Due to the popularity of computers, the advantages of iris machine in health care and prevention are becoming more and more obvious. Many people in the health care industry are using or preparing iris machines. Although the resolution of iris machine is very important, there are still some parameters on iris machine that cannot be ignored. For example, the role of white balance on iris/iris machine is not clear to some people. Some people think that white balance is not so important, while others don't know what white balance is. Here I will talk about the understanding of white balance and talk to iris users.
When we use the old iris machine or iris machine without white balance, you will find that the fluorescent lamp is white to human eyes, but the color of the image taken is a little green; Similarly, if it is under an incandescent lamp, the color of the image will be obviously red, which is what we often call red. The color shift of an image is caused by the color temperature of ambient light. Under different light sources, because of the different color temperatures, the photos taken will have color cast. The reason why people's eyes see them as white is because the human eye has corrected the color temperature. People always thought that it would be nice if the color of the image taken by the camera was exactly the same as that seen by the human eye. However, because the CCD sensor itself does not have this function, it is necessary to correct the output signal, which is called white balance. Using the white balance function to correct, its principle is to control the brightness of the three primary colors of red, green and blue (RGB) in light, so that the maximum light level in the image can reach pure white, and other colors can also be accurate. Therefore, white balance control is to make the color of photos taken under various light conditions completely consistent with the color of the scenery seen by human eyes through image adjustment.
Simply put, white balance is a function that defines "white" as "white" regardless of the ambient light. Color is essentially an explanation of light. What looks white in normal light may not look white in dark light, and "white" under fluorescent light is also "non-white". If the white balance can be adjusted for all this, other colors based on "white" can be correctly restored in the obtained photos. At present, most commercial digital cameras provide white balance adjustment function. As mentioned above, the white balance is closely related to the surrounding light, so the use of the flash will be restricted when the white balance function is started, otherwise the change of ambient light will invalidate the white balance or interfere with the normal white balance.
For the iris digital camera, although the white balance can be adjusted in the image processing software, if you are not familiar with the image software or don't want to bother to adjust it, you'd better choose an iris digital camera with better white balance function.
Professional iris measuring instrument/iris measuring instrument can automatically or manually perform white balance. Even if it is done automatically, its error correction ability is different. Of course, the iridometer/iris machine you choose should be able to control the white balance in both manual and automatic modes, so that you can use the white balance on the iridometer/iris machine according to the ambient light when taking pictures.