Model for Detecting License Plates in Cropped Image - Related to leetcode, -, (2025, 6., vibes

Leetcode - 6. Zigzag Conversion

/** * @param {string} s * @param {number} numRows * @return {string} */ var convert = function ( s , numRows ) { if ( numRows === 1 ) { return ( s ); } else { let res = "" for ( let r = 0 ; r < numRows ; r ++ ) { let inc = ( numRows - 1 ) * 2 ; // Step size for the zigzag pattern for ( let i = r ; i < s . length ; i += inc ) { res += s [ i ]; // Main vertical column // Handle diagonal elements for middle rows (not first/last row) let diag = i + inc - 2 * r ; if ( r > 0 && r < numRows - 1 && diag < s . length ) { res += s [ diag ]; } } } return res } };

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Psychological safety isn’t about fluffy “niceness” — it is the foundation of agile teams that innovate, adapt, and deliver.

Sunshine And March Vibes (2025 Wallpapers Edition).

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Model for Detecting License Plates in Cropped Image

Now that we have per-car images, we need to find license plates. License plates might not be present, or might be otherwise difficult to find with heuristic, thus we use YOLO again to find the license plate bounding box.

We now have cropped images per car. Our high-level goal is OCR on the license plate. OCR needs a tight view to only the license plate characters, and not other distractions. This means within our cropped images, we should find license plate (this article), and crop image to just license plate (next).

We tested heuristics to find license plates such as contour-detection, and they did not generalize well. See image examples below – illustrating that even with reliable car detection, license plates can be easy (centered, large), harder (off-center, smaller), or even not-present. YOLO proved to be a advanced tool for variation, and thus we train second model for license plates.

Easy-to-see license plate. Centered, large.

Also easy, but less-easy. License plate is no longer centered on car. Can’t find license plate based on location in cropped image. And license plate is smaller in this view.

Harder example. This is a real output from step 3 model for detecting cars. Just not-yet in-frame. Contour heuristic thinks this is a license plate, but we need model capable of understanding its incomplete, and to move on.

Collect training data Run step 1 through 4 for a bit to collect training data. In my case, I compiled ~30 cropped images of cars with visible license plates. Example such as the following: Label training data This is time-consuming and manual step, but essential.

I used [website] (same as step 3). I recommend their tooling. I’m sure there’s alternatives if you prefer, but roboflow made e2e process easier. Training the YOLO model requires label data in a particular format, which roboflow automates, and roboflow has online tooling to streamline your labeling data.

Hand-label your images. I suggest learning the hotkeys. Sample labeling from roboflow - one of many.

Sample labeling from roboflow - one of many I suggest defining guidelines for yourself to mitigate the monotony. My bounding boxes for labeling generally stretched within the license plate - not encircling the plate border itself. Otherwise top-left to bottom-right within the plate rectangle, and repeat. I’m not saying use the same bounding box. I’m suggesting: know what your guideposts are. Knowing your guideposts will make your labeling consistent and help the tedium.

Download training data. This is just the formatted xml capturing all your bounding boxes for training. Train model YOLO Note that my output model is “v27” ie I trained several models to experiment with different parameters. I recommend testing and iterating on configurations that work for you: nano model vs medium, less epochs or more, etc.

On MacBook M1 Pro with 32GB memory, took <1 hour to train the winning model. from ultralytics import YOLO ########### # Training # Load the model baseDir = ' / Users / japollock / Projects / TrainHighwayCarDetector / ' model = YOLO ( baseDir + ' resources / yolov8n . pt ' ) results = model . train ( imgsz = 1280 , # epochs=100, # batch=16, # device='mps', data = baseDir + ' resources / v4data_LP / data . yaml ' , name = ’ yolov8n_100_16_LP_v27 ’ ) ########### Test YOLO. I trained five model variants on model and epoch variations. nano, medium, xlarge models, and 50 or 100 epochs. I measured performance on precision, recall, map50, and map50-95. Long story short, all variants had near-equal very good performance. Thus I choose simplest model nano with default epochs from ultralytics import YOLO import cv2 from PIL import Image import imutils ########### # predict baseDir = ' / Users / japollock / Projects / TrainHighwayCarDetector / ' ########### # model model = YOLO ( baseDir + ' src / runs / detect / yolov8n_100_16_LP_v27 / weights / best . pt ' ) ########### # images img = cv2 . imread ( baseDir + ' photos / yolo_licensePlates / licensePlates / IMG_4566_0002 . jpg ' ) results = model . predict ( source = img , imgsz = 1280 ) cv2 . imshow ( "image" , results [ 0 ]. plot ()) cv2 . waitKey ( 0 ).

Sample classification from best model. “license-plates” is the classifier label.

Now we have model detecting license plates inside the cropped image for cars. This enables next step, which is to crop down image to just license plate characters, on the way to OCR after.

Next Link: Crop bounding box for license plate.

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Sunshine And March Vibes (2025 Wallpapers Edition)

Sunshine And March Vibes (2025 Wallpapers Edition).

Do you need a little inspiration boost? Well, then our new batch of desktop wallpapers is for you. Designed by the community for the community, the wallpapers in this collection are the perfect opportunity to get your desktop ready for spring — and, who knows, maybe they’ll spark some new ideas, too. Enjoy! Do you need a little inspiration boost? Well, then our new batch of desktop wallpapers is for you. Designed by the community for the community, the wallpapers in this collection are the perfect opportunity to get your desktop ready for spring — and, who knows, maybe they’ll spark some new ideas, too. Enjoy!

With the days getting noticeably longer in the northern hemisphere, the sun coming out, and the flowers blooming, March fuels us with fresh energy. And even if spring is far away in your part of the world, you might feel that 2025 has gained full speed by now — the perfect opportunity to put all those plans you’ve made and ideas you’ve been carrying around to action!

To cater for some extra inspiration this March, artists and designers from across the globe once again challenged their creative skills and designed a new batch of desktop wallpapers to accompany you through the month. As every month, you’ll find their artworks compiled below — together with some timeless March favorites from our archives that are just too good to be forgotten.

This post wouldn’t exist without the kind support of our wonderful community who diligently contributes their designs each month anew to keep the steady stream of wallpapers flowing. So, a huge thank-you to everyone who shared their artwork with us this time around! If you, too, would like to get featured in one of our upcoming wallpapers posts, please don’t hesitate to join in. We can’t wait to see what you’ll come up with! Happy March!

. We respect and carefully consider the ideas and motivation behind each and every artist’s work. This is why we give all artists the full freedom to explore their creativity and express emotions and experience through their works. This is also why the themes of the wallpapers weren’t anyhow influenced by us but rather designed from scratch by the artists themselves.

and express emotions and experience through their works. This is also why the themes of the wallpapers weren’t anyhow influenced by us but rather designed from scratch by the artists themselves. Submit your wallpaper design! 👩‍🎨.

Feeling inspired? We are always looking for creative talent and would love to feature your desktop wallpaper in one of our upcoming posts. Join in ↬.

with calendar: 640x480, 800x600, 1024x768, 1152x864, 1280x720, 1280x800, 1280x960, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3200x2000.

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with calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

without calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

“March, the month of transition between winter and spring, is dedicated to Rosa Parks and her great phrase: ‘You must never be fearful about what you are doing when it is right.’” — Designed by Veronica Valenzuela from Spain.

with calendar: 640x480, 800x480, 1024x768, 1280x720, 1280x800, 1440x900, 1600x1200, 1920x1080, 1920x1440, 2560x1440.

without calendar: 640x480, 800x480, 1024x768, 1280x720, 1280x800, 1440x900, 1600x1200, 1920x1080, 1920x1440, 2560x1440.

with calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

without calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

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“Rays of sunlight had cracked into the bear’s cave. He slowly opened one eye and caught a glimpse of nature in blossom. Is it spring already? Oh, but he is so sleepy. He doesn’t want to wake up, not just yet. So he continues dreaming about those sweet sluggish days while everything around him is blooming.” — Designed by PopArt Studio from Serbia.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

without calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

“Spring is getting closer, and we are waiting for it with open arms. This month, we want to enjoy discovering the northern lights. To do so, we are going to Alaska, where we have the faithful organization of our friend White Fang.” — Designed by Veronica Valenzuela Jimenez from Spain.

without calendar: 640x480, 800x480, 1024x768, 1280x720, 1280x800, 1440x900, 1600x1200, 1920x1080, 1920x1440, 2560x1440.

“Spring is coming! Birds are singing, flowers are blooming, bees are flying… Enjoy this month!” — Designed by Melissa Bogemans from Belgium.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

Designed by Vlad Gerasimov from Georgia.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“After some freezing months, it’s time to enjoy the sun and flowers. It’s party time, colours are coming, so let’s spring!” — Designed by Colorsfera from Spain.

without calendar: 320x480, 1024x768, 1024x1024, 1280x800, 1280x960, 1280x1024, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

Designed by Nathalie Ouederni from France.

without calendar: 1024x768, 1280x1024, 1440x900, 1680x1200, 1920x1200, 2560x1440.

“This month, I want to go to the woods and explore my new world in sunny weather.” — Designed by Zi-Cing Hong from Taiwan.

without calendar: 1024x768, 1152x864, 1280x720, 1280x800, 1280x960, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

without calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 3840x2160.

“Daydreaming of enhanced things, of lovely things, of saddening things.” — Designed by Bhabna Basak from India.

without calendar: 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“A day, even a whole month, isn’t enough to show how much a woman should be appreciated. Dear ladies, any day or month are yours if you decide so.” — Designed by Ana Masnikosa from Belgrade, Serbia.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1040, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“I am the kind of person who prefers the cold but I do love spring since it’s the magical time when flowers and trees come back to life and fill the landscape with beautiful colors.” — Designed by Maria Keller from Mexico.

without calendar: 320x480, 640x480, 640x1136, 750x1334, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1242x2208, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“If all you want is a little orange dinosaur MARCHing (okay, I think you get the pun) across your monitor, this wallpaper was made just for you! This little guy is my design buddy at the office and sits by (and sometimes on top of) my monitor. This is what happens when you have designer’s block and a DSLR.” — Designed by Paul Bupe Jr from Statesboro, GA.

without calendar: 1024x768, 1280x1024, 1440x900, 1920x1080, 1920x1200, 2560x1440.

“Jīngzhé is the third of the 24 solar terms in the traditional East Asian calendars. The word 驚蟄 means ‘the awakening of hibernating insects’. 驚 is ‘to start’ and 蟄 means ‘hibernating insects’. Traditional Chinese folklore says that during Jingzhe, thunderstorms will wake up the hibernating insects, which implies that the weather is getting warmer.” — Designed by Sunny Hong from Taiwan.

without calendar: 800x600, 1280x720, 1280x1024, 1366x768, 1400x1050, 1680x1200, 1920x1080, 2560x1440.

Designed by Nathalie Ouederni from France.

without calendar: 320x480, 1024x768, 1280x1024, 1440x900, 1600x1200, 1680x1200, 1920x1200, 2560x1440.

“Who needs an excuse to look at pizza all month?” — Designed by James Mitchell from the United Kingdom.

without calendar: 1280x720, 1280x800, 1366x768, 1440x900, 1680x1050, 1920x1080, 1920x1200, 2560x1440, 2880x1800.

“Doodles are slowly becoming my trademark, so I just had to use them to express this phrase I’m fond of in the recent past. A bit enigmatic, philosophical. Inspiring, isn’t it?” — Designed by Marta Paderewska from Poland.

without calendar: 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“I made a connection, between the dark side and the unknown lighted and catchy area.” — Designed by Valentin Keleti from Romania.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“As days are getting longer again and the first few flowers start to bloom, we are all waiting for spring to finally arrive.” — Designed by Naioo from Germany.

without calendar: 1280x800, 1366x768, 1440x900, 1680x1050, 1920x1080, 1920x1200.

“On the 17th March, raise a glass and toast St. Patrick on St. Patrick’s Day, the Patron Saint of Ireland.” — Designed by Ever Increasing Circles from the United Kingdom.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1080x1080, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“This March, our calendar design epitomizes the heralds of spring. Soon enough, you’ll be waking up to the singing of swallows, in a room full of sunshine, filled with the empowering smell of daffodil, the first springtime flowers. Spring is the time of rebirth and new beginnings, creativity and inspiration, self-awareness, and inner reflection. Have a budding, thriving spring!” — Designed by PopArt Studio from Serbia.

without calendar: 320x480, 640x480, 800x480, 800x600, 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1366x768, 1440x900, 1440x1050, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440.

“March 2nd marks the birthday of the most creative and extraordinary author ever, Dr. Seuss! I have included an inspirational quote about learning to encourage everyone to continue learning new things every day.” — Designed by Safia Begum from the United Kingdom.

without calendar: 800x450, 1280x720, 1366x768, 1440x810, 1600x900, 1680x945, 1920x1080, 2560x1440.

“Early spring in March is for me the time when the snow melts, everything isn’t very colorful. This is what I wanted to show. Everything comes to life slowly, as this bear. Flowers are banal, so instead of a purple crocus we have a purple bird-harbinger.” — Designed by Marek Kedzierski from Poland.

without calendar: 320x480, 1024x768, 1280x720, 1280x800, 1280x960, 1400x1050, 1600x1200, 1680x1050, 1920x1080, 1920x1200, 2560x1440.

“Spring is round the corner. And very soon plants will grow on some other planets too. Let’s be happy about a new cycle of life.” — Designed by Igor Izhik from Canada.

without calendar: 1024x768, 1024x1024, 1152x864, 1280x720, 1280x800, 1280x960, 1280x1024, 1400x1050, 1440x900, 1600x1200, 1680x1050, 1680x1200, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 2560x1600.

“This month we become children and we travel with Peter Pan. Let’s go to Neverland!” — Designed by Veronica Valenzuela from Spain.

without calendar: 640x480, 800x480, 1024x768, 1280x720, 1280x800, 1440x900, 1600x1200, 1920x1080, 1920x1440, 2560x1440.

without calendar: 1024x768, 1280x1024, 1366x768, 1600x1200, 1680x1200, 1920x1080, 1920x1200, 2560x1440.

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