Scale Image in 2D ROI

Function

Scale the region of ​​interest (ROI) in an image to a specified size.

../../../../../_images/function_description4.png

Usage Scenario

It is usually used for image preprocessing in deep learning related Steps and is usually used with Recover Scaled Images in 2D ROI and deep learning related steps.

Input and Output

../../../../../_images/input_output_28.png

Instruction

This Step is used to scale images in the ROI into a designated size by setting the parameter Color ROI Settings and Ideal Destination Resolution.

Auto Scale

To auto scale the ROI, please follow these steps:

  1. Select the checkbox Auto Scale under Color ROI Settings.

  2. Select the checkbox Same as Input Color ROI & Skip Scaling under Ideal Destination Resolution.

Output Initial ROI Image

To output the initial ROI image, please follow these steps:

  1. Disable Auto Scale under Color ROI Settings.

  2. Set 1 as the value of Customized Scale.

  3. Select the checkbox Same as Input Color ROI & Skip Scaling under Ideal Destination Resolution.

Scale ROI Image by a Particular Degree

To output ROI image of a particular size, please follow these steps:

  1. Disable Auto Scale under Color ROI Settings.

  2. Set Customized Scale according to your need. When the value of this parameter is higher than 1, image will be magnified. If the value is lower than 1, image will be reduced.

  3. Select the checkbox Same as Input Color ROI & Skip Scaling under Ideal Destination Resolution.

Output ROI Image of Designated Width and Height

To out put ROI image of designated width and height, please follow these steps:

  1. Disable the Same as Input Color ROI & Skip Scaling under Ideal Destination Resolution.

  2. Set the value of Width and Height according to your need.

  3. Choose whether to select Padding according to your need.

Parameters

Color ROI Settings

Description: This parameter decides the way to set color ROI.

List of options:

  • ROIByFile: The default setting. Set and identify ROI in a visualize way according to the coordinatess of the top left vertex and bottom right vertex.

  • ROIByParam: Set the ROI by configuring the parameters manually, including the coordinate of the top left vertex and the width and height of the ROI.

ROIByFile

Color ROI File
Description: This parameter sets the ROI of color image. Please refer to Set 2D ROI for more information. In the image below, point A is the top left vertex, B is the bottom right vertex.
../../../../../_images/roi_by_file.png

Hint

The coordinate of the top left vertex of the initial image is (0, 0).

ROIByParam

Start X
Description: The x-coordinate of the ROI’s top left vertex.
Default Value: 0
Instruction: Start X + Width < Initial image width
Start Y
Description: The y-coordinate of the ROI’s top left vertex.
Default Value: 0
Instruction: Start Y + Height < Initial image height
Width
Description: The width of the ROI.
Default Value: 0
Instruction: Start X + Width < Initial image width
Height
Description: The width of the ROI.
Default Value: 0
Instruction: Start Y + Height < Initial image height
../../../../../_images/roi_by_param.png

Hint

The coordinate of the top left vertex of the initial image is (0, 0).

Method to Update Color ROI
Description: This parameter decides the type of ROI.
List of Options:

  • Origin: The initial color image of the ROI.

  • AdaptivemodifiedRoiOrigin: Use the border of the image to adjust the color ROI and adaptively adjust the center of the non-zero point area of the image to the center of the ROI.

  • BoundRect: Extract the bounding rectangle area of the input image and replace the original image with the circumscribed rectangle of the non-zero point of the image to calculate the zoom ratio.

Color ROI Scaling

Auto Scale
Description: This parameter automatically adjusts the size of the ROI image.
Default Setting: Selected
Customized Scale:
Description: This parameter designates the degree to which the ROI is scaled.
Default Setting: Scaled image size = Initial ROI size × Customized scaling factor. As shown below, the image on the left is of the initial size, with a customized scaling factor of 0.5.

Hint

You can set the parameter only when Auto Scale is not selected.

Ideal Destination Resolution

Same as Input Color ROI & Skip Scaling
Description: This parameter decides whether the size of the image output is set the same as that of the image after Color ROI Scaling setting.
Default Setting: Selected

Hint

When this checkbox is not selected, the size of the image output will be scaled.

Width/Height
Description: This parameter sets the width and height of the ROI (in px).
Default Setting: 1024 px
Instruction: Set according to your actual need.

Hint

You can set the parameter only when Ideal Destination Resolution is not selected.

Padding Color

Hint

  • Padding is needed only when the ROI width and height are customized.

  • The value of R, G, and B can be set only when the checkbox padding is selected.

Padding
Description: This parameter is used to fill the extra space of the ROI when it is scaled up to a particular size.
List of Values: Selected
Instruction: It is recommended to fill the space with black (0,0,0) or grey (128,128,128).
Adjustment Example: The image on the left below is the scaled-up ROI without padding. When padding is used, the size of the ROI image must be designated, and the extra space will be filled up by color, as the image on the right side shows below.
../../../../../_images/scale_filling.png
R / G / B
Description: Color image is made up of 3 colors: R, G, and B. Different R / G / B values can fill the image with different colors.
Default Value: 0
Range of Value: 0–255