JPS62139084A - Picture processor - Google Patents

Abstract

PURPOSE:To obtain a high definition picture by adding a circuit which generates the address of an output start picture element in a picture processing device which performs the rotation of a picture accompanies by a magnification and a reduction. CONSTITUTION:An X address and a Y address of the output start picture element are set respectively at an X address register 50 and a Y address register 54. Also, at an increment register 51, tan theta (theta represents a rotating angle) is set. Next, by inputting a picture element clock to a synchronizing signal 56, an address centering each picture element in a line 21 to approximate the straight line of a result picture from the output start picture element in a main scanning direction can be found. The address centering the output picture element is found one by one, and simultaneously, a dot in an original picture corresponding to each address of the output picture element is found, and a picture element data is found from the dot. In this way, the high definition picture can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field) The present invention relates to a digital image processing device, and particularly to an image processing device that rotates an image while enlarging and reducing the image.

<Prior art> Conventionally, in this type of device, when the original image is rotated by 30' around the origin as shown in Fig. 2, the starting point of the output pixel of the resultant image is at the sub-scanning direction of the original image. It is the pixel center on the straight line 15, and the pixel data of the original image is used up to the straight line 14 in the sub-scanning direction of the result image, and the pixel data of the result image is written from the straight line 14 to the straight line 17, or the pixel at the output start point of the result image is written. The address of center 12.13 was calculated using a complicated calculation formula. Therefore, if it is applied to a processing device that requires high image quality and high speed, such as color image processing, it will take time to perform complex calculations, and if it is implemented using hardware, the scale of the hardware will increase. However, there was a drawback that the same pixel data was damaged in certain areas, resulting in deterioration of image quality.

<Objective> The present invention eliminates the drawbacks of the conventional example described above, and at the same time, it is possible to process rotation operations at arbitrary angles accompanied by enlargement/reduction at arbitrary magnifications while synchronizing the sub-scanning of the input image, and at the same time, to produce an image that does not cause deterioration in image quality. The purpose is to provide processing equipment.

<Embodiment> The subject matter of the present invention is when the coordinates of the output pixel of the resulting digital image become an irrational number including a decimal point, that is, when the coordinates of the output pixel of the resultant digital image become an irrational number including a decimal point. ! The aim is to match the address of the output pixel of the resulting digital image in corner rotation processing with the input timing of the original digital image, that is, to find it in synchronization with the synchronization in the sub-scanning direction of the input of the original digital image. There are many ways to determine the address of the output pixel of the resulting digital image, but in this example, we first use digital differential analysis to minimize the distance from the straight line in the sub-scanning direction of the resulting digital image to the address of the output pixel. The address of the output pixel is determined, and the address of the straight line in the main scanning direction of the resulting digital image is determined using the digital differential analysis method using the address of the output pixel determined here as the initial value. As will be explained below with reference to the drawings, since the explanatory embodiment is in a cylinder, rotation by an angle of 30' around the origin of the same size of the plane will be considered. FIG. 3 is an enlarged view of the area around the origin of FIG. 2. The circles in FIG.
The starting pixel center of 21.22 is shown.

A conceptual diagram for determining the address of the center of the starting pixel is shown in FIG. 4. Reference numeral 36 in FIG. 0 represents a straight line in the sub-scanning direction of the resultant image shown in FIG. Also, θ in the figure is 30'' because the rotation is 30 degrees in this example. Also, 33 and 34 indicate the distance from the straight line 36 when the pixel center moves from 30 to 31 or 32, respectively. While adding and subtracting this distance, the address of the pixel center on each rask that is closest to the straight line 26 in FIG. 3 is the line 27 in FIG. The reason is shown below.

In the explanation of the embodiment, the process for determining the address of the start pixel 24 in FIG. 3 will be described. The latch 42 in FIG. The increment value O of the address in the Y-axis direction of 28 is stored in the increment register l, 45 as 33 in FIG. 4, that is, co530°=
o, 8660 is stored in the increment register 2.43, and 34 in FIG. , in Figure 3, the straight line 2 starts from the starting pixel 23.
It is assumed that the distance SO up to 6 has been calculated and set by a device not shown in FIG. 1 using hardware or software. The comparator 1 at 40 determines whether the result register at 48 is less than or equal to 0. The result at that time is passed to the comparator 2 at 41, and when the value in the result register 48 is less than or equal to O, it is determined whether the latch 42 is at O or not. These signals are passed to the selector 46, which passes the 4
When the value of 8 is greater than O, the value of increment register 2 of 4ρ is -0, 5, and the value of 48 is less than 0 and the value of 42 is 1.
In this case, the value of the increment register l of 45 is 0.8660, and the value of 48
When the value of is less than O and the value of 42 is 0, the sum of 43 and 45, 0.366, is selected and added to the result register 48, and at the same time, the above three states are sent out as a signal from 49, as shown in FIG. When the value of 48 is greater than 0, 1 is subtracted from the Y-axis address of the starting pixel and
If the value of 8 is below O and the value of 42 is 1, add 1 to the X-axis address of the start pixel, and if the value of 48 is below O and 4
When the value of 2 is O, the start pixel on each raster can be set by adding 1 to the X-axis address of the start pixel and subtracting 1 from the Y-axis address using hardware or software. This is to find the pixel address.

Since this circuit is composed of an adder, a comparator, and a selector, it is possible to reduce the cost per circuit and achieve sufficiently high speed.

Next, the X and Y addresses of the output start pixel determined above are respectively stored in the X address register 50 and Y address register 54 in FIG. 5, and j an30°=0 is stored in the increment register 51.
．． 57735 by a device not shown in FIG.

After being set by hardware or software, by inputting a pixel clock to the synchronization signal 56, a straight line in the main scanning direction of the resultant image from the output start pixel is approximated as shown in FIG. The address of each pixel center of the line 21 can be found.

At the same time as calculating the addresses of each of the output pixel centers, the points in the original image corresponding to the addresses of each of these output pixels are calculated using a device not shown in FIG. The process of obtaining pixel data of output pixels is performed using hardware or software.

In the above embodiment, in order to obtain the address of the output start pixel of the result image, the distance from the straight line in the sub-scanning direction of the result image is calculated by selecting and adding two increment values, and the distance is minimized. I asked for the address of the starting pixel.

j an(+= ÷ 10 min.
is an integer ------- (2) Using the fact that the value of tanO is expressed as the sum of fractions where the denominator is an integer and the numerator is 1, for example, when θ = 300, tan30・-111 It is expressed as -7-cho 1 Y-cho τryo -(1). Figure 6 shows a conceptual diagram when calculating the address of the starting pixel using this formula.
This is used to find the address of the start pixel of the main raster. Considering a triangle where the angle between the fourth point 61 from the origin of the perpendicular line 64 and the angle 65 from the origin 60 is 30', calculate the address of the X axis of the vertex 62 from the denominator value of equation (1) as L4/2J + L4/13J + L4/2341J = 2 L'' is the symbol to be cut off. Next, 61.62 is closed at the apex and the Y-axis address of the apex 63 where the angle of 66 is 30' is found in the same manner as L2/2J + L2/13J + L2/2341J = 1, and the X and Y addresses of the starting pixel 63 can be found. An example of the starting pixel obtained using this method is shown in Figure 7.
The circles in the figure are the starting pixels of each raster.

Therefore, the denominator values of equation (2) for any angle are a, b,
By memorizing c... in memory, rotation of any angle can be handled. Furthermore, the precision of the fraction, that is, the value of the denominator, can be determined by the amount of rotation allowed. For example, if it corresponds to A4 paper L6Pel, the denominator value may be up to 4752.

<Effect> As explained above, by adding an image processing device that has a circuit that generates the address of the output start pixel, it is possible to easily process high-quality images in synchronization with input image data. be.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment for determining the address of a starting pixel;
Figure 2 is an explanatory diagram of a rotation of 30' around the origin of the plane, Figure 3 is an enlarged view of the locus of the starting pixel, Figure 4 is a conceptual diagram for determining the address of the starting pixel, and Figure 5 is the resulting image. FIG. 6 is a conceptual diagram of determining the address of the starting pixel, and FIG. 7 is a diagram showing the locus of the starting pixel determined based on the concept of FIG. 6. 2 drawings

Claims (3)

[Claims] (1) In an image processing device that rotates an image while enlarging/reducing it, an image that is uniquely determined by the rotation angle,
An image processing device having means for determining a straight line in the main scanning direction of an image after rotation. (2) An image processing apparatus characterized in that an output start pixel on a straight line is determined from among the addresses of the centers of pixels on the straight line determined in the first item in synchronization with sub-scanning of the input image. (3) An image processing device characterized in that pixel data at the center of each pixel on the straight line determined in the first item is determined from an input image.