The Universal Image Quality Index compares two grids (greyscale images) using the three parameters luminance, contrast and structure. This is done for each pixel using a moving window as specified by the kernel radius.
| | Name | Type | Identifier | Description | Constraints |
| Input | First Grid | Grid (input) | GRID_A | - | - |
| Second Grid | Grid (input) | GRID_B | - | - |
| Output | Universal Image Quality Index | Grid (output) | QUALITY | The product of correlation, luminance and contrast similarity. | - |
| Correlation (*) | Grid (optional output) | CORRELATION | The correlation coefficient. | - |
| Luminance (*) | Grid (optional output) | LUMINANCE | The similarity of mean luminance. | - |
| Contrast (*) | Grid (optional output) | CONTRAST | The similarity of contrast. | - |
| Options | Grid system | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
| k1 | Floating point | K1 | - | Minimum: 0.000000 Maximum: 1.000000 Default: 0.010000 |
| k2 | Floating point | K2 | - | Minimum: 0.000000 Maximum: 1.000000 Default: 0.030000 |
| L | Integer | L | The dynamic range for the image pixel, i.e. the number of different grey values. | Minimum: 0 Default: 255 |
| Kernel Type | Choice | KERNEL_TYPE | The shape of the filter kernel. | Available Choices: [0] Square [1] Circle Default: 1 |
| Kernel Radius | Integer | KERNEL_RADIUS | The kernel radius in cells. | Minimum: 0 Default: 2 |
| (*) optional |