JPH0114059Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic diagnostic apparatus using a random scanning CRT.

A random scanning CRT is a CRT that can perform scanning by appropriately switching the signals input to the X and Y axes, but the first scanning line immediately after switching the X and Y axes signals is It is known to scan an area shifted from the position on the CRT screen.

FIG. 1 is a diagram showing an example of scanning of a random scanning CRT in a conventional ultrasonic diagnostic apparatus. In other words, Figure 1 shows an example in which characters are displayed on a CRT by switching between X-axis and Y-axis scanning after completing the vertical scan (scanning lines L ₁ to L _o ) of an ultrasound tomographic image. FIG. The switching moves from point S to point T as shown in FIG. 1, but the first scanning line l ₁ after switching is the following scanning line l ₂ to T as shown in FIG.
l Scan different relative positions from _k . This phenomenon is
This is due to the responsiveness specific to CRT. Therefore,
The error in the scanning position is influenced by the distance between points S and T, or between points V and P. Similarly, the other scanning lines l ₂ to _{l k} do not strictly correspond to the input signal, but since these scanning lines are relatively equidistant, the error in their scanning position is Inconspicuous.

Conventional random scanning CRTs, as shown in Figure 1, increase the brightness at a certain point on the scanning line and display characters that are a set of the brightness points (indicated by black circles in Figure 1) on the CRT. can do.
However, since the position of the first scanning line _l1 after switching is relatively shifted from the other scanning lines _l2 to _lk , the displayed characters are distorted and difficult to read.

The present invention was developed in view of these points, and it is an ultrasonic diagnostic device that can display accurate characters on a CRT even during random scanning by applying a special sweeping means. This is what we provide.

FIG. 2 is a diagram showing a display state of a random scanning type CRT according to the present invention. In FIG. 2, a vertical scan shows an ultrasonic tomographic image, and a horizontal scan shows a character display. Note that the relationship between the vertical and horizontal scanning directions is not limited to that shown in FIG. The scanning order in the display in FIG. 2 is the same as in FIG. 1, with a shift from the vertical scan end point S to the horizontal scan start point T, and then from the horizontal scan end point V to the vertical scan start point P. Repeated scanning to shift to .

FIG. 3 is a time chart of signals of various parts in the ultrasonic diagnostic apparatus according to the present invention. This third
The main parts of the present invention will be briefly explained using figures.

Figure 1 shows the clock pulse, and the period of this signal is
One of the scan lines is scanned during t _p . Figure 2 shows the digit signal A (described in detail later), which is a signal that changes from HIGH to LOW each time the scanning direction changes (for example, from horizontal scanning to vertical scanning). . FIG. 3 shows a signal that becomes LOW level for one period t _p of the clock pulse after the polarity of the digit signal A changes. FIG. 4 shows a step-like level signal corresponding to the scanning position. That is, it is a signal whose level changes by one step each time the clock pulse shown in FIG. 1 is generated. Figure 5 shows a sawtooth signal that performs sweeping. Figure 6 shows a bright spot pulse signal that displays a bright spot on a CRT.The point where the pulse hits becomes a bright spot, and since the brightness is low in other parts, no scanning line is displayed. However, in FIGS. 1 and 2, scanning lines are shown for the sake of explanation. Figure 7 is
3 shows the scanning lines of FIG. 2 corresponding to the time chart of FIG.

The scanning of FIG. 2 will now be described with reference to FIG. In FIG. 2, when the vertical scanning (final scanning line L _o ) is completed, there is a command to switch between the X and Y axes (digit signal A changes), and the scanning line is shifted from point S to point T. As shown in FIG. 2, the first scanning line l ₁ (dotted line) scans a shifted position as in the conventional case, but in the present invention, the scanning line l ₁ (dotted line) is scanned using the signal D shown in FIG. 3. The bright spot pulse signal for displaying characters is controlled not to be applied to the CRT during this period. Therefore the first scan line l ₁ is CRT
not displayed above. Then, the second scan line l ₁ ^- is
Since the level signal shown in FIG. 3 does not change from that of scanning line _l1 , the same position as scanning line _l1 is scanned. Then, the signal D is applied to the scanning line l ₁ ^- as shown in FIG.
Since it is HIGH during the period, the bright spot pulse signal is
Applied to CRT. Here, the distance between the end point of scanning line l ₁ and the starting point of scanning line l ₁ ^- has the same distance relationship as the following scanning l ₂ to l _k , so the previous scanning line l ₁ should be scanned. scan the correct location. In this invention,
Since the bright spot pulse signal is added to the electron gun (not shown) of the CRT for scanning from the time of this second scanning line l ₁ ^- , accurate characters can be displayed as shown in Figure 2. I can do it.

Although the scanning order was explained as an example in the explanation of FIG. 2, the present invention is not limited to this scanning order, and when the X-axis and Y-axis are switched, the first The feature is that the scanning line is not displayed on the CRT, but the second scanning line is displayed on the CRT.

Figure 4 shows the CRT of the ultrasound diagnostic device according to the present invention.
FIG. 3 is a diagram showing an example of a drive circuit.

In FIG. 4, reference numeral 1 denotes an oscillator that outputs the clock pulse shown in FIG. 31.

2 is a control circuit which introduces this clock pulse and also receives a digit signal A from a counter which will be described later.
is also introduced, and a pulse train of clock pulses (the solid line pulse train in FIG. 3) is output by cutting out one clock pulse immediately after this digit signal A changes. Furthermore, this control circuit 2 outputs a signal D that is "LOW" for one period t _p of the clock pulse in synchronization with the change in the digit signal A. Since the configuration of the control circuit 2 that implements such functions can be easily configured using logic circuits, a detailed description of the configuration will be omitted in this specification.

3 is a counter, and a third
The pulse train indicated by the solid line in FIG. 1 is introduced and counted.
Then, the counted value is added to a DA converter and a bright spot pulse generator, which will be described later.

Reference numeral 4 denotes a bright spot pulse generator, which is composed of, for example, a ROM. Brightness information for generating predetermined characters and figures is written in multiple bits at each address of this ROM. For example, for one address,
Luminance information constituting one scanning line segment, such as 0010100..., is written in multiple bits. Here, the bit signal "1" indicates a bright spot pulse. The count signal of the counter 3 is used as an address signal for this ROM. As mentioned above, the third
Since one period t _p of the clock pulse in FIG. 1 corresponds to one scanning line, the count value of the counter 3 that counts the clock pulses corresponds to the position of the scanning line. That is, by adding the count value of this counter 3 to the bright spot pulse generator 4 (for example, ROM), the third
Bright spot pulses forming predetermined characters and figures as shown in FIG. 6 can be generated.

Reference numeral 5 denotes a DA converter, which inputs the count value signal of the counter 3 and converts this signal into a step-like level signal (analog signal) corresponding to the scanning position. This is shown in FIG. 6 is used as a sweep signal by a sawtooth generator. A changeover switch 7 has input terminals a, b and output terminals c, d, and is switched by the output signal A of the counter 3. 8 is a random scanning type CRT with three input terminals X, Y, and Z.
Signals to drive the X and Y axes of the CRT are input,
A signal for controlling brightness is input to the input terminal Z. 9 is a gate.

In FIG. 4, the signal from the counter 3 to the control circuit 2 and the changeover switch 7 is designated as A, the output signal of the oscillator 1 is designated as B, the output signal of the control circuit 2 and introduced into the counter 3 is designated as C, and the signal sent to the gate 9 is designated as A. Let D be the signal to be introduced.

The output signal B of the oscillator 1 is introduced into the counter 3 via the control circuit 2, and the output signal B is also introduced into the sawtooth wave generator 6, the output of which is introduced into the changeover switch 7. The output of the counter 3 is introduced into the luminance pulse generator 4 and the DA converter 5, and the signal A is introduced into the changeover switch 7 and the control circuit 2.
will be introduced to The output of the DA converter 5 is introduced into a changeover switch 7. The output signal D of the control circuit 2 is introduced into the gate 9, and the output of the bright spot pulse generator 4 is sent to the Z of the random scanning CRT 8 via the gate 9.
introduced into the axis. In addition, the output of the changeover switch 7 is
Introduced to the X and Y axes of random scanning CRTs.

The operation of the apparatus shown in FIG. 4 will be explained with reference to the time chart shown in FIG.

The oscillator 1 outputs pulses as shown in FIG. 3 (including pulses indicated by solid lines and dotted lines). Since the counter 3 counts these clock pulses via the control circuit 2, the counter 3 indicates the counted value.
Each digit signal goes “HIGH” in order as counting progresses.
becomes. As mentioned above, one period t _p of the clock pulse corresponds to one scanning period.

Here, when the count value of the counter 3 switches to horizontal scanning after N (for example, after performing the vertical scan of L ₁ ^- ~L _o shown in FIG. 2), the digit signal A of the counter that changes exactly with the count value N is applied to the control circuit 2 and the changeover switch 7.

Therefore, the changeover switch 7 is switched in synchronization with the change in the digit signal A, and the X-axis and Y-axis inputs of the random scanning CRT are switched. As a result, up until now, for example, the level signal shown in FIG. 3 is applied to the X-axis, and the sweep signal shown in _FIG ^. It becomes a horizontal scan like l _k . Note that for the positions on the CRT screen occupied by the vertical scan L ₁ ^- ~L _o and the horizontal scan L ₁ ^- ~L _k shown in Figure 2, a controller (not shown) normally applies an offset voltage to the X-axis and Y-axis of the CRT. In addition to controlling,
Since the control for this offset has no direct relation to the present invention, a description thereof will be omitted.

On the other hand, the control circuit 2 applies to the counter 3 a pulse train of clock pulses obtained by cutting out one clock pulse (the pulse indicated by the dotted line in FIG. 3 1) that first occurs after the rising or falling edge of the digit signal A. Therefore, the count value of counter 3 is 2t _p for 2 cycles after changing the scanning direction (see Figure 3, 1).
does not change its contents (see Figure 3, 4). That is,
The CRT is controlled so that the first two scanning lines (l ₁ and l ₁ ^- in FIG. 2) after changing the scanning direction scan the same position. It has already been explained that the most actual l ₁ and l ₁ ^- have a positional relationship as shown in FIG.

In this manner, the count contents of the counter 3 do not change during the period 2t _p immediately after changing the scanning direction, so the bright spot pulse generator 4 is accessed by the counter 3 at the same address during this period 2t _p . Therefore, the same bright spot pulse is output during the periods of the scanning lines l ₁ and l ₁ ^- shown in FIG. 3 and 7. but,
Due to the action of the signal D output from the control circuit 2 (a signal that becomes "LOW" for one cycle of the clock pulse t _p in synchronization with the change in the digit signal A), the gate 9 is closed during the period of the scanning line _l1 . (because signal D is LOW), random scanning type CRT8 has
No bright spot pulse signal is applied (the bright spot pulse indicated by the dotted line in FIG. 3 is not applied to the CRT 8). That is,
Scanning line _l1 is controlled not to be displayed.

As described above, according to the present invention, when there is a switch between the X-axis and the Y-axis, the first pulse input to the counter 3 is cut by one pulse by the action of the control circuit 2, so that the first scan after the switch is The line is not displayed on the CRT,
Therefore, accurate characters, symbols, figures, etc. can be obtained without distortion.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of scanning of a random scanning CRT in a conventional ultrasound diagnostic device, Fig. 2 is a diagram showing a display state of a random scanning CRT according to the present invention, and Fig. 3 is a diagram showing a display state of a random scanning CRT according to the present invention. random scanning type
Time chart of signals applied to CRT, 4th
The figure is a diagram showing an example of a CRT drive circuit of an ultrasonic diagnostic apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Oscillator, 2... Control circuit, 3... Counter, 4... Bright spot pulse generator, 5... D-A converter, 6... Saw wave generator, 7... Changeover switch, 8
...Random scanning CRT, 9...gate.

Claims (1)

[Claims for Utility Model Registration] A bright spot pulse signal that generates a bright spot is introduced on the Z axis, and a sawtooth sweep signal and a step level signal corresponding to the scanning position are switched on the X axis and Y axis. Random scanning type that allows you to switch between horizontal and vertical scanning by adding
In an ultrasonic diagnostic apparatus equipped with a CRT, a counter that counts clock pulses introduced via a control circuit described later and outputs a signal indicating the counted value and a digit signal A generated every fixed counted value; A D-A converter is introduced, which converts this signal into a step-like level signal corresponding to the scanning position and outputs it, and a counter's count value signal is introduced. A bright spot pulse generator that outputs a bright spot pulse signal that generates a bright spot on a scanning line, a clock pulse and the digit signal A are introduced, and the first clock pulse generated after the rise and fall of the digit signal A is set to 1. A pulse train of clock pulses that has been cut off is added to the counter, and a signal D having a pulse width of one period of the clock pulse is applied in synchronization with the rising and falling points of the digit signal A.
a control circuit that outputs the signal D and the bright spot pulse signal;
An ultrasonic diagnostic apparatus comprising: means 9 for not applying a bright spot pulse signal to a random scanning CRT for a period of pulse width;