Mäta årringar med din telefon
Innehållsförteckning
Del 1: Finns det behov av en app för att räkna årringar?
Del 2: Borrkärnor
| Model | Lens | Min Focus Distance (Observed) | Min Focus Distance (Apple) | Aperture | FOV | Pixel per MM (Observed) | Pixel per MM (Apple) |
|---|---|---|---|---|---|---|---|
| iPhone 17 Pro Max | Ultrawide | 20 mm | 20 mm | 2.2 | 106.2 | - | - |
| iPhone 17 Pro Max | Wide | 145 mm | 200 mm | 1.78 | 72.04 | - | - |
| iPhone 17 Pro Max | Tele | 750 mm | 1160 mm | 2.8 | 14.3 | - | - |
| iPhone 16 Pro | Ultrawide | 20 mm | 20 mm | 2.2 | 106.2 | - | - |
| iPhone 16 Pro | Wide | 155 mm | 200 mm | 1.78 | 72.04 | - | - |
| iPhone 16 Pro | Tele | 900 mm | 1350 mm | 2.8 | 16.4 | - | - |
| iPhone 15 Pro Max | Ultrawide | 20 mm | 20 mm | 2.2 | 106.2 | - | - |
| iPhone 15 Pro Max | Wide | 180 mm | 200 mm | 1.78 | 72.04 | - | - |
| iPhone 15 Pro Max | Tele | 900 mm | 1350 mm | 2.8 | 16.41 | - | - |
| iPhone 15 | Ultrawide | 100 mm | - | 2.4 | 106.56 | - | - |
| iPhone 15 | Wide | 100 mm | 150 mm | 1.6 | 68.16 | - | - |
| iPhone 14 Pro | Ultrawide | 20 mm | 20 mm | 2.2 | 106.2 | - | - |
| iPhone 14 Pro | Wide | 160 mm | 200 mm | 1.78 | 71.29 | 32.2 | - |
| iPhone 13 Pro | Ultrawide | - | 20 mm | 1.8 | 101.9 | 89.6 | 96.0 |
| iPhone 13 Pro | Wide | - | 150 mm | 1.5 | 67.1 | 33.6 | 21.5 |
| iPhone 13 Pro | Tele | - | -- | 2.8 | 25.2 | 25.2 | 15.1 |
| iPhone 12 Pro Max | Ultrawide | Not sharp at close Dist. | -- | 2.4 | 102.9 | - | - |
| iPhone 12 Pro Max | Wide | 120 mm | 150 mm | 1.6 | 67.7 | 32.3 | 21.5 |
| iPhone 12 Pro Max | Tele | Hard to get close | - | 2.2 | 30.1 | 32.3 | 15.1 |
| iPhone 12 Pro | Ultrawide | Not sharp at close Dist. | - | 2.4 | 102.9 | - | - |
| iPhone 12 Pro | Wide | 100 mm | 120 mm | 1.6 | 67.1 | 40.3 | 26.8 |
| iPhone 12 Pro | Tele | Hard to get close | - | 2.0 | 37.0 | - | - |
| iPhone 11 | Ultrawide | Not sharp at close Dist. | -- | 2.4 | 102.9 | - | - |
| iPhone 11 | Wide | - | 120 mm | 1.8 | 66.48 | 43 | 27.1 |
| iPhone XR | Wide | - | 120 mm | 1.8 | - | 36 | - |
| iPhone SE2 | Wide | - | 100 mm | 1.8 | - | - | - |
| iPhone 7 | Wide | - | 100 mm | 1.8 | 58.98 | 44.3 | 37.2 |
Comparison of photo quality between iPhone models

iPhone 7. Unsharp and problems with the white balance

iPhone 8. Unsharp and some problem with automatic white balance.

iPhone SE2. Sharper and better white balance than the older phones above.

iPhone XR. Similar result as iPhone SE2.

iPhone 11. Sharp. The quality is really good. Better than XR and SE2.

iPhone 12 Pro Max. The minimum focus distance is larger than for the ordinary 12 Pro and 11. It Is harder to get sharp images.

iPhone 13 Pro. UltraWide angle camera. Very sharp images. Will need special adjustments to avoid blurry edges.

iPhone 13 Pro. Wide angle camera. Not quite as good as 11,12 or 12 Pro.

Visual guide showing the stitching process

Navigation flow between different views
Del 3: Varför vi övergav projektet

Image 1: Drill core from Pine. It is hard to count the annual rings.

Image 2: Drill core from Pine. You often get dirt on the drill core. It sometimes makes it harder to count and will make automatic counting even harder.
Lärdomar
Jag lärde mig mycket, inklusive följande:
Del 4: Återbesök av projektet 3 år senare
Under åren som följt har det funnits mycket intresse för ämnet. Det har också skett några förbättringar i kamerorna på telefonerna och det har också funnits några intressanta publikationer inom området.
Over the last five years, automated tree-ring detection has rapidly evolved from fragile, rule-based image processing toward robust deep-learning approaches. Early progress came from applying convolutional neural networks to ring-boundary segmentation, enabling far greater tolerance to noise, uneven sanding, and variable lighting. A major milestone was the use of instance-segmentation models such as Mask R-CNN to detect annual ring boundaries in both scanner and smartphone images (Kim et al., 2023). Shortly after, fully automated pipelines emerged that combine deep learning with post-processing and export to standard dendrochronology formats (Poláček et al., 2023). These methods were accompanied by open-source implementations, making state-of-the-art ring detection reproducible and accessible (TRG-ImageProcessing on GitHub). More recently, new annotated datasets and semantic-segmentation baselines have been released to address challenging hardwood surfaces and rough samples (Wu et al., 2024). Transformer-based segmentation models have also been applied to high-resolution wood microsections, improving boundary delineation in anatomically complex samples (García-Hidalgo et al., 2024). At the same time, large foundation segmentation models have lowered the barrier to interactive annotation and rapid prototyping (Kirillov et al., 2023). The open-source release of these models has accelerated experimentation across research and applied product development (Segment Anything on GitHub). Together, these advances now make high-precision, automated ring counting from photographs a realistic foundation for field-ready and mobile applications.
Vi har lagt till data för de senaste iPhone-linserna och kamerorna i listorna
Vi ser fram emot att se var allt detta kommer att sluta