Convert

The Convert group appears on the Adjust ribbon. The options in this group allow you to convert an image from one format to another. You can use the options in this group to convert an image from monochrome to color, or from one bit depth to another, or both. You can also convert images to a 'floating point' format prior to performing mathematical operations on them so that data isn't lost due to clipping (see Mono FPoint and Color FPoint below for more information). The pull-down list box at the top of the Convert group contains the following options:

Click on the Apply button to create a copy of the active image in the selected format using the currently-selected conversion options. 

The converted image will be placed into a new image window.  Your original image will not be affected by the conversion. 

Conversion Options

Click on the down arrow to the right of the Apply button to display the Convert Options dialog. The options on this dialog are described below.

Scale Pixel Values: If you are converting from lower to higher bit depth, this option multiplies each pixel by 257 for 8 to 16 bit conversions, or by 16.0625 for 12 to 16 and 8 to 12 bit conversions. Conversely, if you are converting from higher to lower bit depth, this option divides each pixel by 257 or 16.0625, respectively. The effect is to appropriately scale the values of the source image from its bit-depth range to the bit-depth range of the resulting image.

If you are converting to a floating point image: This option is the same as selecting Direct Copy Pixel Values (described below).

Best Fit Pixel Values: This option is the same as selecting Scale Pixel Values, but in addition to scaling the pixels to a higher or lower bit depth, it also scales them from the full pixel dynamic range to the best-fit dynamic range. The best fit dynamic range is automatically determined by Image-Pro the same here as it is determined by the Best Fit option on the Adjust ribbon.

Direct Copy Pixel Values: This option copies the values of the source image directly directly to the resulting converted image.
If you are converting to a floating point image: This feature ensures that the pixel/color channel values in the resulting floating point image are equivalent to the pixel/color channel values of the source image; also, the bit depth of the source image is maintained in the converted image.

If you are converting from lower to higher bit depth: This feature copies values directly. The result of this conversion will usually look blank, as the direct copy of values results in images whose values are only small fractions of the dynamic range.

If you are converting from higher to lower bit depth: This feature copies the pixel values directly to the destination image, clipping the values to the destination image’s dynamic range if necessary.

Select the Apply Best Fit check box to have Image-Pro determine which method is optimal.

Custom Conversion Pixel Values: The Custom conversion option allows complete control over the image conversion. The Input Range and Output Range controls are only enabled when “Custom conversion” is selected.  

Note: Custom conversion is the default option when the source image bit-depth is the same as the destination image bit depth; thereby allowing users to stretch or shrink the luminance range in the destination image.

  • Source Range: The Input Range controls set the beginning (Start) and ending (End) values of the dynamic range of the input. Image pixels less than the Start value will be converted to the Output Range Start value, and image pixels greater than the End value will be converted to the Output Range End value.
  • Destination Range: The Output Range controls set the beginning (Start) and ending (End) values of the dynamic range of the output.  Image pixels less than the Start value of the Source Range will be converted to the Output Range Start value, and image pixels greater than the End value of the Source Range will be converted to the Output Range End value.

Note: The case where a floating point source image with a RangeMin to RangeMax of 0.0 to 255.0 is converted to any 8-bit type is special-cased to just do a direct conversion without any dialog being shown.

Mono 8bpp

Select Mono 8bpp from the Convert drop-down menu if you want to convert your image to a 8 bits per pixel monochrome image.

The pixel values for the resulting 8 bit image are on a scale of 0 - 255. The source image's pixel values are scaled to the 8-bit range based on the option you select in the Apply pull-down menu.

If you are converting a color image to Mono 8bpp, the three color channels (red, green, and blue) for each pixel are merged into a single grayscale intensity value according to the following formula: .3 Red + .59 Green + .11 Blue.

If you are converting a floating point image to Mono 8bpp, pixels with values less than zero will be converted to 0, and pixels with values greater than the top of the source image's bit-depth range will be converted to 255.

Mono 12bpp

Select Mono 12bpp from the Convert drop-down menu if you want to convert your image to a 12 bits per pixel monochrome image.

The pixel values for the resulting 12 bit image are on a scale of 0 - 4095. The source image's pixel values are scaled to the 12-bit range based on the option you select in the Apply pull-down menu.

If you are converting a color image to Mono 12bpp, the three color channels (red, green, and blue) for each pixel are merged into a single grayscale intensity value according to the following formula: .3 Red + .59 Green + .11 Blue.

If you are converting a floating point image to Mono 12bpp, pixels with values less than zero will be converted to 0, and pixels with values greater than the top of the source image's bit-depth range will be converted to 4095.

Mono 16bpp

Select Mono 16bpp from the Convert drop-down menu if you want to convert your image to a 16 bits per pixel monochrome image.

The pixel values for the resulting 16 bit image are on a scale of 0 - 65,535. The source image's pixel values are scaled to the 16-bit range based on the option you select in the Apply pull-down menu.

If you are converting a color image to Mono 16bpp, the three color channels (red, green, and blue) for each pixel are merged into a single grayscale intensity value according to the following formula: .3 Red + .59 Green + .11 Blue.

If you are converting a floating point image to Mono 16bpp, pixels with values less than zero will be converted to 0, and pixels with values greater than the top of the source image's bit-depth range will be converted to 65,535.

Mono FPoint

Select Mono FPoint from the Convert drop-down menu if you want to convert your image to a variable depth, Mono FPoint image.  You might want to convert an image to a Mono FPoint image to eliminate the clipping at 0 and/or at the top of the range (e.g., 255 for 8bpp images) which occurs when arithmetic operations are performed. Floating point images can contain negative values and values greater than the top of the source image's bit-depth range.

The bit depth of the resulting floating point image is determined based on your selection in the Apply pull-down menu.

If you are converting a color image to Mono FPoint, the three color channels (red, green, and blue) for each pixel are merged into a single grayscale intensity value according to the following formula: .3 Red + .59 Green + .11 Blue.

Color 24bpp

Select Mono 24bpp from the Convert drop-down menu if you want to convert your image to a 24 bits per pixel color image.

The resulting image will have three 8-bit color channels (red, green, and blue) with intensities ranging from 0 to 255 per channel. The source image's pixel values are scaled to the 8-bit range based on the option you select in the Apply pull-down menu.

If you are converting a monochrome image to Color 24bpp, the three color channels (red, green, and blue) are given the same value.

If you are converting a floating point image to Color 24bpp, color channels with values less than zero will be converted to 0, and color channels with values greater than the top of the source image's bit-depth range will be converted to 255.

Color 36bpp

Select Mono 32bpp from the Convert drop-down menu if you want to convert your image to a 32 bits per pixel color image.

The resulting image will have three 12-bit color channels (red, green, and blue) with intensities ranging from 0 to 4095 per channel. The source image's pixel values are scaled to the 12-bit range based on the option you select in the Apply pull-down menu.

If you are converting a monochrome image to Color 32bpp, the three color channels (red, green, and blue) are given the same value.

If you are converting a floating point image to Color 32bpp, color channels with values less than zero will be converted to 0, and color channels with values greater than the top of the source image's bit-depth range will be converted 4095.

Color 48bpp

Select Mono 48bpp from the Convert drop-down menu if you want to convert your image to a 48 bits per pixel color image.

The resulting image will have three 12-bit color channels (red, green, and blue) with intensities ranging from 0 to 4095 per channel. The source image's pixel values are scaled to the 12-bit range based on the option you select in the Apply pull-down menu.

If you are converting a monochrome image to Color 48bpp, the three color channels (red, green, and blue) are given the same value.

If you are converting a floating point image to Color 48bpp, color channels with values less than zero will be converted to 0, and color channels with values greater than the top of the source image's bit-depth range will be converted 4095.

Color FPoint

Select Color FPoint from the Convert drop-down menu if you want to convert your image to a variable depth, Color FPoint image.  You might want to convert an image to a Color FPoint image to eliminate the clipping at 0 and/or at the top of the range (e.g., 255 for 8bpp images) which occurs when arithmetic operations are performed. Floating point images can contain negative values and values greater than the top of the range.

The bit depth of the resulting floating point image is determined based on your selection in the Apply pull-down menu.

Monochrome images are converted to Color FPoint images by converting the grayscale pixel values to floating-point R, G, and B values. For example, if Direct Copy Pixel Values is selected in the Apply pull-down list box, a pixel with a grayscale value of 128 would be converted to R=128.0, G=128.0, and B=128.0.

Color images are converted to Color FPoint images by converting each channel's intensity value to a floating-point value. For example, if Direct Copy Pixel Values is selected in the Apply pull-down list box, a pixel with values R=128, G=128, and B=0 would be converted to R=128.0, G=128.0, and B=0.0.