| 摘要 |
PURPOSE:To make adjustment of an image easy in terms of density and contrast by changing at least, any of an upper reference potential or a lower reference potential of an A/D converter which quantizes an image signal while such a reference potential is interlocked to a volume control attached to the outside of a main unit. CONSTITUTION:Signals from volume controls 101, 102 for image quality adjustment of a user attached on the outside (front panel and other appropriate parts) of the main unit of a video printer, are converted by impedance conversion circuits 103, 104. After this, an upper reference potential (+Vref) and a lower reference potential (-Vref) for quantization of an A/D converter 105 are controlled. Then an entered image signal 110 is subjected to A/D conversion and the converted signal is connected to a printing device 106. A non-linear property transformation device can be installed between 101 and 103, or between 102 and 104. |
