Accurate measurement of characteristic curves of II-TV digital systems by use of aluminum stepwedge technique.
Accurate measurement of characteristic curves of II-TV digital systems by use of aluminum stepwedge technique.
复制标题
利用铝阶梯楔技术精确测量 II-TV 数字系统的特性曲线。
作者：
Fujita,H;Doi,K
为了准确确定通过铝阶梯楔的不同阶梯透射并入射到图像增强器（II）-TV数字系统上的相对X射线强度，我们使用了连接到II输出的100 mm相机。II-TV数字系统的特性曲线（将输出像素值与输入相对X射线强度相关联）是通过使用在65和90 kV两种能量下测量的铝衰减曲线来确定的。我们发现两条曲线在实验误差范围内一致;这一结果表明特征曲线不依赖于所使用的X射线束质量。此外，为了精确测量特性曲线，必须将X射线束准直到约0.6×10 cm的窄宽度，以便消除阶梯楔从较薄部分到较厚部分的遮蔽眩光效应。
In order to determine accurately the relative x‐ray intensities transmitted through the different steps of an aluminum stepwedge and incident on an image intensifier (II)–TV digital system, we used a 100‐mm camera which was attached to the II output. The characteristic curves of an II–TV digital system, which relate the output pixel value to the input relative x‐ray intensity, were determined at 65 and 90 kV by the use of the aluminum attenuation curves measured at the two energies. We found that the two curves agreed within the experimental errors; this result indicates that the characteristic curve does not depend on the x‐ray beam quality used. Furthermore, for accurate measurement of the characteristic curve, it is necessary to collimate the x‐ray beams to a narrow width, approximately 0.6×10 cm, so that the effect of veiling glare from the thinner to the thicker parts of the stepwedge is eliminated.