JPH04334282A - Picture processor - Google Patents

Abstract

PURPOSE:To release an operator from the troublesome operation that the setting of the filtering factor is repeated as necessary when the filtering processing is performed for the picture signal with the desired filtering factor. CONSTITUTION:The plural necessary filtering factors are preliminarily stored in a filtering factor storage circuit 15. The X-ray information on the X-ray exposure condition and the X-ray detection result is inputted in a dose/filtering factor decision circuit 17 and the optimum filtering factor is outputted by estimating the X-ray amount. In accordance with this, a factor selection circuit 18 takes out the corresponding optimum filtering factor from the storage circuit 15 automatically and makes a filtering circuit 9 output the factor. As the optimum filtering factor is always supplied, the troublesome operations for the operator can be unnecessitated.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus equipped with filtering means for filtering an image signal using a desired filtering coefficient.

0002

2. Description of the Related Art For example, when displaying an X-ray fluoroscopic image on a monitor based on an image signal obtained by an X-ray diagnostic device, filtering processing such as spatial filtering is performed on the image signal in order to make the fluoroscopic image easier to see. Image processing is being performed to perform

FIG. 5 shows a conventional configuration in which an image processing device is applied to an X-ray diagnostic device. 1
4 is an X-ray tube that irradiates X-rays to the subject 3 with X-ray exposure conditions set by the X-ray controller 2, and 4 displays an optical image based on the amount of X-rays transmitted through the subject 3. I. I. (image intensifier), 5 is a photomultiplier, 6 is an optical system, 7 is an I. I. 4 is a TV camera that takes the displayed optical image and outputs an image signal; 8 is a filtering circuit 9 of the image processing device 10 that converts the image signal into a digital signal;
This is an A/D converter that outputs to.

Necessary filtering coefficients are fixedly set in advance in the filtering circuit 9, or any filtering coefficient can be manually changed by a filtering coefficient setting section 11. 1
2 is a D/A converter that converts the filtered image signal into an analog signal, and 13 is a monitor consisting of a CRT display or the like that displays an X-ray fluoroscopic image based on the analog image signal.

The filtering coefficient of the filtering circuit 9 is small (
When the amount of transmitted X-rays is high (high S/N image), the value is set to a large (strong) value. That is, when fluoroscopy is performed with a low dose such as normal fluoroscopy, the S/N characteristic of the image signal is poor, so filtering processing is performed using a small filtering coefficient. On the other hand, when fluoroscopy is performed with a high dose such as pulse fluoroscopy, the S/N characteristic of the image signal is excellent, so filtering processing is performed using a large filtering coefficient.

[0006]

[Problems to be Solved by the Invention] In conventional image processing devices, the filtering coefficients in the filtering circuit are fixed or can be changed manually. The problem is that it becomes complicated. That is,
If the filtering coefficient is fixed, necessary components must be replaced each time, and even if the filtering coefficient can be changed, the operation of changing the filtering coefficient must be repeated each time. Therefore, while observing fluoroscopic images on a monitor, operators such as X-ray technicians and doctors have to change the filtering coefficients every time the image S/N changes, which places a considerable burden on them. Therefore, there is a risk that diagnostic efficiency will decrease.

The present invention has been made in response to the above-mentioned problems, and it is an object of the present invention to provide an image processing device that automatically sets filtering coefficients, thereby freeing the operator from complicated operations. This is the purpose. [Structure of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a filtering method that performs filtering processing on an image signal obtained from a subject using a desired filtering coefficient according to the S/N characteristic. In an image processing apparatus, the image processing apparatus includes a means for presetting and storing a plurality of necessary filtering coefficients, and a means for determining and outputting an optimal filtering coefficient according to various factors affecting the S/N characteristic. and means for receiving an input of an optimum filtering coefficient, taking out the corresponding filtering coefficient from the storage means, and outputting it to the filtering means.

[0009]

[Operation] A plurality of necessary filtering coefficients are prepared in advance, and the optimal filtering coefficient is determined according to factors that affect the S/N characteristics of the image signal, such as X-ray exposure conditions and X-ray detection results. and output it. Based on this, a corresponding filtering coefficient is automatically extracted from the previously prepared filtering coefficients and supplied to the filtering means. Accordingly, when filtering an image signal using a desired filtering coefficient according to the S/N characteristic, the optimum filtering coefficient is automatically set and output to the filtering means. Therefore, the operator is freed from the troublesome operation of repeatedly setting filtering coefficients each time.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example in which the image processing apparatus of the present invention is implemented in an X-ray diagnostic apparatus, in which 1 is an X-ray tube, 2 is an X-ray controller, 3 is a subject, and 4 is an I.D. I. , 5 is a photomulti, 6 is an optical system, 7 is a TV camera, 8 is an A/D converter,
9 is a filtering circuit, 10 is an image processing device, 12 is a D/A converter, and 13 is a monitor, and the above configuration is the same as the conventional one.

15 is a filtering coefficient storage circuit RO
A plurality of filtering coefficients K1, K2, . . . , Kn necessary for filtering processing are set and stored in advance. Necessary filtering coefficients are taken out via a switch 16 under the control of a coefficient selection circuit 18, which will be described later, and can be output to the filtering circuit 9.

Reference numeral 17 denotes a dose/filtering coefficient determination circuit that receives the X-ray exposure conditions input from the X-ray controller 2, the photomulti signal input from the photomultiplier 5, the ND filter value input from the optical system 6, and the TV T input from camera 7
The amount of transmitted X-rays is estimated according to various factors that affect the S/N characteristic of the image signal, such as the V-iris value, and the filtering coefficient corresponding to this is determined and output.

For example, the dose/filtering coefficient determination circuit 17 has a determination table as shown in FIG. 2, and the optimum filtering coefficient is determined according to the estimated dose value D on the vertical axis. It is configured. As an example, if the estimated X-ray dose value falls between D1 and D2, in this case K2 will be determined to be the optimal filtering coefficient and will be output.

Reference numeral 18 denotes a coefficient selection circuit which receives the optimum filtering coefficient from the dose/filtering coefficient determination circuit 17, controls the switch 16 based on this, and selects the corresponding filtering coefficient from the filtering coefficient storage circuit 15. is taken out and output to the filtering circuit 9. Next, the operation of this embodiment will be explained.

When X-rays are irradiated from the X-ray tube 1 to the subject 3 for fluoroscopy, the S/N characteristics of the image signal are affected by the dose/filtering coefficient determination circuit 17 as described above. Various factors include X-ray exposure conditions, photomal signal,
By inputting the ND filter value, TV iris value, etc., this judgment circuit 17 estimates the X-ray dose in this case, determines the optimal filtering coefficient, and selects the coefficient selection circuit 18.
Output to.

Based on this, the coefficient selection circuit 18 selects the corresponding filtering coefficient from the filtering coefficient storage circuit 15.
Select one of them, take it out via the switch 16, and output it to the filtering circuit 9. As a result, the filtering circuit 9 uses the input filtering coefficients to perform filtering processing on the image signal sent from the A/D converter 8, and then outputs the filtered signal to the D/A converter 12. Next, based on the image signal output from the D/A converter 12, the monitor 13 displays an X-ray fluoroscopic image (filtered image) that has been filtered using the optimal filtering coefficient.

According to this embodiment, when X-ray fluoroscopy is performed, based on the optimal filtering coefficient determined by the dose/filtering coefficient determination circuit 17, the corresponding filtering coefficient is selected by the coefficient selection circuit 18. Since the filtering coefficients are automatically taken out from the filtering coefficient storage circuit 15 and output to the filtering circuit 9 under control, the filtering circuit 9 can always perform filtering processing on the image signal using the optimum filtering coefficients.

As a result, when performing X-ray fluoroscopy, even when changing the fluoroscopy conditions midway through and switching from low-dose normal fluoroscopy to high-dose pulsed fluoroscopy, the filtering coefficient is low according to the low dose in the case of normal fluoroscopy. However, in the case of pulse fluoroscopy, high filtering coefficients corresponding to high doses are automatically set, allowing filtering processing to be performed under optimal conditions.

[0020] Therefore, the operator is freed from the conventional complicated operation of repeatedly setting the filtering coefficient every time the X-ray dose changes, and this eliminates the additional burden and prevents a decrease in diagnostic efficiency. become able to.

In the above embodiment, the X-ray diagnostic equipment
Although the description has been given using the case of performing line fluoroscopy as an example, the same effect can be obtained not only when performing fluoroscopy but also when applying to photographing.

In addition, in the present embodiment, in order to determine the optimal filtering coefficient, the dose/filtering coefficient determination circuit 17 uses factors such as X-ray exposure conditions and photomultiplier signals that affect the S/N characteristics of the image signal. Although the example has been described in which X-ray information consisting of X-ray detection results is input, the present invention is not limited to this. In short, input information for determining the optimal filtering coefficient may be any factor as long as it affects the S/N characteristic of the image signal. For example, since the S/N characteristic is affected by differences in the diagnosis target parts, differences in body pressure between the target parts, etc., these can be used as input information for determining the optimal filtering coefficient.

FIG. 3 shows another embodiment of the present invention.
This shows a configuration in which a filtering circuit 9 and a recursive filter circuit 20 are combined. A recursive filter is used to improve the S/N characteristic, and when noise N is mixed in the signal S as shown in the upper part of Fig. 4, by adding and averaging the signals, the recursive filter shown in Fig. 4 As shown in the lower diagram, only the signal can be obtained by eliminating the noise component. Therefore, the S/N characteristic can be improved by utilizing the function of this recursive filter, and the filtering coefficient supplied to the filtering circuit 9 can be set higher by this improvement. Therefore, there is an advantage that an image that is easier to see can be displayed on the monitor. Although this embodiment has been described as an example in which the optimal filtering coefficient is automatically set, a manual setting section may also be provided so that the filtering coefficient can be finely adjusted as necessary.

[0024]

[Effects of the Invention] As described above, according to the present invention, the optimal filtering coefficient is automatically set and filtering processing is performed, so that the operator is not required to manually set the filtering coefficient each time. You can always obtain the optimal filtered image without having to worry about operations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an image processing apparatus of the present invention.

FIG. 2 is an explanatory diagram of the operating principle of the device of this embodiment.

FIG. 3 is a block diagram showing the main parts of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of the operating principle of the embodiment of FIG. 3;

FIG. 5 is a block diagram showing a conventional device.

[Explanation of symbols]

1 X-ray tube 2 X-ray controller 9 Filtering circuit 10 Image processing device 13 Monitor 15 Filtering coefficient storage circuit 16 Switch 17 Dose/filtering coefficient determination circuit 18 Coefficient selection circuit 20 Recursive filter circuit

Claims (1)

[Claims] Claim 1. An image processing apparatus comprising a filtering means for performing filtering processing on an image signal obtained from a subject using a desired filtering coefficient according to the S/N characteristic, including a plurality of necessary filtering coefficients. means for setting and storing the optimum filtering coefficient in advance; a means for determining and outputting an optimal filtering coefficient according to various factors affecting the S/N characteristic; and a filtering coefficient corresponding to the input of the optimal filtering coefficient. an image processing apparatus, comprising means for taking out the image from the storage means and outputting it to the filtering means.