Lightfield

Lytro Illum: Getting in-depth about depth by Brenda (Hartshorn) Licitra

The most interesting thing about what the Lytro Illum can do that has an advantage over traditional photography, is that you can play with the depth in the scene.  This feature has the effect of allowing the viewer to feel more immersed in the scene by having the added 3D information of experiencing the illusion of depth off a 2D screen.  For the most part, the Illum's software is able to detect the depth of objects in the scene correctly.  However, there are a few conditions that confuse the processing which will result in some artifacts that will need to be manually corrected by pulling the depth map into Photoshop (or any other image editing software.)  In this post, I will discuss some challenging situations that the software has trouble with and cover how to correct the depth maps for processing.

Note: In the images shown below, areas shaded in blue are what the software is choosing as the near depth and the orange tinted areas are what is being interpreted as the far depth.


Texture & Patterns

Main Street, Chinese Camp, CA

Main Street, Chinese Camp, CA

As you can see from the depth map above, the software had a hard time choosing the correct depths for this busy scene.  The part of the wall that had been stuccoed over is so much smoother and brighter than the surrounding that this area became processed as being a different depth than the bricks.

Contrast: Low & High

Stalactites in the Black Chasm Cavern National Landmark.

Stalactites in the Black Chasm Cavern National Landmark.

Since the texture and tone of the stalactites are very similar to each other, it had trouble processing the correct depth in the upper left corner of the image for part of the far stalactite that borders the near one.  You can also see that the edge detection for this object type is a bit poor since the tip and edges of the formations are being mapped as part of the far depth.  The bottom right corner of the image is also not creating the correct depth map either but for different reasons.  If there are parts of the image that lack detail and either reach near pure black or pure white, the software is unable to estimate the depth correctly.  This area will become a depth artifact when processing and will either appear to be part of your foreground or background.

Blue marble rock formation near Volcano, CA.

Blue marble rock formation near Volcano, CA.

At the moment there does not appear to be a contestant rule for which the software chooses.  In the stalactite image, it incorrectly made part of the blackness of the cave a near depth.  While in contrast the image to the right, the software chose to make the mossy rock part of the far depth.

The software also has trouble with areas that are near white. The image below is a good example, as the bright parts of the clouds are being interpreted as being near.

Hatch Creek near Don Pedro Reservoir.

Hatch Creek near Don Pedro Reservoir.

Fixing the Depth Map

For users that have image editing software, Lytro has enabled a feature that allows them to easily correct the depth map.

  1. After selecting the image that you would like to fix, go to File>Export and select Depth Map from the drop down menu.  Select where you would like your file to be exported, and click Export.  You can then open the files in an image editor that allows you to manually paint the correct depth tone, like Photoshop.
  2. Open both of the files that are created in your image editor and use the color image as a layer on top of the gray scale depth image.  Photoshop may pop-up with an warning saying "The target document has a different depth than the source document.  This may result in lower than expected quality.  Are you sure you want to proceed?"  Just ignore this and click Yes as you are just using the image as a reference layer so you can better see what you are editing.  
  3. In your Layers pallet, drag the opacity of your reference layer down to about 20% or to a percent where you can see both layers.  For the depth map, the lighter tone represents the far depth and darker tone represents the near depth.  
  4. Select the Depth Map (Background layer) and the Eye dropper tool.  Set the Eye dropper tool to only sample the Current Layer from the drop down menu.  Use the Eye dropper to select an area with the same depth of the area that you would like to fix. 
  5. Now switch to the Paint Brush to correct the desired area.  You can resample depth area colors by holding Alt/Option to temporarily switch back and forth between the Eye dropper and Paint brush.  If you have large areas that need to be corrected, it can be easier to use the selection tools on the Reference layer image and then switch back to the Depth layer to paint in the desired area more precisely.  For this, you will want to turn the opacity of the Reference layer image back up to 100% temporarily while making the selection.
  6. Once you have addressed all problem areas, you can then delete the Reference image layer and save.
  7. You may now go back to the Lytro Desktop app.  Navigate to File>Import.  Under the Import drop down menu choose Selected Depth Maps, click Browse to find the file you would like to update, and then click Import.  After that it will just take a couple minutes to update the processing on your lightfield.

Lightfields at Pinnacles NP by Brenda (Hartshorn) Licitra

Took my Lytro Illum camera hiking and captured some lightfield of rock formations and a talus cave at Pinnacles National Park.  Although the park is home to the California condor and Townsend big-eared bats, I was not fortunate enough to see any.

The rock formation once part of the Neenach Volcano and sat on the San Andreas Fault.  The volcano was split in two as the Pacific Plate slid north nearly 200 miles.  The remain part that sits on the North American Plate is located near Lancaster, not to be confused with the Trona Pinnacles near Ridgecrest.  The Neenach formation is not open to the public as it is on private land.

Introducing the Lytro Illum Lightfield Camera by Brenda (Hartshorn) Licitra

New Toys!

Why yes, Christmas did come early.  I've been keeping an eye out for prices on the Lytro Illum and I was able to get it for a steal off Woot.com last month.  I started playing around with different scenarios captures to see what this new technology had to offer.  
Lytro is attempting to brand the concept as Living Pictures, but let's get it straight.. it's a lightfield.  

With the Illum, there are many small lenses over the sensor to be able to capture the light rays from different positions.  In theory, this allows the software to be able to estimate depth so that the user can click on different areas of the image.  When the file is processed and exported, it allows the user to change what they would like to focus on and also allows for slight changes in the viewing perspective to create a more engaging experience.  However, with all new technology- there are going to be some bugs.  Where to do I file my P0s?  I'm not saying it's horrible, on the contrary- it is actually a very impressive piece of equipment for how small and user friendly it is.  But it's far from being professional publishing grade.  I do however think the Illum will end up being a very good preview tool by professionals in this new technology.  Much like how Polaroid was used as a preview in studio photography for large and medium format cameras back in the silver age of film. And for those of you hipsters out there that keep saying film is making a come back: No, son... just no.

Since the Illum is attempting to estimate depth in it's processing, I decided to push the device to its limits by putting it in various tricky scenarios and visit some of my favorite places in the process.  This will be the first of a many part series going over the subject of lightfield subject matters, processing, and user experience.  However, as an introduction I am going to proceed with this post as editorial on the location so you can create your own first impressions.

Welcome to Main Street

I hadn't visited Chinese Camp for nearly 15 years.  With all the housing development that has occurred in California over the last 10 years, let me tell you: Chinese Camp was not one of them.  The only thing that changed was the fact that the mummified bat that hanging in the window of an abandoned building had fallen down.  You read that correctly, mummified bat.  When I had first visited, one of the locals approached my dad and I awkwardly with the amazement and excitement that they would be actually able to speak to another person that day.  He gave us a short tour and pointed out that I should take a photo of the bat.  It had gotten trapped between the screen and the window and overtime naturally dried out entombed in the attic window.

During the Gold Rush, Chinese Camp was actually a significant town as it is located at the intersection of HWY 49 (which connects all of the major mining towns) and HWY 120 (which was the supply route from Stockton.)  It was originally named Camp Washington, but grew to be known as Chinese Camp as it was home to 5,000 Chinese during the Gold Rush.  It was also home to one of the first Tong Wars in California that consisted of 2,000 people from 2 rival clans.  However, because there were only a few firearms were used during the fight and weapons used were mostly handmade knives and mining tools, there were very few people that died although many were injured.

Today, Main Street is a whole one block long.  The whole town consists about 8 blocks total and a population of 126 according to the 2010 census.  However, those numbers could also be contributing from the surrounding rural ranch areas.  I would say about half of the town itself where the post office, fire station, and gas station are located are abandoned buildings.  Most of these buildings have boarded up windows and have walls that have fallen down.  They would seem completely uninhabitable and probably are condemned, I did however observer evidence that someone was taking shelter in one of the old buildings.  Despite their deteriorate state, they are protected from being torn down or remodeled because it is considered a historic site.  I would understand if this was a state/county/national park or if the city took the effort to attract tourists to the area that these buildings should remain intact.  However, the current condition of them are so poor I can't imagine they are doing anything good for the community.  There are many other mining towns in the area that have kept up the look of their downtown's, host festivals, and attract a number of people on their way to the snow or lake, who like wine tasting, enjoy little shops, or want to get a feel of what the gold rush was like.  As much as I do enjoy taking photos of rust, property value and a healthy economy is something that comes to the front of my mind when looking at these depressed places.  Or a more pointed question: Who would want to live out here?

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