High dynamic range high-speed camera photonfocus shooting under strong light background
Before the photonfocus linlog technology was born, the quantum integral time response of the conventional industrial camera CCD (CCD or CMOS) was linear, and its dynamic range mainly depended on the minimum signal-to-noise ratio and the maximum full-well capacity of the sensor pixel. Two parameters. The dynamic range of conventional industrial cameras is between 40dB and 60dB. The dynamic range of the human eye is logarithmic, and the dynamic range is up to 180dB, ie, 1,000,000,000:1. It is a natural and excellent visual system.
In the field of welding detection, intrusion detection with strong light background and large dynamic range image acquisition applications, a large dynamic range high-speed camera is very necessary.
Subsequently, when the first CMOS image sensor with a logarithmic response characteristic emerged, the industry was very excited. It mainly consisted of a photodiode, a load pipe, a source follower, and a line selector tube. The load pipe had a constant bias voltage on the gate. The output signal of the pixel unit has a logarithmic relationship with the intensity of the incident light signal. However, the CMOS image sensor with logarithmic response characteristics also has certain flaws:
1) No overall electronic shutter (cannot acquire high-speed moving images),
2) Hysteresis effect of the image (cannot be applied in sharp change of field of view),
3) Temperature effect (poor thermal stability, calibration required).
Photonfocus high dynamic range high-speed cameras use their patented Linlog technology to completely overcome the above-mentioned drawbacks. The global shutter's pixel electronic shutter can obtain images in high-speed motion; charge storage area independent reset electrodes can eliminate image hysteresis; Linlog technology: only compress images. The response to near saturated and saturated regions preserves the sensitivity and linearity of the image in low-light areas, ensures the quality of images in low-illumination areas, and extends the dynamic range of the entire sensor up to 120dB, which is unique in the industry.
Figure 1 photonfocus Linlog time response curve
Explanation: Figure 1 shows the photonfocus Linlog technology response curve. It is found from the figure that with Linlog technology, as the light intensity increases, the gray value changes significantly more slowly than the linear response changes. The Linlog technology CMOS camera can improve the image in high brightness areas. Visual effects, and can be adjusted according to the actual application environment and detection requirements Linlog parameters to obtain the best high-quality images.
1. Photonfocus high dynamic range camera shooting case a
Figure 2 does not use photonfocus Linlog technology
Figure 3 Using photonfocus Linlog technology
Description: Figure 2 is not using the photonfocus Linlog technology camera to obtain the window brightness image, from the figure can be found out of the window scene completely invisible; Figure 3 is the use of Linlog technology to obtain high brightness window image, the window outside the scene can be seen clear. Comparing the images obtained in the high brightness areas of the windows in the two figures, it was found that using the Linlog technology, a clear image can still be obtained in a high brightness area.
2. Photonfocus high dynamic range camera shooting case b
Figure 3 Laser triangulation without photonfocus Linlog technology
Figure 4 Laser triangulation using photonfocus Linlog technology
Explanation: By comparing Fig. 3 with Fig. 4, we can find that in the laser triangulation image using Linlog technology, the pixels of the weld structure and the edge material area work in the linear region, while the laser lines of the triangular profile work in the right direction. The number-responsive area ensures the reliable and reliable detection of strong laser-reflective laser pointers and many details of the weld structure at the edges, making it easy to acquire high-brightness images.
3. Photonfocus large dynamic range high-speed camera shooting case c
Figure 5 No photonfocus Linlog technology camera detected during welding
Figure 6 Photonfocus Linlog technology camera in the welding process detection
Explanation: By comparing Fig. 5 with Fig. 6, we can find that cameras without photonfocusLinlog technology cannot obtain high-luminance area images during welding detection, and cameras with photonfocusLinlog technology can still perform high-brightness even during welding detection. Clear imaging.
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