Method for selecting image data source in optical instrument

[0010] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0011] At present, when performing subsequent processing on the captured images, all captured images are subjected to a contrast enhancement operation. After the image contrast is enhanced, the original image will inevitably lose its original characteristics, especially the image with a dark background. Therefore, the existing image selection method will affect the subsequent operation accuracy.

[0012] Such as figure 1 As shown: in order to improve the accuracy of image data processing, reduce the time of image processing, and reduce the subsequent operation of image data due to contrast enhancement, the method for selecting image data sources of the present invention includes the following steps:

[0013] a. Provide image processing device and capture image data source from optical sensor;

[0014] The image processing device includes a DSP (digital signal processor), and the image processing device is used to perform necessary processing operations on the image data source to ensure that the image data can meet usage requirements;

[0015] b. Detect and filter out the inherent noise signal contained in the image data source;

[0016] The inherent noise signal is the interference signal generated by the hardware circuit to the image data, and the inherent noise signal contained in the image data source is filtered through a conventional filtering method, which improves the accuracy of the operation of the image data source;

[0017] c. The image processing device extracts the exposure time Te of the image data after removing the inherent noise signal, and calculates the average gray value R of the image data TH;

[0018] The exposure time Te of the image data source is related to the brightness of the background of the image data. When the background of the image data is dark, the exposure time required by the optical sensor to collect the image is long; the image processing device can extract the image based on the information of the image data Data exposure time Te; meanwhile, according to the gray value of the image data, calculate the gray average value R of the image data TH;

[0019] d. When the exposure time Te of the image data obtained above is less than the set time TH1 or the gray average value R of the image data TH When it is greater than the set value TH2, the image processing device performs contrast enhancement on the image data; the image processing device uses a conventional contrast enhancement method on the image data;

[0020] When the exposure time Te of the image data obtained above is less than the set time TH1 or the gray average value of the image data R TH When it is greater than the set value TH2, it means that the background of the image data source captured by the optical sensor is brighter, and the image data source can be contrast enhanced. The image data can be contrast enhanced by the image processing device to improve the contrast of the image data and ensure the image Data follow-up operations, the image processing device's follow-up operations on image data include image recognition, motion recognition or image compression;

[0021] The image processing device extracts the maximum gray value Rmax of the image data and the minimum gray value Rmin of the image data after removing the inherent noise signal, when the image data exposure time Te is greater than the set time TH1, the gray average value R of the image data TH Is less than the set value TH2, and the difference Rc between the maximum gray value Rmax of the image data and the minimum gray value Rmin of the image data is less than the set value TH3, the image processing device performs contrast enhancement on the image data;

[0022] When the exposure time Te is greater than the set value TH1 and the gray average value of the image data R TH When it is less than the set value TH2, it means that the background of the image data captured by the optical sensor is dark; and when the difference Rc between the maximum gray value Rmax of the image data and the minimum gray value Rmin of the image data is greater than the set value TH3, description If the dynamic range of the image is larger, it can indicate that the quality of the obtained image data is better and meets the requirements of subsequent processing. At this time, the image data does not need to be enhanced, and the subsequent processing of the image data can be directly performed. Since, when contrast enhancement is performed on image data with a dark background, personnel will destroy the characteristics of the original data, especially the edge pixel values ​​of the image data. The present invention selects the properties of the image data to avoid contrast enhancement for all images. Operation reduces the time for image data processing and improves the accuracy of subsequent processing. The above-mentioned set thresholds TH1, TH2, and TH3 are all obtained through multiple tests and debugging based on the test model.

[0023] The image processing device filters out the inherent noise signal in the image data, and extracts the exposure time Te, the maximum gray value Rmax and the minimum gray value Rmin of the image data, and calculates the average gray value R of the image data TH And the difference Rc between the maximum gray value Rmax and the minimum gray value Rmin; when the exposure time Te of the image data is greater than the set value TH1 and the average gray value of the image data R TH When the value is less than the set value TH2, it means that the captured image background is dark; when the difference Rc between the maximum gray value Rmax and the minimum gray value Rmin is greater than the set value TH3, it indicates that the dynamic range of the image data is large , The contrast of the image is better, and there is no need to enhance the contrast of the image, avoiding the change of image properties caused by the contrast enhancement of the dark background image, ensuring the nature of the image data, and providing accurate positioning for subsequent image processing. The processing time for image data is reduced, the accuracy of image data processing is improved, and the process steps are simple, safe and reliable. After the image data is selected and processed, the image processing device can perform corresponding operations on the selected image, which can meet the requirements of subsequent processing accuracy.

[0024] The image processing device of the present invention filters out the inherent noise signal in the image data, extracts the exposure time Te, the maximum gray value Rmax and the minimum gray value Rmin of the image data, and calculates the gray average value R of the image data TH And the difference Rc between the maximum gray value Rmax and the minimum gray value Rmin; when the exposure time Te of the image data is greater than the set value TH1 and the average gray value of the image data R TH When the value is less than the set value TH2, it means that the captured image background is dark; when the difference Rc between the maximum gray value Rmax and the minimum gray value Rmin is greater than the set value TH3, it indicates that the dynamic range of the image data is large , The contrast of the image is better, there is no need to enhance the contrast of the image, to ensure the nature of the image data, provide accurate positioning for subsequent image processing, reduce the processing time of image data, and improve the accuracy of image data processing. The process steps are simple, safe and reliable.