MULTITONE WEDGE READING OUT DEVICE

摘要

PURPOSE:To make it possible to obtain a picture of (n+1) tone wedges in a facsimile and so on by using (n) kinds of binary signals obtained by irradiating one scanning line of a draft to be read out with (n) kinds of different luminous source intensity. CONSTITUTION:The picture image of draft 1 is irradiated by fluorescent lamp 2. Light quantity sensor 4 detects the quantity of light of fluorescent lamp 2 and outputs an electric signal corresponding to the detected quantity of light to light quantity detecting circuit 5. Circuit 5 generates an electric signal when the quantity of light of fluorescent lamp 2 consists with the value which has been previously set up and excitates solid scanning light photodetecting element 7 to make a picture signal generate. Circuit 5 has plural thresholds for the quantity of light of fluorescent lamp 2 and the necessary threshold is decided according to the sensitivity of element 7. Video amplifier discriminator 8 amplifies the analog picture signal read by element 7, discriminates the signal within a fixed threshold and outputs a binary signal. Thus, a picture image having 3 tone wedges can be obtained by 2 kinds of binary signals obtained by irradiating a draft with 2 kinds of luminous source intensity.