焦距

5Calibration of the laser optical axis of the basic principles and methods isdiscussed, laser target designator axis calibration device is designed, the key technologythat a large caliber, long focal distance from the axis parabolic reflector design is solved,and the cross target line which can be used for a wide variety of observation devices isdesigned, the final calibration accuracy is 0.05mrad.

5论述了激光光轴校正的基本原理和方法，设计了激光目标指示器光轴校正装置，解决了其中的关键技术：大口径、长焦距离轴抛物面反射镜的设计问题，并设计了可用于多种观瞄装置的十字靶标，最终的校正精度达0.05mrad。

The focal length f is the distance of the focus of an optical system from the assigned main point.

焦距f 是光学系统主点到焦点的距离。

But only with the right focal distance and correct aperture could we get the true pictures.

只有我们调对了焦距，对准了光圈，才有可能得到真实的图像。

An experimental investigation of the combination of a long focal distance Bragg-Fresnel lens with a bimorph mirror is described.

描述了对长焦距布拉格-菲涅耳透镜与可变曲率半径反射镜组合所做的实验研究。

Focal length: The distance between the centre of a lens and its principal focus.

焦距：镜头中心与其主焦点的距离。

Correct under the guiding of route, we successfully design and have trial-produced the one kind of new long large-scale camera of focal distance.

在正确路线的指引下，我们成功地设计和试制了一种新型长焦距大型照相机。

The magnifying glass focal distance may around adjust up and down, suits each kind of age the crowd use.

放大镜焦距可上下前后调节，适合各种年龄的人群使用。

Since it is unable to provide the correct focal distance data to the camera, it inevitably brings the calculation adjustment error which can cause the vibration due to the system error.

因为无法向相机提供正确的焦距数据，必然带来AS功能引入的计算校正误差，会导致系统错误造成的抖动。

In order to obtain the optimal process treatment of a laser-engraving technical, this study was to investigate the process efficiency relationships between wood species and speed, electric current and focal distance.

试验目的在于探讨木质材料激光雕刻时，木材的种类、切割速度、电流以及焦距等与加工质量之间的相关性，以获得木材激光雕刻最佳的工艺参数。

On Image-Collecting, trapezoidal distortion is one of the most common distortion. We present a rectification method for it. In the case of knowing the focal distance and the size of CCD, the only parameter needed to know to restore the image is the angle of the camera axis with the ground.

摘要图像采集中的梯形失真是工程中最常见的失真之一，对此本文提出一种校正方法，在已知摄像机的镜头焦距和CCD大小的情况下，仅需要知道摄像机中轴线与地面的倾角一个参数，不需要控制点，就可以恢复原始图像。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。