JPH0740732B2 - Image processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a still image transmission device for transmitting a video signal such as a television signal via a telephone line or the like.

<Background> In recent years, a system has been considered in which a TV signal is transmitted using a telephone line or the like, and the receiving side prints it using photographic paper or a video printer. FIG. 1 is a schematic diagram showing the entire system.

Reference numeral 1 is a rotating magnetic sheet, and 2 is a motor for rotationally driving it. The reproducing head 3 is arranged on the rotating magnetic sheet 1, and a still image for one field or one frame is reproduced here. The reproduced signal is input to the video process circuit 4, where it is converted into an NTSC signal or a line-sequential signal. This video signal is displayed by the motor 5.
Input to RGB Matrices 6. In the RBG matrix 6, the reproduced video signal is matrix-operated to obtain the R, G and B components. Further, these signal components are subjected to complementary color conversion, γ correction, masking and other processing in the image processing circuit 7. This output is digitalized by the A / D converter 8, for example 8bit
Is quantized into 256 levels. The respective data of Yl, Mg and Cy are sequentially stored in the frame memory 9 for each operation described later, and this data is read according to the transmission rate of the transmission line. At this time, the data is added with a phase synchronization signal in the transmission signal forming circuit 10 so that the receiving side can print or plate at the same timing. 11 forms a transmitter, the output of which is transmitted to the receiving side via the communication line K.

On the reception side, the transmitted data is temporarily stored in a frame memory, and this is sequentially A / D converted and converted into Yl (yellow), Cy (cyan), and Mg (magenta) analog signals, and via the NTSC encoder 15. The image is displayed on the monitor 16 and is also supplied to the printing device 14. Yl, Cy, Mg obtained by the printing device 14
For example, when the photosensitive material is exposed for each color component from the signal and the negative is ink jet printing, it is used for controlling the ink amount.

At this time, when obtaining the imprint, the imprint data must be set so that the 8-bit 256-gradation can be effectively used, in addition to synchronizing the system between transmission and reception.

<Objective> In order to fulfill the above request at the time of transmission, the present invention sends the level of the brightest or whitest part of the image to be printed, sets this level as the full level, and sends it thereafter. It is an object of the present invention to provide a still image transmission device that determines the level of the received printing data based on the data.

<Embodiment> FIGS. 2 and 3 are views for explaining an embodiment of the present invention. FIG. 2 shows the form of the signal to be transmitted. First, a pulse for system synchronization appears. In this case, for example, the printing apparatus is a cylindrical photosensitive drum, which is wound around the drum and sequentially recorded by rotating the printing paper or the printing paper in horizontal lines. The application pulse appears in the cycle T. During this period, the rotary motor is phase locked. Next, when the white level signal period comes and the whitest part in the image is the optimum level, for example, 80-bit quantization, this level (FIG. 2A) is set to 255. Subsequently, in the image period, image signals for one frame continuously appear according to the transmitter.

However, in order to create the printing negatives for yellow, magenta, and cyan, the output signals of Yl, Mg, and Cy are required separately, so the signal shown in FIG. It is given before each color image signal.

FIG. 3 is a specific block diagram of the printing device 14 on the receiving side in FIG.

The signal of FIG. 2 is input from the terminal 17, and this is led to the synchronizing pulse extracting circuit 18 and the gain setting circuit 19. The output of the gain setting circuit 19 is the white level detection circuit 20 and the exposure drive circuit 21.
Entered in. The white level detection circuit 20 detects the level A in the white level signal period shown in FIG. 2, and the gain is adjusted so that the video signal level during the subsequently input image period becomes the maximum level 255, for example, in the case of 8-bit quantization. Set the gain of the setting circuit 19. The video signal thus obtained is input to the exposure drive circuit 21, and the exposure amount is obtained in an analog manner. Finally, this exposure amount is given to the exposure element 22 to expose the photosensitive surface.

The synchronizing pulse of the period T extracted by the synchronizing pulse extracting circuit 18 becomes one input signal of the phase comparing circuit 25, and the other input is a pulse corresponding to the rotational phase obtained from the PG head 24 of the photosensitive drum 23. The signals are input, and the phase comparison circuit 25 performs phase comparison between these two inputs. The output corresponding to the phase error obtained here controls the rotation of the motor drive circuit 26 and rotationally synchronizes the photosensitive drum motor 23 with the system synchronization pulse.

In the above-described embodiment, the case where the photosensitive negative is formed on the photosensitive drum has been described, but a printer device such as an ink jet may be used.

Further, although the level detected by the white level detection circuit 19 is set to 255 by 8-bit quantization, it may be set to a slightly lower level in consideration of level saturation.

As described above, according to the present invention, the image processing means for receiving and processing the transmission data including the color image signal of at least one frame, the receiving means for receiving the transmission data, the transmission A detection unit that includes data and that is set for each frame and that detects a reference signal that is the maximum level signal in the color image signals that form the one frame, and the reference signal that is detected by the detection unit is Gain control means for converting the color image signal of one frame to a full level expressible and controlling the gain of the color image signal of the one frame based on the conversion, and the frame set for each frame. Since the gain control of the color image signal is performed using the reference signal which is the maximum level signal of Can be prevented from saturating the highlight part of the received color image signal even if is different for each frame,
Even if the dynamic range of the received color image signal is narrow, it is possible to always obtain a received image with a wide dynamic range.

[Brief description of drawings]

FIG. 1 is an overall system diagram of transmission / reception, FIG. 2 is a diagram showing a signal form for printing, and FIG. 3 is a concrete block diagram of a printing apparatus.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motoaki Kawasaki 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Plant (56) Reference JP-A-49-43527 (JP, A) JP A 57-7683 (JP, A)

Claims (1)

[Claims] 1. An image processing apparatus for receiving and processing transmission data including at least one frame of a color image signal, comprising: receiving means for receiving the transmission data, the one frame being included in the transmission data. Detecting means for detecting a reference signal which is set for each frame and which is a maximum level signal in the color image signals constituting the one frame; full reference capable of expressing the reference signal detected by the detecting means by the color image signal of the one frame. And a gain control unit for controlling the gain of the color image signal of one frame based on the conversion.