| 摘要 |
A device for substantially instantaneously converting a tonal image, such as a photograph, to a line drawing which depicts the lines formed by the borders of contrasting portions of the tonal image. The tonal image is scanned by a video scanner to produce a time varying video signal which signal is then differentiated to produce a signal consisting of pulses representative of predetermined selected levels of changes in tone, color, or shade. The signal is supplied to a pulse generator which produces a pulse of uniform width and height for each input pulse suitable for processing by a video receiver. The video receiver, being synchronized with the video scanner, is provided with means to instantaneously display a line drawing of the tonal image. Circuit control means are also provided to vary the uniform width of the lines in the resulting line drawing and to control the selection of lines in the line drawing in accordance with its corresponding significance in the tonal image. |
