<p>A color filter (F) has a plurality of successively arranged recurrent groups of different color stripes. An image pickup tube (2) has a photoelectrical conversion target exposed to lights which passed through the color filter and an index signal generation pattern. The image pickup tube outputs a signal containing a color signal component determined by a carrier which is modulated with the individual color stripes of each recurrent group of the color filter (F). The output signal from the image pickup tube (2) also contains an index signal component which depends on the index pattern. A first memory (63) holds at least part of the index signal component. The index signal component held by the memory is periodically updated. A second memory (65) holds a portion of the output signal from the image pickup tube which was obtained under conditions where a predetermined color light illuminates the photoelectrical conversion target via the color filter (F). A reference signal is generated in accordance with the index signal component read from the first memory and with the signal portion read from the second memory. A color signal is detected from the output signal of the image pickup tube by use of the reference signal.</p>
