting filter comprises two low color temperature conversion filters and three high color temperature conversion filters, and the three high color temperature conversion filters have the same color temperature characteristic and different light amount adjustment characteristics. The optical filter automatic conversion circuit described. (10) The automatic optical filter conversion circuit according to claim 9, wherein the optical filter is provided with a filter position sensing means for sensing the position of the corresponding filter.