This is a simple tutorial on how to use Photoshop tools to find the height of a person, matched against an object or person with a known height or the very least, a good range. The estimate is rough depending on the quality of the source image and skill of the person.
Note: All the "clicking" here will be left click, unless otherwise stated!
Requirements:
- Photoshop
- Clear photo with geometry
Overhead:
- It might be necessary to straighten the subject through photo manipulation, this isn't exactly trivial
- Comparisons must be made on the same plane, because of perspective distortion
- Remember to save progress (shift+ctrl+s, as psd), especially if you're using a pirated copy of the software.
Issues:
- Shit smartphone lenses have distortion, typically slight barrel distortion for mid-range ones (not a big deal) and heavy pincushion distortion for wide angle lenses. This must be corrected and can be very difficult if the phone model is unknown. My suggestion is to move on to a different photo, avoid the modern "wide angle" type shots.
- Fisheye photos can't be (easily) used
Source image:
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Angle corrected by
@PlasticOwls
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Image analysis:
Remember, we want clean and good geometry.
- Pathway with gridded tiles
- Traffic bollards with typical height of 18-20 inches
- Car wheels with typical diameter of 18 inches (regulated)
- Background buildings, the yellow umbrellas and green roof
- Clear vanishing point at the pig's head
- Trees planted in approximate lines
- Electricity poles
- Gunt appears taller than Warski because he's closer to the camera, the two wiggers are on an angle
I'll be using the pathway, the road, and the buildings first to find a singular vanishing point.
Firstly, Ctrl+Alt+C to make the canvas larger, I put in 200%.
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Create a blank layer on top of the source image:
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Optional: Right click, blending options. Choose "Color Overlay", select a colour you want. This will allow the colours to be consistent and avoid the headache of changing brush colours.
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Now press "P" for the pen tool. You want the first one:
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Click on a spot and drag it along.
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Use this to extend the line further out, or correct the position, or both. Ideally, we want it to extend all the way out so the lines are on the same plane as the fighting White niggers in public, showing the world that the word nigger is an adjective and a noun applicable to every group, not a racist slur.
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Press "B" for brush, set brush size to 1-2 pixels, hardness to 100%. Click on one end of the line drawn by the pen tool.
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Then go to the opposite extremity, hold shift, and click there. This will draw a nice straight line.
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Now, press "P" for the pen tool again and press "Esc" several times to get rid of the previous lines, and repeat. Similar to the image above, we can see a vanishing point is converging. I like to use different layers that are colour coded for different objects because I'm autistic.
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Everything along this vanishing point will have the same height. Now we need lines for an object we'd like to use. I'm using the bollards as illustrated above, with my retarded spelling error. Let's add 2 lines for each end of those bollards, using a new layer. The pen tool will be used again. Same method as previously mentioned. Now, the bollards are encapsulated. I used the top as a guide previously, so it's just one blue line. Everything along these 2 lines have the same height.
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What we need to do now is some mapping, map the bollard onto the gunt in question. Our canvas is too small, so make it larger. Ctrl+Alt+C again. I put in 300% which still doesn't seem large enough, so I shift-clicked to select all layers, and dragged everything to a corner. Clicking "V" swaps to the move tool for repositioning, then ctrl+D to deselect afterwards.
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We would like some guiding lines, ctrl+R creates a ruler frame. Click-drag-down on the top will bring a line down. We will encase the pig here. The bollards' guiding lines must intersect with our ruler lines. We will now use the pen too ("P") to extend the couple of existing lines. Ideally with forethought, this step should be avoided by creating a sufficiently large workspace.
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Using the pen anchor point tool, the line is extended and adjusted for a best fit. Hold "Alt" and use the "scroll wheel" to zoom in and out.
"Close enough", once again, "B" for brush, click on one end, shift click on the other to draw a line. Repeat for the other end of the bollard.
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Reeeesult:
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Remember how everything along these lines are of the same height? All we have to do now is draw a line perpendicular to the light blue ruler guide at the intersection, to meet the upmost line. To do this, (surprise!!!) use the pen tool, holding shift allows one to draw a line perpendicularly up.
I've created a new layer and used the brush tool to make another line, by using the same "shift-click" method. I increased the brush size a little here.
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Let's draw a second line for the gunt, between the two ruler guides. Again, brush tool "shift clicking". Do this with a new layer. I used one of those vertical rulers as a guide.
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Now click on "V", we can move the two lines for comparison, by "hold-clicking" on them and dragging. To make stuff neater, I created a group. Shift-click the two lines and click on that folder icon.
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Click on the bollard layer, "Ctrl+J" to create a copy, we need multiples here. After the copy is made, hold "shift" and drag the new layer up, it will maintain its position on the canvas. Place it above the previous. 3 bollard lines are now stacked.
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It's basically complete, all we have to do now is determining the gunt's equivalent height in measurement units of traffic bollards. We will find out the percentages with the ruler tool. Primary school level of calculations are involved.
Top of bollard: 18.6%
Top of pig: 20.4%
Bottom of bollard: 23.7%
23.7-18.6=5.1
20.4-18.6=1.8
1.8/5.1≈0.353 → 35.3%
1-35.3%=64.7%
So the gunt's height is 264.7% of a bollard.
Likewise, we can use the measurement tool if you find mathematics threatening. Right click on the bottom, above the colour patches, and choose Ruler Tool.
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Hold "shift", drag up. Height of excess bollard is 56.58 pixels. It's shown as a negative here because direction is considered, we want the magnitude (absolute value).
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Height of one bollard:
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56.58/161.31≈35.08%
So, 3-0.3508=2.6492=264.92%
Similar to 264.7%, the result above.
What's the height of the bollard? Typically, they can be 16-25 inches. We can see it's taller than the wheels, so perhaps using wheels with known regulated diameters of 18 inches is a better choice. Anyway, it'll be easy to redo bits of this for the wheels. The height of the bollard is likely 54-62cm.
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I'll redo this for the wheel later. The pig can grunt about his supposed 5'11 all he likes, these bollards are obviously not anywhere near 70cm tall.