在使用工业内窥镜检测前,应注意提前了解产品的性能参数、使用环境、检测工况、被检测目标等具体情况,方能实现更好的检测效果。影响工业内窥镜检测效果的几个主要因素有:
Before using the industrial endoscope, we should pay attention to the performance parameters of the product, the use environment, the detection condition, the detected target and other specific conditions in advance, in order to achieve better detection effect. There are several main factors that affect the detection effect of industrial endoscope
1、照明条件(光源)
1. Lighting conditions (light source)
内窥镜检测大多使用内窥镜自带光源进行照明。一般条件下,要求内窥镜检测照明光源色温不低于5600K,照明强度不低于2600lm。工业内窥镜一般有前置和后置两种照明方式。前置照明是通过将数颗LED灯珠集成于探头前端,这种方式成本较低,而且寿命短、容易损坏。后置照明则是通过导光光纤,将内置于主机的LED光源传导到前端用于照明。这种照明方式大大提高了照明亮度,而且寿命较长。目前主流的电子视频内窥镜大部分采用后置导光。
Endoscope detection mostly uses the light source of endoscope for illumination. Under general conditions, the color temperature of the light source for endoscope detection should not be lower than 5600k, and the illumination intensity should not be lower than 2600lm. Industrial endoscopes generally have two lighting modes: front and back. The front lighting is realized by integrating several LED lamp beads into the front end of the probe, which has the advantages of low cost, short service life and easy damage. The rear lighting transmits the LED light source built in the host to the front for lighting through the light guide fiber. This lighting method greatly improves the brightness of lighting, and has a long life. At present, most of the mainstream electronic video endoscopes use rear light guide.
2、探头位置与角度
2. Probe position and angle
通常在距离检测区域5~25mm范围内观察图像的效果非常好 ,因此往往需要内窥镜探头尽量靠近观测点。探头与观察物平面在45゜~90゜范围内都可以达到较好的观察效果,在实际工作中是通过反复改变探头与观察点的位置与角度找到合适的观察位置,并获得不错的检测效果。
Generally, it is very good to observe the image within the range of 5 ~ 25 mm from the detection area, so the endoscopic probe is often required to be as close to the observation point as possible. The probe and observation plane can achieve good observation effect in the range of 45 ゜ ~ 90 ゜. In practical work, we can find the appropriate observation position by repeatedly changing the position and angle of the probe and observation point, and obtain good detection effect.
3、检测通道
3. Detection channel
探头可以通过狭小、弯曲的通道进行检测。选择通道时应了解通道的情况,检测时尽量靠近需要检测位置,选择进入长度短的通道,尽量减少探头需要弯曲的次数及程度;考虑由上到下,由高到低的通道;优先选择宽阔的通道;使用辅助工具(如居中器等),保证探头在产品通道中的正确方向;应采用边观察边通过的方法在通道中行进。
The probe can detect through narrow and curved channel. When selecting the channel, we should first understand the situation of the channel. When detecting, we should try to be close to the position to be detected. We should choose the channel with short length to reduce the number and degree of bending of the probe; First, we consider the channel from top to bottom and from high to low; Wide channel is preferred; It is recommended to use auxiliary tools (such as centering device) to ensure the correct direction of the probe in the product channel; We should use the method of observing and passing through the channel.
4、图像畸变
4. Image distortion
内窥镜的图像畸变是通过透镜观察物体产生的变形现象,随着从透镜中心到边缘距离的加大,图像形态会发生改变。图像的畸变会对缺陷的判断及测量产生影响。直杆镜、光纤镜观察时图像的畸变较大,视频内窥镜可通过计算机进行较正。
The image distortion of endoscope is the deformation phenomenon of observing the object through the lens. With the increase of the distance from the center of the lens to the edge, the image shape will change. The distortion of image will affect the judgment and measurement of defects. The distortion of the image is large when observed by the straight rod mirror and the optical fiber mirror, and the video endoscope can be corrected by the computer.
5、图像分辨率
5. Image resolution
图像分辨率指图像中存储的信息量,是每英寸图像内有多少个像素点,分辨率的单位为PPI(Pixels Per Inch),通常叫做像素每英寸。图像分辨率一般被用于ps中,用来改变图像的清晰度。图像分辨率越高图像越清晰。图像分辨率是内窥镜自身重要技术指标,可直接影响到探测的结果。
Image resolution refers to the amount of information stored in the image, which is the number of pixels per inch of the image. The unit of resolution is PPI (pixels per inch), which is usually called pixel per inch. Image resolution is generally used in PS to change the definition of the image. The higher the image resolution, the clearer the image. Image resolution is an important technical index of endoscope, which can directly affect the detection results.
6、图像放大倍数
6. Image magnification
图像放大分为光学变焦和数码变焦,前者通过改变焦距,放大图像不改变清晰度,后者则是利用软件放大,相当于通过软件处理对已有像素周边的色彩进行判断,根据周边的色彩情况插入经特殊算法加入的像素,这种情况下放大倍数越高会使图像更模糊。
Image magnification is divided into optical zoom and digital zoom. The former enlarges the image without changing the definition by changing the focal length, while the latter enlarges the image by using software, which is equivalent to judging the color around the existing pixels by software processing, and inserting the pixels added by a special algorithm according to the surrounding color. In this case, the higher the magnification, the more blurred the image.
7、可检测其小缺陷
7. Small defects can be detected
可检测小缺陷则与图像清晰度、测量精度等指标密切相关。
Small defects that can be detected are closely related to image clarity, measurement accuracy and other indicators.
8、物体表面的反射率
8. Reflectivity of object surface
不同的物体表面有不同的反射率,和物体的材料和表面的粗糙程度都有关系。在实际检测中,有些较为光亮的反射面,在亮度较高时反而难以实现较为准确的检测效果。因此实际检测工作中应该根据具体的情况选择内窥镜照明的强度以便得到清晰有用的结果。一般情况下工业内窥镜都具有多级照明调节功能,有部分产品则会采用软件控制自动调光,可以根据环境进行调整照明亮度。
Different surfaces have different reflectivity, which is related to the material and surface roughness. In the actual detection, it is difficult to achieve a more accurate detection effect when the brightness of some brighter reflectors is higher. Therefore, the intensity of endoscope illumination should be selected according to the actual situation in order to get clear and useful results. In general, industrial endoscope has multi-level lighting adjustment function, some products will use software to control automatic dimming, which can adjust the lighting brightness according to the environment.