JP3361555B2 - Printer contour enhancement processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION,Used for linters
The present invention relates to an outline emphasis processing device. [0002] 2. Description of the Related Art Halftone hard copies from video images
In the thermal printer to be created, the input video image
Is processed as it is and printed.
In many cases, the sharpness is reduced due to blurring. For this reason, contour strength
Normally, a tone adjustment process is performed. This contour enhancement process
Changes the density value of a certain pixel according to the density values of surrounding pixels.
To enhance the outline of the image.
You. In the contour emphasis processing, the main scanning direction (thermal head)
In the main scanning direction and the sub-scanning direction.
Some are applied in both directions. On the other hand, video images are recorded according to the recording method.
There is a frame picture and a field picture.
It is composed of half the scanning lines of the frame image. Fret
With a thermal printer that prints
If is a field image, print it as is
And compressed in half in the sub-scanning direction orthogonal to the scanning line.
Two scan lines to create a hard copy of the image
Interpolate one scanning line in between and convert it to a frame image
are doing. [0004] By the way, the conventional contour
Is the emphasis processing the reason why the arithmetic circuit can be simplified?
Are often applied only in the main scanning direction.
There is a disadvantage that the sharpness in the sub-scanning direction tends to be insufficient.
You. For this reason, contour enhancement processing is performed in both the main scan and sub-scan directions.
Is applied to the pseudo-framed image described above,
Diagonal jagged lines may be emphasized or may look like human skin.
A mosaic fixed pattern is placed on an image having a smooth gradation change.
There was a problem that turn noise was generated. According to the present invention, when an input image is a frame image,
In this case, the contour strength is well balanced in both main scanning and sub-scanning directions.
Performs key processing and the input image is a field image
If necessary, make sure that the diagonal lines do not impair the smoothness.
Guo can do emphasisRupLinta contour enhancement processor
The purpose is to provide. [0006] [MEANS FOR SOLVING THE PROBLEMS]
The present inventionNoThe linter's contour enhancement processor
To indicate whether the image is a field image or a frame imagemeansWhen,
This switchingmeansInput image is linked to the field image
, Only the main scanning direction is emphasized, and the input image
If is a frame image, both the main scanning and sub-scanning directions
With edge enhancement processing means for enhancing the edge
It is. [0007] [Action] Whether the input image is a frame image or a field image is determined.
SwitchmeansIs operated. If the input image is a field image
Is interpolated and converted to a frame image
After that, contour enhancement processing is applied only in the main scanning direction and printed.
Is done. If the input image is a frame image,
Contour enhancement processing is performed in both the main scan and sub-scan directions.
Printed. [0008] DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
Whether the image recording method is frame recording or field recording
Switch the switch SW beforehand
Good. Then, for example, a video taken with an electronic still camera
Set the off-roppy to the still video player.
The video signal reproduced here is sent to the Y / C separation circuit 11.
It is input and separated into a luminance signal Y and a chrominance signal C. this
The color signal C is converted by the decoder 12 into color difference signals RY and BY.
And these luminance signal Y and color difference signals RY, B
−Y is quantized by the A / D converter 13 and, for example,
It is converted into a digital signal of 64 gradations. This digital
Luminance data Y ', color difference data R'-Y', B '
−Y ′ is written to the image memory 14. When the changeover switch SW is turned to the "field" side,
If it has been replaced, the CPU 15
4, the luminance data Y 'and the chrominance data R'
−Y ′, B′−Y ′ are read into the pseudo-frame processing unit 16.
After interpolating this and framing it,
Rewrite to the image memory 14. With this framing,
Thus, one scanning line is interpolated between two scanning lines. This
In the embodiment, the brightness data of the surrounding pixels
Interpolation processing is performed in consideration of the degree data.
Of the scan line is used as it is. Of course, color difference day
Data, consider the color difference data of the surrounding pixels.
Good. Next, referring to FIG. 2 to FIG.
The data interpolation process will be described. Here, this interpolation processing
The principle is not only luminance data but also color difference data and density data.
2 and 3, the image data is
It will be described as an example. FIG. 2 shows a line (running) to be interpolated.
Inspection line) and the two lines above and below (hatchin)
From the pixel x to be interpolated.
This shows a 3 × 3 pixel taken out.
Image data of pixels A, B, and C_D, B_D,
C_DAnd image data of pixels F, G, and H on the lower line
To each F_D, G _D, H_DAnd from now on, D '= A_D+ F_D x '= B_D+ G_D E '= C_D+ H_D S1 = | A_D-H_D| S2 = | B_D-G_D| S3 = | C_D-F_D| Is calculated. Note that, for convenience, the left and right pixels of the interpolation pixel x are
The pixels are D and E. As shown in FIG. 3, first, D ', x',
Compare E '. D '<x' <E 'or D'> x '>
If E ', the pixels A, B, C, D, x, E,
The brightness or density of the region consisting of F, G, H gradually decreases in the scanning direction.
Can be considered as changing. In this case
Represents image data B of pixels B and G in the vertical direction._D, G_DSupplement
Image data x of inter-pixel x_DIs interpolated,
Since only the stepped image causes drooping, the pixels A,
H image data A_D, H_DOr image data of images C and F
Data C_D, F_DInterpolation is performed for those with a close correlation
U. S1, S2, S3 are compared, and S1 <S2 <
If S3, the image data A of the pixels A and H_D, H
_DAverage value of (A_D+ H_D) / 2 is the image data of the interpolation pixel x.
Data x_DAnd Also, when S1> S2> S3,
Is the image data C of the images C and F_D, F_DAverage value of (C
_D+ F_D) / 2 is the image data x of the interpolation pixel x_DAnd
If neither of these, D '<x' <E 'or
Are not D '> x'> E ', pixels A, B, C,
The brightness or density of the region consisting of D, x, E, F, G, H
Because it does not change gradually, it is in the vertical direction of the interpolation pixel x
Image data B of pixels B and G_D, G_DIs the image of the interpolation pixel x
Data x_DIs interpolated. That is, x_D= (B_D+ G_D) /
Let it be 2. As shown in FIG. 4, luminance data Y ', chrominance
Data R'-Y 'and B'-Y' are pseudo-frame-forming processing units.
16 are input to the field memories 17 respectively.
a, 17c and 17e. Next, the brightness data
Is read out from the field memory 17a and interpolated.
The direction of interpolation by the direction discriminating circuit 18, that is, as shown in FIG.
From vertical direction, upper right and lower left direction and upper left and lower right direction
The direction with the smallest difference value is selected. And the interpolation performance
For example, x_D= (A_D+ H_D) / 2
An operation is performed, and the luminance data x of the interpolation pixel x is calculated._DBut
Field memory 17b. One field complement
After the inter-process, alternately from the field memories 17a and 17b
, One line at a time_DIs read out,
The image memory 14 stores luminance data for one screen of a frame image
Is written to. The color difference data R 'of the line to be interpolated
−Y ′, the data input to the field memory 17c.
Data is input to the field memory 17d.
You. Then, alternately from the field memories 17c and 17d
, Color difference data R'-Y 'is read out one line at a time.
This is the color difference data R'-Y 'of the frame image for one screen
Is written to the image memory 14. Similarly,
Color difference data B'-Y 'which is the same as the
Input to the field memory 17f, and a frame for one screen
It is read out as image color difference data B'-Y '. At the time of printing, the image memory 14
Degree data Y 'and color difference data R'-Y', B'-Y '
The color is adjusted by the digital manual color adjustment circuit 21.
Adjustment of the density is made. This corrected luminance data
Y 'and the color difference data R'-Y', B'-Y '
After the hue is corrected by the trust hue correction circuit 22, the contour
The signal is input to the correction circuit 23. The luminance data input to the contour correction circuit 23
Y 'and the color difference data R'-Y', B'-Y 'are shown in FIG.
With a spatial filter like this, only in the main scanning direction
Edge enhancement processing is performed. For example, the pixel A shown in FIG.
B and C image data (luminance data and color difference data)
A_D, B_D, C_DPerform this contour enhancement process for
And the image data B of the pixel B with the edge emphasized_D’
formula B_D’= −KA_D+ (1 + 2K) B_D-KC_D Is calculated. Here, K is a coefficient indicating the degree of emphasis.
And usually about 0.1 to 0.5. On the other hand, the input video signal is
In the case of, set the changeover switch SW to the "frame" side.
deep. In this case, naturally, the pseudo-frame processing is performed.
The data read from the image memory 14 is not
The signal is then processed. In the case of this frame image,
Luminance data Y 'and chrominance data input to the positive circuit 23
R'-Y 'and B'-Y' are spatial filters as shown in FIG.
Contours in both the main scan and sub-scan directions.
Is adjusted. For example, for a 3 × 3 pixel shown in FIG.
When this contour enhancement is performed, the image data E of the pixel E is obtained.
_DIs calculated by the following equation._D’. E_D’= A_D(KL) + B_D(*) + C_D(KL) + D_D(**) + E_D(***) + F_D(**) + G_D(KL) + H_D(*) + I_D(KL) * = − L · (1 + 2K) ** =-K ・ (1 + 2L) *** = (1 + 2L) ・ (1 + 2K) It is. However, A_D, B_D, C_D, D_D, E_D,
F_D, G_D, H_D, I_DAre the pixels A, B, C, D, E,
F, G, H, and I image data, and K is the main scanning direction.
L is a coefficient indicating the degree of enhancement, and L is the degree of enhancement in the sub-scanning direction.
Is a constant to represent. Brightness data Y 'subjected to contour enhancement processing, color difference
The data R'-Y 'and B'-Y' are
Is converted to three primary color signals of yellow, magenta, and cyan.
You. The yellow, magenta, and cyan signals have halftone correction and
The shading correction circuit 25 causes the thermal head 2
6 and the coloring characteristics of the thermosensitive recording paper 23.
Halftone correction and shading correction are performed. This
Thermal head by yellow, magenta and cyan signals
26 is driven. First, the yellow signal for one frame
Is supplied to the thermal head 26 one line at a time.
The thermal head 26 is driven based on this. This thema
Head 26 is a yellow thermosensitive coloring layer of thermosensitive recording paper 27.
To record a yellow image line by line. this
The part where the yellow image is recorded is ultraviolet light for yellow
UV light of a predetermined wavelength is irradiated by a lamp to fix the light.
It is. After light fixing of yellow image recording, for example,
The thermal recording paper 27 attached to the platen is the thermal head
26, thermal recording of magenta image starts
You. In this magenta recording, a magenta signal for one line
Is supplied to the thermal head 26 and the thermal recording paper 27
The magenta thermosensitive coloring layer is thermally recorded one line at a time.
Is fixed with an ultraviolet lamp for use. Finally, the cyan signal
Therefore, the cyan thermosensitive coloring layer of the thermosensitive recording paper 23 does not have one line.
One heat is recorded. This thermal head 26 is well known.
Many heating elements are arranged in a line in the main scanning direction.
Have been. The structure of the thermal recording paper 27 is as shown in FIG.
From opaque coated paper or plastic film.
A cyan thermosensitive coloring layer 32, magenta
Thermosensitive coloring layer 33, yellow thermosensitive coloring layer 34, protective layer 35
Are sequentially layered. Each of these thermosensitive coloring layers 32 to 3
4 are layered from the surface in the order of thermal recording. Shi
The thermosensitive coloring layer 32 includes an electron-donating dye precursor and an electron-receiving dye.
Containing a soluble compound as a main component,
Colors Ann. The magenta thermosensitive coloring layer 33 has a maximum absorption.
A diazonium salt compound having an absorption wavelength of about 365 nm;
Contains a coupler that reacts with this and develops magenta color
are doing. This magenta thermosensitive coloring layer 33 is
After thermal recording of a magenta image with a pad 25, 365 nm
When irradiated with ultraviolet light in the vicinity, the diazonium salt compound
It loses its coloring ability. The yellow thermosensitive coloring layer 34 has a maximum absorption wavelength.
Is about 420 nm, and a diazonium salt compound
Contains a coupler that develops a yellow color upon thermal reaction
You. This yellow thermosensitive coloring layer 34 has a thickness of around 420 nm.
Irradiation with near-ultraviolet light causes light fixation and loss of coloring ability.
In FIG. 1, the fixing ultraviolet lamp is not shown.
I have. Further, the luminance signal Y and the chrominance signal C of the field image
Are already separated, the luminance signal Y and the color
The signal C is directly input to the decoder 12 from the S terminal. The image to be printed is
After the color is adjusted by the digital manual color adjustment circuit 21, D
TV monitor via A / A converter 28 and encoder 29
It is projected on 30 and printed while checking the color etc.
Work can be done. In the embodiment described above, the thermosensitive coloring layer is laminated.
Thermal printer that records images on thermal recording paper
However, the present invention is not limited to this.
Sublimation type thermal transfer recording method using ink sheet
A thermal printer or the like may be used. Also, line pudding
However, the present invention is also applicable to a serial printer.
Can be applied. [0025] As described in detail above, the present inventionNo
According to the linter's contour enhancement processing device, the input image
The main scanning method is used for contour enhancement depending on whether the image is framed or framed.
Direction or only in the main scanning and sub-scanning directions
Is selected, so if the input image is a frame image,
Edge enhancement processing with good balance in both main scanning and sub-scanning directions
Can be performed, and the input image
If it is, it will not impair the smoothness of the diagonal line
The contour emphasis can be performed as follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a thermal printer. FIG. 2 is an explanatory diagram showing 3 × 3 reference pixels. FIG. 3 is a flowchart showing a sequence for determining an interpolation direction. FIG. 4 is a circuit diagram showing the internal structure of a pseudo-frame processing unit. FIG. 5 is an explanatory diagram illustrating a configuration of a spatial filter for performing edge enhancement processing in a main scanning direction. FIG. 6 is an explanatory diagram showing a structure of a thermosensitive recording paper. FIG. 7 is an explanatory diagram showing a configuration of a spatial filter for performing edge enhancement processing in both main scanning and sub-scanning directions. FIG. 8 is an explanatory diagram showing a 3 × 3 pixel extracted from a frame image centering on a pixel for which contour enhancement is performed; [Description of Signs] 16 Pseudo-frame conversion processing unit 18 Interpolation direction discrimination circuit 19 Interpolation calculation circuit 23 Contour correction circuit 26 Thermal head 27 Thermal recording paper SW switch

Claims (1)

(57) [Claims] [Claim 1] When an input image is a field image, it is interpolated and converted into a frame image and then printed. When the input image is a frame image, a signal is output as it is. in the processing to print to pulp printer, switching the input image indicates whether field image or frame picture
Means , in conjunction with the operation of the switching means , when the input image is a field image, the contour is emphasized only in the main scanning direction,
Main scanning and the contour emphasizing subscanning bidirectional edge enhancement processing means and edge enhancement processing apparatus features and to pulp printer in that a when the input image is a frame image.