Patent Application
20060133579
The present invention relates generally to a digital radiograph sensor, more specifically to a dental X-ray digital radiograph sensor, marked with a cross that is opaque to x-rays thereon.
Recent development of X-ray digital radiography enables surgical operation of dental diseases with real time observation of the rear inside of a patient's teeth. Direct transport of digital radiographic image into a computer and production of an output image, enlarged to window size on a computer monitor makes it hard to figure out a precise measurement of a tooth or other vital structures. In addition to this, various kinds of distorted of images are produced depending on the position of the radiographic sensor. A distorted image is created due to 1) an angulations and 2) position of the sensor. Angulations of the sensor lead to a radiograph that is expanded or shrunken, laterally or vertically. Such distorted images are seen from bisecting techniques and causes significant error when the clinician is trying to measure the length between critical structures. The purpose of the current invention is to correct angulations errors due to sensor's position, and allow a clinician to precisely measure the distance from point A to point B with a click of a mouse.
U.S. Pat. No. 6,765,609 to Kinoshita illustrates a solid-state image sensor, which has a two-dimensional matrix of a plurality of pixels used to sense the two-dimensional spatial distribution of radioactive rays, light rays, electrons, ions, or the like, is provided with an aperture that extends through a substrate at an image sensing unit on which the pixels are arranged, and a signal transfer path that connects signal transfer electrodes for reading images of the respective pixels kept clear of the aperture.
U.S. Pat. No. 6,693,668 to May, et al. illustrates a self-diagnosing image sensor detects and stores maps of functioning and malfunctioning pixels in a memory directly coupled to the sensor. The memory is coupled to an external monitoring computer, which retrieves the pixel map and adjusts the sensor data received from the image sensor in accordance with the retrieved pixel map. A defect discriminator is coupled directly to the image sensor and to the memory for detecting whether a pixel malfunctions, and updates the map accordingly. U.S. Pat. No. 5,995,583 to Schick, et al. illustrates a method and apparatus for producing a X-ray image of a patient's teeth by placing an intra-oral sensor having a plurality of pixels disposed in a linear array inside the patient's mouth, and moving a radiation source around outside of the patient's mouth. The intra-oral sensor detects the radiation that has passed through the patient's teeth and generates corresponding output signals that depend on the amount of radiation arriving at each pixel. The information contained in the output signals is stored and can be used to create an X-ray image of the patient's teeth. The intra-oral sensor can be moved about inside the patient's mouth in coordination with the movement of the radiation source in order to improve the resulting image quality. This method and apparatus can be used to obtain an X-ray image of any number of teeth, including a panoramic image of all of the patient's teeth, in a single, quick, uninterrupted operation.
U.S. Pat. No. 2,881,655 to Eisenschink and U.S. Pat. No. 5,418,610 to Fischer illustrates a vehicle side mirror and U.S. Pat. No. 4,023,029 to Fischer illustrates a back mirror having an image reflecting surface and a distance indicating light reflective indicia of contrasting reflectivity to the image reflecting surface, the indicia being located in such a position on the mirror that when a just passed vehicle appears on the mirror at a certain location with respect to the indicia, it is safe to pull over into the lane in front of the just passed vehicle. One embodiment of the distance indicating indicia is a is reflective horizontal line located below the center of the mirror. This is just to compare the relative distance between my car and the approaching car from a distorted image on a back mirror, not to measure a real distance from a distorted image.
None of the prior arts illustrates a method of measuring the true distance between two points in real time from distorted images.
Recent development of X-ray digital radiography enables surgical operation of dental diseases with real time observation of the rear inside of a patient's teeth. Direct transport of digital radiographic image into a computer and production of an output image, enlarged to window size, on a computer monitor makes it hard to figure out a precise measurement of a tooth or other vital structures. In addition to this, various kind of distorted of images are produced depending on the position of the radiographic sensor. A distorted image is created due to 1) an angulations and 2) position of the sensor. Angulations of the sensor lead to a radiograph that is expanded or shrunken, laterally or vertically. Such a distorted image is seen when using the bisecting technique and causes significant error when the clinician is trying to measure length between critical structures. The purpose of the current invention is to correct angulation's error due to sensor's position, and allow a clinician to precisely measure the distance from point A to point B with a click of a mouse.
A dental X-ray image sensor provided with a radio-opaque cross-mark on the corner of a digital radiograph sensor surface is provided to enable a computer program to recognize true dimension and to rescale any distortion due to angulation's position error in a conventional X-ray digital radiograph system.
On the other end, magnification error that occurs due to placing the sensor father away from the object (teeth) is not very significant (˜5%). Because the size of human mouth is not greater than 4 cm (lingual surface of teeth to lingual surface of contra lateral side), and the sensor (1) must be placed with in range of 2 cm from teeth (3) due to shape of oral cavity. This means that enlargement from dental radiograph is not very significant (5% maximum). This data is collected from actual radiographic experiment with penny exposed in different distances. Therefore, the enlargement effect due to the distance from the tooth (3) is ignored when clinician is measuring distances within digital radiograph.
However, the incubational brings significant errors in measuring the real 5 distances between two points on the tooth (3). Therefore, it should be corrected by more accurate and convenient methods than known to experts in the field of his/her endeavor. This will not only allow correction of improper angulations, but also allow user to estimate precise measurements.
It is very hard to determine what is the correct image and how much it is distorted from the FIGS. of 6-a, b, and c. Meanwhile, from FIGS. 7-a, b, and c, a clinician can figure out how much and in what direction the original image is distorted since the dimension of the radio opaque cross (12) is predetermined by the computer (5).
This new simple technology will advance dentistry to the next level, because dentists will be able to more easily and accurately calculate canal length, distance from inferior alveolar nerve, sinus floor, and other critical structures. In return, we believe that patients will benefit from this technology by receiving safer and more precise surgeries.
