libcamera v0.3.1 Supporting cameras in Linux since 2019

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histogram.h
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1/* SPDX-License-Identifier: BSD-2-Clause */
2/*
3 * Copyright (C) 2019, Raspberry Pi Ltd
4 *
5 * histogram calculation interface
6 */
7
8#pragma once
9
10#include <assert.h>
11#include <limits.h>
12#include <stdint.h>
13#include <type_traits>
14#include <vector>
15
16#include <libcamera/base/span.h>
17#include <libcamera/base/utils.h>
18
19 namespace libcamera {
20
21 namespace ipa {
22
23 class Histogram
24{
25 public:
26 Histogram() { cumulative_.push_back(0); }
27 Histogram(Span<const uint32_t> data);
28
29 template<typename Transform,
30 std::enable_if_t<std::is_invocable_v<Transform, uint32_t>> * = nullptr>
31 Histogram(Span<const uint32_t> data, Transform transform)
32 {
33 cumulative_.resize(data.size() + 1);
34 cumulative_[0] = 0;
35 for (const auto &[i, value] : utils::enumerate(data))
36 cumulative_[i + 1] = cumulative_[i] + transform(value);
37 }
38
39 size_t bins() const { return cumulative_.size() - 1; }
40 uint64_t total() const { return cumulative_[cumulative_.size() - 1]; }
41 uint64_t cumulativeFrequency(double bin) const;
42 double quantile(double q, uint32_t first = 0, uint32_t last = UINT_MAX) const;
43 double interQuantileMean(double lowQuantile, double hiQuantile) const;
44
45 private:
46 std::vector<uint64_t> cumulative_;
47};
48
49} /* namespace ipa */
50
51} /* namespace libcamera */
libcamera::ipa::Histogram
The base class for creating histograms.
Definition histogram.h:24
libcamera::ipa::Histogram::Histogram
Histogram()
Construct an empty Histogram.
Definition histogram.h:26
libcamera::ipa::Histogram::bins
size_t bins() const
Retrieve the number of bins currently used by the Histogram.
Definition histogram.h:39
libcamera::ipa::Histogram::quantile
double quantile(double q, uint32_t first=0, uint32_t last=UINT_MAX) const
Return the (fractional) bin of the point through the histogram.
Definition histogram.cpp:105
libcamera::ipa::Histogram::cumulativeFrequency
uint64_t cumulativeFrequency(double bin) const
Cumulative frequency up to a (fractional) point in a bin.
Definition histogram.cpp:82
libcamera::ipa::Histogram::total
uint64_t total() const
Retrieve the total number of values in the data set.
Definition histogram.h:40
libcamera::ipa::Histogram::Histogram
Histogram(Span< const uint32_t > data, Transform transform)
Create a cumulative histogram.
Definition histogram.h:31
libcamera::ipa::Histogram::interQuantileMean
double interQuantileMean(double lowQuantile, double hiQuantile) const
Calculate the mean between two quantiles.
Definition histogram.cpp:142
libcamera
Top-level libcamera namespace.
Definition backtrace.h:17
libcamera::Transform
Transform
Enum to represent a 2D plane transform.
Definition transform.h:16
utils.h
Miscellaneous utility functions.