Copy and replace pixels

Disponible avec une licence Image Analyst.

The Capture group contains the Copy Region and Replace Region tools. These tools copy or replace pixels from the same dataset or from a different dataset in the map. If using another dataset within the map, use the Source Layer drop-down list to set the correct map layer to use; this layer must have the same bit depth as the raster being edited. The target layer is always the raster dataset that you are editing.

Both Copy Region and Replace Region are tools you can use to improve problematic areas in your imagery, such as areas obscured by clouds. You can replace the clouds with another area that is not cloudy. This replacement region can come from another image overlapping the area, or another area within the same image. While copying a region, and the active region is still in preview mode, you can use the yellow handle in the middle of the region to move it to the appropriate location.

For the best results, the replacement region should be of similar radiometry and seasonality. If the result of your replaced multispectral or panchromatic region does not look seamless, you can use color matching and blending techniques to make the region look seamless. Color matching adjusts the color of the new region to match the base imagery, while blending feathers the pixels along the perimeter of the region. While the region is active and in preview mode, you can use shortcut keys to color match and blend the region into the base imagery. You can only choose one type of color matching method at a time, and additionally you can choose to blend the pixels along the edges. When the preview is acceptable, you can double-click anywhere in the map to update the region.

Color correction shortcut keys for multispectral and panchromatic imagery

Shortcut	Color matching	Blending
Spacebar	None	Yes
Shift	Color match, using all the pixels in the region to compute the match.	No
Shift + Space	Color match, using all the pixels in the region to compute the match.	Yes
Shift + S	Color match, using only the pixels along the perimeter of the region to compute the match.	No
Shift + S + Space	Color match, using only the pixels along the perimeter of the region to compute the match.	Yes

Remarque :

These keyboard shortcuts cannot be used for elevation data or thematic data.

Copy a region

The Copy tool allows you to copy a region from a raster layer, and paste that region onto a different raster dataset that you want to edit. For example, you may want to copy an existing neighborhood to replace a neighborhood obscured by clouds. This is similar to a copy and paste operation using a block of pixels.

The workflow follows these three steps:

1. Start a Pixel Editor session.
2. Copy and replace a region.
3. Save your edits.

Start a Pixel Editor session

Pixel Editor can only edit one layer at a time per map view. The contextual layer used to start the Pixel Editor session is the only layer that can be edited in that map view. To edit another layer in the map, you must first close Pixel Editor, select the other layer in the Contents pane, and reopen Pixel Editor to operate on that layer.

1. In the Contents pane, highlight the raster layer you want to edit.
2. Click the Imagery tab.
3. Click the Pixel Editor button .

Copy a region

Now that the Pixel Editor session has started, you can copy a region and paste it in a new location. For example, you will use an existing housing development, and use that block of pixels on a vacant lot to visualize what the new lot will look like.

1. Zoom in to the area where you want to copy a region of data.
2. On the Pixel Editor tab, click the drop-down arrow below Region Mode, and choose New .
3. Click the drop-down arrow below Region, and choose Polygon .
4. Draw a polygon around an existing housing development. You will be copying that region to the vacant lot to the northwest.

   

5. Make sure that the Source Layer is on the correct layer, which is the current layer being edited.
6. Click the drop-down arrow below Capture, and choose Copy Region .

   If a region is not selected when you choose Copy Region, you can create a polygon region.

7. In the middle of the copied polygon, a small yellow circle will appear in the center of the polygon. Click and hold your mouse button on the circle, and drag it to the area in the map where you want to place it.

   

   Drag the yellow circle to move the copied region to another location.

8. While the region is still in preview mode, you can choose to color correct or blend the region. Keep the shortcut keys held down to preview the color correction results.

   Color matching and blending are only available for multispectral and panchromatic imagery.

9. If you are satisfied with the placement and current color of the region, double-click the display while still holding the shortcut keys, to accept the update. Notice that a copy of the selected region is pasted into the location where the vacant lot used to be.

   

Save your edits

To commit your edits back to the data source, you must save them.

1. In the Save group, click the Save button .

   To save your edits without affecting the source data, save to a new file. In the Save group, click the Save As button , and specify a location and file name for the new file.

2. Click Close Pixel Editor in the Close group when you finish editing the raster dataset.

Replace a region

The Replace tool allows you to cover a region with another block of pixels. It is similar to Copy, except you first choose the region you want to replace. This is useful to replace a region that you want to improve. For example, you may want to replace an area of cloud cover.

The workflow follows these three steps:

1. Start a Pixel Editor session.
2. Replace a region.
3. Save your edits.

Start a Pixel Editor session

Pixel Editor can only edit one layer at a time per map view. The contextual layer used to start the Pixel Editor session is the only layer that can be edited in that map view. To edit another layer in the map, you must first close Pixel Editor, select the other layer in the Contents pane, and reopen Pixel Editor to operate on that layer.

1. In the Contents pane, highlight the raster layer you want to edit.
2. Click the Imagery tab.
3. Click the Pixel Editor button .

Replace a region

Now that the Pixel Editor session is activated, you can replace the cloudy region. In this scenario, you have an overlapping raster that you will use to replace the clouds.

1. Zoom in to the area where you want to copy a region of data.
2. On the Pixel Editor tab, click the drop-down arrow below Region Mode, and choose New .
3. Click the drop-down arrow below Region, and choose Polygon .
4. Draw a polygon around the cloudy area.

   

5. Make sure that your Source Layer is on the correct layer, which is the layer that you are not editing.

   

6. Click the drop-down arrow below Capture, and choose Replace .

   If there is no selected region when you choose Replace, you can create a polygon region.

7. In the middle of the copied polygon, a small yellow circle appears in the center. Click and hold your mouse button on the circle, and drag it to an area on the image where you want to capture the replacement pixels. In this case, you want to use the exact same location, but using the other layer in your Contents pane.
8. While the region is still in preview mode, you can choose to color correct or blend the region. Keep the shortcut keys held down to preview the color correction results. You can choose only one color matching technique at a time.

   Color matching and blending are only available for multispectral and panchromatic imagery.

9. If you are satisfied with the placement and current color of the region, double-click the display while still holding the shortcut keys, to accept the update.

   

Save your edits

To commit your edits back to the data source, you must save them.

1. In the Save group, click the Save button .

   To save your edits without affecting the source data, save to a new file. In the Save group, click the Save As button , and specify a location and file name for the new file.

2. Click Close Pixel Editor in the Close group when you finish editing the raster dataset.