The standard color measurement method is to use a spectrophotometer to obtain the color of the sample by measuring the tristimulus values of the sample.
There are a variety of colors in nature, among all colors, except for bird feathers, etc., which produce colors due to interference, the selective absorption of light by objects is the main reason for producing colors. Color detection and identification of color changes play an important role in industrial applications, for example, in industry to monitor production processes and product quality; in electronic reproduction, it can be used to achieve true reproduction of colors regardless of ambient temperature, humidity, paper and the influence of toner; in medicine, color is often an indicator of disease, which can be used to study pathological conditions; in commodity packaging, automatic control can be achieved by detecting the color of two adjacent labels on a wrapping paper, and in automatic color counting can automatically count the number of various colors.
Classification of color sensors (https://www.easybom.com/c/sensors-transducers/color-sensors)
RGB color sensor
Measurement mode: one is to analyze the ratio of red, green and blue light, and the second is to use the reflected light intensity of the three primary colors of red, green and blue to test the purpose of detection.
Applications: Phytochromes; Water Quality Analysis; Skin Cholesterol.
- Color difference color sensor
To detect the color difference between the measured object and the standard color, it is not necessary to know the specific color of the measured object, but only need to identify and judge the color difference of the two objects, and distinguish the change from one color to another color.
Application: Sorting, quality monitoring and other industries; reading and controlling the color of pulp, paint, color steel plate, etc.; color management of household appliances and car shells.
- The difficulty of color detection
The color information of objects is very extensive, and the determination of color requires three elements of hue, lightness and saturation or the stimulus values of the three primary colors (red, green and blue). The parameters that affect the accuracy of color detection mainly include: illumination light, object reflection, light source orientation, observation orientation and sensor performance, etc. Any change in any parameter will lead to changes in the observed color.
a. The influence of light source;
b. The influence of light source orientation and observation orientation;
c. The influence of the surface reflection condition of the measured object.
- The future direction of sensor development
In modern industrial production, there are more and more and more complex sensor applications, so the demand for more precise and more reliable color sensors is also increasing. Its future development direction is: A. Reduce the manufacturing cost of existing sensors and facilitate industrial-scale use; B. With the continuous emergence of new technologies and new materials, develop color sensors with high sensitivity and fast response based on new principles C. Combined with other sensors, using modern information fusion technology, the information measured by a variety of sensors is fused together to form a comprehensive color sensor.
Summarized by Easybom (https://www.easybom.com).