JP2556761B2 - Video printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video printer for printing an image from an image on a television, a VTR, or the like.

<Prior Art> Generally, in a conventional video printer, an input video signal is A / D converted and loaded into an image memory, and the energization of a thermal head is controlled based on the video signal data read from the image memory. It is configured to print.

<Problems to be Solved by the Invention> However, in such a conventional video printer,
For example, to enable high-quality printing with high gradation for high-quality video input from an external device such as a commercial video camera, A / D conversion is performed to A / D convert the input video signal. A high-resolution circuit is required and a large-capacity image memory is required. However, a large-capacity image memory is used only to support such high-quality video input. Is not desirable.

The present invention has been made in view of the above points,
An object of the present invention is to enable high-quality printing for high-quality video input without increasing the capacity of the image memory.

<Means for Solving the Problem> In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the present invention provides a first A / D conversion circuit for A / D converting an input video signal, and an image memory in which the video signal data A / D converted by the first A / D conversion circuit is written. , A D / A conversion circuit for D / A converting the video signal data read from the image memory, and an input video signal or a video signal from the D / A conversion circuit, based on a switching control signal, A switching circuit for switching and outputting, and a video signal from the switching circuit, which is A / D converted, and further includes the first A / D.
Based on the second A / D conversion circuit having a higher resolution than the conversion circuit and the video signal data from the second A / D conversion circuit,
A print processing circuit for controlling the energization of the thermal head to print a gradation corresponding to the resolution of the second A / D conversion circuit.

<Operation> According to the above configuration, whether the switching circuit prints based on the video signal read from the image memory or directly based on the input video signal without passing through the image memory. Can be switched, and the resolution of the second A / D conversion circuit after the switching circuit is
Since it is higher than the resolution of the first A / D conversion circuit, for example,
In the case of high-quality image input, high-quality printing is possible by performing A / D conversion and printing processing by the high-resolution second A / D conversion circuit without passing through the image memory. On the other hand, since the resolution of the first A / D conversion circuit in the previous stage of the image memory is lower than the resolution of the second A / D conversion circuit,
There is no need to increase the capacity of the image memory in response to high-quality video input.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a block diagram of an embodiment of the present invention.

In the figure, 1 is an analog signal processing circuit for performing predetermined signal processing such as synchronization separation on an input video signal, and 2 is a 6-bit first signal for A / D converting the video signal from the analog signal processing circuit 1. A / D conversion circuit, 3 is an image memory into which the A / D converted video signal data is written, and 4 is a D / A that outputs the video signal data read from the image memory 3 after D / A conversion. It is a conversion circuit.

Reference numeral 5 is a switching circuit for switching and outputting either the video signal from the D / A conversion circuit 4 or the input video signal from the analog signal processing circuit 1 based on the switching control signal, and 6 is the video signal from the switching circuit 5. A decoder circuit for decomposing into R, G, and B color signals, 7 a color signal selection circuit for selecting and outputting color signals according to the printing order, and 8 for a 2-bit second A / D for A / D converting the color signals. The D conversion circuit 9 controls the energization of the thermal head 10 on the basis of the color signal data from the second A / D conversion circuit 8 to control 8 bits corresponding to the resolution of the second A / D conversion circuit 8. , A control circuit for controlling each part, 12 selects whether to directly print with an input video signal or print with a video signal once stored in the image memory 3. It is a selection operation unit.

In the video printer of this embodiment, the resolution of the first A / D conversion circuit 2 for image memory is 6 bits, while the resolution of the second A / D conversion circuit 8 for print processing is 8 bits.
Further, the switching circuit 5 allows the user to select whether to print with the video signal once stored in the image memory 3 or directly with the input video signal without the image memory 3. It is configured to be selectable by 12.

Therefore, in the video printer having the above-mentioned configuration, for example, when a high-quality still image is input from a commercial video camera or the like and the user wants to print it, the selection operation unit 12 must be operated. Thus, the movable contact 5a of the switching circuit 5 is switched to the analog signal processing circuit side 5b.

As a result, the high-quality input video signal is directly supplied to the decoder circuit 6 via the analog signal processing circuit 1 and the switching circuit 5, and the decoder circuit 6 outputs R,
The color signals separated into G and B color signals and sequentially selected by the color signal selection circuit 7 are A / D converted by the high resolution 8-bit second A / D conversion circuit 8 and the print processing circuit 9 And high-quality printing with 8-bit gradation is performed.

In the case of inputting a high-quality image as described above, the second A / D conversion circuit 8 of high resolution is provided without passing through the image memory 3.
By performing A / D conversion and printing processing in step S1, high-quality printing can be performed without increasing the capacity of the image memory 3 in response to high-quality video input.

On the other hand, when inputting a video signal of a normal video,
By operating the selection operation unit 12, the movable contact 5a of the switching circuit 5 is moved.
Switch to D / A conversion circuit side 5c.

As a result, the input video signal is the 6-bit first A /
The A / D conversion is performed by the D conversion circuit 2 and written in the image memory 3, the D / A conversion circuit 4 reads the image from the image memory 3, the D / A conversion is performed, and the D / A conversion circuit 5 outputs the converted signal to the decoder circuit 6. Will be given.

The video signal supplied to the decoder circuit 6 is R, G, B
The color signals that have been separated into the color signals and sequentially selected by the color signal selection circuit 7 are converted into A signals by the 8-bit second A / D conversion circuit 8.
The image is subjected to / D conversion and given to the print processing circuit 9 to print.

Thus, even in the case of the video signal once stored in the image memory 3, the 8-bit A / D conversion is performed and the gradation processing is performed, so that an apparently high quality printing can be performed.

Of course, the present invention can be similarly applied to the case where the R, G, B color signals are directly input as the input video signals.

<Effects of the Invention> As described above, according to the present invention, the printing is performed based on the video signal once stored in the image memory, or the printing is directly performed based on the input video signal without passing through the image memory. Whether to perform it can be switched and selected by the switching circuit, and the resolution of the second A / D conversion circuit in the subsequent stage of the switching circuit is higher than the resolution of the first A / D conversion circuit for the image memory. Therefore, for example, in the case of high-quality video input, the second A /
High-quality printing is possible by performing A / D conversion and printing processing by the D conversion circuit, while the resolution of the first A / D conversion circuit in the preceding stage of the image memory is the same as that of the second A / D conversion circuit. Since it is lower than the resolution of the conversion circuit, it is not necessary to increase the capacity of the image memory in response to high-quality video input.

[Brief description of drawings]

FIG. 1 is a block diagram of an implementation system of the present invention. 2 ... First A / D conversion circuit, 3 ... Image memory, 4 ... D
/ A conversion circuit, 5 ... switching circuit, 8 ... second A / D conversion circuit, 9 ... print processing circuit.

Claims (1)

(57) [Claims] 1. A first A / D conversion circuit (2) for A / D converting an input video signal, and video signal data A / D converted by the first A / D conversion circuit (2). Image memory to be written (3)
A D / A conversion circuit (4) for D / A converting the video signal data read from the image memory (3), and an input video signal or a video signal from the D / A conversion circuit (4). A switching circuit (5) for switching and outputting any one of them based on a switching control signal, and A / D converting a video signal from the switching circuit (5), and the first A / D A second A / D conversion circuit (8) having a higher resolution than the conversion circuit (2),
A floor corresponding to the resolution of the second A / D conversion circuit (8) by controlling the energization of the thermal head (10) based on the video signal data from the second A / D conversion circuit (8). A video printer, comprising: a print processing circuit (9) for printing tones.