Evaluate Image Clarity

Function

This Step measures the clarity of the input images according to the specified method. Different methods have different scales and standards of clarity.

Clarity evaluation is a quantitative evaluation of the clarity of a given image. Since the scales for evaluating the image clarity when different methods are used are different, the clarity values with different methods cannot be compared.

If a group of similar images is input, the values of the images’ clarity can be used to evaluate whether the camera focuses. If a single image is input, a relative clarity value of the image can be obtained.

Usage Scenario

This Step is usually used to assist the parameter and position adjustment of the camera in measurement scenarios.

Input and Output

Parameter Description

Method

Parameter description: This parameter selects the method to evaluate image clarity.

Value list: Energy of Gradient, Brenner, Roberts Cross, SML, Sobel, Tenegrad

Tuning recommendation: The tuning recommendations of using different methods are as follows.

• Energy of Gradient: This method is based on the Energy of Gradient (EOG) function, which is defined as follows.

• Brenner: This method is based on the Brenner function, which is defined as follows.

• Roberts Cross: The method is based on a function of the differential absolute value sum of the Robert operator (the Robert function for short). It is defined as follows.

• SML: The method is improved on the basis of Laplace operator and has better noise immunity. It is defined as follows.

• Sobel: This method is based on the Sobel operator function, which is defined as follows. The equation contains the first-order Sobel operator difference in the X and Y directions of the image.

• Tenegrad: This method is another function based on the Sobel operator, which is defined as follows.

Default value: Brenner

Tuning recommendation: Select the method for evaluating the image clarity according to the actual requirement.